/* eslint-disable no-var */
/* eslint-disable no-plusplus */
/* eslint-disable prefer-arrow-callback */
/* eslint-disable prefer-template */
/* eslint-disable func-names */
/* eslint-disable object-shorthand */

(function (factory) {
    // eslint-disable-next-line no-unused-expressions
    window.Promise || (window.Promise = factory());
    // eslint-disable-next-line padded-blocks
}(function () {

    var STATUS = {
        PENDING: 'pending',
        SEALED: 'sealed',
        FULFILLED: 'fulfilled',
        REJECTED: 'rejected',
    };

    var asyncSettimer = typeof setImmediate !== 'undefined' ? setImmediate : setTimeout;
    var asyncQueue = [];
    var asyncTimer;

    function NOP() { }

    function isArray(value) {
        return Array.isArray ? Array.isArray(value) : Object.prototype.toString.call(value) === '[object Array]';
    }

    function asyncFlush() {
        var i = 0;
        // run
        for (; i < asyncQueue.length; i++) {
            asyncQueue[i][0](asyncQueue[i][1]);
        }

        // reset
        asyncQueue = [];
        asyncTimer = false;
    }

    function asyncCall(callback, arg) {
        asyncQueue.push([callback, arg]);

        if (!asyncTimer) {
            asyncTimer = true;
            asyncSettimer(asyncFlush, 0);
        }
    }

    function publish(promise) {
        var i = 0;
        var callbacks = promise._then;
        promise._then = null;

        for (; i < callbacks.length; i++) {
            // eslint-disable-next-line no-use-before-define
            invokeCallback(callbacks[i]);
        }
    }

    function publishFulfillment(promise) {
        promise._state = STATUS.FULFILLED;
        publish(promise);
    }

    function publishRejection(promise) {
        promise._state = STATUS.REJECTED;
        publish(promise);
    }

    function fulfill(promise, value) {
        if (promise._state === STATUS.PENDING) {
            promise._state = STATUS.SEALED;
            promise._data = value;

            asyncCall(publishFulfillment, promise);
        }
    }

    function resolve(promise, value) {
        // eslint-disable-next-line no-use-before-define
        if (promise === value || !handleThenable(promise, value)) {
            fulfill(promise, value);
        }
    }

    function reject(promise, reason) {
        if (promise._state === STATUS.PENDING) {
            promise._state = STATUS.SEALED;
            promise._data = reason;

            asyncCall(publishRejection, promise);
        }
    }

    function handleThenable(promise, value) {
        var resolved;

        try {
            if (promise === value) {
                throw new TypeError('A promise\'s callback cannot return that same promise');
            }

            if (value && (typeof value === 'function' || typeof value === 'object')) {
                // eslint-disable-next-line vars-on-top
                var then = value.then;

                if (typeof then === 'function') {
                    then.call(value, function (val) {
                        if (!resolved) {
                            resolved = true;

                            if (value !== val) {
                                resolve(promise, val);
                            } else {
                                fulfill(promise, val);
                            }
                        }
                    }, function (reason) {
                        if (!resolved) {
                            resolved = true;

                            reject(promise, reason);
                        }
                    });

                    return true;
                }
            }
        } catch (e) {
            if (!resolved) {
                reject(promise, e);
            }

            return true;
        }

        return false;
    }

    function invokeResolver(fn, promise) {
        function resolvePromise(value) {
            resolve(promise, value);
        }

        function rejectPromise(reason) {
            reject(promise, reason);
        }

        try {
            fn(resolvePromise, rejectPromise);
        } catch (e) {
            rejectPromise(e);
        }
    }

    function invokeCallback(subscriber) {
        var owner = subscriber.owner;
        var settled = owner._state;
        var value = owner._data;
        var callback = subscriber[settled];
        var promise = subscriber.then;

        if (typeof callback === 'function') {
            settled = STATUS.FULFILLED;
            try {
                value = callback(value);
            } catch (e) {
                reject(promise, e);
            }
        }

        if (!handleThenable(promise, value)) {
            if (settled === STATUS.FULFILLED) {
                resolve(promise, value);
            } else if (settled === STATUS.REJECTED) {
                reject(promise, value);
            }
        }
    }

    function Promise(fn) {
        if (!(this instanceof Promise)) {
            throw new TypeError(this + ' is not a promise');
        }
        if (typeof fn !== 'function') {
            throw new TypeError('Promise resolver ' + fn + ' is not a function');
        }

        this._then = [];

        invokeResolver(fn, this);
    }

    Promise.prototype = {
        _state: STATUS.PENDING,
        _then: null,
        _data: undefined,

        then: function (onResolver, onRejection) {
            var subscriber = {
                owner: this,
                then: new Promise(NOP),
                fulfilled: onResolver,
                rejected: onRejection,
            };

            if (this._state === STATUS.FULFILLED || this._state === STATUS.REJECTED) {
                // already resolved
                asyncCall(invokeCallback, subscriber);
            } else {
                // subscribe
                this._then.push(subscriber);
            }
            return subscriber.then;
        },
        // eslint-disable-next-line quote-props
        'catch': function (onRejection) {
            return this.then(null, onRejection);
        },
    };

    // eslint-disable-next-line no-extend-native
    Object.defineProperty(Promise.prototype, 'constructor', { value: Promise });

    Promise.all = function (promises) {
        var This = this;

        if (!isArray(promises)) {
            throw new TypeError(promises + ' is not an array');
        }

        return new This(function (onresolve, onreject) {
            var results = [];
            var remaining = 0;
            var i = 0;
            var promise;

            function resolver(index) {
                remaining++;
                return function (value) {
                    results[index] = value;
                    if (!--remaining) {
                        onresolve(results);
                    }
                };
            }

            for (; i < promises.length; i++) {
                promise = promises[i];

                if (promise && typeof promise.then === 'function') {
                    promise.then(resolver(i), onreject);
                } else {
                    results[i] = promise;
                }
            }

            if (!remaining) {
                onresolve(results);
            }
        });
    };

    Promise.race = function (promises) {
        var This = this;

        if (!isArray(promises)) {
            throw new TypeError(promises + ' is not an array');
        }

        return new This(function (onresolve, onreject) {
            var i = 0;
            var promise;
            for (; i < promises.length; i++) {
                promise = promises[i];

                if (promise && typeof promise.then === 'function') {
                    promise.then(onresolve, onreject);
                } else {
                    onresolve(promise);
                }
            }
        });
    };

    Promise.resolve = function (value) {
        var This = this;

        if (value && typeof value === 'object' && value.constructor === This) {
            return value;
        }

        return new This(function (onresolve) {
            onresolve(value);
        });
    };

    Promise.reject = function (reason) {
        var This = this;

        return new This(function (onresolve, onreject) {
            onreject(reason);
        });
    };

    return Promise;
}));