import fs from 'node:fs';
import path from 'node:path';
import winston from 'winston';
import { config } from '../config.js';

fs.mkdirSync(config.logDir, { recursive: true });

const logFormat = winston.format.combine(
  winston.format.timestamp(),
  winston.format.errors({ stack: true }),
  winston.format.json()
);

export const logger = winston.createLogger({
  level: config.isProduction ? 'info' : 'debug',
  format: logFormat,
  transports: [
    new winston.transports.File({ filename: path.join(config.logDir, 'system.log'), maxsize: 5_000_000, maxFiles: 5 }),
    ...(!config.isProduction
      ? [new winston.transports.Console({
        format: winston.format.combine(winston.format.colorize(), winston.format.simple())
      })]
      : [])
  ]
});

export function readSystemLog(limit = 300) {
  // System logs are line-delimited JSON; malformed historic lines are returned as plain messages.
  const file = path.join(config.logDir, 'system.log');
  if (!fs.existsSync(file)) return [];
  const content = fs.readFileSync(file, 'utf8');
  return content
    .trim()
    .split('\n')
    .filter(Boolean)
    .slice(-limit)
    .map((line) => {
      try {
        return JSON.parse(line);
      } catch {
        return { level: 'info', message: line };
      }
    });
}