/**
 * 简单日志工具
 * 支持日志级别和格式化输出
 */

const config = require('../config');

const LEVELS = {
  debug: 0,
  info: 1,
  warn: 2,
  error: 3
};

const COLORS = {
  debug: '\x1b[36m',   // cyan
  info: '\x1b[32m',    // green
  warn: '\x1b[33m',    // yellow
  error: '\x1b[31m',   // red
  reset: '\x1b[0m'
};

const currentLevel = LEVELS[config.log.level] || LEVELS.info;
const colorize = config.log.colorize && process.stdout.isTTY;

function formatTime() {
  const d = new Date();
  return d.toISOString().replace('T', ' ').slice(0, 19);
}

function formatMessage(level, ...args) {
  const timestamp = formatTime();
  const prefix = `[${timestamp}] [${level.toUpperCase()}]`;

  if (colorize) {
    return `${COLORS[level]}${prefix}${COLORS.reset} ${args.join(' ')}`;
  }
  return `${prefix} ${args.join(' ')}`;
}

const logger = {
  debug(...args) {
    if (currentLevel <= LEVELS.debug) {
      console.log(formatMessage('debug', ...args));
    }
  },

  info(...args) {
    if (currentLevel <= LEVELS.info) {
      console.log(formatMessage('info', ...args));
    }
  },

  warn(...args) {
    if (currentLevel <= LEVELS.warn) {
      console.warn(formatMessage('warn', ...args));
    }
  },

  error(...args) {
    if (currentLevel <= LEVELS.error) {
      console.error(formatMessage('error', ...args));
    }
  },

  // 请求日志中间件
  requestLogger(req, res, next) {
    const start = Date.now();
    res.on('finish', () => {
      const duration = Date.now() - start;
      const status = res.statusCode;
      const level = status >= 400 ? 'warn' : 'info';
      logger[level](`${req.method} ${req.path} ${status} ${duration}ms`);
    });
    next();
  }
};

module.exports = logger;