import {
  AndRule,
  type DataRef,
  OrRule,
  type Rule,
  type RuleTestResponse,
} from '@os-team/lexical-rules';
import { type Parser } from './Parser.js';
import ChoiceParser, { type Choice } from './ChoiceParser.js';
import SeqParser, { type Seq } from './SeqParser.js';
import NameRule from '../rules/NameRule.js';
import createLazyParser from './createLazyParser.js';
import QuantifierRule, { type Quantifier } from '../rules/QuantifierRule.js';

type CpContent = string | Choice | Seq;
export type Cp = CpContent | [CpContent, '?' | '*' | '+'];

/**
 * See https://www.w3.org/TR/xml/#NT-cp
 */
class CpParser implements Parser<Cp> {
  private readonly choiceParser: ChoiceParser;

  private readonly seqParser: SeqParser;

  private readonly rule: Rule<[string | Choice | Seq, Quantifier]>;

  public constructor() {
    const nameRule = new NameRule(); // Name
    this.choiceParser = createLazyParser<Choice, ChoiceParser>(ChoiceParser); // choice
    this.seqParser = createLazyParser<Seq, SeqParser>(SeqParser); // seq
    const quantifierRule = new QuantifierRule(); // ('?' | '*' | '+')?
    const nameOrChoiceOrSeqRule = new OrRule([
      nameRule,
      this.choiceParser,
      this.seqParser,
    ]);
    this.rule = new AndRule([nameOrChoiceOrSeqRule, quantifierRule]); // (Name | choice | seq) ('?' | '*' | '+')?
  }

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

    const [content, quantifier] = res;
    const cp: Cp = quantifier ? [content, quantifier] : content;

    return [true, nextPos, cp];
  }

  public build(data: Cp) {
    const [content, quantifier = ''] = Array.isArray(data) ? data : [data];

    let strContent: string;
    if (typeof content === 'string') {
      strContent = content;
    } else if (content.type === 'CHOICE') {
      strContent = this.choiceParser.build(content);
    } else {
      strContent = this.seqParser.build(content);
    }

    return `${strContent}${quantifier}`;
  }
}

export default CpParser;