var React = require('react');
var Paper = require('./paper');
var Classable = require('../mixins/classable');
var Draggable = require('react-draggable2');

var Slider = React.createClass({

	mixins: [Classable],

	propTypes: {
	  required: React.PropTypes.bool,
	  disabled: React.PropTypes.bool,
	  min: React.PropTypes.number,
	  max: React.PropTypes.number,
	  step: React.PropTypes.number,
	  error: React.PropTypes.string,
	  description: React.PropTypes.string,
	  name: React.PropTypes.string.isRequired,
	  onChange: React.PropTypes.func,
	  onDragStart: React.PropTypes.func,
	  onDragStop: React.PropTypes.func
	},

	getDefaultProps: function() {
	  return {
	    required: true,
	    disabled: false,
	    defaultValue: 0,
	    min: 0,
	    max: 1,
	    dragging: false
	  };
	},

	getInitialState: function() {
	  var value = this.props.value;
	  if (value == null) value = this.props.defaultValue;
	  var percent = (value - this.props.min) / (this.props.max - this.props.min);
	  if (isNaN(percent)) percent = 0;
	  return {
	    value: value,
	    percent: percent
	  }
	},

	componentWillReceiveProps: function(nextProps) {
	  if (nextProps.value != null) {
	    this.setValue(nextProps.value);
	  }
	},

	render: function() {

		var classes = this.getClasses('dig-input', {
		  'dig-error': this.props.error != null
		});

		var sliderClasses = this.getClasses('dig-slider', {
		  'dig-slider-zero': this.state.percent == 0,
		  'dig-disabled': this.props.disabled
		});

		var percent = this.state.percent;
		if (percent > 1) percent = 1; else if (percent < 0) percent = 0;

		return (
			<div className={classes} style={this.props.style}>
			  <span className="dig-input-highlight"></span>
			  <span className="dig-input-bar"></span>
			  <span className="dig-input-description">{this.props.description}</span>
			  <span className="dig-input-error">{this.props.error}</span>
			  <div className={sliderClasses} onClick={this._onClick}>
			    <div ref="track" className="dig-slider-track">
			      <Draggable axis="x" bound="point"
			        cancel={this.props.disabled ? '*' : null}
			        start={{x: (percent * 100) + '%'}}
			        onStart={this._onDragStart}
			        onStop={this._onDragStop}
			        onDrag={this._onDragUpdate}>
			        <div className="dig-slider-handle" tabIndex={0}></div>
			      </Draggable>
			      <div className="dig-slider-selection dig-slider-selection-low"
			        style={{width: (percent * 100) + '%'}}>
			        <div className="dig-slider-selection-fill"></div>
			      </div>
			      <div className="dig-slider-selection dig-slider-selection-high"
			        style={{width: ((1 - percent) * 100) + '%'}}>
			        <div className="dig-slider-selection-fill"></div>
			      </div>
			    </div>
			  </div>
			  <input ref="input" type="hidden"
			    name={this.props.name}
			    value={this.state.value}
			    required={this.props.required}
			    min={this.props.min}
			    max={this.props.max}
			    step={this.props.step} />
			</div>
		);
	},

	getValue: function() {
	  return this.state.value;
	},

	setValue: function(i) {
	  // calculate percentage
	  var percent = (i - this.props.min) / (this.props.max - this.props.min);
	  if (isNaN(percent)) percent = 0;
	  // update state
	  this.setState({
	    value: i,
	    percent: percent
	  });
	},

	getPercent: function() {
	  return this.state.percent;
	},

	setPercent: function (percent) {
	  var value = this._percentToValue(percent);
	  this.setState({value: value, percent: percent});
	},

	clearValue: function() {
	  this.setValue(0);
	},

	_onClick: function (e) {
	  // let draggable handle the slider
	  if (this.state.dragging || this.props.disabled) return;
	  var value = this.state.value;
	  var node = this.refs.track.getDOMNode();
	  var boundingClientRect = node.getBoundingClientRect();
	  var offset = e.clientX - boundingClientRect.left;
	  this._updateWithChangeEvent(e, offset / node.clientWidth);
	},

	_onDragStart: function(e, ui) {
	  this.setState({
	    dragging: true
	  });
	  if (this.props.onDragStart) this.props.onDragStart(e, ui);
	},

	_onDragStop: function(e, ui) {
	  this.setState({
	    dragging: false
	  });
	  if (this.props.onDragStop) this.props.onDragStop(e, ui);
	},

	_onDragUpdate: function(e, ui) {
	  if (!this.state.dragging) return;
	  if (!this.props.disabled) this._dragX(e, ui.position.left);
	},

	_dragX: function(e, pos) {
	  var max = this.refs.track.getDOMNode().clientWidth;
	  if (pos < 0) pos = 0; else if (pos > max) pos = max;
	  this._updateWithChangeEvent(e, pos / max);
	},

	_updateWithChangeEvent: function(e, percent) {
	  if (this.state.percent === percent) return;
	  this.setPercent(percent);
	  var value = this._percentToValue(percent);
	  if (this.props.onChange) this.props.onChange(e, value);
	},

	_percentToValue: function(percent) {
	  return percent * (this.props.max - this.props.min) + this.props.min;
	}

});

module.exports = Slider;