/**
 *
 */
var InsertionSort = function() {
    //===== Action management.
    //
    this.preSort = function(arr) {
        this
            .instruct(Itemgroup.background, 1, 0, 0, arr.length, Visualizer.bg0)

            .instruct(Itemgroup.message, 0, 0, 1, `Comparisons: ${this.comparisons}`)
            .instruct(Itemgroup.message, 0, 0, 2, `Swaps: ${this.swaps}`)
            .instruct(Itemgroup.message, 0, 0, 3, ``)
            .instruct(Itemgroup.message, 0, 0, 4, ``)
            .instruct(Itemgroup.message, 0, 100, 5, `Starting sort.`)
    };

    //
    this.midSort = function(arr, i, j) {
        this
            .instruct(Itemgroup.background, 1, 0, 0, arr.length, Visualizer.bg0)
            .instruct(Itemgroup.background, 1, 0, j, j, Visualizer.bg1)
            .instruct(Itemgroup.background, 1, 0, (j - 1), (j - 1), Visualizer.bg1)

            .instruct(Itemgroup.message, 0, 0, 1, `Comparisons: ${this.comparisons}`)
            .instruct(Itemgroup.message, 0, 0, 4, `Comparing [${j - 1}] and [${j}]`)
            .instruct(Itemgroup.message, 0, 100, 5, ``)
    };

    //
    this.swap = function(arr, j) {
        this
            .instruct(Itemgroup.message, 0, 0, 2, `Swaps: ${this.swaps}`)
            .instruct(Itemgroup.message, 0, 0, 5, `${arr[j]} < ${arr[j - 1]}, swapped.`)
            .instruct(Itemgroup.swap, 1, 300, j - 1, j)

        if (j - 1 > 0) {
            this.instruct(Itemgroup.message, 0, 0, 3, `Continuing downstream...`)
        }
        else {
            this.instruct(Itemgroup.message, 0, 0, 3, ``)
        }
    };

    //
    this.postSort = function(arr) {
        this
            .instruct(Itemgroup.background, 1, 0, 0, arr.length, Visualizer.bg0)

            .instruct(Itemgroup.message, 0, 0, 1, `Comparisons: ${this.comparisons}`)
            .instruct(Itemgroup.message, 0, 0, 2, `Swaps: ${this.swaps}`)
            .instruct(Itemgroup.message, 0, 0, 3, ``)
            .instruct(Itemgroup.message, 0, 0, 4, ``)
            .instruct(Itemgroup.message, 0, 100, 5, `Sorting complete.`)
    };
};

InsertionSort.prototype = Object.create(Sorter.prototype);

/**
 *
 */
InsertionSort.prototype.init = function() {
    var len = this.shuffled.length;

    this.actions = [];
    this.swaps = 0;
    this.comparisons = 0;

    this
        .instruct(Itemgroup.items, 0, 0, len)
        .instruct(Itemgroup.items, 1, 0, len)
        .instruct(Itemgroup.items, 2, 0, len)

    for (var i = 0; i < len; i++) {
        this.instruct(Itemgroup.text, 1, 0, i, this.shuffled[i]);
    }

    this
        .instruct(Itemgroup.foreground, 1, 0, 0, len, Visualizer.fg0)
        .instruct(Itemgroup.background, 1, 0, 0, len, Visualizer.bg0)

        .instruct(Itemgroup.opacity, 0, 0, 0, len, 0)
        .instruct(Itemgroup.opacity, 2, 0, 0, len, 0)
};

/**
 *
 */
InsertionSort.prototype.sort = function(arr) {
    var len = arr.length;
    var i;
    var j;
    var tmp;

    this.preSort(arr);

    for (i = 0; i < len; i++) {
        for (j = i; j > 0; j--) {
            this.comparisons++;
            this.midSort(arr, i, j);

            if (arr[j - 1] > arr[j]) {
                this.swaps++;
                tmp = arr[j - 1];
                arr[j - 1] = arr[j];
                arr[j] = tmp;

                this.swap(arr, j);
            }
            else {
                break;
            }
        }
    }

    this.postSort(arr);
    return arr;
};