import type { FormatTextState, FormatText } from '@erudit-js/core/formatText';

type LanguageFormatText = (text: string) => string;

const formatTextLoaders: Partial<
  Record<LanguageCode, () => Promise<{ default: LanguageFormatText }>>
> = {
  ru: () => import('../formatters/ru'),
};

export let formatText: FormatText;

export async function initFormatText() {
  const languageCode = ERUDIT.config.language.current;

  const formatTextLoader =
    languageCode in formatTextLoaders
      ? formatTextLoaders[languageCode]
      : undefined;

  let languageFormatText: LanguageFormatText = (text) => text;
  if (formatTextLoader) {
    languageFormatText = (await formatTextLoader()).default;
  }

  function _formatText(text: string, state?: FormatTextState): string;
  function _formatText(text: undefined, state?: FormatTextState): undefined;
  function _formatText(
    text?: string,
    state?: FormatTextState,
  ): string | undefined;
  function _formatText(
    text?: string,
    state?: FormatTextState,
  ): string | undefined {
    if (text === undefined) {
      return text;
    }

    //
    // Normalize spacing (new lines, spaces)
    //

    {
      text = text
        .trim()
        .replace(/\r\n/gm, '\n')
        .replace(/\n{3,}/gm, '\n\n')
        .replace(/[ \t]+/gm, ' ');
    }

    //
    // Normalize dashes
    //

    {
      text = text.replace(/(^| )--($| )/gm, '$1—$2');
    }

    //
    // Normalize quotes
    //

    {
      const quoteSymbols: [string, string] = (() => {
        switch (languageCode) {
          case 'ru':
            return ['«', '»'];
          default:
            return ['“', '”'];
        }
      })();

      let quoteOpen = state?.quote === 'opened';
      text = text.replaceAll(/"/gm, () => {
        quoteOpen = !quoteOpen;
        if (state) {
          state.quote = quoteOpen ? 'opened' : 'closed';
        }
        return quoteOpen ? quoteSymbols[0] : quoteSymbols[1];
      });
    }

    //
    // Normalize ellipsis
    //

    {
      text = text.replace(/\.{3}/gm, '…');
    }

    //
    // Language-specific formatting
    //

    return languageFormatText(text);
  }

  formatText = _formatText;
}