import mysql from 'mysql2/promise';
import { config } from '../config/config.js';
import { logger } from '../logger/logger.js';

let pool = null;

/**
 * Initializes the MySQL database pool and ensures schema exists.
 */
export async function initializeDatabase() {
  if (!config.dbUsername) {
    logger.warn('db_disabled', { reason: 'No DB_USERNAME configured, database logging is disabled' });
    return;
  }

  try {
    pool = mysql.createPool({
      host: config.dbHost,
      port: config.dbPort,
      database: config.dbDatabase,
      user: config.dbUsername,
      password: config.dbPassword,
      waitForConnections: true,
      connectionLimit: 10,
      queueLimit: 0
    });

    // Test connection and auto-create the table if not exists
    const conn = await pool.getConnection();
    await conn.query(`
      CREATE TABLE IF NOT EXISTS \`call_logs\` (
        \`id\` INT AUTO_INCREMENT PRIMARY KEY,
        \`session_id\` VARCHAR(36) NOT NULL UNIQUE,
        \`ride_id\` VARCHAR(255) NOT NULL,
        \`driver_id\` VARCHAR(255) NOT NULL,
        \`passenger_id\` VARCHAR(255) NOT NULL,
        \`driver_ip\` VARCHAR(45) NULL DEFAULT NULL,
        \`passenger_ip\` VARCHAR(45) NULL DEFAULT NULL,
        \`driver_conn_ip\` VARCHAR(45) NULL DEFAULT NULL,
        \`passenger_conn_ip\` VARCHAR(45) NULL DEFAULT NULL,
        \`status\` VARCHAR(50) NOT NULL DEFAULT 'created',
        \`initiated_by\` VARCHAR(255) NULL DEFAULT NULL,
        \`end_reason\` VARCHAR(255) NULL DEFAULT NULL,
        \`created_at\` TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
        \`connected_at\` TIMESTAMP NULL DEFAULT NULL,
        \`ended_at\` TIMESTAMP NULL DEFAULT NULL,
        INDEX \`idx_session_id\` (\`session_id\`),
        INDEX \`idx_ride_id\` (\`ride_id\`)
      ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
    `);
    conn.release();
    logger.info('db_initialized', { host: config.dbHost, database: config.dbDatabase });
  } catch (err) {
    logger.error('db_initialization_failed', { error: err.message });
    // Soft fallback: log the failure but do not crash the signaling server
    pool = null;
  }
}

/**
 * Logs session creation to the database with pre-registered client IPs.
 */
export async function logSessionCreated(sessionID, rideID, driverID, passengerID, driverIP = null, passengerIP = null) {
  if (!pool) return;
  try {
    await pool.query(
      `INSERT INTO call_logs (session_id, ride_id, driver_id, passenger_id, driver_ip, passenger_ip, status, created_at)
       VALUES (?, ?, ?, ?, ?, ?, 'created', NOW())`,
      [sessionID, rideID, driverID, passengerID, driverIP, passengerIP]
    );
  } catch (err) {
    logger.error('db_log_session_created_failed', { session_id: sessionID, error: err.message });
  }
}

/**
 * Logs session status transition to active and records the connection IPs.
 */
export async function logSessionActive(sessionID, driverConnIP = null, passengerConnIP = null) {
  if (!pool) return;
  try {
    await pool.query(
      `UPDATE call_logs SET status = 'active', connected_at = NOW(), driver_conn_ip = ?, passenger_conn_ip = ? WHERE session_id = ?`,
      [driverConnIP, passengerConnIP, sessionID]
    );
  } catch (err) {
    logger.error('db_log_session_active_failed', { session_id: sessionID, error: err.message });
  }
}

/**
 * Logs the initiator (caller) of the call when the first SDP offer is received.
 */
export async function logSessionInitiator(sessionID, initiatorID) {
  if (!pool) return;
  try {
    await pool.query(
      `UPDATE call_logs SET initiated_by = ? WHERE session_id = ? AND initiated_by IS NULL`,
      [initiatorID, sessionID]
    );
  } catch (err) {
    logger.error('db_log_session_initiator_failed', { session_id: sessionID, initiator_id: initiatorID, error: err.message });
  }
}

/**
 * Logs call termination reason and end time.
 */
export async function logSessionEnded(sessionID, endReason) {
  if (!pool) return;
  try {
    await pool.query(
      `UPDATE call_logs SET status = 'ended', ended_at = NOW(), end_reason = ? WHERE session_id = ?`,
      [endReason, sessionID]
    );
  } catch (err) {
    logger.error('db_log_session_ended_failed', { session_id: sessionID, error: err.message });
  }
}