/**
 * Module dependencies.
 */

var EventEmitter = require('events').EventEmitter;
var Pending = require('./pending');
var create = require('lodash.create');
var debug = require('debug')('mocha:runnable');
var milliseconds = require('./ms');
var utils = require('./utils');

/**
 * Save timer references to avoid Sinon interfering (see GH-237).
 */

/* eslint-disable no-unused-vars, no-native-reassign */
var Date = global.Date;
var setTimeout = global.setTimeout;
var setInterval = global.setInterval;
var clearTimeout = global.clearTimeout;
var clearInterval = global.clearInterval;
/* eslint-enable no-unused-vars, no-native-reassign */

/**
 * Object#toString().
 */

var toString = Object.prototype.toString;

/**
 * Expose `Runnable`.
 */

module.exports = Runnable;

/**
 * Initialize a new `Runnable` with the given `title` and callback `fn`.
 *
 * @api private
 * @param {string} title
 * @param {Function} fn
 */
function Runnable(title, fn) {
  this.title = title;
  this.fn = fn;
  this.async = fn && fn.length;
  this.sync = !this.async;
  this._timeout = 2000;
  this._slow = 75;
  this._enableTimeouts = true;
  this.timedOut = false;
  this._trace = new Error('done() called multiple times');
}

/**
 * Inherit from `EventEmitter.prototype`.
 */

Runnable.prototype = create(EventEmitter.prototype, {
  constructor: Runnable
});

/**
 * Set & get timeout `ms`.
 *
 * @api private
 * @param {number|string} ms
 * @return {Runnable|number} ms or Runnable instance.
 */
Runnable.prototype.timeout = function(ms) {
  if (!arguments.length) {
    return this._timeout;
  }
  if (ms === 0) {
    this._enableTimeouts = false;
  }
  if (typeof ms === 'string') {
    ms = milliseconds(ms);
  }
  debug('timeout %d', ms);
  this._timeout = ms;
  if (this.timer) {
    this.resetTimeout();
  }
  return this;
};

/**
 * Set & get slow `ms`.
 *
 * @api private
 * @param {number|string} ms
 * @return {Runnable|number} ms or Runnable instance.
 */
Runnable.prototype.slow = function(ms) {
  if (!arguments.length) {
    return this._slow;
  }
  if (typeof ms === 'string') {
    ms = milliseconds(ms);
  }
  debug('timeout %d', ms);
  this._slow = ms;
  return this;
};

/**
 * Set and get whether timeout is `enabled`.
 *
 * @api private
 * @param {boolean} enabled
 * @return {Runnable|boolean} enabled or Runnable instance.
 */
Runnable.prototype.enableTimeouts = function(enabled) {
  if (!arguments.length) {
    return this._enableTimeouts;
  }
  debug('enableTimeouts %s', enabled);
  this._enableTimeouts = enabled;
  return this;
};

/**
 * Halt and mark as pending.
 *
 * @api private
 */
Runnable.prototype.skip = function() {
  throw new Pending();
};

/**
 * Return the full title generated by recursively concatenating the parent's
 * full title.
 *
 * @api public
 * @return {string}
 */
Runnable.prototype.fullTitle = function() {
  return this.parent.fullTitle() + ' ' + this.title;
};

/**
 * Clear the timeout.
 *
 * @api private
 */
Runnable.prototype.clearTimeout = function() {
  clearTimeout(this.timer);
};

/**
 * Inspect the runnable void of private properties.
 *
 * @api private
 * @return {string}
 */
Runnable.prototype.inspect = function() {
  return JSON.stringify(this, function(key, val) {
    if (key[0] === '_') {
      return;
    }
    if (key === 'parent') {
      return '#<Suite>';
    }
    if (key === 'ctx') {
      return '#<Context>';
    }
    return val;
  }, 2);
};

/**
 * Reset the timeout.
 *
 * @api private
 */
Runnable.prototype.resetTimeout = function() {
  var self = this;
  var ms = this.timeout() || 1e9;

  if (!this._enableTimeouts) {
    return;
  }
  this.clearTimeout();
  this.timer = setTimeout(function() {
    if (!self._enableTimeouts) {
      return;
    }
    self.callback(new Error('timeout of ' + ms + 'ms exceeded. Ensure the done() callback is being called in this test.'));
    self.timedOut = true;
  }, ms);
};

/**
 * Whitelist a list of globals for this test run.
 *
 * @api private
 * @param {string[]} globals
 */
Runnable.prototype.globals = function(globals) {
  this._allowedGlobals = globals;
};

/**
 * Run the test and invoke `fn(err)`.
 *
 * @api private
 * @param {Function} fn
 */
Runnable.prototype.run = function(fn) {
  var self = this;
  var start = new Date();
  var ctx = this.ctx;
  var finished;
  var emitted;

  // Sometimes the ctx exists, but it is not runnable
  if (ctx && ctx.runnable) {
    ctx.runnable(this);
  }

  // called multiple times
  function multiple(err) {
    if (emitted) {
      return;
    }
    emitted = true;
    self.emit('error', err || new Error('done() called multiple times; stacktrace may be inaccurate'));
  }

  // finished
  function done(err) {
    var ms = self.timeout();
    if (self.timedOut) {
      return;
    }
    if (finished) {
      return multiple(err || self._trace);
    }

    self.clearTimeout();
    self.duration = new Date() - start;
    finished = true;
    if (!err && self.duration > ms && self._enableTimeouts) {
      err = new Error('timeout of ' + ms + 'ms exceeded. Ensure the done() callback is being called in this test.');
    }
    fn(err);
  }

  // for .resetTimeout()
  this.callback = done;

  // explicit async with `done` argument
  if (this.async) {
    this.resetTimeout();

    try {
      this.fn.call(ctx, function(err) {
        if (err instanceof Error || toString.call(err) === '[object Error]') {
          return done(err);
        }
        if (err != null) {
          if (Object.prototype.toString.call(err) === '[object Object]') {
            return done(new Error('done() invoked with non-Error: ' + JSON.stringify(err)));
          }
          return done(new Error('done() invoked with non-Error: ' + err));
        }
        done();
      });
    } catch (err) {
      done(utils.getError(err));
    }
    return;
  }

  if (this.asyncOnly) {
    return done(new Error('--async-only option in use without declaring `done()`'));
  }

  // sync or promise-returning
  try {
    if (this.pending) {
      done();
    } else {
      callFn(this.fn);
    }
  } catch (err) {
    done(utils.getError(err));
  }

  function callFn(fn) {
    var result = fn.call(ctx);
    if (result && typeof result.then === 'function') {
      self.resetTimeout();
      result
        .then(function() {
          done();
        },
        function(reason) {
          done(reason || new Error('Promise rejected with no or falsy reason'));
        });
    } else {
      done();
    }
  }
};
