import { BasicInterceptor } from 'growi-commons';

import mtu from './MarkdownTableUtil';
import MarkdownTable from '../../models/MarkdownTable';

/**
 * Interceptor for markdown table
 */
export default class MarkdownTableInterceptor extends BasicInterceptor {

  /**
   * @inheritdoc
   */
  isInterceptWhen(contextName) {
    return (
      contextName === 'preHandleEnter'
    );
  }

  /**
   * return boolean value whether processable parallel
   */
  isProcessableParallel() {
    return false;
  }

  addRow(cm) {
    // get lines all of table from current position to beginning of table
    const strFromBot = mtu.getStrFromBot(cm);
    let table = MarkdownTable.fromMarkdownString(strFromBot);

    mtu.addRowToMarkdownTable(table);

    const strToEot = mtu.getStrToEot(cm);
    const tableBottom = MarkdownTable.fromMarkdownString(strToEot);
    if (tableBottom.table.length > 0) {
      table = mtu.mergeMarkdownTable([table, tableBottom]);
    }

    mtu.replaceMarkdownTableWithReformed(cm, table);
  }

  reformTable(cm) {
    const tableStr = mtu.getStrFromBot(cm) + mtu.getStrToEot(cm);
    const table = MarkdownTable.fromMarkdownString(tableStr);
    mtu.replaceMarkdownTableWithReformed(cm, table);
  }

  removeRow(editor) {
    editor.replaceLine('\n');
  }

  /**
   * @inheritdoc
   */
  async process(contextName, ...args) {
    const context = Object.assign(args[0]); // clone
    const editor = context.editor; // AbstractEditor instance

    // do nothing if editor is not a CodeMirrorEditor
    if (editor == null || editor.getCodeMirror() == null) {
      return context;
    }

    const cm = editor.getCodeMirror();

    const isInTable = mtu.isInTable(cm);
    const isLastRow = mtu.getStrToEot(cm) === editor.getStrToEol();

    if (isInTable) {
      // at EOL in the table
      if (mtu.isEndOfLine(cm)) {
        this.addRow(cm);
      }
      // last empty row
      else if (isLastRow && mtu.emptyLineOfTableRE.test(editor.getStrFromBol() + editor.getStrToEol())) {
        this.removeRow(editor);
      }
      else {
        this.reformTable(cm);
      }

      // report to manager that handling was done
      context.handlers.push(this.className);
      return context;
    }

  }

}