import * as codemirror from 'codemirror';

import markdownTable from 'markdown-table';

class MarkdownTableHelper {

  constructor() {
    // https://github.com/markdown-it/markdown-it/blob/d29f421927e93e88daf75f22089a3e732e195bd2/lib/rules_block/table.js#L83
    // https://regex101.com/r/7BN2fR/7
    this.tableAlignmentLineRE = /^[-:|][-:|\s]*$/;
    this.linePartOfTableRE = /^\|[^\r\n]*|[^\r\n]*\|$|([^\|\r\n]+\|[^\|\r\n]*)+/; // own idea

    this.isMatchedContext = this.isMatchedContext.bind(this);
    this.handleNewLine = this.handleNewLine.bind(this);

    this.newlineAndIndentContinueMarkdownTable = this.newlineAndIndentContinueMarkdownTable.bind(this);
    this.pasteText = this.pasteText.bind(this);

    this.getBot = this.getBot.bind(this);
    this.getEot = this.getEot.bind(this);
    this.getBol = this.getBol.bind(this);
    this.getStrFromBot = this.getStrFromBot.bind(this);
    this.getStrToEot = this.getStrToEot.bind(this);
    this.getStrFromBol = this.getStrFromBol.bind(this);
    this.parseFromTableStringToJSON = this.parseFromTableStringToJSON.bind(this);
  }

  /**
   * return whether context is matched by table
   * @param {any} editor An editor instance of CodeMirror
   */
  isMatchedContext(editor) {
    console.log('MarkdownTableHelper.isMatchedContext');
    // get strings from BOL(beginning of line) to current position
    const strFromBol = this.getStrFromBol(editor);
    console.log('strFromBol: ' + strFromBol);
    console.log('will return ' + (this.linePartOfTableRE.test(strFromBol) ? 'true' : 'false'));
    return this.linePartOfTableRE.test(strFromBol);
  }

  /**
   * handle new line
   * @param {any} editor An editor instance of CodeMirror
   */
  handleNewLine(editor) {
    console.log('MarkdownTableHelper.handleNewLine');
    this.newlineAndIndentContinueMarkdownTable(editor);
  }

  /**
   * insert new line with auto shaping format of Markdown table
   * @param {any} editor An editor instance of CodeMirror
   */
  newlineAndIndentContinueMarkdownTable(editor) {
    console.log('MarkdownTableHelper.newlineAndIndentContinueMarkdownTable');
    if (!this.isMatchedContext(editor)) return;

    // get lines all of table from current position to beginning of table
    const strTableLines = this.getStrFromBot(editor);
    console.log('strTableLines: ' + strTableLines);

    const table = this.parseFromTableStringToJSON(editor, this.getBot(editor), editor.getCursor());
    console.log('table: ' + JSON.stringify(table));
    const strTableLinesFormated = table;
    console.log('strTableLinesFormated: ' + strTableLinesFormated);

    // replace the lines to strFormatedTableLines
    editor.getDoc().replaceRange(strTableLinesFormated, this.getBot(editor), editor.getCursor());
    codemirror.commands.newlineAndIndent(editor);
  }

  /**
   * paste text
   * @param {any} editor An editor instance of CodeMirror
   * @param {any} event
   * @param {string} text
   */
  pasteText(editor, event, text) {
    // [TODO] replace to formated table markdown
  }

  /**
   * return the postion of the BOT(beginning of table)
   * (It is assumed that current line is a part of table)
   */
  getBot(editor) {
    const firstLine = editor.getDoc().firstLine();
    const curPos = editor.getCursor();
    let line = curPos.line - 1;
    for (; line >= firstLine; line--) {
      const strLine = editor.getDoc().getLine(line);
      if (!this.linePartOfTableRE.test(strLine)) {
        break;
      }
    }
    const botLine = Math.max(firstLine, line + 1);
    return { line: botLine, ch: 0 };
  }

  /**
   * return the postion of the EOT(end of table)
   * (It is assumed that current line is a part of table)
   */
  getEot(editor) {
    const lastLine = editor.getDoc().lastLine();
    const curPos = editor.getCursor();
    let line = curPos.line + 1;
    for (; line <= lastLine; line++) {
      const strLine = editor.getDoc().getLine(line);
      if (!this.linePartOfTableRE.test(strLine)) {
        break;
      }
    }
    const eotLine = Math.min(line - 1, lastLine);
    const lineLength = editor.getDoc().getLine(eotLine).length;
    return { line: eotLine, ch: lineLength };
  }

  /**
   * return the postion of the BOL(beginning of line)
   */
  getBol(editor) {
    const curPos = editor.getCursor();
    return { line: curPos.line, ch: 0 };
  }

  /**
   * return strings from BOT(beginning of table) to current position
   */
  getStrFromBot(editor) {
    const curPos = editor.getCursor();
    return editor.getDoc().getRange(this.getBot(editor), curPos);
  }

  /**
   * return strings from current position to EOT(end of table)
   */
  getStrToEot(editor) {
    const curPos = editor.getCursor();
    return editor.getDoc().getRange(curPos, this.getEot(editor));
  }

  /**
   * return strings from BOL(beginning of line) to current position
   */
  getStrFromBol(editor) {
    const curPos = editor.getCursor();
    return editor.getDoc().getRange(this.getBol(editor), curPos);
  }

  /**
   * returns object whose described by 'markdown-table' format
   *   ref. https://github.com/wooorm/markdown-table
   * @param {string} lines all of table
   */
  parseFromTableStringToJSON(editor, posBeg, posEnd) {
    console.log("parseFromTableStringToJSON: posBeg.line: " + posBeg.line + ", posEnd.line: " + posEnd.line);
    let contents = [];
    let aligns = [];
    for (let pos = posBeg; pos.line <= posEnd.line; pos.line++) {
      const line = editor.getDoc().getLine(pos.line);
      console.log("line#" + pos.line + ": " + line);

      if (this.tableAlignmentLineRE.test(line)) {
        // parse line which described alignment
        const alignRuleRE = [
          { align: 'c', regex: /^:-+:$/ },
          { align: 'l', regex: /^:-+$/  },
          { align: 'r', regex: /^-+:$/  },
        ];
        let lineText = "";
        lineText = line.replace(/^\||\|$/g, ''); // strip off pipe charactor which is placed head of line and last of line.
        lineText = lineText.replace(/\s*/g, '');
        aligns = lineText.split(/\|/).map(col => {
          const rule = alignRuleRE.find(rule => col.match(rule.regex));
          return (rule != undefined) ? rule.align : '';
        });
      } else {
        // parse line whether header or body
        let lineText = "";
        lineText = line.replace(/\s*\|\s*/g, '|');
        lineText = lineText.replace(/^\||\|$/g, ''); // strip off pipe charactor which is placed head of line and last of line.
        const row = lineText.split(/\|/);
        console.log('row: ' + row);
        contents.push(row);
      }
    }
    console.log('contents: ' + JSON.stringify(contents));
    console.log('aligns: ' + JSON.stringify(aligns));
    return markdownTable(contents, { align: aligns } );
  }
}

// singleton pattern
const instance = new MarkdownTableHelper();
Object.freeze(instance);
export default instance;