var React = require('react');
var Classable = require('../mixins/classable');

var EnhancedTextarea = React.createClass({
	
	mixins: [Classable],

	propTypes: {
		onChange: React.PropTypes.func,
		onHeightChange: React.PropTypes.func,
		textareaClassName: React.PropTypes.string,
		rows: React.PropTypes.number 
	},

	getDefaultProps: function() {
		return {
			rows: 1
		};
	},

	getInitialState: function() {
		return {
			height: this.props.rows * 24
		};
	},

	componentDidMount: function() {
		this._syncHeightWithShadow();
	},

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

  	render: function() {
  		var {
  		  className,
  		  onChange,
  		  onHeightChange,
  		  textareaClassName,
  		  rows,
  		  valueLink,
  		  ...other,
  		} = this.props;

  		var classes = this.getClasses('dig-enhanced-textarea');
  		var textareaClassName = 'dig-enhanced-textarea-input';
  		var style = {
  		  height: this.state.height + 'px'
  		};

  		if (this.props.textareaClassName) {
  		  textareaClassName += ' ' + this.props.textareaClassName;
  		}

  		if (this.props.hasOwnProperty('valueLink')) {
  		  other.value = this.props.valueLink.value;
  		}

	    return (
	      <div className={classes}>
	      	<textarea 
	      	ref="shadow"
	      	className="dig-enhanced-textarea-shadow"
	      	tabIndex="-1"
	      	rows={this.props.rows}
	      	defaultValue={this.props.defaultValue}
	      	readOnly={true}
	      	value={this.props.value} />
	      	<textarea 
	      	{...other}
	      	ref="input"
	      	className={textareaClassName}
	      	rows={this.props.rows}
	      	style={style}
	      	onChange={this._handleChange} />
	      </div>
	    );
	  },

	  getInputNode: function() {
	    return this.refs.input.getDOMNode();
	  },

	  _syncHeightWithShadow: function(newValue, e) {
	    var shadow = this.refs.shadow.getDOMNode();
	    var currentHeight = this.state.height;
	    var newHeight;

	    if (newValue !== undefined) shadow.value = newValue;
	    newHeight = shadow.scrollHeight;

	    if (currentHeight !== newHeight) {
	      this.setState({height: newHeight});
	      if (this.props.onHeightChange) this.props.onHeightChange(e, newHeight);
	    }
	  },

	  _handleChange: function(e) {
	    this._syncHeightWithShadow(e.target.value);

	    if (this.props.hasOwnProperty('valueLink')) {
	      this.props.valueLink.requestChange(e.target.value);
	    }

	    if (this.props.onChange) this.props.onChange(e);
	  }
});

module.exports = EnhancedTextarea;