// utils/logger.js
import fs from 'node:fs';
import path from 'node:path';
import { fileURLToPath } from 'node:url';

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);

const projectRoot = path.resolve(__dirname, '..');
const LOG_DIR = path.join(projectRoot, 'logs');

// Ensure logs directory exists
if (!fs.existsSync(LOG_DIR)) {
  fs.mkdirSync(LOG_DIR, { recursive: true });
}

const getLogFileName = () => {
  const date = new Date().toISOString().split('T')[0];
  return path.join(LOG_DIR, `${date}.log`);
};

// Cleanup logs older than 14 days
const cleanOldLogs = () => {
  try {
    const files = fs.readdirSync(LOG_DIR);
    const now = Date.now();
    const fourteenDaysAgo = now - (14 * 24 * 60 * 60 * 1000);

    files.forEach(file => {
      if (!file.endsWith('.log')) return;
      const filePath = path.join(LOG_DIR, file);
      const stats = fs.statSync(filePath);
      if (stats.mtimeMs < fourteenDaysAgo) {
        fs.unlinkSync(filePath);
      }
    });
  } catch (err) {
    console.error(`[LOGGER] Failed to clean old logs: ${err.message}`);
  }
};

// Run cleanup on startup
cleanOldLogs();

const levels = {
  info:  'INFO ',
  warn:  'WARN ',
  error: 'ERROR',
  debug: 'DEBUG'
};

/**
 * Safe string conversion for any value
 */
function safeString(value) {
  if (value === null) return 'null';
  if (value === undefined) return 'undefined';
  if (typeof value === 'object') {
    try {
      return JSON.stringify(value, null, 2);
    } catch (e) {
      return `[Object ${Object.prototype.toString.call(value)}]`;
    }
  }
  return String(value);
}

export function logger(module, message, level = 'info') {
  const effectiveLevel = (process.env.LOG_LEVEL || 'info').toLowerCase();
  const levelOrder = { debug: 10, info: 20, warn: 30, error: 40 };
  if ((levelOrder[level] || 20) < (levelOrder[effectiveLevel] || 20)) {
    return; // filtered
  }

  const now = new Date();
  const year = now.getFullYear();
  const month = String(now.getMonth() + 1).padStart(2, '0');
  const day = String(now.getDate()).padStart(2, '0');
  const hours = String(now.getHours()).padStart(2, '0');
  const minutes = String(now.getMinutes()).padStart(2, '0');
  const seconds = String(now.getSeconds()).padStart(2, '0');
  const millis = String(now.getMilliseconds()).padStart(3, '0');

  const timestamp = `${year}-${month}-${day} ${hours}:${minutes}:${seconds}.${millis}`;
  const levelStr = levels[level] || 'INFO ';

  // Ultra-safe message conversion
  let messageStr = '';
  if (message == null) {
    messageStr = message === null ? 'null' : 'undefined';
  } else if (typeof message === 'object') {
    try {
      messageStr = JSON.stringify(message, null, 2);
    } catch (e) {
      messageStr = `[Object]`;
    }
  } else {
    messageStr = String(message);
  }

  const logLine = `[${timestamp}] [${levelStr}] [${module}] ${messageStr}\n`;

  // Console output
  if (level === 'error') {
    console.error(logLine.trim());
  } else if (level === 'warn') {
    console.warn(logLine.trim());
  } else {
    console.log(logLine.trim());
  }

  // Write to daily log file
  try {
    const logFile = getLogFileName();
    fs.appendFileSync(logFile, logLine, 'utf8');
  } catch (err) {
    console.error(`[LOGGER] Failed to write to log file: ${err.message}`);
  }
}

// Convenience methods
export const logInfo  = (module, msg) => logger(module, msg, 'info');
export const logWarn  = (module, msg) => logger(module, msg, 'warn');
export const logError = (module, msg) => logger(module, msg, 'error');
export const logDebug = (module, msg) => logger(module, msg, 'debug');

export default logger;