import { IListParser } from '../block';
import { Recursion } from '../context';
import { Parser, List, Node } from '../../combinator/parser';
import { union, inits, some, recursion, block, line, validate, indent, rewrite, open, fallback, lazy, fmap } from '../../combinator';
import { ulist_, fillFirstLine } from './ulist';
import { olist_ } from './olist';
import { inline } from '../inline';
import { contentline } from '../source';
import { visualize, trimBlank } from '../visibility';
import { unwrap, invalid } from '../util';
import { html, defrag } from 'typed-dom/dom';

export const ilist: IListParser = lazy(() => block(validate(
  /[-+*] /y,
  ilist_)));

export const ilist_: IListParser = lazy(() => block(fmap(validate(
  /[-+*](?:$|[ \r\n])/y,
  recursion(Recursion.block, some(union([
    fmap(fallback(
      inits([
        open(/[-+*](?:$|[ \r\n])/y, line(visualize(trimBlank(some(inline)))), true),
        indent(union([ulist_, olist_, ilist_])),
      ]),
      ilistitem),
      ns => new List([new Node(html('li', defrag(unwrap(fillFirstLine(ns)))))])),
  ])))),
  ns => new List([
    new Node(html('ul', {
      class: 'invalid',
      ...invalid('list', 'syntax', 'Use "-" instead of "+" or "*"'),
    }, unwrap(ns))),
  ]))));

export const ilistitem = rewrite(
  inits([
    contentline,
    indent<Parser<string>>(({ source }, output) => output.append(new Node(source))),
  ]),
  ({ source }, output) => output.import(new List([
    new Node(''),
    new Node(html('span', {
      class: 'invalid',
      ...invalid('list', 'syntax', 'Fix the indent or the head of the list item'),
    }, source.replace(/\r?\n/, '')))
  ])));