/// <reference path="./Tween.d.ts" />

export let _tweens: Tween[] = [];

export let REVISION = '14';

export let getAll = function () {
    return _tweens;
};

export let removeAll = function () {
    _tweens = [];
};

export let add = function (tween) {
    _tweens.push(tween);
};

export let remove = function (tween) {
    let i = _tweens.indexOf(tween);
    if (i !== -1) {
        _tweens.splice(i, 1);
    }
};

export let update = function (time) {

    if (_tweens.length === 0) return false;

    let i = 0;

    time = !!time ? time : (typeof window !== 'undefined' && window.performance !== undefined && window.performance.now !== undefined ? window.performance.now() : Date.now());

    while (i < _tweens.length) {
        if (_tweens[i].update(time)) {
            i++;
        } else {
            _tweens.splice(i, 1);
        }
    }

    return true;
};

export class Tween {
    _object;
    _valuesStart = {};
    _valuesEnd = {};
    _valuesStartRepeat = {};
    _duration = 1000;
    _repeat = 0;
    _yoyo = false;
    _isPlaying = false;
    _reversed = false;
    _delayTime = 0;
    _startTime = NaN;
    _easingFunction = Easing.Linear.None;
    _interpolationFunction = Interpolation.Linear;
    _chainedTweens = [];
    _onStartCallback = null;
    _onStartCallbackFired = false;
    _onUpdateCallback = null;
    _onRepeatCallback = null;
    _onCompleteCallback = null;
    _onStopCallback = null;

    constructor(object) {
        this._object = object;
        // Set all starting values present on the target object
        for (let field in object) {
            this._valuesStart[field] = parseFloat(object[field]);
        }
    }

    to(properties, duration) {
        if (duration !== undefined) {
            this._duration = duration;
        }
        this._valuesEnd = properties;
        return this;
    }

    start(time?: number) {

        add(this);

        this._isPlaying = true;

        this._onStartCallbackFired = false;

        this._startTime = !!time ? time : (typeof window !== 'undefined' && window.performance !== undefined && window.performance.now !== undefined ? window.performance.now() : Date.now());
        this._startTime += this._delayTime;

        for (let property in this._valuesEnd) {

            // check if an Array was provided as property value
            if (this._valuesEnd[property] instanceof Array) {

                if (this._valuesEnd[property].length === 0) {
                    continue;
                }

                // create a local copy of the Array with the start value at the front
                this._valuesEnd[property] = [this._object[property]].concat(this._valuesEnd[property]);

            }

            this._valuesStart[property] = this._object[property];

            if ((this._valuesStart[property] instanceof Array) === false) {
                this._valuesStart[property] *= 1.0; // Ensures we're using numbers, not strings
            }

            this._valuesStartRepeat[property] = this._valuesStart[property] || 0;

        }

        return this;
    }

    stop() {
        if (!this._isPlaying) {
            return this;
        }

        remove(this);
        this._isPlaying = false;

        if (this._onStopCallback !== null) {
            this._onStopCallback.call(this._object);

        }

        this.stopChainedTweens();
        return this;
    }

    stopChainedTweens() {
        for (let i = 0, numChainedTweens = this._chainedTweens.length; i < numChainedTweens; i++) {
            this._chainedTweens[i].stop();
        }
    }

    delay(amount) {
        this._delayTime = amount;
        return this;
    }

    repeat(times) {
        this._repeat = times;
        return this;
    }

    yoyo(yoyo) {
        this._yoyo = yoyo;
        return this;
    }

    easing(easing) {
        this._easingFunction = easing;
        return this;
    }

    interpolation(interpolation) {
        this._interpolationFunction = interpolation;
        return this;
    }

    chain(...tweens) {
        this._chainedTweens = tweens;
        return this;
    }

    onStart(callback) {
        this._onStartCallback = callback;
        return this;
    }

    onUpdate(callback) {
        this._onUpdateCallback = callback;
        return this;
    }

    onRepeat(callback) {

        this._onRepeatCallback = callback;
        return this;

    }

    onComplete(callback) {
        this._onCompleteCallback = callback;
        return this;
    }

    onStop(callback) {
        this._onStopCallback = callback;
        return this;
    }

    update(time) {

        let property;

        if (time < this._startTime) {
            return true;
        }

        if (this._onStartCallbackFired === false) {

            if (this._onStartCallback !== null) {
                this._onStartCallback.call(this._object);
            }

            this._onStartCallbackFired = true;
        }

        let elapsed = (time - this._startTime) / this._duration;
        elapsed = elapsed > 1 ? 1 : elapsed;

        let value = this._easingFunction(elapsed);

        for (property in this._valuesEnd) {

            let start = this._valuesStart[property] || 0;
            let end = this._valuesEnd[property];

            if (end instanceof Array) {

                this._object[property] = this._interpolationFunction(end, value);

            } else {

                // Parses relative end values with start as base (e.g.: +10, -3)
                if (typeof (end) === 'string') {
                    end = start + parseFloat(end);
                }

                // protect against non numeric properties.
                if (typeof (end) === 'number') {
                    this._object[property] = start + (end - start) * value;
                }

            }

        }

        if (this._onUpdateCallback !== null) {

            this._onUpdateCallback.call(this._object, value);

        }

        if (elapsed === 1) {

            if (this._repeat > 0) {

                if (isFinite(this._repeat)) {
                    this._repeat--;
                }

                // reassign starting values, restart by making startTime = now
                for (property in this._valuesStartRepeat) {

                    if (typeof (this._valuesEnd[property]) === 'string') {
                        this._valuesStartRepeat[property] = this._valuesStartRepeat[property] + parseFloat(this._valuesEnd[property]);
                    }

                    if (this._yoyo) {
                        let tmp = this._valuesStartRepeat[property];
                        this._valuesStartRepeat[property] = this._valuesEnd[property];
                        this._valuesEnd[property] = tmp;
                    }

                    this._valuesStart[property] = this._valuesStartRepeat[property];

                }

                if (this._yoyo) {
                    this._reversed = !this._reversed;
                }

                this._startTime = time + this._delayTime;

                if (this._onRepeatCallback !== null) {
                    this._onRepeatCallback(this._object);
                }

                return true;

            } else {

                if (this._onCompleteCallback !== null) {

                    this._onCompleteCallback.call(this._object);

                }

                for (let i = 0, numChainedTweens = this._chainedTweens.length; i < numChainedTweens; i++) {

                    this._chainedTweens[i].start(time);

                }

                return false;

            }

        }

        return true;

    }
}

export let Easing: TweenEasing = {

    Linear: {
        None: function (k) {
            return k;
        }
    },

    Quadratic: {
        In: function (k) {
            return k * k;
        },

        Out: function (k) {
            return k * (2 - k);
        },

        InOut: function (k) {
            if ((k *= 2) < 1) return 0.5 * k * k;
            return -0.5 * (--k * (k - 2) - 1);
        }
    },

    Cubic: {
        In: function (k) {
            return k * k * k;
        },

        Out: function (k) {
            return --k * k * k + 1;
        },

        InOut: function (k) {
            if ((k *= 2) < 1) return 0.5 * k * k * k;
            return 0.5 * ((k -= 2) * k * k + 2);
        }

    },

    Quartic: {
        In: function (k) {
            return k * k * k * k;
        },

        Out: function (k) {
            return 1 - (--k * k * k * k);
        },

        InOut: function (k) {
            if ((k *= 2) < 1) return 0.5 * k * k * k * k;
            return -0.5 * ((k -= 2) * k * k * k - 2);
        }

    },

    Quintic: {
        In: function (k) {
            return k * k * k * k * k;
        },

        Out: function (k) {
            return --k * k * k * k * k + 1;
        },

        InOut: function (k) {
            if ((k *= 2) < 1) return 0.5 * k * k * k * k * k;
            return 0.5 * ((k -= 2) * k * k * k * k + 2);
        }

    },

    Sinusoidal: {
        In: function (k) {
            return 1 - Math.cos(k * Math.PI / 2);
        },

        Out: function (k) {
            return Math.sin(k * Math.PI / 2);
        },

        InOut: function (k) {
            return 0.5 * (1 - Math.cos(Math.PI * k));
        }

    },

    Exponential: {
        In: function (k) {
            return k === 0 ? 0 : Math.pow(1024, k - 1);
        },

        Out: function (k) {
            return k === 1 ? 1 : 1 - Math.pow(2, -10 * k);
        },

        InOut: function (k) {
            if (k === 0) return 0;
            if (k === 1) return 1;
            if ((k *= 2) < 1) return 0.5 * Math.pow(1024, k - 1);
            return 0.5 * (-Math.pow(2, -10 * (k - 1)) + 2);
        }
    },

    Circular: {
        In: function (k) {
            return 1 - Math.sqrt(1 - k * k);
        },

        Out: function (k) {
            return Math.sqrt(1 - (--k * k));
        },

        InOut: function (k) {
            if ((k *= 2) < 1) return -0.5 * (Math.sqrt(1 - k * k) - 1);
            return 0.5 * (Math.sqrt(1 - (k -= 2) * k) + 1);
        }
    },

    Elastic: {
        In: function (k) {
            let s, a = 0.1, p = 0.4;
            if (k === 0) return 0;
            if (k === 1) return 1;
            if (!a || a < 1) {
                a = 1;
                s = p / 4;
            } else s = p * Math.asin(1 / a) / (2 * Math.PI);
            return -(a * Math.pow(2, 10 * (k -= 1)) * Math.sin((k - s) * (2 * Math.PI) / p));
        },

        Out: function (k) {
            let s, a = 0.1, p = 0.4;
            if (k === 0) return 0;
            if (k === 1) return 1;
            if (!a || a < 1) {
                a = 1;
                s = p / 4;
            } else s = p * Math.asin(1 / a) / (2 * Math.PI);
            return (a * Math.pow(2, -10 * k) * Math.sin((k - s) * (2 * Math.PI) / p) + 1);
        },

        InOut: function (k) {
            let s, a = 0.1, p = 0.4;
            if (k === 0) return 0;
            if (k === 1) return 1;
            if (!a || a < 1) {
                a = 1;
                s = p / 4;
            } else s = p * Math.asin(1 / a) / (2 * Math.PI);
            if ((k *= 2) < 1) return -0.5 * (a * Math.pow(2, 10 * (k -= 1)) * Math.sin((k - s) * (2 * Math.PI) / p));
            return a * Math.pow(2, -10 * (k -= 1)) * Math.sin((k - s) * (2 * Math.PI) / p) * 0.5 + 1;
        }
    },

    Back: {
        In: function (k) {
            let s = 1.70158;
            return k * k * ((s + 1) * k - s);
        },

        Out: function (k) {
            let s = 1.70158;
            return --k * k * ((s + 1) * k + s) + 1;
        },

        InOut: function (k) {
            let s = 1.70158 * 1.525;
            if ((k *= 2) < 1) return 0.5 * (k * k * ((s + 1) * k - s));
            return 0.5 * ((k -= 2) * k * ((s + 1) * k + s) + 2);
        }
    },

    Bounce: {
        In: function (k) {
            return 1 - TWEEN.Easing.Bounce.Out(1 - k);
        },

        Out: function (k) {
            if (k < (1 / 2.75)) {
                return 7.5625 * k * k;
            } else if (k < (2 / 2.75)) {
                return 7.5625 * (k -= (1.5 / 2.75)) * k + 0.75;
            } else if (k < (2.5 / 2.75)) {
                return 7.5625 * (k -= (2.25 / 2.75)) * k + 0.9375;
            } else {
                return 7.5625 * (k -= (2.625 / 2.75)) * k + 0.984375;
            }
        },

        InOut: function (k) {
            if (k < 0.5) return TWEEN.Easing.Bounce.In(k * 2) * 0.5;
            return TWEEN.Easing.Bounce.Out(k * 2 - 1) * 0.5 + 0.5;
        }

    }
};

export let Interpolation: TweenInterpolation = {

    Linear: function (v, k) {
        let m = v.length - 1, f = m * k, i = Math.floor(f), fn = TWEEN.Interpolation.Utils.Linear;

        if (k < 0) return fn(v[0], v[1], f);
        if (k > 1) return fn(v[m], v[m - 1], m - f);

        return fn(v[i], v[i + 1 > m ? m : i + 1], f - i);
    },

    Bezier: function (v, k) {
        let b = 0, n = v.length - 1, pw = Math.pow, bn = TWEEN.Interpolation.Utils.Bernstein, i;

        for (i = 0; i <= n; i++) {
            b += pw(1 - k, n - i) * pw(k, i) * v[i] * bn(n, i);
        }

        return b;
    },

    CatmullRom: function (v, k) {
        let m = v.length - 1, f = m * k, i = Math.floor(f), fn = TWEEN.Interpolation.Utils.CatmullRom;

        if (v[0] === v[m]) {
            if (k < 0) i = Math.floor(f = m * (1 + k));

            return fn(v[(i - 1 + m) % m], v[i], v[(i + 1) % m], v[(i + 2) % m], f - i);
        } else {
            if (k < 0) return v[0] - (fn(v[0], v[0], v[1], v[1], -f) - v[0]);
            if (k > 1) return v[m] - (fn(v[m], v[m], v[m - 1], v[m - 1], f - m) - v[m]);

            return fn(v[i ? i - 1 : 0], v[i], v[m < i + 1 ? m : i + 1], v[m < i + 2 ? m : i + 2], f - i);
        }
    },

    Utils: {
        Linear: function (p0, p1, t) {
            return (p1 - p0) * t + p0;
        },

        Bernstein: function (n, i) {
            let fc = TWEEN.Interpolation.Utils.Factorial;
            return fc(n) / fc(i) / fc(n - i);
        },

        Factorial: (function () {
            let a = [1];

            return function (n) {
                let s = 1, i;
                if (a[n]) return a[n];
                for (i = n; i > 1; i--) s *= i;
                return a[n] = s;
            };

        })(),

        CatmullRom: function (p0, p1, p2, p3, t) {
            let v0 = (p2 - p0) * 0.5, v1 = (p3 - p1) * 0.5, t2 = t * t, t3 = t * t2;
            return (2 * p1 - 2 * p2 + v0 + v1) * t3 + (-3 * p1 + 3 * p2 - 2 * v0 - v1) * t2 + v0 * t + p1;
        }
    }
};