/*

[ ] arrow keys
[ ] min() max() step() commands of yore

[x] only validate input box on blur, not on keydown
[x] enter key blurs
[x] decimals
[x] step
[x] dy to drag friction
[x] negative slider
[x] hover behavior

*/

Gui.register('controller-number', function(value) {

  return typeof value == 'number';

});

Polymer('controller-number', {

  value: 0,
  decimals: 3,
  computed: {

    slider: 'min !== undefined && max !== undefined'

  },

  ready: function() {

    var _this = this;

    window.addEventListener('keydown', function(e) {
      if (e.keyCode == 18) _this._alt = true;
    }, false);

    window.addEventListener('keyup', function(e) {
      if (e.keyCode == 18) _this._alt = false;
    }, false);

    this.super();

  },

  init: function(min, max, step) {

    this.min = min;
    this.max = max;
    this.step = step;

  },

  // Observers
  // -------------------------------

  valueChanged: function(newValue) {

    if (this.step !== undefined) {
      this.value = Math.round(this.value / this.step) * this.step;
    }

    if (this.min !== undefined) {
      this.value = Math.max(this.value, this.min);
    }

    if (this.max !== undefined) {
      this.value = Math.min(this.value, this.max);
    }

    this.super();
  },

  minChanged: function() {

    this.value = Math.max(this.value, this.min);
    this.update();

  },

  maxChanged: function() {

    this.value = Math.min(this.value, this.max);
    this.update();

  },

  update: function() {

    var ratio = this.map(this.value, this.min, this.max, 0, 1);

    if (this.min < 0 && this.max > 0) {

      this.$.container.classList.add('straddle-zero');

      var zero = this.map(0, this.min, this.max, 0, 1);

      if (this.value >= 0) {

        this.$.fill.style.left = zero * 100 + '%';
        this.$.fill.style.width = (ratio - zero) * 100 + '%';
        this.$.fill.style.right = '';

      } else {

        this.$.fill.style.left = '';
        this.$.fill.style.width = (zero - ratio) * 100 + '%';
        this.$.fill.style.right = (1 - zero) * 100 + '%';

      }

    } else {

      this.$.container.classList.remove('straddle-zero');

      if (this.max > 0) {

        this.$.fill.style.left = 0;
        this.$.fill.style.width = ratio * 100 + '%';
        this.$.fill.style.right = '';

      } else {

        this.$.fill.style.left = '';
        this.$.fill.style.width = (1 - ratio) * 100 + '%';
        this.$.fill.style.right = 0;

      }

    }

    this.$.knob.style.left = ratio * 100 + '%';

    this.$.container.classList.toggle('positive', this.value >= 0);
    this.$.container.classList.toggle('negative', this.value < 0);

    this.super();

  },


  // Events
  // -------------------------------

  click: function(e) {

    this.$.input.select();

  },

  keydown: function(e) {

    if (e.keyCode == 13) {
      this.$.input.blur();
    }

  },

  down: function(e) {

    e.preventDefault();
    this._rect = this.$.track.getBoundingClientRect();
    if (!this._alt) this.value = this.valueFromX(e.x);

  },

  up: function(e) {

    // this.$.container.classList.add( 'transition');

  },

  trackstart: function(e) {

    // this.$.container.classList.remove( 'transition');
    this._dragFriction = 1;

  },

  trackx: function(e) {

    if (this.step === undefined) {

      var dv = this.valueFromDX(e.ddx);

      if (this._alt) dv /= 10;

      this.value += dv * this._dragFriction;

    } else {

      this.value = this.valueFromX(e.pageX);

    }
  },

  tracky: function(e) {

    this._dragFriction = Math.max(0.01,
                           Math.min(1, this.map(e.dy, 50, 300, 1, 0.1)));

  },

  blur: function(e) {

    var v = parseFloat(this.$.input.value);

    if (v === v) {
      this.value = v;
    }

  },



  // Filters
  // -------------------------------

  truncate: function(v) {

    if (v % 1 !== 0 && this.decimals !== undefined) {
      return this.limitDecimals(v, this.decimals);
    } else {
      return v;
    }

  },


  // Helpers
  // -------------------------------

  limitDecimals: function(v, maxDecimals) {

    var str = v.toString();
    var numDecimals = str.substring(str.indexOf('.') + 1).length;

    str = v.toFixed(Math.min(numDecimals, this.decimals));

    for (var z, i = 0, l = str.length; i < l; i++) {
      if (str.charAt(i) !== '0') {
        z = i;
      }
    }

    return str.substring(0, z + 1);

  },

  valueFromX: function(x) {

    return this.map(x, this._rect.left, this._rect.right, this.min, this.max);

  },

  valueFromDX: function(dx) {

    return this.map(dx, 0, this._rect.width, 0, this.max - this.min);

  }

});