<?php

function mysqlMirrorConnection(): PDO {
    $dsn = trim((string)getConfigVal('database.mysql.dsn', ''));
    if ($dsn === '') throw new RuntimeException('MySQL DSN is missing');
    $pdo = new PDO(
        $dsn,
        (string)getConfigVal('database.mysql.username', ''),
        (string)getConfigVal('database.mysql.password', ''),
        [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION]
    );
    $pdo->exec("CREATE TABLE IF NOT EXISTS sqlite_mirror_rows (
        source_db VARCHAR(255) NOT NULL,
        table_name VARCHAR(128) NOT NULL,
        row_key VARCHAR(255) NOT NULL,
        row_json LONGTEXT NOT NULL,
        synced_at BIGINT NOT NULL,
        PRIMARY KEY(source_db,table_name,row_key)
    )");
    return $pdo;
}

function mirrorAllSQLiteDatabases(): array {
    $main = storagePath((string)getConfigVal('database.main_db', 'db/chat.sqlite'));
    $files = is_file($main) ? [$main] : [];
    $archiveRoot = storagePath((string)getConfigVal('archive.archive_dir', 'archive'));
    foreach (glob($archiveRoot . '/*/*/*.sqlite') ?: [] as $file) $files[] = $file;
    $mysql = mysqlMirrorConnection();
    $upsert = $mysql->prepare("INSERT INTO sqlite_mirror_rows
        (source_db,table_name,row_key,row_json,synced_at) VALUES (?,?,?,?,?)
        ON DUPLICATE KEY UPDATE row_json=VALUES(row_json),synced_at=VALUES(synced_at)");
    $count = 0;
    foreach ($files as $file) {
        $sqlite = new PDO('sqlite:' . $file);
        $sqlite->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);
        $tables = $sqlite->query("SELECT name FROM sqlite_master WHERE type='table' AND name NOT LIKE 'sqlite_%'")
            ->fetchAll(PDO::FETCH_COLUMN);
        foreach ($tables as $table) {
            $quoted = '"' . str_replace('"', '""', $table) . '"';
            foreach ($sqlite->query("SELECT rowid AS _mirror_rowid,* FROM $quoted") as $row) {
                $key = (string)($row['id'] ?? $row['_mirror_rowid']);
                unset($row['_mirror_rowid']);
                $source = str_starts_with($file, ROOT_DIR . '/')
                    ? substr($file, strlen(ROOT_DIR) + 1)
                    : $file;
                $upsert->execute([
                    $source, $table, $key,
                    json_encode($row, JSON_UNESCAPED_SLASHES), time(),
                ]);
                $count++;
            }
        }
    }
    return ['databases' => count($files), 'rows' => $count];
}