import process from 'process';

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

const currentLevelStr = (process.env.LOG_LEVEL || 'info').toLowerCase();
const currentLevel = LOG_LEVELS[currentLevelStr] !== undefined ? LOG_LEVELS[currentLevelStr] : 1;

const ANSI_COLORS = {
  DEBUG: '\x1b[36mDEBUG\x1b[0m',   // Cyan
  INFO: '\x1b[32mINFO\x1b[0m',     // Green
  WARN: '\x1b[33mWARN\x1b[0m',     // Yellow
  ERROR: '\x1b[31mERROR\x1b[0m'    // Red
};

/**
 * Helper to print log structured JSON objects to stdout.
 * @param {string} levelName 
 * @param {string} eventName 
 * @param {object} [attributes] 
 */
function writeLog(levelName, eventName, attributes = {}) {
  const levelNum = LOG_LEVELS[levelName];
  if (levelNum < currentLevel) {
    return;
  }

  const levelUpper = levelName.toUpperCase();
  const logEntry = {
    timestamp: new Date().toISOString(),
    level: `__COLOR_LEVEL_${levelUpper}__`,
    event: eventName,
    ...attributes
  };

  let jsonStr = JSON.stringify(logEntry);
  const coloredLevel = ANSI_COLORS[levelUpper] || levelUpper;
  jsonStr = jsonStr.replace(`"__COLOR_LEVEL_${levelUpper}__"`, `"${coloredLevel}"`);

  process.stdout.write(jsonStr + '\n');
}

export const logger = {
  debug: (event, attrs) => writeLog('debug', event, attrs),
  info: (event, attrs) => writeLog('info', event, attrs),
  warn: (event, attrs) => writeLog('warn', event, attrs),
  error: (event, attrs) => writeLog('error', event, attrs)
};