import React, { PureComponent } from 'react';
import PropTypes from 'prop-types';
import { Session } from 'meteor/session';
import { defineMessages, injectIntl } from 'react-intl';
import injectWbResizeEvent from '/imports/ui/components/presentation/resize-wrapper/component';
import Button from '/imports/ui/components/button/component';
import logger from '/imports/startup/client/logger';
import PadService from './service';
import CaptionsService from '/imports/ui/components/captions/service';
import { notify } from '/imports/ui/services/notification';
import { styles } from './styles';

const intlMessages = defineMessages({
  hide: {
    id: 'app.captions.pad.hide',
    description: 'Label for hiding closed captions pad',
  },
  tip: {
    id: 'app.captions.pad.tip',
    description: 'Label for tip on how to escape closed captions iframe',
  },
  takeOwnership: {
    id: 'app.captions.pad.ownership',
    description: 'Label for taking ownership of closed captions pad',
  },
  takeOwnershipTooltip: {
    id: 'app.captions.pad.ownershipTooltip',
    description: 'Text for button for taking ownership of closed captions pad',
  },
  interimResult: {
    id: 'app.captions.pad.interimResult',
    description: 'Title for speech recognition interim results',
  },
  dictationStart: {
    id: 'app.captions.pad.dictationStart',
    description: 'Label for starting speech recognition',
  },
  dictationStop: {
    id: 'app.captions.pad.dictationStop',
    description: 'Label for stoping speech recognition',
  },
  dictationOnDesc: {
    id: 'app.captions.pad.dictationOnDesc',
    description: 'Aria description for button that turns on speech recognition',
  },
  dictationOffDesc: {
    id: 'app.captions.pad.dictationOffDesc',
    description: 'Aria description for button that turns off speech recognition',
  },
  speechRecognitionStop: {
    id: 'app.captions.pad.speechRecognitionStop',
    description: 'Notification for stopped speech recognition',
  },  
});

const propTypes = {
  locale: PropTypes.string.isRequired,
  ownerId: PropTypes.string.isRequired,
  currentUserId: PropTypes.string.isRequired,
  padId: PropTypes.string.isRequired,
  readOnlyPadId: PropTypes.string.isRequired,
  name: PropTypes.string.isRequired,
  amIModerator: PropTypes.bool.isRequired,
  intl: PropTypes.shape({
    formatMessage: PropTypes.func.isRequired,
  }).isRequired,
};

class Pad extends PureComponent {
  static getDerivedStateFromProps(nextProps) {
    if (nextProps.ownerId !== nextProps.currentUserId) {
      return ({ listening: false });
    }
    return null;
  }

  constructor(props) {
    super(props);

    this.state = {
      listening: false,
    };

    const { locale, intl } = props;
    this.recognition = CaptionsService.initSpeechRecognition(locale);

    this.toggleListen = this.toggleListen.bind(this);
    this.handleListen = this.handleListen.bind(this);
    
    this.recognition.addEventListener('end', () => {
      const { listening } = this.state;
      if (listening) {
        notify(intl.formatMessage(intlMessages.speechRecognitionStop), 'info', 'warning');
        this.stopListen();
      }
    });
  }

  componentDidUpdate() {
    const {
      locale,
      ownerId,
      currentUserId,
    } = this.props;

    if (this.recognition) {
      this.recognition.lang = locale;
      if (ownerId !== currentUserId) this.recognition.stop();
    }
  }

  handleListen() {
    const {
      locale,
    } = this.props;

    const {
      listening,
    } = this.state;

    if (this.recognition) {
      // Starts and stops the recognition when listening.
      // Throws an error if start() is called on a recognition that has already been started.
      if (listening) {
        this.recognition.start();
      } else {
        this.recognition.stop();
      }

      // Stores the voice recognition results that have been verified.
      let finalTranscript = '';

      this.recognition.onresult = (event) => {
        const {
          resultIndex,
          results,
        } = event;

        // Stores the first guess at what was recognised (Not always accurate).
        let interimTranscript = '';

        // Loops through the results to check if any of the entries have been validated,
        // signaled by the isFinal flag.
        for (let i = resultIndex; i < results.length; i += 1) {
          const { transcript } = event.results[i][0];
          if (results[i].isFinal) finalTranscript += `${transcript} `;
          else interimTranscript += transcript;
        }

        // Adds the interimTranscript text to the iterimResultContainer to show
        // what's being said while speaking.
        if (this.iterimResultContainer) {
          this.iterimResultContainer.innerHTML = interimTranscript;
        }

        const newEntry = finalTranscript !== '';

        // Changes to the finalTranscript are shown to in the captions
        if (newEntry) {
          const text = finalTranscript.trimRight();
          CaptionsService.appendText(text, locale);
          finalTranscript = '';
        }
      };

      this.recognition.onerror = (event) => {
        logger.error({
          logCode: 'captions_recognition',
          extraInfo: { error: event.error },
        }, 'Captions pad error on recognition');
      };
    }
  }

  toggleListen() {
    const {
      listening,
    } = this.state;

    this.setState({
      listening: !listening,
    }, this.handleListen);
  }
  
  stopListen() {
    this.setState({ listening: false });
  }

  render() {
    const {
      locale,
      intl,
      padId,
      readOnlyPadId,
      ownerId,
      name,
      amIModerator,
    } = this.props;

    if (!amIModerator) {
      Session.set('openPanel', 'userlist');
      window.dispatchEvent(new Event('panelChanged'));
      return null;
    }

    const { listening } = this.state;
    const url = PadService.getPadURL(padId, readOnlyPadId, ownerId);

    return (
      <div className={styles.pad}>
        <header className={styles.header}>
          <div className={styles.title}>
            <Button
              onClick={() => {
                Session.set('openPanel', 'userlist');
                window.dispatchEvent(new Event('panelChanged'));
              }}
              aria-label={intl.formatMessage(intlMessages.hide)}
              label={name}
              icon="left_arrow"
              className={styles.hideBtn}
            />
          </div>
          {CaptionsService.canIDictateThisPad(ownerId)
            ? (
              <span>
                <Button
                  onClick={() => { this.toggleListen(); }}
                  label={listening
                    ? intl.formatMessage(intlMessages.dictationStop)
                    : intl.formatMessage(intlMessages.dictationStart)}
                  aria-describedby="dictationBtnDesc"
                  color="primary"
                  disabled={!this.recognition}
                />
                <div id="dictationBtnDesc" hidden>
                  {listening
                    ? intl.formatMessage(intlMessages.dictationOffDesc)
                    : intl.formatMessage(intlMessages.dictationOnDesc)}
                </div>
              </span>
            )
            : null}
          {CaptionsService.canIOwnThisPad(ownerId)
            ? (
              <Button
                color="primary"
                tooltipLabel={intl.formatMessage(intlMessages.takeOwnershipTooltip, { 0: name })}
                onClick={() => { CaptionsService.takeOwnership(locale); }}
                aria-label={intl.formatMessage(intlMessages.takeOwnership)}
                label={intl.formatMessage(intlMessages.takeOwnership)}
              />
            ) : null}
        </header>
        {listening ? (
          <div>
            <span className={styles.interimTitle}>
              {intl.formatMessage(intlMessages.interimResult)}
            </span>
            <div
              className={styles.processing}
              ref={(node) => { this.iterimResultContainer = node; }}
            />
          </div>
        ) : null}
        <iframe
          title="etherpad"
          src={url}
          aria-describedby="padEscapeHint"
        />
        <span id="padEscapeHint" className={styles.hint} aria-hidden>
          {intl.formatMessage(intlMessages.tip)}
        </span>
      </div>
    );
  }
}

export default injectWbResizeEvent(injectIntl(Pad));

Pad.propTypes = propTypes;