import fs from 'node:fs';
import path from 'node:path';

import pino, { type Logger } from 'pino';

import type { AppConfig } from './config.js';

const LOG_RETENTION_DAYS = 7;

function cleanupExpiredLogs(logsDir: string) {
  if (!fs.existsSync(logsDir)) {
    return;
  }

  const expiryTime = Date.now() - LOG_RETENTION_DAYS * 24 * 60 * 60 * 1000;

  for (const entry of fs.readdirSync(logsDir, { withFileTypes: true })) {
    if (!entry.isFile() || !entry.name.startsWith('server.log')) {
      continue;
    }

    const fullPath = path.join(logsDir, entry.name);
    const stats = fs.statSync(fullPath);
    if (stats.mtimeMs < expiryTime) {
      fs.rmSync(fullPath, { force: true });
    }
  }
}

export function createLogger(config: AppConfig): Logger {
  fs.mkdirSync(config.logsDir, { recursive: true });
  cleanupExpiredLogs(config.logsDir);

  const transport = pino.transport({
    targets: [
      {
        target: 'pino-roll',
        level: config.logLevel,
        options: {
          file: path.join(config.logsDir, 'server.log'),
          mkdir: true,
          size: '10m',
          frequency: 'daily',
          dateFormat: 'yyyy-MM-dd',
        },
      },
      {
        target: 'pino/file',
        level: config.logLevel,
        options: {
          destination: 1,
        },
      },
    ],
  });

  return pino(
    {
      level: config.logLevel,
      timestamp: pino.stdTimeFunctions.isoTime,
      base: undefined,
    },
    transport,
  );
}