/*
 * SPDX-FileCopyrightText: 2021 The HedgeDoc developers (see AUTHORS file)
 *
 * SPDX-License-Identifier: AGPL-3.0-only
 */

import { Editor, Hint, Hints, Pos } from 'codemirror'
import { findWordAtCursor, Hinter, search } from './index'

const wordRegExp = /^```((\w|-|_|\+)*)$/
let allSupportedLanguages: string[] = []

const codeBlockHint = (editor: Editor): Promise<Hints | null> => {
  return import(/* webpackChunkName: "highlight.js" */ '../../../common/hljs/hljs').then(
    (hljs) =>
      new Promise((resolve) => {
        const searchTerm = findWordAtCursor(editor)
        const searchResult = wordRegExp.exec(searchTerm.text)
        if (searchResult === null) {
          resolve(null)
          return
        }
        const term = searchResult[1]
        if (allSupportedLanguages.length === 0) {
          allSupportedLanguages = hljs.default
            .listLanguages()
            .concat('csv', 'flow', 'html', 'js', 'markmap', 'abc', 'graphviz', 'mermaid', 'vega-lite')
        }
        const suggestions = search(term, allSupportedLanguages)
        const cursor = editor.getCursor()
        if (!suggestions) {
          resolve(null)
        } else {
          resolve({
            list: suggestions.map(
              (suggestion: string): Hint => ({
                text: '```' + suggestion + '\n\n```\n',
                displayText: suggestion
              })
            ),
            from: Pos(cursor.line, searchTerm.start),
            to: Pos(cursor.line, searchTerm.end)
          })
        }
      })
  )
}

export const CodeBlockHinter: Hinter = {
  wordRegExp,
  hint: codeBlockHint
}