import React from 'react'
import {
  DraftHelpers,
  MessageUtils,
  MessageBodyProcessor,
  QuotedHTMLTransformer,
  AttachmentStore,
} from 'nylas-exports';
import {
  InjectedComponentSet,
  RetinaImg,
} from 'nylas-component-kit';

import EmailFrame from './email-frame';
import {encodedAttributeForFile} from './inline-image-listeners';

const TransparentPixel = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR4nGNikAQAACIAHF/uBd8AAAAASUVORK5CYII="

export default class MessageItemBody extends React.Component {
  static displayName = 'MessageItemBody';
  static propTypes = {
    message: React.PropTypes.object.isRequired,
    downloads: React.PropTypes.object.isRequired,
  };

  constructor(props, context) {
    super(props, context);
    this._mounted = false;
    this.state = {
      showQuotedText: DraftHelpers.isForwardedMessage(this.props.message),
      processedBody: null,
    };
  }

  componentWillMount() {
    this._unsub = MessageBodyProcessor.subscribe(this.props.message, (processedBody) =>
      this.setState({processedBody})
    );
  }

  componentDidMount() {
    this._mounted = true;
  }

  componentWillReceiveProps(nextProps) {
    if (nextProps.message.id !== this.props.message.id) {
      if (this._unsub) { this._unsub() }
      this._unsub = MessageBodyProcessor.subscribe(nextProps.message, (processedBody) =>
        this.setState({processedBody})
      );
    }
  }

  componentWillUnmount() {
    this._mounted = false;
    if (this._unsub) { this._unsub() }
  }

  _onToggleQuotedText = () => {
    this.setState({
      showQuotedText: !this.state.showQuotedText,
    });
  }

  _mergeBodyWithFiles(body) {
    let merged = body;

    // Replace cid: references with the paths to downloaded files
    for (const file of this.props.message.files) {
      const download = this.props.downloads[file.id];

      // Note: I don't like doing this with RegExp before the body is inserted into
      // the DOM, but we want to avoid "could not load cid://" in the console.

      if (download && download.state !== 'finished') {
        const inlineImgRegexp = new RegExp(`<\\s*img.*src=['"]cid:${file.contentId}['"][^>]*>`, 'gi')
        // Render a spinner
        merged = merged.replace(inlineImgRegexp, () =>
          '<img alt="spinner.gif" src="nylas://message-list/assets/spinner.gif" style="-webkit-user-drag: none;">'
        );
      } else {
        // Render the completed download. We include data-nylas-file so that if the image fails
        // to load, we can parse the file out and call `Actions.fetchFile` to retrieve it.
        // (Necessary when attachment download mode is set to "manual")
        const cidRegexp = new RegExp(`cid:${file.contentId}(['"])`, 'gi')
        merged = merged.replace(cidRegexp, (text, quoteCharacter) =>
          `file://${AttachmentStore.pathForFile(file)}${quoteCharacter} data-nylas-file="${encodedAttributeForFile(file)}" `
        );
      }
    }

    // Replace remaining cid: references - we will not display them since they'll
    // throw "unknown ERR_UNKNOWN_URL_SCHEME". Show a transparent pixel so that there's
    // no "missing image" region shown, just a space.
    merged = merged.replace(MessageUtils.cidRegex, `src="${TransparentPixel}"`)

    return merged;
  }

  _renderBody() {
    const {message} = this.props;
    const {showQuotedText, processedBody} = this.state;

    if (typeof message.body === "string" && typeof processedBody === "string") {
      return (
        <EmailFrame
          showQuotedText={showQuotedText}
          content={this._mergeBodyWithFiles(processedBody)}
          message={message}
        />
      );
    }

    return (
      <div className="message-body-loading">
        <RetinaImg
          name="inline-loading-spinner.gif"
          mode={RetinaImg.Mode.ContentDark}
          style={{width: 14, height: 14}}
        />
      </div>
    );
  }

  _renderQuotedTextControl() {
    if (!QuotedHTMLTransformer.hasQuotedHTML(this.props.message.body)) {
      return null;
    }
    return (
      <a className="quoted-text-control" onClick={this._onToggleQuotedText}>
        <span className="dots">&bull;&bull;&bull;</span>
      </a>
    );
  }

  render() {
    return (
      <span>
        <InjectedComponentSet
          matching={{role: "message:BodyHeader"}}
          exposedProps={{message: this.props.message}}
          direction="column"
          style={{width: '100%'}}
        />
        {this._renderBody()}
        {this._renderQuotedTextControl()}
      </span>
    );
  }
}
