/**
 *
 */
var SelectionSort = 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, min) {
        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, i, i, '#435C11')

            .instruct(Itemgroup.message, 0, 0, 1, `Comparisons: ${this.comparisons}`)
            .instruct(Itemgroup.message, 0, 0, 3, `Current value: ${arr[i]}`)
            .instruct(Itemgroup.message, 0, 0, 4, `Current minimum: ${arr[min]}`)
            .instruct(Itemgroup.message, 0, 100, 5, `Comparing: ${arr[min]} and ${arr[j]}`)
    };

    //
    this.newmin = function(arr, min) {
        this
            .instruct(Itemgroup.message, 0, 0, 4, `New minimum: ${arr[min]}`)
            .instruct(Itemgroup.message, 0, 100, 5, ``)
    };

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

            .instruct(Itemgroup.message, 0, 0, 2, `Swaps: ${this.swaps}`)
            .instruct(Itemgroup.message, 0, 0, 4, ``)
            .instruct(Itemgroup.message, 0, 0, 5, `Swap current and minimum.`)
            .instruct(Itemgroup.swap, 1, 300, i, min)
    };

    //
    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.`)
    };
};

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

/**
 *
 */
SelectionSort.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)
};

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

    this.preSort(arr);

    for (i = 0; i < len; i++) {
        min = i;
        for (j = i + 1; j < len; j++) {
            this.comparisons++;
            this.midSort(arr, i, j, min);

            if (arr[j] < arr[min]) {
                min = j;
                this.newmin(arr, min);
            }
        }

        if (min !== i) {
            this.swaps++;
            tmp = arr[i];
            arr[i] = arr[min];
            arr[min] = tmp;

            this.swap(arr, i, min);
        }
    }

    this.postSort(arr);

    return arr;
};