import { pool } from '../db';

/**
 * Migration System for God Mode
 * Handles transactional execution of SQL migration files
 */

export interface MigrationResult {
    success: boolean;
    migrationsRun: number;
    error?: string;
    rolledBack?: boolean;
}

/**
 * Run multiple SQL commands in a single transaction
 * Automatically rolls back if ANY command fails
 */
export async function runMigrations(sqlCommands: string[]): Promise<MigrationResult> {
    const client = await pool.connect();
    let migrationsRun = 0;

    try {
        await client.query('BEGIN');
        console.log('🔱 [Migration] Starting transaction...');

        for (const command of sqlCommands) {
            // Skip empty commands or comments
            const trimmed = command.trim();
            if (!trimmed || trimmed.startsWith('--')) {
                continue;
            }

            console.log(`[Migration] Executing: ${trimmed.substring(0, 100)}...`);
            await client.query(trimmed);
            migrationsRun++;
        }

        await client.query('COMMIT');
        console.log(`✅ [Migration] Successfully committed ${migrationsRun} migrations`);

        return {
            success: true,
            migrationsRun
        };

    } catch (error: any) {
        await client.query('ROLLBACK');
        console.error('❌ [Migration] Error - Rolling back all changes:', error.message);

        return {
            success: false,
            migrationsRun,
            error: error.message,
            rolledBack: true
        };

    } finally {
        client.release();
    }
}

/**
 * Run a single large SQL file (like migrations)
 * Splits by semicolon and runs each statement in transaction
 */
export async function runMigrationFile(sqlContent: string): Promise<MigrationResult> {
    // Split by semicolon, but be smart about it
    const statements = sqlContent
        .split(';')
        .map(s => s.trim())
        .filter(s => s.length > 0);

    return runMigrations(statements);
}

/**
 * Check if migrations have been run
 */
export async function getMigrationStatus(): Promise<{
    tables: string[];
    lastMigration?: Date;
}> {
    try {
        const result = await pool.query(`
            SELECT table_name 
            FROM information_schema.tables 
            WHERE table_schema = 'public' 
            ORDER BY table_name
        `);

        return {
            tables: result.rows.map((r: { table_name: string }) => r.table_name)
        };
    } catch (error) {
        return {
            tables: []
        };
    }
}