// logger.js
const churchill = require("churchill");

const { Console, File } = churchill.trasports;

const createNamespace = churchill({
  transports: [
    Console.create(),
    File.create({ filename: "error.log", maxLevel: "error" }),
    File.create({ filename: "combined.log" })
  ]
});

// worker-a.js
const logger = require('./logger')('worker:a')
logger.error('Got an error!', new Error('Err!'))
logger.warn('Ups?')
logger.info('Log me with some data!', { here: { are: 'some metadata' }})
// the default max log level is info (anything below will not be logged by default)
logger.verbose('Hello!')
logger.debug( ... )
logger.silly( ... )

const LEVELS = {
  error: 0,
  warn: 1,
  info: 2, // Default maximum log level
  verbose: 3,
  debug: 4,
  silly: 5
};

const customLevels = {
  critical: 0,
  warning: 1,
  log: 2,
  debug: 3
};

const customColors = {
  critical: "red",
  warning: "orange",
  log: "blue",
  debug: "gray"
};

churchill({ levels: customLevels, colors: customColors });

const util = require("util");

const customGlobalFormat = info => {
  return { ...info, logger: "churchill:" };
};

const customFormat = info => {
  const { logger, namespace, timestamp, level, ms, args } = info;

  return `${logger}${namespace} ${level} ${args.map(arg => util.format(arg)).join(" ")} +${ms}ms`;
};

const createLogger = churchill({
  format: customGlobalFormat,
  transports: [Console.create({ format: customFormat })]
});

const loggerA = createLogger("worker:a");
const loggerB = createLogger("worker:b");
const loggerC = createLogger("worker:c");

loggerA.info("test", { metadata: "some info" });
// churchill:worker:a info test { metadata: 'some info' } +1ms
loggerB.info("test", { metadata: "some info" });
// churchill:worker:b info test { metadata: 'some info' } +0ms
loggerC.error("test", { metadata: "some info" });
// churchill:worker:c error test { metadata: 'some info' } +0ms

const { Transport } = require("@alesmenzel/churchill");

// Here is a simple transport that logs to stdout and has option to provide a prefix
// Note: it does not correcly handle stream backpressure
class CustomTransport extends Transport {
  constructor(opts) {
    super(opts);
    const { prefix = "" } = opts;
    this.prefix = prefix;
  }

  /**
   * Log a Message
   * @param {Object} info Message
   * @param {*} [output] Output of the global formatting function
   * @param {Logger} logger Logger
   */
  async log(info, output, logger) {
    const out = this.format(info, output, logger);
    const prefixed = custom ? `${this.prefix}${out}` : out;
    // Transport is also an EventEmitter, so you can emit events
    if (custom) {
      this.emit("some-event", info);
    }
    process.stdout.write(prefixed); // naively log to console
  }
}

// It is recommented to provide a factory to create your logger
CustomTransport.create = opts => {
  return new CustomTransport(opts);
};

module.exports = CustomTransport;

process.on("uncaughtException", err => {
  logger.error(err);
  // Note: if you use any asynchronous transport, you will need to wait till it is written before exiting the program
});