/**
 *
 */
function Visualizer(parent) {
    var top = document.createElement('div');
    top.className = 'top';
    parent.appendChild(top);

    var bottom = document.createElement('div');
    bottom.className = 'bottom';
    parent.appendChild(bottom);

    var controls = this.initControls();
    parent.querySelector('.bottom').appendChild(controls);

    var messages = this.initMessages();
    parent.querySelector('.bottom').appendChild(messages);

    var range = this.initRange();
    parent.querySelector('.bottom').appendChild(range);

    this.svg = d3.select(parent.querySelector('.top')).append('svg');
    this.groups = null;
    this.parent = parent;
    this.sorter = null;

    switch(parent.attributes['data-algorithm'].value) {
        case 'quick':
            this.sorter = new QuickSort();
            break;

        case 'merge':
            this.sorter = new MergeSort();
            break;

        case 'selection':
            this.sorter = new SelectionSort();
            break;

        case 'bubble':
            this.sorter = new BubbleSort();
            break;

        case 'insertion':
            this.sorter = new InsertionSort();
            break;

        case 'shell':
            this.sorter = new ShellSort();
            break;

        case 'radix':
            this.sorter = new RadixSort();
            break;

        default:
            throw new Error('Unrecognized sort type.');
    }

    // this.instructions = null;
    // this.currentInstruction = 0;

    this.initItems(10);
};

// Public static properties (mutable)
Visualizer.spacerW  = 5;
Visualizer.itemW    = 14;
Visualizer.itemH    = 50;
Visualizer.itemY    = 20;

/**
 *
 */
Visualizer.prototype.followInstruction = function(index) {
    if (index >= this.sorter.instructions.length) {
        return;
    }

    var i = this.sorter.instructions[index];
    console.log(i);

    // NOTE interesting pattern here
    if (typeof this[i[0]] === 'function') {
        this[i[0]](i);

        if (i[1] === true) {
            setTimeout(this.followInstruction.bind(this, index + 1), 400);
        }
        else {
           this.followInstruction(index + 1);
        }
    }
    // TODO document this
    else if (this[i[0]] !== undefined) {
        console.warn(this[i[0]]);
    }
    else {
        console.error(i);
        throw new Error('Unidentified instruction.');
    }
};