#!/usr/bin/env python3
"""
Shinkan Jinkendo - Database Migrations Runner

Runs all SQL migrations in backend/migrations/ directory
Tracks executed migrations in schema_migrations table
"""
import os
import sys
import psycopg2
from psycopg2 import sql
import time

def get_db_connection():
    """Get database connection with retries"""
    max_retries = 30
    for i in range(max_retries):
        try:
            conn = psycopg2.connect(
                host=os.getenv("DB_HOST", "localhost"),
                port=os.getenv("DB_PORT", "5432"),
                database=os.getenv("DB_NAME", "shinkan_dev"),
                user=os.getenv("DB_USER", "shinkan_dev"),
                password=os.getenv("DB_PASSWORD", "dev_password")
            )
            print(f"✓ Connected to database: {os.getenv('DB_NAME')}")
            return conn
        except psycopg2.OperationalError as e:
            if i < max_retries - 1:
                print(f"Waiting for database... ({i+1}/{max_retries})")
                time.sleep(2)
            else:
                print(f"✗ Failed to connect to database after {max_retries} attempts")
                raise

def init_migrations_table(conn):
    """Create schema_migrations table if not exists"""
    with conn.cursor() as cur:
        cur.execute("""
            CREATE TABLE IF NOT EXISTS schema_migrations (
                id SERIAL PRIMARY KEY,
                migration VARCHAR(255) UNIQUE NOT NULL,
                executed_at TIMESTAMP DEFAULT NOW()
            )
        """)
        conn.commit()
    print("✓ Migrations table initialized")

def get_executed_migrations(conn):
    """Get list of already executed migrations"""
    with conn.cursor() as cur:
        cur.execute("SELECT migration FROM schema_migrations ORDER BY migration")
        return set(row[0] for row in cur.fetchall())

def get_pending_migrations(executed):
    """Get list of pending migrations from migrations directory"""
    migrations_dir = "/app/migrations"
    if not os.path.exists(migrations_dir):
        migrations_dir = "backend/migrations"  # Local development

    all_migrations = []
    for filename in sorted(os.listdir(migrations_dir)):
        if filename.endswith('.sql') and filename[0].isdigit():
            migration_name = filename.replace('.sql', '')
            if migration_name not in executed:
                all_migrations.append((migration_name, os.path.join(migrations_dir, filename)))

    return all_migrations

def run_migration(conn, migration_name, filepath):
    """Run a single migration file"""
    print(f"Running migration: {migration_name}")

    with open(filepath, 'r', encoding='utf-8') as f:
        sql_content = f.read()

    try:
        with conn.cursor() as cur:
            # Execute migration
            cur.execute(sql_content)

            # Record migration
            cur.execute(
                "INSERT INTO schema_migrations (migration) VALUES (%s)",
                (migration_name,)
            )

        conn.commit()
        print(f"  ✓ {migration_name} executed successfully")
        return True

    except Exception as e:
        conn.rollback()
        print(f"  ✗ {migration_name} failed: {e}")
        return False

def main():
    """Main migrations runner"""
    print("=" * 60)
    print("Shinkan Jinkendo - Database Migrations")
    print("=" * 60)

    try:
        # Connect to database
        conn = get_db_connection()

        # Initialize migrations tracking
        init_migrations_table(conn)

        # Get executed and pending migrations
        executed = get_executed_migrations(conn)
        pending = get_pending_migrations(executed)

        if not pending:
            print("✓ No pending migrations - database is up to date")
            return 0

        print(f"\nFound {len(pending)} pending migration(s):")
        for name, _ in pending:
            print(f"  - {name}")
        print()

        # Run pending migrations
        failed = []
        for migration_name, filepath in pending:
            if not run_migration(conn, migration_name, filepath):
                failed.append(migration_name)
                break  # Stop on first failure

        conn.close()

        # Summary
        print("\n" + "=" * 60)
        if failed:
            print(f"✗ Migration failed: {failed[0]}")
            print("=" * 60)
            return 1
        else:
            print(f"✓ All migrations executed successfully ({len(pending)} total)")
            print("=" * 60)
            return 0

    except Exception as e:
        print(f"\n✗ Error: {e}")
        return 1

if __name__ == "__main__":
    sys.exit(main())