/** 
 * @jsx React.DOM
 */

/**
 * 判斷是否為 LI Tab 節點
 */
function isTabNode (node) {
  return node.nodeName === 'LI' &&
         node.getAttribute('role') === 'tab';
}

/**
 * 簡易的替 tab 取一個唯一的 ID
 */
var uuid = (function() {
  var count = 0;
  return function () {
    return 'react-tab-' + count++;
  }
})();

/**
 * 由上而下的開發流程，先定義 App 的結構。 
 */

var App = React.createClass({
  render: function () {
    return (
      <div className='container'>
        <Tabs selectedIndex={0}>
          <TabList>
            <Tab>Iron man</Tab>
            <Tab>Superman</Tab>
            <Tab>Lucy</Tab>
          </TabList>

          <TabPanel>
            鋼鐵人系列電影
          </TabPanel>

          <TabPanel>
            超人再起
          </TabPanel>

          <TabPanel>
            露西 100 %
          </TabPanel>
        </Tabs>
      </div>
    );
  }
});


/**
 * Tabs 
 */
var Tabs = React.createClass({
  propTypes: {
    selectedIndex: React.PropTypes.number
  },
  getDefaultProps: function () {
    return {
      selectedIndex: 0
    }
  },
  getInitialState: function () {
    return {
      selectedIndex: this.props.selectedIndex
    }
  },
  handleSelected: function (index) {
    if (index === this.state.selectedIndex) return;
    if (index < 0) return;
    this.setState({selectedIndex: index});
  },
  handleClick: function (e) {
    var node = e.target;
    if (isTabNode(node)) {
      var index =   [].slice.call(node.parentNode.children).indexOf(node);
      this.handleSelected(index);
    }
  },
  render: function () {
    var count = 0, index = 0;
    var state = this.state;
    var children = React.Children.map(this.props.children, function (child) {
      var component = null;
 
      if (count++ === 0) {
        component = React.addons.cloneWithProps(child, {
          ref: 'tablist',
          children: React.Children.map(child.props.children, function (tab) {
            var ref = 'tab-' + index,
                selected = state.selectedIndex === index;
            
            index++;
            
            return React.addons.cloneWithProps(tab, {
              ref: ref,
              selected: selected
            });
          })
        });
        index = 0;
      } else {
        var ref = 'panel-' + index,
            selected = state.selectedIndex === index;
        
        index++;
        
        component = React.addons.cloneWithProps(child, {
          ref: ref,
          selected: selected
        });
      }
      return component;
    });
    
    return (
      <div className='react-tabs'
           onClick={this.handleClick}>
        {children}
      </div>
    )
  }
});


/**
 * Tab 選單列的標簽
 */
var Tab = React.createClass({
  getInitialState: function () {
    return {
      selected: false
    }
  },
  componentDidMount: function () {
    if (this.props.selected) {
      this.getDOMNode().setAttribute('selected', 'selected');
    } else {
      this.getDOMNode().removeAttribute('selected');
    }
  },
  componentDidUpdate: function () {
    if (this.props.selected) {
      this.getDOMNode().setAttribute('selected', 'selected');
    } else {
      this.getDOMNode().removeAttribute('selected');
    }
  },
  render: function () {
    var cx = React.addons.classSet;
    var classes = cx({
      'react-tab': true,
      'active': this.props.selected
    });
    
    return (
      <li className={classes} role='tab'>
        {this.props.children}
      </li>
    )
  }
});


/**
 * TabList: Tab 標簽的容器
 */
var TabList = React.createClass({
  render: function () {
    return (
      <ul className='react-tab-list' role='tablist'>
        {this.props.children}
      </ul>
    );
  }
});

/**
 * TabPanel 對應內容
 */
var TabPanel = React.createClass({
  getDefaultProps: function () {
    return {
      selected: false
    }
  },
  
  render: function () {
    var cx = React.addons.classSet;
    var classes = cx({
      'react-tab-panel': true,
      'active': this.props.selected
    });
    
    return (
      <div className={classes} role='tabpanel'>
        {this.props.children}
      </div>
    )
  }
})

React.renderComponent(
  <App />,
  document.getElementById('example')
)