import mysql.connector
from mysql.connector import pooling
import pydapper
import logging
import json
import os
import sys
from BreCal.schemas import defs

config_path = None
_connection_pool = None


def _load_json(path):
    with open(path, encoding="utf-8") as fh:
        return json.load(fh)


def _build_pool_config(connection_data, pool_name, pool_size):
    pool_config = dict(connection_data)
    pool_config.setdefault("pool_name", pool_name)
    pool_config.setdefault("pool_size", pool_size)
    return pool_config


def initPool(instancePath, connection_filename="connection_data_test.json",
             pool_name="brecal_test_pool", pool_size=10):
    """
    Initialize the MySQL connection pool and load email credentials.
    """
    global config_path, _connection_pool
    try:
        if config_path is None:
            config_path = os.path.join(instancePath, f'../../../secure/{connection_filename}')

        # config_path = 'C:\\temp\\connection_data_test.json'

        print(config_path)
        if not os.path.exists(config_path):
            print('cannot find ' + os.path.abspath(config_path))
            print("instance path", instancePath)
            sys.exit(1)

        connection_data = _load_json(config_path)
        if _connection_pool is None:
            pool_config = _build_pool_config(connection_data, pool_name, pool_size)
            _connection_pool = pooling.MySQLConnectionPool(**pool_config)

        conn_from_pool = _connection_pool.get_connection()
        try:
            commands = pydapper.using(conn_from_pool)
            commands.query("SELECT id from `user` LIMIT 1")
            print("DB connection successful")
        finally:
            conn_from_pool.close()

        credentials_file = "email_credentials_test.json"
        credentials_path = os.path.join(instancePath, f'../../../secure/{credentials_file}')

        # credentials_path = 'C:\\temp\\email_credentials_test.json'

        if not os.path.exists(credentials_path):
            print('cannot find ' + os.path.abspath(credentials_path))
            sys.exit(1)

        defs.email_credentials = _load_json(credentials_path)

    except mysql.connector.PoolError as e:
        logging.error(f"Failed to create connection pool: {e}")
        print(e)
    except Exception as e:
        logging.error("Failed to initialize DB pool: %s", e)
        print(e)


def getPoolConnection():
    if _connection_pool is None:
        raise RuntimeError("Connection pool not initialized. Call initPool first.")
    try:
        return _connection_pool.get_connection()
    except mysql.connector.PoolError as exc:
        logging.error("Connection pool exhausted: %s", exc)
        raise