// Copyright (c) 2013 Adobe Systems Incorporated. All rights reserved.
// 
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// 
// http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
window.mina = (function () {
    var animations = [],
    requestAnimFrame = window.requestAnimationFrame       ||
                       window.webkitRequestAnimationFrame ||
                       window.mozRequestAnimationFrame    ||
                       window.oRequestAnimationFrame      ||
                       window.msRequestAnimationFrame     ||
                       function (callback) {
                           setTimeout(callback, 16);
                       },
    isArray = Array.isArray || function (a) {
        return a instanceof Array ||
            Object.prototype.toString.call(a) == "[object Array]";
    },
    diff = function (a, b, A, B) {
        if (isArray(a)) {
            res = [];
            for (var i = 0, ii = a.length; i < ii; i++) {
                res[i] = diff(a[i], b, A[i], B);
            }
            return res;
        }
        var dif = (A - a) / (B - b);
        return function (bb) {
            return a + dif * (bb - b);
        };
    },
    timer = function () {
        return +new Date;
    },
    sta = function (val) {
        var a = this;
        if (val == null) {
            return a.s;
        }
        var ds = a.s - val;
        a.b += a.dur * ds;
        a.B += a.dur * ds;
        a.s = val;
    },
    speed = function (val) {
        var a = this;
        if (val == null) {
            return a.spd;
        }
        a.spd = val;
    },
    duration = function (val) {
        var a = this;
        if (val == null) {
            return a.dur;
        }
        a.s = a.s * val / a.dur;
        a.dur = val;
    },
    frame = function () {
        for (var i = 0, ii = animations.length; i < ii; i++) {
            var a = animations[i],
                b = a.get(),
                res;
            a.s = (b - a.b) / (a.dur / a.spd);
            if (a.s >= 1) {
                animations.splice(i, 1);
                a.s = 1;
            }
            if (isArray(a.start)) {
                res = [];
                for (var j = 0, jj = a.start.length; j < jj; j++) {
                    res[j] = a.start[j] + (a.end[j] - a.start[j]) * a.easing(a.s);
                }
            } else {
                res = a.start + (a.end - a.start) * a.easing(a.s);
            }
            a.set(res);
        }
        animations.length && requestAnimFrame(frame);
    },
    mina = function (a, A, b, B, get, set, easing) {
        var anim = {
            start: a,
            end: A,
            b: b,
            s: 0,
            dur: B - b,
            spd: 1,
            get: get,
            set: set,
            easing: easing || mina.linear,
            status: sta,
            speed: speed,
            duration: duration
        };
        animations.push(anim);
        animations.length == 1 && requestAnimFrame(frame);
        return anim;
    };
    mina.time = timer;

    mina.linear = function (n) {
        return n;
    };
    mina.easeout = function (n) {
        return Math.pow(n, 1.7);
    };
    mina.easein = function (n) {
        return Math.pow(n, .48);
    };
    mina.easeinout = function (n) {
        var q = .48 - n / 1.04,
            Q = Math.sqrt(.1734 + q * q),
            x = Q - q,
            X = Math.pow(Math.abs(x), 1 / 3) * (x < 0 ? -1 : 1),
            y = -Q - q,
            Y = Math.pow(Math.abs(y), 1 / 3) * (y < 0 ? -1 : 1),
            t = X + Y + .5;
        return (1 - t) * 3 * t * t + t * t * t;
    };
    mina.backin = function (n) {
        var s = 1.70158;
        return n * n * ((s + 1) * n - s);
    };
    mina.backout = function (n) {
        n = n - 1;
        var s = 1.70158;
        return n * n * ((s + 1) * n + s) + 1;
    };
    mina.elastic = function (n) {
        if (n == !!n) {
            return n;
        }
        return Math.pow(2, -10 * n) * Math.sin((n - .075) *
            (2 * Math.PI) / .3) + 1;
    };
    mina.bounce = function (n) {
        var s = 7.5625,
            p = 2.75,
            l;
        if (n < (1 / p)) {
            l = s * n * n;
        } else {
            if (n < (2 / p)) {
                n -= (1.5 / p);
                l = s * n * n + .75;
            } else {
                if (n < (2.5 / p)) {
                    n -= (2.25 / p);
                    l = s * n * n + .9375;
                } else {
                    n -= (2.625 / p);
                    l = s * n * n + .984375;
                }
            }
        }
        return l;
    };
    
    return mina;
})();