<?PHP
/**
 * Functions for connecting to and checking other DBs.
 *
 * @file
 *
 * @author Joshua Ramon Enslin <joshua@museum-digital.de>
 */

if (!file_exists(__DIR__ . '/../conf/dbsToCompare.php')) return;

/**
 * Function to connect to all versions to compare the current one with.
 * Returns an array of database connections.
 *
 * @return array<MDMysqli>
 */
function connectToCompareDBs():array {

    include __DIR__ . '/../conf/dbsToCompare.php';
    if (empty($dbsToCompare)) return [];

    $connections = [];
    foreach ($dbsToCompare as $key => $db) {
        $connections[$key] = md_mysqli_connect($db['hostname'], $db['username'], $db['password'], $db['databasename']);
        if (mysqli_connect_error()) {
            throw new Exception("Error connecting to database " . $db['hostname']);
        }
    }
    return $connections;

}

/**
 * Checks the number a given set of times appeared in eveents in a given version.
 *
 * @param array<MDMysqli> $connections   Array of DB connections from which to query.
 * @param integer         $timeID        ID of the time entry to check.
 * @param string          $currentSubset Name of the current version.
 *
 * @return array{0: integer, 1: integer}
 */
function checkTimes(array $connections, int $timeID, string $currentSubset):array {

    list($numberofusage, $currentAmount) = [[], 0]; // Set defaults
    foreach ($connections as $dbName => $connection) {

        $eergebnis = $connection->do_read_query("SELECT 1
            FROM `ereignis`
            WHERE `zeiten_id` = " . $connection->escape_string((string)$timeID) . "
            LIMIT 2");

        $numberofusage[$dbName] = $anzahl_ergebnis = $eergebnis->num_rows;
        if (strtolower($dbName) == strtolower($currentSubset)) $currentAmount = $anzahl_ergebnis;

        $eergebnis->close(); unset($eergebnis);
    }
    return [(int)array_sum($numberofusage), $currentAmount];

}

/**
 * Checks the number a given person / institution appeared in events across versions.
 *
 * @param array<MDMysqli> $connections   Array of DB connections from which to query.
 * @param integer         $timeID        ID of the time entry to check.
 * @param string          $currentSubset Name of the current version.
 *
 * @return array{0: integer, 1: integer}
 */
function checkPersinst(array $connections, int $timeID, string $currentSubset):array {

    list($numberofusage, $currentAmount) = [[], 0]; // Set defaults
    foreach ($connections as $dbName => $connection) {

        $eergebnis = $connection->do_read_query("SELECT 1
            FROM `ereignis`
            WHERE `persinst_id` = " . $connection->escape_string((string)$timeID) . "
            LIMIT 2");

        $numberofusage[$dbName] = $anzahl_ergebnis = $eergebnis->num_rows;
        if (strtolower($dbName) == strtolower($currentSubset)) $currentAmount = $anzahl_ergebnis;

        $eergebnis->close(); unset($eergebnis);
    }
    return [(int)array_sum($numberofusage), $currentAmount];

}

/**
 * Checks the number a given place appeared in events across versions.
 *
 * @param array<MDMysqli> $connections   Array of DB connections from which to query.
 * @param integer         $timeID        ID of the time entry to check.
 * @param string          $currentSubset Name of the current version.
 *
 * @return array{0: integer, 1: integer}
 */
function checkPlace(array $connections, int $timeID, string $currentSubset):array {

    list($numberofusage, $currentAmount) = [[], 0]; // Set defaults
    foreach ($connections as $dbName => $connection) {

        $eergebnis = $connection->do_read_query("SELECT 1
            FROM `ereignis`
            WHERE `orte_id` = " . $connection->escape_string((string)$timeID) . "
            LIMIT 2");

        $numberofusage[$dbName] = $anzahl_ergebnis = $eergebnis->num_rows;
        if (strtolower($dbName) == strtolower($currentSubset)) $currentAmount = $anzahl_ergebnis;

        $eergebnis->close(); unset($eergebnis);
    }
    return [(int)array_sum($numberofusage), $currentAmount];

}

/**
 * Checks the number a given tag appeared in events across versions.
 *
 * @param array<MDMysqli> $connections   Array of DB connections from which to query.
 * @param integer         $tagID         ID of the tag entry to check.
 * @param string          $currentSubset Name of the current version.
 *
 * @return array{0: integer, 1: integer}
 */
function checkTag(array $connections, int $tagID, string $currentSubset):array {

    list($numberofusage, $currentAmount) = [[], 0]; // Set defaults
    foreach ($connections as $dbName => $connection) {

        $eergebnis = $connection->do_read_query("SELECT 1
            FROM `v_objekt_tag2`
            WHERE `tag_id` = " . $connection->escape_string((string)$tagID) . "
            LIMIT 2");

        $numberofusage[$dbName] = $anzahl_ergebnis = $eergebnis->num_rows;
        if (strtolower($dbName) == strtolower($currentSubset)) $currentAmount = $anzahl_ergebnis;

        $eergebnis->close(); unset($eergebnis);
    }
    return [(int)array_sum($numberofusage), $currentAmount];

}