import React from 'react';
import PropTypes from 'prop-types';

import * as codemirror from 'codemirror';

import { UnControlled as ReactCodeMirror } from 'react-codemirror2';
require('codemirror/lib/codemirror.css');
require('codemirror/addon/display/autorefresh');
require('codemirror/addon/edit/matchbrackets');
require('codemirror/addon/edit/matchtags');
require('codemirror/addon/edit/closetag');
require('codemirror/addon/edit/continuelist');
require('codemirror/addon/hint/show-hint');
require('codemirror/addon/hint/show-hint.css');
require('codemirror/addon/search/searchcursor');
require('codemirror/addon/search/match-highlighter');
require('codemirror/addon/scroll/annotatescrollbar');
require('codemirror/mode/gfm/gfm');
require('codemirror/theme/eclipse.css');

import Dropzone from 'react-dropzone';

import pasteHelper from './PasteHelper';
import emojiAutoCompleteHelper from './EmojiAutoCompleteHelper';


export default class Editor extends React.Component {

  constructor(props) {
    super(props);

    // https://regex101.com/r/7BN2fR/2
    this.indentAndMarkPattern = /^([ \t]*)(?:>|\-|\+|\*|\d+\.) /;

    this.state = {
      value: this.props.value,
      dropzoneActive: false,
      isUploading: false,
    };

    this.getCodeMirror = this.getCodeMirror.bind(this);
    this.setCaretLine = this.setCaretLine.bind(this);
    this.forceToFocus = this.forceToFocus.bind(this);
    this.dispatchSave = this.dispatchSave.bind(this);

    this.onDragEnterForCM = this.onDragEnterForCM.bind(this);
    this.onDragLeave = this.onDragLeave.bind(this);
    this.onDrop = this.onDrop.bind(this);

    this.renderOverlay = this.renderOverlay.bind(this);
  }

  componentDidMount() {
    // initialize caret line
    this.setCaretLine(0);
    // set save handler
    codemirror.commands.save = this.dispatchSave;
  }

  getCodeMirror() {
    return this.refs.cm.editor;
  }

  forceToFocus() {
    const editor = this.getCodeMirror();
    // use setInterval with reluctance -- 2018.01.11 Yuki Takei
    const intervalId = setInterval(() => {
      this.getCodeMirror().focus();
      if (editor.hasFocus()) {
        clearInterval(intervalId);
      }
    }, 100);
  }

  /**
   * set caret position of codemirror
   * @param {string} number
   */
  setCaretLine(line) {
    const editor = this.getCodeMirror();
    editor.setCursor({line: line-1});   // leave 'ch' field as null/undefined to indicate the end of line
  }

  /**
   * remove overlay and set isUploading to false
   */
  terminateUploadingState() {
    this.setState({
      dropzoneActive: false,
      isUploading: false,
    });
  }

  /**
   * insert text
   * @param {string} text
   */
  insertText(text) {
    const editor = this.getCodeMirror();
    editor.getDoc().replaceSelection(text);
  }

  /**
   * dispatch onSave event
   */
  dispatchSave() {
    if (this.props.onSave != null) {
      this.props.onSave();
    }
  }

  /**
   * dispatch onUpload event
   */
  dispatchUpload(files) {
    if (this.props.onUpload != null) {
      this.props.onUpload(files);
    }
  }

  onDragEnterForCM(editor, event) {
    const dataTransfer = event.dataTransfer;

    // do nothing if contents is not files
    if (!dataTransfer.types.includes('Files')) {
      return;
    }

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

  onDragLeave() {
    this.setState({ dropzoneActive: false });
  }

  onDrop(accepted, rejected) {
    // rejected
    if (accepted.length != 1) { // length should be 0 or 1 because `multiple={false}` is set
      this.setState({ dropzoneActive: false });
      return;
    }

    const file = accepted[0];
    this.dispatchUpload(file);
    this.setState({ isUploading: true });
  }

  renderOverlay() {
    const overlayStyle = {
      position: 'absolute',
      zIndex: 1060, // FIXME: required because .content-main.on-edit has 'z-index:1050'
      top: 0,
      right: 0,
      bottom: 0,
      left: 0,
    };

    return (
      <div style={overlayStyle} className="dropzone-overlay">
        {this.state.isUploading &&
          <span className="dropzone-overlay-content">
            <i className="fa fa-spinner fa-pulse fa-fw"></i>
            <span className="sr-only">Uploading...</span>
          </span>
        }
        {!this.state.isUploading && <span className="dropzone-overlay-content"></span>}
      </div>
    );
  }

  render() {
    const flexContainer = {
      height: '100%',
      display: 'flex',
      flexDirection: 'column',
    }
    const expandHeight = {
      height: '100%',
    }

    let accept = 'null';  // reject all
    let className = 'dropzone';
    if (!this.props.isUploadable) {
      className += ' dropzone-unuploadable';
    }
    else {
      accept = 'image/*'
      className += ' dropzone-uploadable';

      if (this.props.isUploadableFile) {
        className += ' dropzone-uploadablefile';
        accept = '';  // allow all
      }
    }

    // uploading
    if (this.state.isUploading) {
      className += ' dropzone-uploading';
    }

    return (
      <div style={flexContainer}>
        <Dropzone
          ref="dropzone"
          disableClick
          disablePreview={true}
          style={expandHeight}
          accept={accept}
          className={className}
          acceptClassName="dropzone-accepted"
          rejectClassName="dropzone-rejected"
          multiple={false}
          onDragLeave={this.onDragLeave}
          onDrop={this.onDrop}
        >
          { this.state.dropzoneActive && this.renderOverlay() }

          <ReactCodeMirror
            ref="cm"
            editorDidMount={(editor) => {
              // add event handlers
              editor.on('paste', pasteHelper.pasteHandler);
            }}
            value={this.state.value}
            options={{
              mode: 'gfm',
              theme: 'eclipse',
              lineNumbers: true,
              tabSize: 4,
              indentUnit: 4,
              lineWrapping: true,
              autoRefresh: true,
              autoCloseTags: true,
              matchBrackets: true,
              matchTags: {bothTags: true},
              // match-highlighter, matchesonscrollbar, annotatescrollbar options
              highlightSelectionMatches: {annotateScrollbar: true},
              // markdown mode options
              highlightFormatting: true,
              // continuelist, indentlist
              extraKeys: {
                "Enter": "newlineAndIndentContinueMarkdownList",
                "Tab": "indentMore",
                "Shift-Tab": "indentLess",
              }
            }}
            onScroll={(editor, data) => {
              if (this.props.onScroll != null) {
                this.props.onScroll(data);
              }
            }}
            onChange={(editor, data, value) => {
              if (this.props.onChange != null) {
                this.props.onChange(value);
              }

              // Emoji AutoComplete
              emojiAutoCompleteHelper.showHint(editor);
            }}
            onDragEnter={this.onDragEnterForCM}
          />
        </Dropzone>

        <button type="button" className="btn btn-default btn-block btn-open-dropzone" onClick={() => {this.refs.dropzone.open()}}>
          <i className="fa fa-paperclip" aria-hidden="true"></i>&nbsp;
          Attach files by dragging &amp; dropping,&nbsp;
          <span className="btn-link">selecting them</span>,&nbsp;
          or (TBD) pasting from the clipboard.
        </button>
      </div>
    )
  }

}

Editor.propTypes = {
  value: PropTypes.string,
  isUploadable: PropTypes.bool,
  isUploadableFile: PropTypes.bool,
  onChange: PropTypes.func,
  onScroll: PropTypes.func,
  onSave: PropTypes.func,
  onUpload: PropTypes.func,
};