/**
 * Copyright (c) 2013 Petka Antonov
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:</p>
 * 
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
"use strict";
function Deque(capacity) {
    this._capacity = getCapacity(capacity);
    this._length = 0;
    this._front = 0;
    this._makeCapacity();
    if (isArray(capacity)) {
        var len = capacity.length;
        for (var i = 0; i < len; ++i) {
            this[i] = capacity[i];
        }
        this._length = len;
    }
}

Deque.prototype.toArray = function Deque$toArray() {
    var len = this._length;
    var ret = new Array(len);
    var front = this._front;
    var capacity = this._capacity;
    for (var j = 0; j < len; ++j) {
        ret[j] = this[(front + j) & (capacity - 1)];
    }
    return ret;
};

Deque.prototype.push = function Deque$push(item) {
    var argsLength = arguments.length;
    var length = this._length;
    if (argsLength > 1) {
        var capacity = this._capacity;
        if (length + argsLength > capacity) {
            for (var i = 0; i < argsLength; ++i) {
                this._checkCapacity(length + 1);
                var j = (this._front + length) & (this._capacity - 1);
                this[j] = arguments[i];
                length++;
                this._length = length;
            }
            return length;
        }
        else {
            var j = this._front;
            for (var i = 0; i < argsLength; ++i) {
                this[(j + length) & (capacity - 1)] = arguments[i];
                j++;
            }
            this._length = length + argsLength;
            return length + argsLength;
        }

    }

    if (argsLength === 0) return length;

    this._checkCapacity(length + 1);
    var i = (this._front + length) & (this._capacity - 1);
    this[i] = item;
    this._length = length + 1;
    return length + 1;
};

Deque.prototype.pop = function Deque$pop() {
    var length = this._length;
    if (length === 0) {
        return void 0;
    }
    var i = (this._front + length - 1) & (this._capacity - 1);
    var ret = this[i];
    this[i] = void 0;
    this._length = length - 1;
    return ret;
};

Deque.prototype.shift = function Deque$shift() {
    var length = this._length;
    if (length === 0) {
        return void 0;
    }
    var front = this._front;
    var ret = this[front];
    this[front] = void 0;
    this._front = (front + 1) & (this._capacity - 1);
    this._length = length - 1;
    return ret;
};

Deque.prototype.unshift = function Deque$unshift(item) {
    var length = this._length;
    var argsLength = arguments.length;


    if (argsLength > 1) {
        var capacity = this._capacity;
        if (length + argsLength > capacity) {
            for (var i = argsLength - 1; i >= 0; i--) {
                this._checkCapacity(length + 1);
                var capacity = this._capacity;
                var j = (((( this._front - 1 ) &
                    ( capacity - 1) ) ^ capacity ) - capacity );
                this[j] = arguments[i];
                length++;
                this._length = length;
                this._front = j;
            }
            return length;
        }
        else {
            var front = this._front;
            for (var i = argsLength - 1; i >= 0; i--) {
                var j = (((( front - 1 ) &
                    ( capacity - 1) ) ^ capacity ) - capacity );
                this[j] = arguments[i];
                front = j;
            }
            this._front = front;
            this._length = length + argsLength;
            return length + argsLength;
        }
    }

    if (argsLength === 0) return length;

    this._checkCapacity(length + 1);
    var capacity = this._capacity;
    var i = (((( this._front - 1 ) &
        ( capacity - 1) ) ^ capacity ) - capacity );
    this[i] = item;
    this._length = length + 1;
    this._front = i;
    return length + 1;
};

Deque.prototype.peekBack = function Deque$peekBack() {
    var length = this._length;
    if (length === 0) {
        return void 0;
    }
    var index = (this._front + length - 1) & (this._capacity - 1);
    return this[index];
};

Deque.prototype.peekFront = function Deque$peekFront() {
    if (this._length === 0) {
        return void 0;
    }
    return this[this._front];
};

Deque.prototype.get = function Deque$get(index) {
    var i = index;
    if ((i !== (i | 0))) {
        return void 0;
    }
    var len = this._length;
    if (i < 0) {
        i = i + len;
    }
    if (i < 0 || i >= len) {
        return void 0;
    }
    return this[(this._front + i) & (this._capacity - 1)];
};

Deque.prototype.isEmpty = function Deque$isEmpty() {
    return this._length === 0;
};

Deque.prototype.clear = function Deque$clear() {
    this._length = 0;
    this._front = 0;
    this._makeCapacity();
};

Deque.prototype.toString = function Deque$toString() {
    return this.toArray().toString();
};

Deque.prototype.valueOf = Deque.prototype.toString;
Deque.prototype.removeFront = Deque.prototype.shift;
Deque.prototype.removeBack = Deque.prototype.pop;
Deque.prototype.insertFront = Deque.prototype.unshift;
Deque.prototype.insertBack = Deque.prototype.push;
Deque.prototype.enqueue = Deque.prototype.push;
Deque.prototype.dequeue = Deque.prototype.shift;
Deque.prototype.toJSON = Deque.prototype.toArray;

Object.defineProperty(Deque.prototype, "length", {
    get: function() {
        return this._length;
    },
    set: function() {
        throw new RangeError("");
    }
});

Deque.prototype._makeCapacity = function Deque$_makeCapacity() {
    var len = this._capacity;
    for (var i = 0; i < len; ++i) {
        this[i] = void 0;
    }
};

Deque.prototype._checkCapacity = function Deque$_checkCapacity(size) {
    if (this._capacity < size) {
        this._resizeTo(getCapacity(this._capacity * 1.5 + 16));
    }
};

Deque.prototype._resizeTo = function Deque$_resizeTo(capacity) {
    var oldFront = this._front;
    var oldCapacity = this._capacity;
    var oldDeque = new Array(oldCapacity);
    var length = this._length;

    arrayCopy(this, 0, oldDeque, 0, oldCapacity);
    this._capacity = capacity;
    this._makeCapacity();
    this._front = 0;
    if (oldFront + length <= oldCapacity) {
        arrayCopy(oldDeque, oldFront, this, 0, length);
    } else {        var lengthBeforeWrapping =
            length - ((oldFront + length) & (oldCapacity - 1));

        arrayCopy(oldDeque, oldFront, this, 0, lengthBeforeWrapping);
        arrayCopy(oldDeque, 0, this, lengthBeforeWrapping,
            length - lengthBeforeWrapping);
    }
};


var isArray = Array.isArray;

function arrayCopy(src, srcIndex, dst, dstIndex, len) {
    for (var j = 0; j < len; ++j) {
        dst[j + dstIndex] = src[j + srcIndex];
    }
}

function pow2AtLeast(n) {
    n = n >>> 0;
    n = n - 1;
    n = n | (n >> 1);
    n = n | (n >> 2);
    n = n | (n >> 4);
    n = n | (n >> 8);
    n = n | (n >> 16);
    return n + 1;
}

function getCapacity(capacity) {
    if (typeof capacity !== "number") {
        if (isArray(capacity)) {
            capacity = capacity.length;
        }
        else {
            return 16;
        }
    }
    return pow2AtLeast(
        Math.min(
            Math.max(16, capacity), 1073741824)
    );
}

module.exports = Deque;