ody_migr_server.prg

<?php
/**
 * File: ody_migr_server.prg
 * This file is a server for ody_migr_client.prg. Client/server communication happens via ajax post request and http response.
 */

// **********************************************************************************************
// Top portion: import required libraries, check permissions and extract string queries and/or post data
// **********************************************************************************************

$monLibrary= dirname(__FILE__) . "/../library";
$sharedLibrary= dirname(__FILE__) . "/../../shared/library";

// Includes necessary files
require_once("$monLibrary/cu_top.i");
require_once("$monLibrary/ck_hticket.i");
require_once("$sharedLibrary/hcuCommon.i");
require_once("$sharedLibrary/cu_flagconst.i");

if (!CheckPerm($link, $Hu, basename($_SERVER['SCRIPT_NAME']), $_SERVER['REMOTE_ADDR'])) {
      header("Location: /hcuadm/hcu_noperm.prg");
      exit;
}

// session id for migration audit log file
$AUDIT_LOG_TRANSACTION = bin2hex(openssl_random_pseudo_bytes(8));

// **********************************************************************************************
// Specify some global variables and utility functions
// **********************************************************************************************

/**
 * function GetSecret()
 * @return The secret string to create / verify the passphrase.
 */
function GetSecret() {
    return "n3c3s1t@m0\$Mud@rT0d@\$L@\$C0\$@\$!";
}

/**
 * function CreateHash($action, $cu)
 * @return sha1 of the action, cu, and the secret string.
 */
function CreateHash($action, $cu) {
    return sha1("${action}${cu}" . GetSecret());
}

$passed_arguments = "";
$secret_key = GetSecret();
putenv("ODY_MIGR_SECRET_KEY=$secret_key");

$response = array("success"=> False, "message" => "");

/**
 * Get logs directory path
 *
 * @param $cu -- credit union code
 * @return str path to logs directory
 */
function GetLogsDir($cu) {
    return "/home/" . strtolower($cu) . "/logs";
}

/**
 * Get tmp directory path
 *
 * @param $cu -- credit union code
 * @return str path to tmp directory
 */
function GetTmpDir($cu) {
    return "/home/" . strtolower($cu) . "/tmp";
}

/**
 * Get wip lock file name given $cu and $category
 *
 * @param $cu -- credit union code
 * @param $category -- migration data  category
 *
 * @return wip lock file full path
 */
function getWIPFile($cu, $category, $operation) {
    return GetTmpDir($cu) . "/.ody_migr_" . $operation . "_" . $category . ".wip";
}

/**
 * Get switch accounts setting file
 *
 * @param $cu -- credit union code
 *
 * @return str path to switch accounts setting file
 */
function getSwitchAccountsSettingFile($cu) {
    return GetTmpDir($cu) . "/.ody_migr_include_switchaccounts_in_final_migr";
}

/**
 * Get done lock file name given $cu and $category
 *
 * @param $cu -- credit union code
 * @param $category -- migration data  category
 *
 * @return completed lock file full path
 */
function getDoneFile($cu, $category, $operation) {
    return GetTmpDir($cu) . "/.ody_migr_" . $operation . "_" . $category . ".done";
}

/**
 * Delete WIP file
 *
 * @param $cu -- credit union code
 * @param $category -- migration data  category
 *
 * @return success or failure response array
 */
function deleteWIPFile($cu, $category, $operation) {
    $wip_file = getWIPFile($cu, $category, $operation);

    if (unlink($wip_file)) {
        return array("success"=> True, "message" => "Lock ('wip') file deleted successfully.");
    } else {
        return array("success"=> False, "message" => "Something went wrong while deleting lock ('wip') file: " . $wip_file);
    }
}

/**
 * Mark wip lockfile as done (after migration completion)
 *
 * @param $cu -- credit union code
 * @param $category -- migration data  category
 *
 * @return success or failure response array
 */
function markWIPAsComplete($cu, $category, $operation) {
    $wip_file = getWIPFile($cu, $category, $operation);
    $done_file = getDoneFile($cu, $category, $operation);

    if (file_exists($wip_file)) {
        $cmd = "mv $wip_file $done_file";

        $results = system($cmd);

        if ($results === false) {
            return array("success"=> False, "message" => "Marking WIP file as Done failed.");
        } else {
            // update memdata and memhist execution count
            if ($category == "memdata" || $category == "memhist") {

                $final_migr_memcount_file = getFinalMigrationConfigFile($cu);
                if(file_exists($final_migr_memcount_file) && (($fileStr = file_get_contents($final_migr_memcount_file)) != False)) {
                    $mem_count_arr = explode(",", explode("\n", $fileStr)[1]);
                    $memdata_count = (int)$mem_count_arr[0];
                    $memhist_count = (int)$mem_count_arr[1];
                    if ($category == "memdata") {
                        $memdata_count++;
                    }
                    if ($category == "memhist") {
                        $memhist_count++;
                    }
                    $new_vals = "memdata_count,memhist_count\n" . $memdata_count . "," . $memhist_count ."\n";
                    file_put_contents($final_migr_memcount_file, $new_vals);
                }
            }
            return array("success"=> True, "message" => "WIP marked as Done." . $wip_file);
        }
    } else {
        return array("success"=> False, "message" => "WIP file does not exist." . $wip_file);
    }
}

/**
 * Get log file
 *
 * @param $cu -- credit union code
 * @param $category -- migration data category
 * @param $operation -- migration operation
 *
 * @return log file full path
 */
function getLogFile($cu, $operation, $category) {
    return GetLogsDir($cu) . "/ody_migr_" . $operation . "_" . $category . ".log";
}

/**
 * Get monitor lock file path
 *
 * @param $cu -- credit union code
 *
 * @return monitor lock file full path
 */
function getMonitorLockFile($cu) {
    return GetTmpDir($cu) . "/.ody_migr_monitor_lock";
}


/**
 * Get public_html path
 *
 * @param $cu -- credit union code
 *
 * @return public_html full path
 */
function getPublicHtmlPath($cu) {
    return "/home/" . strtolower($cu) . "/public_html";
}

/**
 * Get public_html path
 *
 * @param $cu -- credit union code
 *
 * @return public_html full path
 */
function getLockFileForPreventingFurtherMigration($cu, $cat_group) {
    if($cat_group == "Settings") {
        return GetTmpDir($cu) . "/.ody_migr_prevent_further_settings_migration";
    } else { // Admin
        return GetTmpDir($cu) . "/.ody_migr_prevent_further_admin_migration";
    }
}


/**
 * Update progress stats
 *
 * @param $line -- log string
 * @param $category -- migration data category
 *
 * @return completed so far and total tables/members count statistic of $category migration
 */
function updateProgress($line, $category) {
    if ($category == "memdata") {
        $res_progress_arr = explode("/", trim(explode("|", trim(explode("[PROGRESS] Members imported:", $line)[1]))[0]));
        return $res_progress_arr;

   } else {
        return array(0, 0);
   }
}

/**
 * Get account cross reference csv file path
 *
 * @param $cu -- credit union code
 *
 * @return account cross reference file full path
 */
function getAccCrossRefFile($cu) {
    return GetTmpDir($cu) . "/ody_migr_user_id_cross_reference.csv";
}

/**
 * Get final migration main lock file
 *
 * @param $cu -- credit union code
 *
 * @return account cross reference file full path
 */
function getFinalMigrationMainLock($cu) {
    return GetTmpDir($cu) . "/.ody_migr_final";
}

/**
 * Get final migration main completion lock file
 *
 * @param $cu -- credit union code
 *
 * @return str final migration completion lock file
 */
function getFinalMigrationDoneLock($cu) {
    return GetTmpDir($cu) . "/.ody_migr_final.complete";
}

/**
 * Get orphan member list file path
 *
 * @param $cu -- credit union code
 *
 * @return str orphan member list file path
 */
function getOrphanMemberListFile($cu) {
    return GetTmpDir($cu) . "/ody_migr_mammoth_orphaned_members.csv";
}

/**
 * Get final migration config lock file
 *
 * @param $cu -- credit union code
 *
 * @return str final migration config lock file
 */
function getFinalMigrationConfigFile($cu) {
    return GetTmpDir($cu) . "/.ody_migr_members_exec_count";
}

/**
 * Parse a log file line by line
 *
 * @param $file -- log file to read
 * @param $category -- migration data category
 * @param $operation -- migration operation
 *
 * @return log_content => all logs written by migration process so far
           end_of_log => flag to indicate if migration completed or not
           file_status => file existence message
           progress_status => total and so far completed progress information to be used to populate progress bar
 */
function readContent($file, $operation, $category, $cu) {
    $endOfLog = false;
    $logContent = [];

    $progress_current = 0;
    $progress_total = 0;

    if (!file_exists($file)) {
        $progress_status = array("current"=>$progress_current, "total"=>$progress_total);
        $file_status = "Log file '" .$file . "' does not exist.";
        return array("does_not_exist" => True, "log_content" => $logContent, "end_of_log"=> $endOfLog, "file_status" => $file_status, "progress_status"=>$progress_status);
    }

    $fileHandle = fopen($file, 'r');
    $file_status = "Log file '" . $file . "' exists.";

    while (!feof($fileHandle)) {
       $line = fgets($fileHandle);
       if ($line == false) {
            break;
       }

       if (strpos($line, "[PROGRESS] ") !== false && $operation == "migrate") {
            $progress_update = updateProgress($line, $category);
            $progress_current = $progress_update[0];
            $progress_total = $progress_update[1];
       }

       $logContent[] = $line;

       if (strpos($line, "MIGRATION DONE") !== false) {
            $endOfLog = true;
            auditLogMigrationExecution($cu, "", $operation, $category, "Migration completed. Marked by browser auto-refresh.");
            break;
       }
    }
    fclose($fileHandle);

    $progress_status = array("current"=>$progress_current, "total"=>$progress_total);
    return array("does_not_exist" => False, "log_content" => $logContent, "end_of_log"=> $endOfLog, "file_status" => $file_status, "progress_status"=>$progress_status);
}


/**
 * function deleteOdysseyTemporaryFiles($cu)
 *
 * ****IMPORTANT: CAUTION CAUTION CAUTION****
 *
 * SINCE THIS FUNCTION WILL BE CALLED AFTER THE GO LIVE DAY, PLEASE
 * DO NOT ADD ANY CODE THAT WILL DELETE ANY DATABASE RELATED DATA. AT
 * THIS POINT, WE ARE DONE MIGRATING PRODDUCTION DATA FROM MAMMOTH TO
 * ODYSSEY AND WE CERTAINLY DON'T WANT TO MESS AROUND WITH THE MIGRATED
 * DATA ON THE DATABASE AFTER THE FINAL DATA MIGRATION.
 *
 * This function only deletes temporary files (in the filesystem) in
 * Odyssey and Mammoth after migration completion and touches a lock
 * file that prevents the "Import Mammoth Data" screen on the monitor
 * from displaying the migration related html elements on the screen.
 *
 * @param $cu -- the Credit Union code (uppercase.)
 *
 * @return response text to append to notification bar in the client
 */
function deleteOdysseyTemporaryFiles($cu) {

    $memhist_file = "memhist";
    $memhist_acc_file = "memhist_accounthistory";
    $memhist_loan_file = "memhist_loanhistory";

    $lowercaseCu = strtolower($cu);

    $dir = "/home/$lowercaseCu/tmp";
    $memhist_file = "$dir/${memhist_file}";
    $memhist_acc_file = "$dir/${memhist_acc_file}";
    $memhist_loan_file = "$dir/${memhist_loan_file}";

    if (is_dir($dir)) {
        $all_success = True;

        if (file_exists($memhist_file)) {
            $all_success = $all_success && unlink($memhist_file);
        }

        if (file_exists($memhist_acc_file)) {
            $all_success = $all_success && unlink($memhist_acc_file);
        }

        if (file_exists($memhist_loan_file)) {
            $all_success = $all_success && unlink($memhist_loan_file);
        }

        if($all_success) {
            return "[Cleanup ODY] Temporary files deleted.";
        } else {
            // only a few files might have been deleted (not a critical operation)
            return "[Cleanup ODY] Something went wrong while deleting temporary files.";
        }
    } else {
        return "[Cleanup ODY] No such directory '$dir'.";
    }
}

/**
 * function makeMammothEndpointCall($server, $cu, $action, $hash)
 * Calls the Mammoth endpoint for the export.
 *
 * @param $server -- www4, www3, www5, or www6.  www doesn't return anything specific to the Credit Union.
 * @param $cu -- the Credit Union code (uppercase.)
 * @param $action -- the action to perform.
 * @param $hash -- the passphrase to check.
 * @param $parameters -- any additional parameters that need to be passed to Mammoth.
 *
 * @return array of the response.  Mammoth endpoint returns data in a JSON encoded structure.
 */
function makeMammothEndpointCall($server, $cu, $action, $hash, $parameters = array()) {

    if (!isset($parameters) || !is_array($parameters)) {
        $parameters = array();
    }
    $parameters["passphrase"] = $hash;
    $parameters["action"] = $action;
    $url = "";

    $parameters = http_build_query($parameters);
    $url = "${server}.homecu.net/hcuadm/mOdysseyMigrExp.prg?cu=" . urlencode($cu) . "&" . $parameters;

    $ch = curl_init($url);

    curl_setopt($ch, CURLOPT_USERPWD, "nobody:no1home");
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); // get response as string
    curl_setopt($ch, CURLOPT_FOLLOWLOCATION, true);
    curl_setopt($ch, CURLOPT_FORBID_REUSE, true); // For testing, there are a lot of the same calls but make sure that it is fresh.
    curl_setopt($ch, CURLOPT_FRESH_CONNECT, true); // For testing, there are a lot of the same calls but make sure that it is fresh.

    $response = curl_exec($ch);

    $response = isset($response) && trim($response) != "" ? HCU_JsonDecode($response)
                                                            : array("action" => $action, "error" => "CURL call didn't return anything. (" . __FILE__ . ":" . __LINE__ . ")", "data" => array());

    return $response;
}

/**
 * Validate migration options before execution
 *
 * @param $cu -- credit union code
 * @param $operation -- clean/migrate/summar
 * @param $category -- migration category
 *
 * @return Array response array
 */
function validateOptionsBeforeScriptExecution($cu, $operation, $category) {
    $valid_response = array("success"=> True, "message" => "Options validated.");
    // Request validation if operation=clean
    if ($operation == "clean") {
        // check if Settings (settings) data category is locked from deleted.
        $preventSettingsLockFile = getLockFileForPreventingFurtherMigration($cu, "Settings");
        if(file_exists($preventSettingsLockFile) && $category == "settings") {
            return array("success"=> False, "message" => "Data category '$category' ALREADY MIGRATED and (possibly) MODIFIED on the target system. 'clean' operations for 'settings' is LOCKED to PREVENT ACCIDENTAL DELETIONS.");
        }
        // check if Admin (admin) data category is locked from deleted.
        $preventAdminLockFile = getLockFileForPreventingFurtherMigration($cu, "Admin");
        if(file_exists($preventAdminLockFile) && $category == "admin") {
            return array("success"=> False, "message" => "Data category '$category' ALREADY MIGRATED. 'clean' operation 'admin' is LOCKED to PREVENT ACCIDENTAL DELETIONS.");
        }

        // do not allow to run 'clean-switchaccounts' -- UI also validates this
        if($category == "switchaccounts") {
            return array("success"=> False, "message" => "INVALID migration operation '$operation'" . "-" ."'$category' for direct deletion.");
        }

        // do not allow clean if the WIP file exists for the same category
        $wip_file_migrate = getWIPFile($cu, $category, "migrate");
        if(file_exists($wip_file_migrate)) {
            return array("success"=> False, "message" => "Cannot clean up in-progress work 'migrate-$category'");
        }
    }

    return $valid_response;
}

/**
 * Execute python migration script
 *
 * @param $server -- Mammoth endpoint
 * @param $operation -- Migration operation (migrate, summary, clean)
 * @param $cu -- credit union CU code
 * @param $category -- migration data category
 * @param $username -- Mammoth credential - username
 * @param $password -- Mammoth credential - password
 *
 * @return success or failure response
 */
function executeMigrationScript($server, $operation, $cu, $category, $username, $password, $bg=True) {

    $PYTHON_EXEC = "/usr/bin/python3";
    $rootScriptsDir = "/opt/odyssey/tools/bin";
    if (getenv("DEVMODE") == "1") {
        $rootScriptsDir = "/project/app/tools/bin";
    }

    $cmd =   $PYTHON_EXEC . " " . $rootScriptsDir . "/ody_migr_executor.py "
         . escapeshellarg($server) . " "
         . escapeshellarg($operation) . " "
         . escapeshellarg(strtoupper($cu)) . " "
         . escapeshellarg($category) . " "
         . escapeshellarg($username) . " "
         . escapeshellarg($password)  . " "
         . " > /dev/null";

    if ($bg == True) {
        $cmd .= " &";
    }

    // audit log data migration execution
    auditLogMigrationExecution($cu, $username, $operation, $category, "Started.");

    // cleanup exiting log before executing migrate and summary operations
    if ($operation == "migrate" || $operation == "summary") {
        $migrate_summary_log_file = getLogFile($cu, $operation, $category);
        if (file_exists($migrate_summary_log_file)) {
            unlink($migrate_summary_log_file);
        }
    }

    // execute migration script
    exec($cmd, $scriptOutput, $returnStatus);

    if ($returnStatus > 0) {
        return array("success"=> False,
                     "message" =>  "(" . $rootScriptsDir  .") " . " ".join($scriptOutput));
    } else {
        return array("success"=> True,
                     "message" => " Migration operation ('" . $operation . " - " . $category . "') STARTED successfully. <br>(" . $rootScriptsDir  .") " . " ".join($scriptOutput));
    }
}

/**
 * Write migration execution audit log to a file
 *
 * @param $cu -- credit union CU code
 * @param $atttempted_username -- Username used in the migration screen
 * @param $migr_operation -- migration operation to be logged (migrate, clean, etc.)
 * @param $migr_category -- {settings,admin,memdata,memhist,switchaccounts,final}
 * @param $comment -- optional column for additional information about the log record
 *
 */
function auditLogMigrationExecution($cu, $attempted_username, $migr_operation, $migr_category, $comment="") {
    global $AUDIT_LOG_TRANSACTION, $Hu;
    $current_monitor_user = $Hu;
    $date_now = new DateTime('now', new DateTimeZone('America/Boise'));
    $date_log= $date_now->format('Y-m-d:H-i-s:T');
    $audit_log_file = "/home/${cu}/tmp/ody_migr_execution_logs.csv";
    $audit_log_record = array($AUDIT_LOG_TRANSACTION,
                              $date_log,
                              $cu,
                              $current_monitor_user,
                              strtoupper($attempted_username),
                              $migr_operation,
                              $migr_category,
                              $comment);

    # should only be created once, and not to be deleted
    if (!file_exists($audit_log_file)) {
        $audit_log_header = array("SessionId",
                                  "Date",
                                  "CreditUnion",
                                  "MonitorUser",
                                  "EnteredUsername",
                                  "Operation",
                                  "Category(ies)",
                                  "Comment");
        touch($audit_log_file);
        $fp = fopen($audit_log_file, "a");
        fputcsv($fp, $audit_log_header);
    } else {
        $fp = fopen($audit_log_file, "a");
    }

    fputcsv($fp, $audit_log_record);
    fclose($fp);
}


/**
 * Cleanup lock files after clean operation is completed
 *
 * @param $cu -- credit union CU code
 * @param $category -- Migration Category
 * @param $operation -- Migration operation
 *                      - only clean is relevant
 *
 * @return null
 */
function cleanupAfterClean($cu, $category, $operation) {
    if ($operation == "clean") {
        // delete lock file for previous migrate-$category completion
        $done_file = getDoneFile($cu, $category, "migrate");
        if(file_exists($done_file)) {
            unlink($done_file);

            // clean invalidates previous migration of the same category, delete
            // the log file for migrate-$category, if any
            $migrate_log_file = getLogFile($cu, "migrate", $category);
            if(file_exists($migrate_log_file)) {
                unlink($migrate_log_file);
            }

            $summary_log_file = getLogFile($cu, "summary", $category);
            if(file_exists($summary_log_file)) {
                unlink($summary_log_file);
            }

            if ($category == "memdata") {
                // delete switchaccounts temp files when cleaning memdata
                $sa_migrate_done_file = getDoneFile($cu, "switchaccounts", "migrate");
                if(file_exists($sa_migrate_done_file)) {
                    // remove done file
                    unlink($sa_migrate_done_file);

                    // remove log file
                    $sa_migrate_log_file = getLogFile($cu, "migrate", "switchaccounts");
                    if(file_exists($sa_migrate_log_file)) {
                        unlink($sa_migrate_log_file);
                    }

                    // remove summary log file
                    $sa_summary_log_file = getLogFile($cu, "summary", "switchaccounts");
                    if(file_exists($sa_summary_log_file)) {
                        unlink($sa_summary_log_file);
                    }
                }
                // delete loanapps temp files when cleaning memdata
                $loanapp_migrate_done_file = getDoneFile($cu, "loanapp", "migrate");
                if(file_exists($loanapp_migrate_done_file)) {
                    // remove done file
                    unlink($loanapp_migrate_done_file);

                    // remove log file
                    $loanapp_migrate_log_file = getLogFile($cu, "migrate", "loanapp");
                    if(file_exists($loanapp_migrate_log_file)) {
                        unlink($loanapp_migrate_log_file);
                    }

                    // remove log file
                    $loanapp_summary_log_file = getLogFile($cu, "summary", "loanapp");
                    if(file_exists($loanapp_summary_log_file)) {
                        unlink($loanapp_summary_log_file);
                    }
                }
            }
        }

        // deleting settings invalidates locking Settings
        if($category == "settings") {
            $preventSettingsLockFile = getLockFileForPreventingFurtherMigration($cu, "Settings");
            if(file_exists($preventSettingsLockFile)) {
                unlink($preventSettingsLockFile);
            }
        }

        // deleting admin invalidates locking of Admin
        if($category == "admin") {
            $preventAdminLockFile = getLockFileForPreventingFurtherMigration($cu, "Admin");
            if(file_exists($preventAdminLockFile)) {
                unlink($preventAdminLockFile);
            }
        }
    }
}

/**
 * Execute finam members migration
 *
 * @param $server -- Mammoth endpoint
 * @param $cu -- credit union CU code
 * @param $username -- Mammoth credential - username
 * @param $password -- Mammoth credential - password
 *
 * @return success or failure response
 */
function executeFinalMigration($server, $cu, $username, $password) {
    // return if final migration execution already completed
    if (file_exists(getFinalMigrationDoneLock($cu))) {
        return array("success"=> False,
                     "message" =>  "<b>Final migration (migrate-{memdata,memhist}) already executed once."
                     . " Re-migration is not advised. If you really need to run this again, speak to a"
                     . " develolper to reset final migration before trying again. </b>");
    }

    $python_exec = "/usr/bin/python3";
    $root_script_dir = "/opt/odyssey/tools/bin";
    if (getenv("DEVMODE") == "1") {
        $root_script_dir = "/project/app/tools/bin";
    }
    $developer_help_msg = " Please contact a developer to look into it.";

    $final_migr_lck = getFinalMigrationMainLock($cu);

    // if final migration lock file exist, return without execution
    if (file_exists($final_migr_lck)) {
        return array("success"=> False,
                     "message" =>  "Final migration (members data) already IN PROGRESS."
                     . $developer_help_msg);
    }
    // if in-progress (memdata/switchaccounts/loanapp/memhist) lock files exist,
    // return without execution
    elseif (file_exists(getWIPFile($cu, "memdata", "migrate"))
            || file_exists(getWIPFile($cu, "switchaccounts", "migrate"))
            || file_exists(getWIPFile($cu, "loanapp", "migrate"))
            || file_exists(getWIPFile($cu, "memhist", "migrate"))) {

        return array("success"=> False,
                     "message" =>  "Final migration (members data) cannot be executed."
                     . $developer_help_msg);
    } else { // compose a execute final migration
        // add memdata migration script
        $executing_categories = "memdata";
        $cmd_memdata =   $python_exec . " " . $root_script_dir . "/ody_migr_executor.py "
                     . escapeshellarg($server) . " "
                     . escapeshellarg("migrate") . " "
                     . escapeshellarg(strtoupper($cu)) . " "
                     . escapeshellarg("memdata") . " "
                     . escapeshellarg($username) . " "
                     . escapeshellarg($password)  . " "
                     . " > /dev/null";

        // add switchaccounts if configured
        if (file_exists(getSwitchAccountsSettingFile($cu))) {
            $cmd_switchaccounts = $python_exec . " " . $root_script_dir . "/ody_migr_executor.py "
                                . escapeshellarg($server) . " "
                                . escapeshellarg("migrate") . " "
                                . escapeshellarg(strtoupper($cu)) . " "
                                . escapeshellarg("switchaccounts") . " "
                                . escapeshellarg($username) . " "
                                . escapeshellarg($password)  . " "
                                . " > /dev/null";

            $cmd_memdata = $cmd_memdata . " && " . $cmd_switchaccounts;
            $executing_categories .= ", switchaccounts";
        }

        // add loanapp; credit unions with no associated loan apps will complete
        // safely (i.e. migrate no data)
        $cmd_loanapp = $python_exec . " " . $root_script_dir . "/ody_migr_executor.py "
                     . escapeshellarg($server) . " "
                     . escapeshellarg("migrate") . " "
                     . escapeshellarg(strtoupper($cu)) . " "
                     . escapeshellarg("loanapp") . " "
                     . escapeshellarg($username) . " "
                     . escapeshellarg($password)  . " "
                     . " > /dev/null";

        $cmd_memdata = $cmd_memdata . " && " . $cmd_loanapp;
        $executing_categories .= ", loanapp";

        $cmd_memhist =   $python_exec . " " . $root_script_dir . "/ody_migr_executor.py "
                     . escapeshellarg($server) . " "
                     . escapeshellarg("migrate") . " "
                     . escapeshellarg(strtoupper($cu)) . " "
                     . escapeshellarg("memhist") . " "
                     . escapeshellarg($username) . " "
                     . escapeshellarg($password)  . " "
                     . " > /dev/null";

        $cmd = "(" . $cmd_memdata . " && " . $cmd_memhist . ") > /dev/null 2>&1 &";
        $executing_categories .= ", memhist";

        // create an initial wip file for memdata, and execute the command
        if (touch(getWIPFile($cu, "memdata", "migrate")) && touch($final_migr_lck)) {
            // log final migration execution
            auditLogMigrationExecution($cu, $username, "migrate", "Final", "Started.");
            // execute migration script
            exec($cmd, $script_output, $return_status);
        } else {
            // cleanup after itself
            if(file_exists($final_migr_lck)) {
                unlink($final_migr_lck);
            }
            if(file_exists(getWIPFile($cu, "memdata", "migrate"))) {
                unlink(getWIPFile($cu, "memdata", "migrate"));
            }
            return array("success"=> True,
                         "message" => " Failed creating initial WIP lock file (memdata) for Final migration. "
                         . $developer_help_msg);
        }

        if ($return_status > 0) {
            // cleanup after itself
            if(file_exists($final_migr_lck)) {
                unlink($final_migr_lck);
            }
            if(file_exists(getWIPFile($cu, "memdata", "migrate"))) {
                unlink(getWIPFile($cu, "memdata", "migrate"));
            }
            return array("success"=> False,
                         "message" =>  "Final migration (" + $executing_categories + ") execution returned non-zero exit code. ("
                         . $root_script_dir  . ") " . " ".join($script_output) . "."
                         . $developer_help_msg);
        } else {
            return array("success"=> True,
                         "message" => " Final migration ('migrate-{" . $executing_categories . "}'') STARTED successfully. ("
                         . $root_script_dir  . ") ");
        }
    }

}

/**
 * Delete multiple categories
 *
 * @param $cu -- credit union CU code
 * @param $cat_del_list -- list of categories to delete
 * @param $is_forced_cleanup -- do not check for validation if true for final migration
 *
 * @return success or failure response
 */
function deleteMultipleCategories($cu, $cat_del_list, $is_forced_cleanup=False) {

    if (count($cat_del_list) == 0 && $is_forced_cleanup == False) {
        return array("success"=> True, "message" => "No categories selected for deletion.");
    } else {
        $all_success = True;
        $success_categories = array();
        $failed_categories = array();
        // log multiple categories deletion execution
        auditLogMigrationExecution($cu, "", "attempted-multiple-clean", implode(":", $cat_del_list));
        foreach($cat_del_list as $category) {

            if ($is_forced_cleanup == True) {
                // do not check for validation if the call is for reset final migration
                $validationResponseStatus = True;
            } else {
                // validate options before execution
                $validationResponse = validateOptionsBeforeScriptExecution($cu, "clean", $category);
                $validationResponseStatus = $validationResponse["success"];
            }

            if ($validationResponseStatus == True) {
                // server=www4 is just to meet the argument validation, Mammoth server identification is not required for deletion
                // do not execute migration script in background
                $response_category = executeMigrationScript("www4", "clean", $cu, $category, "", "", $bg=False);

                if ($response_category["success"]) {
                    // delete completion lock file and log files if $operation == "clean"
                    // ONLY after SUCCESSFUL completion of clean operation
                    cleanupAfterClean($cu, $category, "clean");

                    $success_categories[] = $category;
                } else {
                    $failed_categories[] = $category;
                }
            } else {
                $response_category = $validationResponse;
                $failed_categories[] = $category;
            }

            $all_success = $response_category["success"] && $all_success;
            $response_category["category"] = $category;
        }
        // log categories that were deleted successfully
        auditLogMigrationExecution($cu, "", "successful-multiple-clean", implode(":", $success_categories));
        if($is_forced_cleanup == False) {
            if ($all_success) {
                return array("success"=> True, "message" => "Successfully cleaned up all SELECTED (and UNLOCKED) categories. [ " . implode(", ", $success_categories) . " ] were cleaned. ");
            } else {
                return array("success"=> False, "message" => "Cleaned categories: [ " . implode(", ", $success_categories) . " ]. Categories not cleaned (probably set LOCKED): [ " .implode(",", $failed_categories) . " ]. ");
            }
        }
    }
}

/**
 * Get a list of completed categories
 *
 * @param $cu -- credit union CU code
 *
 * @return array list of completed categories
 */
function getCurrentDoneCategoryList($cu) {
    $done_list = array();
    foreach (glob(GetTmpDir($cu) . "/.ody_migr_migrate_*.done") as $filename) {
        $filename_pieces = explode("_", $filename);
        $category_frm_filename = explode(".", $filename_pieces[count($filename_pieces) - 1])[0];
        $done_list[] = $category_frm_filename;
    }
    return $done_list;
}

/**
 * Get a list of WIP categories
 *
 * @param $cu -- credit union CU code
 *
 * @return array list of WIP categories
 */
function getCurrentWIPCategoryList($cu, $migrate_only=False) {
    $wip_list = array();
    $glob_collection = array();
    if ($migrate_only) {
        $glob_collection = glob(GetTmpDir($cu) . "/.ody_migr_migrate*.wip");
    } else {
        $glob_collection = glob(GetTmpDir($cu) . "/.ody_migr_*.wip");
    }
    foreach ($glob_collection as $filename) {
        $filename_only = explode(".", $filename)[1];
        $cat_operation_str = explode("ody_migr_", $filename_only)[1];
        $wip_list[] = str_replace("_", "-", $cat_operation_str);
    }
    return $wip_list;
}

/**
 * Get a list of currently available log files
 *
 * @param $cu -- credit union CU code
 *
 * @return array list of currently available log files
 */
function getCurrentLogsList($cu) {
    $logs_list= array();

    foreach (glob(GetLogsDir($cu) . "/ody_migr_*.log") as $log_file) {
        $filename_only = explode(".", $log_file)[0];
        $cat_operation_str = explode("ody_migr_", $filename_only)[1];

        list($op, $cat) = explode("_", $cat_operation_str);

        // list only completed logs for migrate operation; not clean and summary
        // 2019/09/11: including "clean" logs has a bug that removes
        // migrate-{category} logs when "Fetch Log" is clicked from the monitor
        if ($op == "migrate") {
            if (file_exists(getDoneFile($cu, $cat, $op))) {
                $logs_list[] = str_replace("_", "-", $cat_operation_str);
            }
        }
    }
    return $logs_list;
}


/**
 * Execute fix_public_html.pl script
 *
 * @param $cu -- credit union CU code
 * @param $from -- from domain
 * @param $to -- to domain
 *
 * @return success or failure response
 */
function executeFixPublicHtmlScript($cu, $from, $to) {
    $perl_exec = "/usr/bin/env perl";
    $root_script_dir = "/opt/odyssey/tools/bin";
    if (getenv("DEVMODE") == "1") {
        $root_script_dir = "/project/app/tools/bin";
    }

    $cmd = $perl_exec . " " . $root_script_dir . "/fix_public_html.pl " . escapeshellarg($cu) . " " . escapeshellarg($from) . " " . escapeshellarg($to) . " " . " > /dev/null";

    exec($cmd, $script_output, $return_status);

    if ($return_status > 0) {
        return array("success"=> False, "message" =>  "(" . $root_script_dir  .") " . " ".join($script_output));
    } else {
        return array("success"=> True, "message" => "public_html embedded links updated successfully. (" . $root_script_dir  .") " . " ".join($script_output));
    }
}

/**
 * function GetCuList($dbh)
 * Gets a list of open Credit Unions, which server they are on, and if they are live, batch, or web only.
 *
 * @param $dbh -- the database connection
 *
 * @return $error -- the error message if there is an error
 * @return $cuinfo -- a list of open CUs.
 */
function GetCuList($dbh) {
    try {
        global $SYS_TYPE_CLOSED, $SYS_TYPE_LIVE, $SYS_TYPE_BATCH, $SYS_TYPE_WEBONLY;
        $sql = "select user_name, www_server, case when (coalesce(system_options, 0)" .
             " & $SYS_TYPE_LIVE) <> 0 then 'Live'" .
             " when (coalesce(system_options, 0) & $SYS_TYPE_BATCH) <> 0 then 'Batch'" .
             " when (coalesce(system_options, 0) & $SYS_TYPE_WEBONLY) <> 0 then 'Web Only'" .
             " else 'Other' end as cutype from cuinfo" .
             " where (coalesce(system_options, 0) & $SYS_TYPE_CLOSED) = 0" .
             " order by user_name";

        $sth = db_query($sql, $dbh);
        if (!$sth) {
          throw new exception ("Select query failed.", 2);
        }

        $results = db_fetch_all($sth);
        $results = $results === false ? array() : $results;

        $returnArray = array("error" => "", "cuinfo" => $results);
    } catch (exception $e) {
        $returnArray = array("error" => $e->getMessage());
    }
    return $returnArray;
}
/**
 * Main function to respond to ajax post request made from Monitor UI client (ody_migr_client.prg)
 *
 * Each post request MUST contain 'post_purpose' parameter, based on which, this function serves the resource. Each option might have differntly
 * prepared response object which is handled accordingly on the client side. Here are the options for post_purpose or get_puspose:
 *
 * post_purpose:
 * [POST] execute_script: Runs python migration script in background
 * [POST] execute_final_migration: migrate both memdata and memhist
 * [POST] start_memhist_sa_wip_for_final_migration: execute memhist as a part of final migration
 * [POST] reset_migration_state: remove final migration related lock files and cleanup memdata and memhist
 * [POST] manage_migration_state: handle on-page-load and on-completion migration states
 * [POST] handle_switchaccounts_setting: create/delete lock file to persist switchaccounts setting
 * [POST] fetch_log:    This option parses log file for given data category and returns response with log content and information to update progress bar.
 * [POST] disable_monitor: This creates the monitor lock file in intented location to disable monitor UI.
 * [POST] check_monitor_lock: This checks if the monitor lock file exist or not and returns the boolean flag as a part of response.
 * [POST] delete_wip: This deletes work in progress lock file for a particular data category.
 * [POST] get_wip_done_list: This collects and returns list of files .wip and .done extensions for a particular credit union and data category.
 * [POST] get_logs_list: This collects and returns list of log files for current credit union.
 * [POST] clean_all_categories: cleanup multiple selected categories
 * [POST] update_servers_list: This returns a list of updated servers list.
 * [POST] update_categories_list: This returns a list of updated categories list
 * [POST] display_accref_download: This checks if the account reference mappings file exist
 * [POST] fix_public_html: This executes fix_public_html.pl script to update embedded links in public_html in Odyssey
 * [POST] display_hb_info_text: This returns CU settings status (Home Banking, offline status, etc.) information
 * [POST] display_lock_unlock_preventive_buttons: This checks existence of 'done' lock files for settings and member data categories.
 * [POST] lock_unlock_cat_group: toggle preventive button settings using creating and deleting lock files
 * [POST] get_final_migration_flag: return flags to specify if the current migration state is ready to run as final migration

 *
 * get_purpose:
 * GET] acc_cross_ref: This return the account cross reference csv file content
 *
 * @return $response -- final response w.r.t the 'post_purpose' parameter in the http post request
 */
function serveMigrationPurpose() {
    global $link;
    try {

        if ( isset($_GET["get_purpose"]) ) {

            if ($_GET["get_purpose"] == "acc_cross_ref") {
                // WIP files are only created for migrate operation
                if ( isset($_GET["cu"]) ) {
                    $cu = $_GET["cu"];
                } else {
                    throw new exception("'CU' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                $accountCrossRefFile = getAccCrossRefFile($cu);

                if (!file_exists($accountCrossRefFile)) {
                    $response = array("success"=> False, "message" => "'$accountCrossRefFile' file does not exist.");
                } else {
                    // send header information to the browser
                    header("Content-type: text/plain");
                    header("Content-disposition: inline; filename=$accountCrossRefFile");

                    // read the file and send to standard output
                    @readfile($accountCrossRefFile);
                    exit;
                }
            }

        } elseif ( isset($_POST["post_purpose"]) ) {

            // **********************************************************************************************
            // Execute Python script in background and return status
            // **********************************************************************************************

            if ($_POST["post_purpose"] == "execute_script") {

                if ( isset($_POST["server"]) ) {
                    $server = $_POST["server"];
                } else {
                    throw new exception("'server' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                if ( isset($_POST["cu"]) ) {
                    $cu = $_POST["cu"];
                } else {
                    throw new exception("'CU' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                if ( isset($_POST["operation"]) ) {
                    $operation = $_POST["operation"];
                } else {
                    throw new exception("'operation' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 6);
                }

                if ( isset($_POST["category"]) ) {
                    $category = $_POST["category"];
                } else {
                    throw new exception("'category' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 21);
                }

                if ( isset($_POST["username"]) ) {
                    $username = $_POST["username"];
                } else {
                    throw new exception("'username' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 3);
                }

                if ( isset($_POST["password"]) ) {
                    $password = $_POST["password"];
                } else {
                    throw new exception("'password' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 4);
                }

                // operation validation before execution
                // if final migration lock file exists, return without execution
                if (file_exists(getFinalMigrationDoneLock($cu))) {
                    return array("success"=> False,
                                 "message" =>  "<b>Operation NOT ALLOWED. Final migration ('migrate-{memdata,memhist}') already COMPLETED. </b>");
                }

                // if final migration lock file exists, return without execution
                if (file_exists(getFinalMigrationMainLock($cu))) {
                    return array("success"=> False,
                                 "message" =>  "<b>Operation NOT ALLOWED. Final migration step ('migrate-{memdata,memhist}') is IN PROGRESS. </b>");
                }

                $validationResponse = validateOptionsBeforeScriptExecution($cu, $operation, $category);
                if (!$validationResponse["success"]) {
                    return $validationResponse;
                }

                $migration_started_lock = getWIPFile($cu, $category, $operation);
                $migration_done_lock = getDoneFile($cu, $category, $operation);

                if (file_exists($migration_started_lock)) {
                    $response = array("success"=> False,
                                      "message" => "[WIP] Migration process is already IN PROGRESS for '$operation-$category'.");
                } elseif (file_exists($migration_done_lock)) {
                    $response = array("success"=> False,
                                      "message" => "[Done] Migration already COMPLETED for '$operation-$category'.");
                }else {
                    if (touch($migration_started_lock)) {
                        $response = executeMigrationScript($server, $operation, $cu,
                                                           $category, $username, $password);
                    } else {
                        $response = array("success"=> False,
                                          "message" => "Failed to create WIP lock file.");
                    }
                }
            }

            // **********************************************************************************************
            // Execute final members migration script
            // **********************************************************************************************
            elseif ($_POST["post_purpose"] == "execute_final_migration") {

                if ( isset($_POST["server"]) ) {
                    $server = $_POST["server"];
                } else {
                    throw new exception("'server' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                if ( isset($_POST["cu"]) ) {
                    $cu = $_POST["cu"];
                } else {
                    throw new exception("'CU' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                if ( isset($_POST["username"]) ) {
                    $username = $_POST["username"];
                } else {
                    throw new exception("'username' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 3);
                }

                if ( isset($_POST["password"]) ) {
                    $password = $_POST["password"];
                } else {
                    throw new exception("'password' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 4);
                }

                $response = executeFinalMigration($server, $cu, $username, $password);
            }

            // **********************************************************************************************
            // Create WIP file for memhist as a part of final migration
            // **********************************************************************************************

            elseif ($_POST["post_purpose"] == "start_memhist_sa_wip_for_final_migration") {
                if ( isset($_POST["cu"]) ) {
                    $cu = $_POST["cu"];
                } else {
                    throw new exception("'CU' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                if ( isset($_POST["category"]) ) {
                    $category = $_POST["category"];
                } else {
                    throw new exception("'category' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                $memhist_sa_wip = getWIPFile($cu, $category, "migrate");
                if (touch($memhist_sa_wip)) {
                    $response = array("success"=> True, "message" => "[Final Migration] WIP file created for " . $category . " category.");
                } else {
                    $response = array("success"=> False, "message" => "[Final Migration] WIP file could not be created for " . $category . " category.");
                }
            }

            // **********************************************************************************************
            // reset migration state
            // **********************************************************************************************

            elseif ($_POST["post_purpose"] == "reset_migration_state") {
                if ( isset($_POST["cu"]) ) {
                    $cu = $_POST["cu"];
                } else {
                    throw new exception("'CU' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }
                // audit log Reset Migration State click
                auditLogMigrationExecution($cu, "", "Reset (Final) Migration State", "memdata:memhist", "Button clicked");
                $resp = "";
                $final_migr_lck = getFinalMigrationMainLock($cu);
                $final_migr_lck_done = getFinalMigrationDoneLock($cu);

                if (file_exists($final_migr_lck)) {
                    unlink($final_migr_lck);
                }

                if (file_exists($final_migr_lck_done)) {
                    unlink($final_migr_lck_done);
                }

                $categories_toclean = array("memdata", "memhist");
                deleteMultipleCategories($cu, $categories_toclean, $is_forced_cleanup=True);
                $categories_toclean[] = "switchaccounts";

                // make sure there are no dangling lock files
                foreach ($categories_toclean as $category) {
                    foreach(array("migrate", "summary") as $op) {
                        $lg_file = getLogFile($cu, $op, $category);
                        if(file_exists($lg_file)) {
                            unlink($lg_file);
                        }
                    }
                    $wip_file = getWIPFile($cu, $category, $op);
                    if(file_exists($wip_file)) {
                        unlink($wip_file);
                    }
                    $done_file = getDoneFile($cu, $category, $op);
                    if(file_exists($done_file)) {
                        unlink($done_file);
                    }
                }

                $response = array("success" => True, "message" => "Migration state (members data and history) has been reset and cleaned. You may proceed with the members migration normally now. ");

            }

            // **********************************************************************************************
            // Complete Final Migration
            // **********************************************************************************************

            elseif ($_POST["post_purpose"] == "manage_migration_state") {
                if ( isset($_POST["cu"]) ) {
                    $cu = $_POST["cu"];
                } else {
                    throw new exception("'CU' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                if ( isset($_POST["final_migration_when"]) ) {
                    $final_migration_when = $_POST["final_migration_when"];
                } else {
                    throw new exception("'CU' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                $final_lck_file = getFinalMigrationMainLock($cu);
                $final_lck_file_complete = getFinalMigrationDoneLock($cu);

                if ($final_migration_when == "on_completion") {
                    $final_migr_completion_msg = "";
                    if (file_exists($final_lck_file)) {
                        if (touch($final_lck_file_complete)) {
                            $final_migr_completion_msg = "[Final Migration] All Migrations COMPLETED. Altering settings and over-writing migrations is not advised. ";
                            $response = array("success"=> True,
                                              "message" => $final_migr_completion_msg);
                        } else {
                            $final_migr_completion_msg = "[Error] Final Migration could not be completed (migration completed but error creating completed lock file.) ";
                            $response = array("success"=> False,
                                              "message" => $final_migr_completion_msg);
                        }
                    }
                    else {
                        $final_migr_completion_msg = "[Error] Final Migration seem to be completed, but required internal migration state violated (not started, but trying to complete? Please consult issue with a developer.) ";
                        $response = array("success"=> False,
                                          "message" => $final_migr_completion_msg);
                    }
                    // log final migration completion
                    auditLogMigrationExecution($cu, "", "migrate", "final", $final_migr_completion_msg);
                }
                // on_pageload
                else  {
                    if (file_exists($final_lck_file_complete) && file_exists($final_lck_file)) {
                        $response = array("success"=> True,
                                          "message" => "[Final Migration] All Migrations COMPLETED. Altering settings and over-writing migrations is not advised. ",
                                          "migr_status" => "completed",
                                          "migr_type" => "final");
                    } else {
                        if (file_exists($final_lck_file)) {
                            $migr_type = "final";
                            $msg_prefix = "[Final Migration] ";
                        } else {
                            $migr_type = "regular";
                            $msg_prefix = "[Regular Migration] ";
                        }

                        $wips = getCurrentWIPCategoryList($cu);

                        if (count($wips) > 1) {
                            $response = array("success"=> False,
                                              "message" =>  "[Invalid] Unexpected multiple in-progress migrations found. Please reset migration states from Settings and re-run migration. ",
                                              "migr_status" => "invalid");
                        } elseif (count($wips) == 1){
                            $category = $wips[0];
                            $response = array("success"=> True,
                                              "message" => "Migration in progress: " . $category,
                                              "migr_status" => "inprogress",
                                              "inprogress_category" => $category);
                        } else {
                            if($migr_type == "final") {
                                $response = array("success"=> False,
                                                  "message" => "No in-progress migration operation found. Please consult issue with a developer. ",
                                                  "migr_status" => "invalid");
                            } else {
                                $response = array("success"=> True,
                                                  "message" => "Normal start up. Good to proceed with the migration steps. ",
                                                  "migr_status" => "normalstart");
                            }
                        }
                        $response["migr_type"] = $migr_type;
                        $response["message"] = $msg_prefix . $response["message"];

                    }
                }
            }

            // **********************************************************************************************
            // Create WIP file for memhist as a part of final migration
            // **********************************************************************************************

            elseif ($_POST["post_purpose"] == "handle_switchaccounts_setting") {
                if ( isset($_POST["cu"]) ) {
                    $cu = $_POST["cu"];
                } else {
                    throw new exception("'CU' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                if ( isset($_POST["action"]) ) {
                    $action = $_POST["action"];
                } else {
                    throw new exception("'action' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                if ( isset($_POST["entity"]) ) {
                    $entity = $_POST["entity"];
                } else {
                    throw new exception("'entity' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }


                if ($entity == "switchaccounts") {
                    $config_file= getSwitchAccountsSettingFile($cu);
                }

                if ($action == "get_setting") {
                    $response = array("success"=> True, "include_or_not" => (file_exists($config_file)));
                }
                // toggle_setting
                else {
                    if(file_exists($config_file)) {
                        $response = array("success"=> (unlink($config_file)));
                    } else {
                        $response = array("success"=> (touch($config_file)));
                    }
                }
            }

            // **********************************************************************************************
            // Fetch log file/content for specific migration
            // **********************************************************************************************

            elseif ($_POST["post_purpose"] == "fetch_log") {

                if ( isset($_POST["cu"]) ) {
                    $cu = $_POST["cu"];
                } else {
                    throw new exception("'CU' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                if ( isset($_POST["operation"]) ) {
                    $operation = $_POST["operation"];
                } else {
                    throw new exception("'operation' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 6);
                }

                if ( isset($_POST["category"]) ) {
                    $category = $_POST["category"];
                } else {
                    throw new exception("'category' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 21);
                }

                $log_path = getLogFile($cu, $operation, $category);
                $result = readContent($log_path, $operation, $category, $cu);

                // audit log any error while fetching log file
                $lastline =end($result["log_content"]);
                if (strpos($lastline, "Error") !== false) {
                    auditLogMigrationExecution($cu, "", $operation, $category, "Log Fetch Error: " . trim(preg_split("/::/", $lastline)[1]));
                }

                $success_msg_prefix = "";
                if ($result["does_not_exist"]) {
                    $msg = "Log file does not exist: " . $log_path . ". ";
                }
                elseif ($result["end_of_log"]) {
                    if ($operation != "migrate") {
                        // delete completion lock file and log files if $operation == "clean"
                        // ONLY after SUCCESSFUL completion of clean operation
                        if($operation == "clean") {
                            cleanupAfterClean($cu, $category, $operation);
                        }
                        $msg = "<b>Operation ('$operation - $category') COMPLETED.</b> Displayed log is COMPLETE. ";

                    } else { // migrate
                        $success_msg_prefix = "<b>Migration ('$operation - $category') COMPLETED.</b> Displayed log is COMPLETE. ";
                    }

                    if ($operation == "migrate") {
                        $handle_wip_response = markWIPAsComplete($cu, $category, $operation);
                    } else {
                        $handle_wip_response = deleteWIPFile($cu, $category, $operation);
                    }

                    if ($handle_wip_response["success"] == False) {
                        $msg = $success_msg_prefix . " WIP file COULD NOT be marked as Done or Deleted. ";
                    } else {
                        $msg = $success_msg_prefix;
                    }

                } else {
                    if ($operation == "migrate") {
                        $msg = "<b>Migration ('$operation - $category') is IN PROGRESS.</b> Displayed log is NOT COMPLETE. ";
                    } else {
                        $msg = "<b>Operation ('$operation - $category') is IN PROGRESS.</b> Displayed log is NOT COMPLETE. ";
                    }
                }

                $response = array("success"=> True, "message" => $msg, "category"=>$category, "log_report" => $result);
            }

            // **********************************************************************************************
            // Fetch log content only for displaying history (no side effects; only display)
            // **********************************************************************************************
            elseif ($_POST["post_purpose"] == "fetch_log_history_only") {

                if ( isset($_POST["cu"]) ) {
                    $cu = $_POST["cu"];
                } else {
                    throw new exception("'CU' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                if ( isset($_POST["operation"]) ) {
                    $operation = $_POST["operation"];
                } else {
                    throw new exception("'operation' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 6);
                }

                if ( isset($_POST["category"]) ) {
                    $category = $_POST["category"];
                } else {
                    throw new exception("'category' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 21);
                }

                $log_path = getLogFile($cu, $operation, $category);
                $response = readContent($log_path, $operation, $category, $cu);

                if ($response["does_not_exist"]) {
                    $response["success"] = False;
                    $response["message"] = "[Log History] Log file does not exist for '$operation-$category'";
                } else {
                    $response["success"] = True;
                    $response["message"] = "[Log History] Displaying logs: '$operation-$category'";
                }
            }

            // **********************************************************************************************
            // Disable Monitor access by creating lock file
            // **********************************************************************************************

            elseif ($_POST["post_purpose"] == "disable_monitor") {

                if ( isset($_POST["cu"]) ) {
                    $cu = $_POST["cu"];
                    if ($cu == "") {
                        throw new exception("Empty 'cucode' name provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                    }
                } else {
                    throw new exception("'CU' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                if ( isset($_POST["server"]) ) {
                    $server = $_POST["server"];
                    if ($server == "") {
                        throw new exception("Empty 'server' name provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                    }
                } else {
                    throw new exception("'server' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                // maintain audit log
                auditLogMigrationExecution($cu, "", "Disable Migration Menu.", "Temporary files cleanup.", "Button clicked.");

                $monitor_lock_file = getMonitorLockFile($cu);

                if (file_exists($monitor_lock_file)) {
                    $response = array("success"=> True, "message" => "Monitor UI already disabled.");
                } else {
                    // create a lock file
                    if (touch($monitor_lock_file)) {
                        // Now, run cleanup of temporary files in Mammoth
                        // Note, success/failure of temporary file cleanup is not that critical
                        // As of 2018-10-05, the only temporary file that we want to cleanup is
                        // /home/*/tmp/memhist.gz file in Mammoth servers. In case this step produces
                        // an error in log message, simply go to the Mammoth location of this $cu
                        // and carefully delete the file.

                        $cleanup_hash = CreateHash("cleanup", $cu);
                        $cleanup_response = makeMammothEndpointCall($server, $cu, "cleanup", $cleanup_hash);

                        $temp_file_deletion_msg_append = "";

                        if ($cleanup_response["error"] == "") {
                            # temporary files are deleted successfully
                            $temp_file_deletion_msg_append = "[Cleanup MMTH] " . $cleanup_response["info"] . ".";
                        } else {
                            $temp_file_deletion_msg_append = "[Cleanup MMTH] " . $cleanup_response["error"] . ".";
                        }

                        // Also, delete temporary 'memhist' files from odyssey.
                        $ody_cleanup_msg = deleteOdysseyTemporaryFiles($cu);

                        $response = array("success"=> True, "message" => "[Monitor Disable] Migration Monitor UI disabled. $temp_file_deletion_msg_append $ody_cleanup_msg");

                    } else {
                        $response = array("success"=> False, "message" => "[Monitor Disable] Something went wrong, could not disable Monitor UI. $temp_file_deletion_msg_append");
                    }
                }

            }

            // **********************************************************************************************
            // Check if monitor lock file exists
            // **********************************************************************************************

            elseif ($_POST["post_purpose"] == "check_monitor_lock") {

                if ( isset($_POST["cu"]) ) {
                    $cu = $_POST["cu"];
                } else {
                    throw new exception("'CU' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                $monitor_lock_file = getMonitorLockFile($cu);

                if (file_exists($monitor_lock_file)) {
                    $response = array("exists"=> True, "lock_file" => $monitor_lock_file);
                } else {
                    $response = array("exists"=> False, "lock_file" => $monitor_lock_file);
                }
            }

            // **********************************************************************************************
            // Delete WIP lock file for specific category after completion or error
            // **********************************************************************************************

            elseif ($_POST["post_purpose"] == "delete_wip") {
                // WIP files are only created for migrate operation

                if ( isset($_POST["cu"]) ) {
                    $cu = $_POST["cu"];
                } else {
                    throw new exception("'CU' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                if ( isset($_POST["category"]) ) {
                    $category = $_POST["category"];
                } else {
                    throw new exception("'category' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 21);
                }

                if ( isset($_POST["operation"]) ) {
                    $operation = $_POST["operation"];
                } else {
                    throw new exception("'operation' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 21);
                }

                if ( isset($_POST["is_final_migr"]) ) {
                    $is_final_migr = $_POST["is_final_migr"];
                } else {
                    throw new exception("'operation' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 21);
                }

                $response = deleteWIPFile($cu, $category, $operation);

                if($is_final_migr) {
                    $final_migr_main_lock = getFinalMigrationMainLock($cu);
                    if (file_exists($final_migr_main_lock)) {
                        $final_migr_unlink_response = unlink($final_migr_main_lock);
                        if($final_migr_unlink_response) {
                            $response["message"] .= " Successfully removed final migration lock file. ";
                        } else {
                            $response["message"] .= " Removing final migration lock file FAILED. ";
                        }
                        $response["success"] = ($response["success"] && $final_migr_unlink_response);
                    }
                }

            }

            // **********************************************************************************************
            // Return list of in-progress and done categories
            // **********************************************************************************************

            elseif ($_POST["post_purpose"] == "get_wip_done_list") {
                // WIP files are only created for migrate operation

                if ( isset($_POST["cu"]) ) {
                    $cu = $_POST["cu"];
                } else {
                    throw new exception("'CU' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                $wip_list = getCurrentWIPCategoryList($cu);
                $done_list = getCurrentDoneCategoryList($cu);
                $final_migr_done = file_exists(getFinalMigrationDoneLock($cu));

                $response = array("success"=> True,
                                  "message" => "Successfully fetched list of wip and done migrations.",
                                  "wip_list" => $wip_list,
                                  "done_list"=>$done_list,
                                  "final_migr_done" => $final_migr_done);
            }

            // **********************************************************************************************
            // Return logs list
            // **********************************************************************************************

            elseif ($_POST["post_purpose"] == "get_logs_list") {

                if ( isset($_POST["cu"]) ) {
                    $cu = $_POST["cu"];
                } else {
                    throw new exception("'CU' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                $logs_list = getCurrentLogsList($cu);

                $response = array("success"=> True, "message" => "Successfully fetched all existing log files.", "logs_list" => $logs_list);
            }

            // **********************************************************************************************
            // Cleanup All Categories
            // **********************************************************************************************

            elseif ($_POST["post_purpose"] == "clean_all_categories") {

                if ( isset($_POST["cu"]) ) {
                    $cu = $_POST["cu"];
                } else {
                    throw new exception("'CU' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                if (file_exists(getFinalMigrationMainLock($cu)) || file_exists(getFinalMigrationDoneLock($cu))) {
                    $response = array("success"=> False, "message" => "Deletion NOT ALLOWED. Final migration already executed or is in progress. ");
                } else {

                    $delete_done_list = array();
                    if ( isset($_POST["delete_done_list"]) ) {
                        $delete_done_list = $_POST["delete_done_list"];
                    } else {
                        throw new exception("'delete_done_list' not provided (must be a list of categories to run clean operation.). (" . __FILE__ . ":" . __LINE__ . ")", 1);
                    }
                    $response = deleteMultipleCategories($cu, $delete_done_list);
                }
            }

            // **********************************************************************************************
            // Update DDL's Categories list for specific CU
            // **********************************************************************************************
            //
            elseif ($_POST["post_purpose"] == "update_server_list") {
                $dbh = $link;
                if ( isset($_POST["cu"]) ) {
                    $cu = $_POST["cu"];
                } else {
                    throw new exception("'CU' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                $associated_servers = array();
                $cu_info_arr = array();

                if (in_array(strtoupper($cu), array("SCRUBCU", "CRUISECU"))) {
                    // return www4 for CUs used for development
                    $associated_servers[] = "www4";
                } else {

                    $cu_info_response = GetCuList($dbh);
                    if (HCU_array_key_exists("cuinfo", $cu_info_response)) {
                        $cu_info_arr = $cu_info_response["cuinfo"];
                        foreach($cu_info_arr as $cuinfo) {
                            if (in_array(trim($cuinfo["cutype"]), array("Live")) && strtoupper(trim($cuinfo["user_name"])) == strtoupper($cu)) {
                                $associated_servers[] = trim($cuinfo["www_server"]);
                            }
                        }
                    }
                }

                if(count($associated_servers) > 0) {
                    $response = array("success"=> True, "message" => "Successfully obtained server list for CU '$cu'.", "server_list" => $associated_servers);
                } else {
                    $response = array("success"=> False, "message" => "CU '$cu' does not exist in any of the Mammoth Servers.");
                }
            }

            // **********************************************************************************************
            // Update DDL's Server list for specific CU
            // **********************************************************************************************
            //
            elseif ($_POST["post_purpose"] == "update_categories_list") {

                if ( isset($_POST["cu"]) ) {
                    $cu = $_POST["cu"];
                } else {
                    throw new exception("'CU' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }
                $categories_list = array();

                $memdata_done_file = getDoneFile($cu, "memdata", "migrate");
                $switchaccount_done_file = getDoneFile($cu, "switchaccounts", "migrate");

                $include_switchaccount_settings_file = getSwitchAccountsSettingFile($cu);

                // first element is used to display as default i.e. settings
                $general_list = array("settings", "admin", "memdata");

                if (file_exists($memdata_done_file)) {
                    $categories_list = $general_list;

                    // only allow switchaccounts if set up in settings for this $cu
                    if (file_exists($include_switchaccount_settings_file)) {
                        if (!file_exists(getDoneFile($cu, "switchaccounts", "migrate"))
                            && !file_exists(getWIPFile($cu, "switchaccounts", "migrate"))) {
                            $categories_list[] = "switchaccounts";
                        }
                    }

                    // allow loanapps after switchaccounts (if configured)
                    if (file_exists($include_switchaccount_settings_file)){
                        if (file_exists(getDoneFile($cu, "switchaccounts", "migrate"))) {
                            $categories_list[] = "loanapp";
                        }
                    } else {
                        $categories_list[] = "loanapp";
                    }
                }

                else {
                    $categories_list = $general_list;
                }

                // make memhist the last element
                $categories_list[] = "memhist";

                $response = array("success"=> True,
                                  "message" => "Updated categories list for CU '$cu'.",
                                  "categories_list" => $categories_list);
            }

            // **********************************************************************************************
            // Show/Hide Account Ref Download Button
            // **********************************************************************************************
            //
            elseif ($_POST["post_purpose"] == "display_accref_download") {

                if ( isset($_POST["cu"]) ) {
                    $cu = $_POST["cu"];
                } else {
                    throw new exception("'CU' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                // get account cross-reference file
                $accCrossRefFile = getAccCrossRefFile($cu);
                // get migration completion mark file
                $memdataDoneFile = getDoneFile($cu, "memdata", "migrate");

                if (file_exists($accCrossRefFile) && file_exists($memdataDoneFile)) {
                    $response = array("success"=> True, "message" => "Show account reference download button.", "show_btn" => True );
                } else {
                    $response = array("success"=> True, "message" => "'migrate-memdata' not completed. Disable account reference download button.", "show_btn" => False );
                }
            }

            // **********************************************************************************************
            // Show/Hide HomeBanking Informational Text
            // **********************************************************************************************
            //
            elseif ($_POST["post_purpose"] == "display_hb_info_text") {

                if ( isset($_POST["cu"]) ) {
                    $cu = $_POST["cu"];
                } else {
                    throw new exception("'CU' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                $cu = trim($cu);
                $dbh = $link;

                // First, see if there's a record for this CU in cuadmin table at all
                $sql = "select count(*) from cuadmin where cu='" . strtoupper($cu) . "';";
                if($qr_result = db_query($sql, $dbh)) {
                    $result_arr = db_fetch_array($qr_result);
                }
                $cuadmin_count = $result_arr[0];

                // If a record exists in cuadmin table for this CU
                if($cuadmin_count == "1") {
                    // fetch flagset2, offlinestat and livebatch infor from cuadmin table
                    $sql_flagset2 = "select flagset2, offlinestat, livebatch from cuadmin where cu='" . strtoupper($cu) . "';";
                    $query_result_record = db_query($sql_flagset2, $dbh);
                    $row = db_fetch_array($query_result_record);

                    $livebatch = trim($row["livebatch"]);
                    $offlinestat = trim($row["offlinestat"]);
                    $flagset2 = $row["flagset2"];

                    // Check if the Allow Member Alerts Processing info is marked CHECKED or not
                    if ($flagset2 & GetFlagsetValue("CU2_ALLOW_MBR_ALERTS")) $flag2_33554432_ck = "CHECKED"; else $flag2_33554432_ck = "";

                    // Check if the Allow Repeating Transactions info is marked CHECKED or not
                    if ($flagset2 & GetFlagsetValue("CU2_PROCRECUR")) $flag2_32_ck = "CHECKED"; else $flag2_32_ck = "";

                    // Get the offline status of the CU, Only applicable for Live CUs
                    if ($livebatch == 'L') {
                        $show_offline_status = True;

                        // initial status "" is considered as "N"
                        if ($offlinestat == 'N' || $offlinestat == "") {
                            $return_offlinestat = "Active";
                        }
                        elseif ($offlinestat == 'U') {
                            $return_offlinestat = "Offline (Auto Up)";
                        }
                        elseif ($offlinestat == 'Y') {
                            $return_offlinestat = "Offline (Stay Down)";
                        }
                        else {
                            $return_offlinestat = "Undefined (Live)";
                        }
                    }
                    else {
                        $show_offline_status = False;
                        $return_offlinestat = "Not Applicable (Batch)";
                    }

                    // Prepare a response accordingly
                    $response = array("success"=> True, "message" => "Settings flags retrieved successfully.", "CU2_ALLOW_MBR_ALERTS" => $flag2_33554432_ck, "CU2_PROCRECUR" => $flag2_32_ck, "show_offline_status" => $show_offline_status, "offlinestat" => $return_offlinestat);
                }
                // if there isn't any record for this CU in cuadmin table
                else {
                    $response = array("success"=> False, "message" => "No 'cuadmin' record exist for " . strtoupper($cu) . ". Run 'migrate-settings'?");
                }
            }


            // **********************************************************************************************
            // Execute fix_public_html.pl script
            // **********************************************************************************************
            //
            elseif ($_POST["post_purpose"] == "fix_public_html") {

                if ( isset($_POST["cu"]) ) {
                    $cu = $_POST["cu"];
                } else {
                    throw new exception("'CU' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                if ( isset($_POST["from"]) ) {
                    $from = $_POST["from"];
                } else {
                    throw new exception("'from domain' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                if ( isset($_POST["to"]) ) {
                    $to = $_POST["to"];
                } else {
                    throw new exception("'to domain' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }
                // maintain audit log
                auditLogMigrationExecution($cu, "", "public_html update ($from->$to)", "public_html directory contents", "Button clicked.");

                $publichtmlPath = getPublicHtmlPath($cu);

                if (file_exists($publichtmlPath)) {
                    $response = executeFixPublicHtmlScript($cu, $from, $to);
                } else {
                    $response = array("success"=> False, "message" => "'public_html' directory does not exist.");
                }
            }

            // **********************************************************************************************
            // Show/Hide Settings and Members Lock/Unlock buttons
            // **********************************************************************************************
            //
            elseif ($_POST["post_purpose"] == "display_lock_unlock_preventive_buttons") {

                if ( isset($_POST["cu"]) ) {
                    $cu = $_POST["cu"];
                } else {
                    throw new exception("'CU' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                if ( isset($_POST["cat_group"]) ) {
                    $cat_group = $_POST["cat_group"];
                } else {
                    throw new exception("'cat_group' (Settings or Admin) not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                if($cat_group == "Admin" or $cat_group == "Settings") {
                    $msg = "";
                    if ($cat_group == "Settings") {

                        if (file_exists(getDoneFile($cu, "settings", "migrate"))) {
                            $msg = "'settings' data category migration has completed. Show Lock/Unlock Settings button.";
                            $show_btn = True;
                        } else {
                            $msg = "'settings' data category migration has not completed. Disable Lock/Unlock Settings button.";
                            $show_btn = False;
                        }
                    } else {

                        if (file_exists(getDoneFile($cu, "admin", "migrate"))) {
                            $msg = "'admin' data category migration has completed completed. Show Lock/Unlock Admin button.";
                            $show_btn = True;
                        } else {
                            $msg = "'admin' data category migration has not completed. Disable Lock/Unlock Admin button.";
                            $show_btn = False;
                        }
                    }
                    if(file_exists(getLockFileForPreventingFurtherMigration($cu, $cat_group))) {
                        $locked = True;
                    } else {
                        $locked = False;
                    }

                    $response = array("success"=> True, "message" => $msg, "show_btn" => $show_btn, "locked" => $locked );
                } else {
                    throw new exception("Invalid 'cat_group': must be either Settings or Admin. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }
            }

            // **********************************************************************************************
            // Handle lock files for Settings and Members Lock/Unlock button operation
            // **********************************************************************************************
            //
            elseif ($_POST["post_purpose"] == "lock_unlock_cat_group") {

                if ( isset($_POST["cu"]) ) {
                    $cu = $_POST["cu"];
                } else {
                    throw new exception("'CU' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                if ( isset($_POST["cat_group"]) ) {
                    $cat_group = $_POST["cat_group"];
                } else {
                    throw new exception("'cat_group' (Admin or Settings) not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                if ( isset($_POST["lock_or_unlock"])) {
                    $lock_or_unlock = $_POST["lock_or_unlock"];
                } else {
                    throw new exception("'lock_or_unlock' (lock or unlock) not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                if ($lock_or_unlock == "lock" or $lock_or_unlock == "unlock") {

                    if($cat_group == "Settings" || $cat_group == "Admin") {
                        if ($cat_group == "Settings") {
                            $settingsDoneFile = getDoneFile($cu, "settings", "migrate");

                            if (file_exists($settingsDoneFile)) {
                                $preventSettingsLockFile = getLockFileForPreventingFurtherMigration($cu, $cat_group);
                                if($lock_or_unlock == "lock") {
                                    touch($preventSettingsLockFile);
                                }
                                // unlock
                                else {
                                    if(file_exists($preventSettingsLockFile)) {
                                        unlink($preventSettingsLockFile);
                                    }
                                }
                            }

                        } else { // Admin
                            $adminDoneFile = getDoneFile($cu, "admin", "migrate");

                            if (file_exists($adminDoneFile)) {
                                $preventAdminLockFile = getLockFileForPreventingFurtherMigration($cu, $cat_group);
                                if($lock_or_unlock == "lock") {
                                    touch($preventAdminLockFile);
                                }
                                // unlock
                                else {
                                    if(file_exists($preventAdminLockFile)) {
                                        unlink($preventAdminLockFile);
                                    }
                                }
                            }
                        }

                    } else {
                        throw new exception("Invalid 'cat_group': must be Admin or Settings. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                    }
                } else {
                    throw new exception("Invalid 'lock_or_unlock': must be lock or unlock. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }
                $lock_unlock_msg = "'". $cat_group . "' is '" . $lock_or_unlock . "ed'.";
                // log Settings/Migrations lock/unlock settings changes
                auditLogMigrationExecution($cu, "", "Toggle lock-unlock", $cat_group, $lock_unlock_msg);
                $response = array("success"=> True, "message" => $lock_unlock_msg);
            }

            // **********************************************************************************************
            // Prepare ready for final migration flag
            // **********************************************************************************************
            //
            elseif ($_POST["post_purpose"] == "get_final_migr_flag") {

                if ( isset($_POST["cu"]) ) {
                    $cu = $_POST["cu"];
                } else {
                    throw new exception("'CU' not provided. (" . __FILE__ . ":" . __LINE__ . ")", 1);
                }

                // get migration completion mark file
                $final_migr_memcount_file = getFinalMigrationConfigFile($cu);
                $show_final_migr_button = False;
                $memdata_count = 0;
                $memhist_count = 0;
                $noWIP = False;

                if (!file_exists($final_migr_memcount_file)) {
                    if(touch($final_migr_memcount_file)) {
                        file_put_contents($final_migr_memcount_file, "memdata_count,memhist_count\n$memdata_count".",". "$memhist_count\n");
                    }
                } else {
                    if (($fileStr = file_get_contents($final_migr_memcount_file)) != False) {
                        $mem_count_arr = explode(",", explode("\n", $fileStr)[1]);
                        $memdata_count = (int)$mem_count_arr[0];
                        $memhist_count = (int)$mem_count_arr[1];
                    }
                }

                // make sure Settings (settings) and Admin(admin) are migrated, updated and locked from accidental deletion
                $SettingsLocked = (file_exists(getLockFileForPreventingFurtherMigration($cu, "Settings")));
                $AdminLocked = (file_exists(getLockFileForPreventingFurtherMigration($cu, "Admin")));
                // but memdata and memhist were ran atleast once each earlier for testing ($memdata_count > 0 && $memhist_count > 0), and
                // memdata and memhist are cleaned up before final migration
                $memdataIsClean = (!file_exists(getDoneFile($cu, "memdata", "migrate")));
                $memhistIsClean = (!file_exists(getDoneFile($cu, "memhist", "migrate")));

                $wip_list = getCurrentWIPCategoryList($cu);
                $noWIP = (count($wip_list) == 0);


                if($memdata_count > 0 && $memhist_count > 0 && $SettingsLocked && $AdminLocked && $memdataIsClean && $memhistIsClean && $noWIP) {
                    $show_final_migr_button = True;
                }
                $response_options = array();
                $response_options["memdata_gt0"] = ($memdata_count >0);
                $response_options["memhist_gt0"] = ($memhist_count >0);
                $response_options["SettingsAdminLocked"] = ($SettingsLocked && $AdminLocked);
                $response_options["memdata_is_clean"] = $memdataIsClean;
                $response_options["memhist_is_clean"] = $memhistIsClean;
                $response_options["no_wip_exists"] = $noWIP;
                $response_options["show_final_migr_button"] = $show_final_migr_button;


                $response = array("success"=> True, "message" => "", "final_migr_resp" => $response_options );
            }

            // **********************************************************************************************
            // Otherwise, unknown request
            // **********************************************************************************************

            else {
                unset($_POST["password"]);
                $passed_arguments = http_build_query($_POST, '', ', ') . " (password not displayed.)";
                $response = array("success"=> False, "message" => "Unknown request. Passed arguments: " . $passed_arguments  );
            }

        } else {
            $msg_suffix = "";
            if (isset($_POST["password"])) {
                unset($_POST["password"]);
                $passed_arguments = http_build_query($_POST, '', ', ') . " (password not displayed.)";
                $msg_suffix = "Passed arguments: " . $passed_arguments;
            }
            $response = array("success"=> False, "message" => "[HTTP parameters error] Not a valid request." . $msg_suffix );

        }
    } catch (exception $e) {
        $msg_suffix = "";
        if (isset($_POST["password"])) {
            unset($_POST["password"]);
            $passed_arguments = http_build_query($_POST, '', ', ') . " (password not displayed.)";
            $msg_suffix = "Passed arguments: " . $passed_arguments;
        }
        $response = array("success"=> False, "message" => "[HTTP parameters error]" . $e->getMessage()) . $msg_suffix;
    }

    return $response;
}

// return http response to the client for this specific request
echo HCU_JsonEncode(serveMigrationPurpose());

?>