/**
 * The examples provided by Facebook are for non-commercial testing and
 * evaluation purposes only.
 *
 * Facebook reserves all rights not expressly granted.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NON INFRINGEMENT. IN NO EVENT SHALL
 * FACEBOOK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
 * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 * @flow
 */
'use strict';

var React = require('react-native');
var {
  ProgressViewIOS,
  StyleSheet,
  View,
  Text,
  TouchableHighlight,
} = React;

class Downloader extends React.Component {

  xhr: XMLHttpRequest;
  cancelled: boolean;

  constructor(props) {
    super(props);
    this.cancelled = false;
    this.state = {
      downloading: false,
      contentSize: 1,
      downloaded: 0,
    };
  }

  download() {
    this.xhr && this.xhr.abort();

    var xhr = this.xhr || new XMLHttpRequest();
    xhr.onreadystatechange = () => {
      if (xhr.readyState === xhr.HEADERS_RECEIVED) {
        var contentSize = parseInt(xhr.getResponseHeader('Content-Length'), 10);
        this.setState({
          contentSize: contentSize,
          downloaded: 0,
        });
      } else if (xhr.readyState === xhr.LOADING) {
        this.setState({
          downloaded: xhr.responseText.length,
        });
      } else if (xhr.readyState === xhr.DONE) {
        this.setState({
          downloading: false,
        });
        if (this.cancelled) {
          this.cancelled = false;
          return;
        }
        if (xhr.status === 200) {
          alert('Download complete!');
        } else if (xhr.status !== 0) {
          alert('Error: Server returned HTTP status of ' + xhr.status + ' ' + xhr.responseText);
        } else {
          alert('Error: ' + xhr.responseText);
        }
      }
    };
    xhr.open('GET', 'http://www.gutenberg.org/cache/epub/100/pg100.txt');
    xhr.send();
    this.xhr = xhr;

    this.setState({downloading: true});
  }

  componentWillUnmount() {
    this.cancelled = true;
    this.xhr && this.xhr.abort();
  }

  render() {
    var button = this.state.downloading ? (
      <View style={styles.wrapper}>
        <View style={styles.button}>
          <Text>Downloading...</Text>
        </View>
      </View>
    ) : (
      <TouchableHighlight
        style={styles.wrapper}
        onPress={this.download.bind(this)}>
        <View style={styles.button}>
         <Text>Download 5MB Text File</Text>
        </View>
      </TouchableHighlight>
    );

    return (
      <View>
        {button}
        <ProgressViewIOS progress={(this.state.downloaded / this.state.contentSize)}/>
      </View>
    );
  }
}

exports.framework = 'React';
exports.title = 'XMLHttpRequest';
exports.description = 'XMLHttpRequest';
exports.examples = [{
  title: 'File Download',
  render() {
    return <Downloader/>;
  }
}];

var styles = StyleSheet.create({
  wrapper: {
    borderRadius: 5,
    marginBottom: 5,
  },
  button: {
    backgroundColor: '#eeeeee',
    padding: 10,
  },
});