const ISSUE_MESSAGES = {
  question_missing: "No user-facing Open Question was generated.",
  question_empty: "The generated Open Question was empty.",
  question_not_interrogative: "The generated Open Question was not a direct interrogative.",
  question_indirect_proposition:
    "The generated Open Question used an indirect uncertainty proposition.",
};

/**
 * Narrow presentation validation only. This does not attempt to prove semantic
 * equivalence with the canonical uncertainty and never rewrites either value.
 */
export function validateOpenQuestionCandidate(candidate) {
  if (candidate === undefined || candidate === null) {
    return { valid: false, category: "question_missing" };
  }

  if (typeof candidate !== "string" || candidate.trim().length === 0) {
    return { valid: false, category: "question_empty" };
  }

  const question = candidate.trim();
  if (/^whether\b/i.test(question)) {
    return { valid: false, category: "question_indirect_proposition" };
  }

  if (!question.endsWith("?")) {
    return { valid: false, category: "question_not_interrogative" };
  }

  return { valid: true, question };
}

/**
 * Remove invalid presentation candidates without changing canonical descriptions,
 * IDs, ordering, relationships, or any other reconstruction content.
 */
export function validateReconstructionOpenQuestions(reconstruction) {
  const issues = [];
  const importantUnknowns = (reconstruction?.importantUnknowns ?? []).map(
    (unknown, index) => {
      const validation = validateOpenQuestionCandidate(unknown.question);
      if (validation.valid) {
        return { ...unknown, question: validation.question };
      }

      const { question: _invalidQuestion, ...canonicalUnknown } = unknown;
      issues.push({
        category: validation.category,
        path: ["reconstruction", "importantUnknowns", index, "question"],
        unknownId: unknown.id,
        message: ISSUE_MESSAGES[validation.category],
        severity: "nonfatal",
      });
      return canonicalUnknown;
    },
  );

  return {
    reconstruction: { ...reconstruction, importantUnknowns },
    issues,
  };
}