import {
  AndRule,
  type DataRef,
  MaybeRule,
  OrRule,
  type Rule,
  type RuleTestResponse,
} from '@os-team/lexical-rules';
import ExternalIDParser, { type ExternalID } from './ExternalIDParser.js';
import type { Parser } from './Parser.js';
import EntityValueRule from '../rules/EntityValueRule.js';
import NDataDeclParser from './NDataDeclParser.js';

export type EntityDef = string | (ExternalID & { nData?: string });

/**
 * See https://www.w3.org/TR/xml/#NT-EntityDef
 */
class EntityDefParser implements Parser<EntityDef> {
  private readonly externalIDParser: ExternalIDParser;

  private readonly nDataDeclParser: NDataDeclParser;

  private readonly rule: Rule<string | [ExternalID, string | undefined]>;

  public constructor() {
    const entityValueRule = new EntityValueRule(); // EntityValue
    this.externalIDParser = new ExternalIDParser(); // ExternalID
    this.nDataDeclParser = new NDataDeclParser(); // NDataDecl
    const maybeNDataDeclRule = new MaybeRule(this.nDataDeclParser); // NDataDecl?
    const externalIDAndMaybeNDataDeclRule = new AndRule([
      this.externalIDParser,
      maybeNDataDeclRule,
    ]); // ExternalID NDataDecl?
    this.rule = new OrRule([entityValueRule, externalIDAndMaybeNDataDeclRule]); // EntityValue | (ExternalID NDataDecl?)
  }

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

    let entityDef: EntityDef;
    if (Array.isArray(res)) {
      const [externalID, nData] = res;
      entityDef = { ...externalID };
      if (nData) entityDef.nData = nData;
    } else {
      entityDef = res;
    }

    return [true, nextPos, entityDef];
  }

  public build(data: EntityDef) {
    if (typeof data === 'string') return `"${data.replaceAll('"', "'")}"`;
    const externalID = this.externalIDParser.build(data);
    const nData = data.nData ? this.nDataDeclParser.build(data.nData) : '';
    return `${externalID}${nData}`;
  }
}

export default EntityDefParser;