"""
migration_photo_verification_toggle.py
=======================================
Adds `photo_verification_enabled` column to the `qr_codes` table.

Uses pymysql directly to avoid SQLAlchemy ORM loading the model
(which would fail if the column doesn't exist yet).

Default: 1 (True) for all existing rows — preserves current behaviour.

Run once on each server (LT and GOV):
    python3 tools/migration_photo_verification_toggle.py

Safe to re-run — skips if column already exists.
"""

import os, sys, re

sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

from dotenv import load_dotenv
load_dotenv()

import pymysql

TABLE  = 'qr_codes'
COLUMN = 'photo_verification_enabled'


def parse_db_url(url):
    """
    Parse DATABASE_URL robustly using regex to handle special characters
    (including @ or : ) in the password.

    Supports:
        mysql+pymysql://user:pass@host:port/dbname
        mysql+pymysql://user:pass@host/dbname
    """
    # Strip driver prefix
    url = re.sub(r'^mysql\+pymysql://', '', url)
    url = re.sub(r'^mysql://', '', url)

    # Split credentials from host/db on the LAST @ before the host
    # Pattern: user:password@host[:port]/dbname[?...]
    m = re.match(
        r'^(?P<user>[^:]+):(?P<password>.+)@(?P<host>[^@:/]+)(?::(?P<port>\d+))?/(?P<db>[^?]+)',
        url
    )
    if not m:
        print(f"[ERROR] Could not parse DATABASE_URL. Raw (redacted): {url[:30]}...")
        sys.exit(1)

    return {
        'host':     m.group('host'),
        'port':     int(m.group('port')) if m.group('port') else 3306,
        'user':     m.group('user'),
        'password': m.group('password'),
        'database': m.group('db'),
    }


def get_connection():
    db_url = os.environ.get('DATABASE_URL', '')
    if not db_url:
        print("[ERROR] DATABASE_URL not set in .env")
        sys.exit(1)

    params = parse_db_url(db_url)
    return pymysql.connect(
        host=params['host'],
        port=params['port'],
        user=params['user'],
        password=params['password'],
        database=params['database'],
        charset='utf8mb4',
        autocommit=False,
    )


def run():
    conn = get_connection()
    try:
        with conn.cursor() as cur:
            # Check if column already exists
            cur.execute(
                "SELECT COUNT(*) FROM information_schema.COLUMNS "
                "WHERE TABLE_SCHEMA = DATABASE() "
                f"AND TABLE_NAME = '{TABLE}' "
                f"AND COLUMN_NAME = '{COLUMN}'"
            )
            exists = cur.fetchone()[0] > 0

            if exists:
                print(f"[SKIP] Column '{COLUMN}' already exists on '{TABLE}'. Nothing to do.")
                return

            print(f"[ADD]  Adding column '{COLUMN}' to '{TABLE}' ...")
            cur.execute(
                f"ALTER TABLE `{TABLE}` "
                f"ADD COLUMN `{COLUMN}` TINYINT(1) NOT NULL DEFAULT 1"
            )
            conn.commit()

            # Verify
            cur.execute(
                "SELECT COUNT(*) FROM information_schema.COLUMNS "
                "WHERE TABLE_SCHEMA = DATABASE() "
                f"AND TABLE_NAME = '{TABLE}' "
                f"AND COLUMN_NAME = '{COLUMN}'"
            )
            if cur.fetchone()[0] > 0:
                print(f"[OK]   Column '{COLUMN}' added. All existing rows default to 1 (enabled).")
            else:
                print(f"[FAIL] Column was not created — check DB permissions.")
                sys.exit(1)

    finally:
        conn.close()


if __name__ == '__main__':
    run()