import {
  AndRule,
  type DataRef,
  LiteralRule,
  OrRule,
  RepetitionRule,
  type Rule,
  type RuleTestResponse,
} from '@os-team/lexical-rules';
import type { Parser } from './Parser.js';
import SRule from '../rules/SRule.js';
import NameRule from '../rules/NameRule.js';

export interface Mixed {
  type: 'MIXED';
  items?: string[];
}

/**
 * The mixed-content declaration.
 * See https://www.w3.org/TR/xml/#NT-Mixed
 */
class MixedParser implements Parser<Mixed> {
  private readonly rule: Rule<
    | [
        string,
        undefined,
        string,
        Array<[undefined, string, undefined, string]>,
        undefined,
        string,
      ]
    | [string, undefined, string, undefined, string]
  >;

  public constructor() {
    const prefixRule = new LiteralRule('('); // '('
    const anySRule = new SRule('*'); // S?
    const pcDataRule = new LiteralRule('#PCDATA'); // '#PCDATA'
    const separatorRule = new LiteralRule('|'); // '|'
    const nameRule = new NameRule(); // Name
    const suffixWithAsteriskRule = new LiteralRule(')*'); // ')*'
    const nameItemRule = new AndRule([
      anySRule,
      separatorRule,
      anySRule,
      nameRule,
    ]); // S? '|' S? Name
    const anyNameItemRule = new RepetitionRule(nameItemRule, 0); // (S? '|' S? Name)*
    const withNameRule = new AndRule([
      prefixRule,
      anySRule,
      pcDataRule,
      anyNameItemRule,
      anySRule,
      suffixWithAsteriskRule,
    ]); // '(' S? '#PCDATA' (S? '|' S? Name)* S? ')*'
    const suffixRule = new LiteralRule(')'); // ')'
    const withoutNameRule = new AndRule([
      prefixRule,
      anySRule,
      pcDataRule,
      anySRule,
      suffixRule,
    ]); // '(' S? '#PCDATA' S? ')'
    this.rule = new OrRule([withNameRule, withoutNameRule]); // '(' S? '#PCDATA' (S? '|' S? Name)* S? ')*' | '(' S? '#PCDATA' S? ')'
  }

  public test(ref: DataRef, pos: number): RuleTestResponse<Mixed> {
    const [isValid, nextPos, res] = this.rule.test(ref, pos);
    if (!isValid || res === undefined) return [false, nextPos];

    const mixed: Mixed = { type: 'MIXED' };
    if (res.length === 6) {
      const [, , , rawNames] = res;
      mixed.items = rawNames.map((item) => item[3]);
    }

    return [true, nextPos, mixed];
  }

  public build(data: Mixed) {
    return data.items && data.items.length > 0
      ? `(#PCDATA|${data.items.join('|')})*`
      : `(#PCDATA)`;
  }
}

export default MixedParser;