// lib/validators/review-validator.mjs
// Validate trekreview frontmatter + body invariants.
// 3-layer pattern (Content → File → CLI shim) mirroring brief-validator.

import { readFileSync, existsSync } from 'node:fs';
import { parseDocument } from '../util/frontmatter.mjs';
import { issue, ok, fail } from '../util/result.mjs';

export const REVIEW_REQUIRED_FRONTMATTER = [
  'type',
  'review_version',
  'task',
  'slug',
  'project_dir',
  'brief_path',
  'scope_sha_end',
  'reviewed_files_count',
  'findings',
];
export const REVIEW_BODY_SECTIONS = ['Executive Summary', 'Coverage', 'Remediation Summary'];

const HEX_ID_RE = /^[0-9a-f]{40}$/;

export function validateReviewContent(text, opts = {}) {
  const strict = opts.strict !== false;
  const doc = parseDocument(text);
  if (!doc.valid) return doc;

  const fm = doc.parsed.frontmatter || {};
  const body = doc.parsed.body || '';
  const errors = [];
  const warnings = [];

  for (const k of REVIEW_REQUIRED_FRONTMATTER) {
    if (!(k in fm)) {
      errors.push(issue('REVIEW_MISSING_FIELD', `Required frontmatter field missing: ${k}`));
    }
  }

  if (fm.type !== undefined && fm.type !== 'trekreview') {
    errors.push(issue('REVIEW_WRONG_TYPE', `frontmatter.type must be "trekreview", got "${fm.type}"`));
  }

  if (fm.findings !== undefined) {
    if (!Array.isArray(fm.findings)) {
      errors.push(issue(
        'REVIEW_BAD_FINDINGS_TYPE',
        `Field "findings" must be an array of finding-IDs, got ${typeof fm.findings}`,
        'Use block-style YAML: `findings:\\n  - <id1>\\n  - <id2>`',
      ));
    } else {
      for (let i = 0; i < fm.findings.length; i++) {
        const id = fm.findings[i];
        if (typeof id !== 'string' || !HEX_ID_RE.test(id)) {
          errors.push(issue(
            'REVIEW_BAD_FINDING_ID',
            `findings[${i}] is not a 40-char hex ID: ${JSON.stringify(id)}`,
          ));
        }
      }
    }
  }

  for (const section of REVIEW_BODY_SECTIONS) {
    const re = new RegExp(`^##\\s+${section}\\b`, 'm');
    if (!re.test(body)) {
      const issueObj = issue('REVIEW_MISSING_SECTION', `Required body section missing: ## ${section}`);
      if (strict) errors.push(issueObj);
      else warnings.push(issueObj);
    }
  }

  if (typeof fm.review_version === 'string') {
    const m = fm.review_version.match(/^(\d+)\.(\d+)$/);
    if (!m) {
      warnings.push(issue('REVIEW_VERSION_FORMAT', `review_version "${fm.review_version}" not in N.M form`));
    }
  }

  return { valid: errors.length === 0, errors, warnings, parsed: { frontmatter: fm, body } };
}

export function validateReview(filePath, opts = {}) {
  if (!existsSync(filePath)) return fail(issue('REVIEW_NOT_FOUND', `File not found: ${filePath}`));
  let text;
  try { text = readFileSync(filePath, 'utf-8'); }
  catch (e) { return fail(issue('REVIEW_READ_ERROR', `Cannot read ${filePath}: ${e.message}`)); }
  const r = validateReviewContent(text, opts);
  return { ...r, parsed: { ...r.parsed, filePath } };
}

if (import.meta.url === `file://${process.argv[1]}`) {
  const args = process.argv.slice(2);
  const strict = !args.includes('--soft');
  const filePath = args.find(a => !a.startsWith('--'));
  if (!filePath) {
    process.stderr.write('Usage: review-validator.mjs [--soft] [--json] <review.md>\n');
    process.exit(2);
  }
  const r = validateReview(filePath, { strict });
  if (args.includes('--json')) {
    process.stdout.write(JSON.stringify({ valid: r.valid, errors: r.errors, warnings: r.warnings }, null, 2) + '\n');
  } else {
    process.stdout.write(`review-validator: ${r.valid ? 'PASS' : 'FAIL'} ${filePath}\n`);
    for (const e of r.errors) process.stderr.write(`  ERROR  [${e.code}] ${e.message}\n`);
    for (const w of r.warnings) process.stderr.write(`  WARN   [${w.code}] ${w.message}\n`);
  }
  process.exit(r.valid ? 0 : 1);
}