import winston from 'winston';

/**
 *  Define your severity levels.
 * With them, You can create log files,
 *see or hide levels based on the running ENV.
 */
const levels = {
  error: 0,
  warn: 1,
  info: 2,
  http: 3,
  debug: 4,
};

/**
 * This method set the current severity based on
 * the current NODE_ENV: show all the log levels
 * if the server was run in development mode; otherwise,
 * if it was run in production, show only warn and error messages.
 */
const level = () => {
  const env = process.env.NODE_ENV || 'development';
  const isDevelopment = env === 'development';
  return isDevelopment ? 'debug' : 'warn';
};

/**
 * Define different colors for each level.
 * Colors make the log message more visible,
 * adding the ability to focus or ignore messages.
 */
const colors = {
  error: 'red',
  warn: 'yellow',
  info: 'green',
  http: 'magenta',
  debug: 'white',
};

/**
 * Tell winston that you want to link the colors
 * defined above to the severity levels.
 */
winston.addColors(colors);

// Chose the aspect of your log customizing the log format.
const format = winston.format.combine(
  // Add the message timestamp with the preferred format
  winston.format.timestamp({format: 'YYYY-MM-DD HH:mm:ss:ms'}),
  /**
   * Tell Winston that the logs must be colored but
   * we bypass this global formatting colorize because generates
   * wrong output characters in file. Add in transports
   */
  // winston.format.colorize({all: true}),
  // Define the format of the message showing the timestamp, the level and the message
  winston.format.printf(
    info => `${info.timestamp} ${info.level}: ${info.message}`
  )
);

/**
 * Define which transports the logger must use to print out messages.
 * In this example, we are using three different transports
 */
const transports = [
  // Allow the use the console to print the messages
  new winston.transports.Console({
    format: winston.format.combine(
      // Integration to format. Tell Winston that the console logs must be colored
      winston.format.colorize({all: true})
    ),
  }),
  // Allow to print all the error level messages inside the error.log file
  new winston.transports.File({
    filename: 'logs/error.log',
    level: 'error',
  }),
  /**
   * Allow to print all the error message inside the all.log file
   * (also the error log that are also printed inside the error.log(
   */
  new winston.transports.File({filename: 'logs/all.log'}),
];

/**
 * Create the logger instance that has to be exported
 * and used to log messages.
 */
const Logger = winston.createLogger({
  level: level(),
  levels,
  format,
  transports,
});

export default Logger;