#!/usr/bin/env node
// Unified validation command: one parse pass, all findings.
//
// Merges the four former tools into a single `node tools/validate.mjs` run:
//   1. tools/eu4_clausewitz/bin/validate.mjs (refs, encoding, loc, unowned-land, ambiguities)
//   2. tools/bin/audit.mjs (duplicate definitions in common/ and events/)
//   3. tools/build_variants.mjs check (English overlay + manifest consistency)
//   4. tools/localisation.ps1 check (localisation source vs built output)
//
// New: province/area/region/trade-node scope refs in events/decisions/missions.
//
// Output: findings grouped by category, file:line:col format, summary count
// per level (error/warn/info). Exit non-zero only on errors.

import { createHash } from 'node:crypto';
import { readdir, readFile, stat } from 'node:fs/promises';
import { dirname, join, relative } from 'node:path';
import { fileURLToPath } from 'node:url';
import process from 'node:process';

import { load } from './eu4_clausewitz/src/index.mjs';
import { readGameText } from './eu4_clausewitz/src/codec.mjs';
import { tokenize } from './eu4_clausewitz/src/lexer.mjs';
import { parse } from './eu4_clausewitz/src/ast.mjs';
import { isDateKey } from './eu4_clausewitz/src/node.mjs';
import { buildDefinedSets, buildRefGraph } from './eu4_clausewitz/src/refs.mjs';
import { runRules, summarize } from './eu4_clausewitz/src/validate.mjs';
import { loadDir } from './eu4_clausewitz/src/overlay.mjs';

import provincesRegistry from './eu4_clausewitz/registry/provinces.mjs';
import countriesRegistry from './eu4_clausewitz/registry/countries.mjs';
import provinceRules, { provinceRefRules } from './eu4_clausewitz/registry/provinces.rules.mjs';
import countryRules, { countryRefRules } from './eu4_clausewitz/registry/countries.rules.mjs';
import encodingRules from './eu4_clausewitz/registry/encoding.rules.mjs';

import { loadManifest, validateManifestAgainstRoot } from './history_language_manifest.mjs';

import { hasUtf8Bom, encodeBuffer } from './eu4_han_convert/src/codec.js';

// --- paths ------------------------------------------------------------------

const root = join(dirname(fileURLToPath(import.meta.url)), '..');
const MOD_ROOT = root;
const VANILLA_ROOT = 'C:/Program Files (x86)/Steam/steamapps/common/Europa Universalis IV';
const GAME_LOCALISATION = join(VANILLA_ROOT, 'localisation');
const REGISTRIES = [provincesRegistry, countriesRegistry];
const MANIFEST_PATH = join(root, 'history_language_manifest.json');
const LOC_MANIFEST_PATH = join(root, 'localisation_manifest.json');
const CODEC_PATH = join(root, 'tools', 'eu4_han_convert', 'src', 'codec.js');
const LOC_SOURCE_ROOT = join(root, 'localisation_source');
const LOC_ENCODED_ROOT = join(root, 'localisation');
const ENGLISH_SOURCE = join(root, 'localisation_english_source');
const ENGLISH_PROVENANCE = join(root, 'localisation_english_provenance.json');
const CHINESE_SOURCE = join(root, 'localisation_source');

// --- helpers ----------------------------------------------------------------

async function walkTxtFiles(dir, out = []) {
  let entries;
  try {
    entries = await readdir(dir, { withFileTypes: true });
  } catch {
    return out;
  }
  for (const entry of entries) {
    const path = join(dir, entry.name);
    if (entry.isDirectory()) await walkTxtFiles(path, out);
    else if (entry.isFile() && entry.name.toLowerCase().endsWith('.txt')) out.push(path);
  }
  return out;
}

async function walkYmlFiles(dir, out = []) {
  let entries;
  try {
    entries = await readdir(dir, { withFileTypes: true });
  } catch {
    return out;
  }
  for (const entry of entries) {
    const path = join(dir, entry.name);
    if (entry.isDirectory()) await walkYmlFiles(path, out);
    else if (entry.isFile() && entry.name.toLowerCase().endsWith('.yml')) out.push(path);
  }
  return out;
}

function rel(path) {
  return relative(MOD_ROOT, path).replace(/\\/g, '/');
}

async function parseFile(path) {
  const { text } = await readGameText(path);
  return { text, tree: parse(tokenize(text)) };
}

async function exists(path) {
  try {
    await stat(path);
    return true;
  } catch (error) {
    if (error.code === 'ENOENT') return false;
    throw error;
  }
}

// ===========================================================================
// Phase 1: Build defined sets + map-level valid ID sets
// ===========================================================================

async function buildMapSets() {
  // Province IDs from definition.csv: "province;red;green;blue;x;x" per line
  const defPath = join(MOD_ROOT, 'map', 'definition.csv');
  const provinces = new Set();
  try {
    const content = await readFile(defPath, 'utf8');
    for (const line of content.split(/\r?\n/)) {
      const trimmed = line.trim();
      if (!trimmed || trimmed.startsWith('#')) continue;
      const id = trimmed.split(';')[0];
      if (/^\d+$/.test(id)) provinces.add(Number(id));
    }
  } catch { /* definition.csv missing - leave empty */ }

  // Areas from area.txt: top-level "<name>_area = { ... }" blocks
  const areas = new Set();
  try {
    const { tree } = await parseFile(join(MOD_ROOT, 'map', 'area.txt'));
    for (const item of tree.items) {
      if (item.kind === 'pair' && item.value.type === 'block') {
        areas.add(item.keyToken.value);
      }
    }
  } catch { /* missing - leave empty */ }

  // Regions from region.txt: top-level "<name>_region = { ... }" blocks
  const regions = new Set();
  try {
    const { tree } = await parseFile(join(MOD_ROOT, 'map', 'region.txt'));
    for (const item of tree.items) {
      if (item.kind === 'pair' && item.value.type === 'block') {
        regions.add(item.keyToken.value);
      }
    }
  } catch { /* missing - leave empty */ }

  // Trade nodes from common/tradenodes/: top-level "<name> = { ... }" blocks
  const tradeNodes = new Set();
  const tradeNodeFiles = await walkTxtFiles(join(MOD_ROOT, 'common', 'tradenodes'));
  for (const path of tradeNodeFiles) {
    const { tree } = await parseFile(path);
    for (const item of tree.items) {
      if (item.kind === 'pair' && item.value.type === 'block') {
        tradeNodes.add(item.keyToken.value);
      }
    }
  }

  return { provinces, areas, regions, tradeNodes };
}

// ===========================================================================
// Phase 2: Ref integrity (from old validate.mjs runRefs)
// ===========================================================================

async function runRefs(eu4, ctx) {
  const graph = await buildRefGraph(eu4, { gameRoot: VANILLA_ROOT, modRoot: MOD_ROOT }, REGISTRIES, ctx.definedSets);
  const rules = [...provinceRefRules, ...countryRefRules];
  return runRules(rules, graph.forward, ctx);
}

// ===========================================================================
// Phase 3: Province/country warnings (from old validate.mjs)
// ===========================================================================

async function collectRecords(eu4, registry) {
  const { entries } = await loadDir({ gameRoot: VANILLA_ROOT, modRoot: MOD_ROOT, relPath: registry.path });
  const collection = await eu4.dir(registry.path);
  const records = [];
  for (const id of entries.keys()) {
    records.push({ id, node: await collection.get(id) });
  }
  return records;
}

async function runProvinceCountryWarnings(eu4, ctx) {
  const provinceRecords = await collectRecords(eu4, provincesRegistry);
  const countryRecords = await collectRecords(eu4, countriesRegistry);
  return [
    ...runRules(provinceRules, provinceRecords, ctx),
    ...runRules(countryRules, countryRecords, ctx),
  ];
}

// ===========================================================================
// Phase 4: Encoding (from old validate.mjs runEncoding)
// ===========================================================================

async function runEncoding() {
  const dirs = [
    join(VANILLA_ROOT, 'history'),
    join(VANILLA_ROOT, 'common'),
    join(MOD_ROOT, 'history'),
    join(MOD_ROOT, 'common'),
  ];
  const files = [];
  for (const dir of dirs) await walkTxtFiles(dir, files);
  const records = [];
  for (const path of files) {
    const { text, bom } = await readGameText(path);
    records.push({ path, text, bom });
  }
  return runRules(encodingRules, records, {});
}

// ===========================================================================
// Phase 5: Overlay ambiguities (from old validate.mjs)
// ===========================================================================

function runAmbiguities(eu4) {
  return eu4.ambiguities
    .filter((a) => !(a.key === 'SOF' && a.layer === 'vanilla'))
    .map((a) => ({
      id: 'overlay-ambiguity',
      level: 'info',
      message: `${a.dir}: key "${a.key}" (${a.layer} layer) is ambiguous between ${a.paths.map((p) => rel(p)).join(', ')}`,
    }));
}

// ===========================================================================
// Phase 6: Duplicate definitions (from audit.mjs)
// ===========================================================================

const AUDIT_SKIP_DIRS = new Set(['common/defines', 'common/custom_gui']);
const AUDIT_SKIP_PREFIXES = ['common/countries'];

function noteKey(buckets, bucket, key, file, line) {
  let byKey = buckets.get(bucket);
  if (!byKey) {
    byKey = new Map();
    buckets.set(bucket, byKey);
  }
  let occ = byKey.get(key);
  if (!occ) {
    occ = [];
    byKey.set(key, occ);
  }
  occ.push({ file, line });
}

function dupFindings(id, level, bucket, key, occ) {
  const sorted = [...occ].sort((a, b) => a.file.localeCompare(b.file) || a.line - b.line);
  return [{
    id,
    level,
    file: sorted[0].file,
    line: sorted[0].line,
    message: `duplicate "${key}" in ${bucket}: ${sorted.map((s) => `${s.file}:${s.line}`).join(', ')}`,
  }];
}

async function runDuplicateDefinitions() {
  const findings = [];

  // --- common/ ---
  const commonBuckets = new Map(); // bucket -> Map<key, Array<{file, line}>>
  const commonFiles = await walkTxtFiles(join(MOD_ROOT, 'common'));
  for (const path of commonFiles) {
    const bucket = rel(join(path, '..'));
    if (AUDIT_SKIP_DIRS.has(bucket) || AUDIT_SKIP_PREFIXES.some((p) => bucket === p || bucket.startsWith(p + '/'))) continue;
    const { tree } = await parseFile(path);
    let keyBucket = bucket;
    if (bucket === 'common/province_names') {
      const stem = rel(path).split('/').pop().replace(/\.txt$/i, '').replace(/_new$/i, '');
      keyBucket = `${bucket}/${stem}`;
    }
    for (const item of tree.items) {
      if (item.kind !== 'pair') continue;
      noteKey(commonBuckets, keyBucket, item.keyToken.value, rel(path), item.keyToken.line);
    }
  }

  for (const [bucket, byKey] of [...commonBuckets.entries()].sort()) {
    for (const [key, occ] of byKey) {
      const files = new Set(occ.map((o) => o.file));
      if (occ.length > 1 && files.size > 1) {
        findings.push(...dupFindings('dup-common-cross-file', 'warn', bucket, key, occ));
      } else if (occ.length > 1) {
        findings.push(...dupFindings('dup-common-in-file', 'warn', bucket, key, occ));
      }
    }
  }

  // --- events/ ---
  const eventIds = new Map(); // id -> Array<{file, line}>
  const eventFiles = await walkTxtFiles(join(MOD_ROOT, 'events'));
  for (const path of eventFiles) {
    const { tree } = await parseFile(path);
    let namespace = null;
    for (const item of tree.items) {
      if (item.kind === 'pair' && item.keyToken.value === 'namespace'
          && item.value.type === 'scalar' && item.value.token) {
        namespace = item.value.token.value;
        continue;
      }
      if (item.kind !== 'pair' || !item.keyToken.value.endsWith('_event')
          || item.value.type !== 'block') continue;
      for (const inner of item.value.items) {
        if (inner.kind === 'pair' && inner.keyToken.value === 'id'
            && inner.value.type === 'scalar' && inner.value.token) {
          let id = inner.value.token.value;
          if (!id.includes('.') && namespace) id = `${namespace}.${id}`;
          let occ = eventIds.get(id);
          if (!occ) {
            occ = [];
            eventIds.set(id, occ);
          }
          occ.push({ file: rel(path), line: inner.keyToken.line });
          break;
        }
      }
    }
  }

  for (const [id, occ] of [...eventIds.entries()].sort((a, b) => a[0].localeCompare(b[0]))) {
    if (occ.length > 1) {
      findings.push(...dupFindings('dup-event-id', 'error', 'events', id, occ));
    }
  }

  // --- common/scripted_effects/ and common/scripted_triggers/ ---
  for (const subdir of ['common/scripted_effects', 'common/scripted_triggers']) {
    const files = await walkTxtFiles(join(MOD_ROOT, subdir));
    const names = new Map(); // name -> Array<{file, line}>
    for (const path of files) {
      const { tree } = await parseFile(path);
      for (const item of tree.items) {
        if (item.kind === 'pair') {
          let occ = names.get(item.keyToken.value);
          if (!occ) {
            occ = [];
            names.set(item.keyToken.value, occ);
          }
          occ.push({ file: rel(path), line: item.keyToken.line });
        }
      }
    }
    const id = subdir === 'common/scripted_effects' ? 'dup-scripted-effect' : 'dup-scripted-trigger';
    for (const [name, occ] of names) {
      if (occ.length > 1) {
        findings.push(...dupFindings(id, 'warn', subdir, name, occ));
      }
    }
  }

  return findings;
}

// ===========================================================================
// Phase 7: Province/area/region/trade-node refs in events/decisions/missions (NEW)
// ===========================================================================

const ENGINE_AREA_KEYWORDS = new Set([
  'random_owned_area', 'random_enemy_area', 'random_neighboring_area',
  'random_area', 'any_owned_area', 'any_area', 'every_owned_area',
  'every_area', 'any_neighbor_area', 'every_neighbor_area',
  'random_neighbor_area', 'has_trade_company_investment_in_area',
]);

const ENGINE_REGION_KEYWORDS = new Set([
  'random_owned_region', 'random_region', 'any_owned_region', 'any_region',
  'every_owned_region', 'every_region', 'random_new_world_region',
  'any_neighbor_region', 'every_neighbor_region', 'random_neighbor_region',
]);

// Trade-node iterator scopes and trigger/effect names that end in _node but
// are NOT trade-node-name scopes. A real trade node scope is just
// "<node_name> = { ... }" where node_name is a lowercase identifier from
// 00_tradenodes.txt.
const ENGINE_TRADE_NODE_KEYWORDS = new Set([
  'any_active_trade_node', 'home_trade_node', 'any_trade_node',
  'every_trade_node', 'random_trade_node', 'any_neighbor_trade_node',
  'every_neighbor_trade_node', 'random_neighbor_trade_node',
  'capital_trade_node', 'random_active_trade_node',
  'every_active_trade_node', 'any_core_trade_node', 'every_core_trade_node',
  'random_core_trade_node', 'all_trade_node',
  'has_privateer_share_in_trade_node', 'has_trade_power_in_trade_node',
  'has_missionary_in_trade_node',
]);

// Prefixes/patterns that indicate a key is a trigger, effect, event_target,
// or variable rather than a named scope. These never represent area/region/
// trade-node definitions.
const NON_SCOPE_PREFIXES = ['has_', 'event_target:', '@', 'set_', 'change_',
  'add_', 'remove_', 'is_', 'can_', 'does_'];

function isNonScopeKey(key) {
  return NON_SCOPE_PREFIXES.some((p) => key.startsWith(p)) || key.includes(':');
}

// Fields whose scalar value should be a province ID
const PROVINCE_ID_FIELDS = new Set([
  'province_id', 'owns_core_province', 'capital', 'capital_province',
  'province', 'target_province', 'hidden_province',
  'fleet_size_province', 'missionary_province', 'reformation_center',
]);

const DATE_LIKE = /^\d{1,4}\.\d{1,2}\.\d{1,2}$/;
const PURE_NUMBER = /^\d+$/;

function walkItems(items, fn) {
  for (const item of items) {
    fn(item);
    if (item.kind === 'pair' && item.value.type === 'block') {
      walkItems(item.value.items, fn);
    }
  }
}

async function runScopeRefs(mapSets) {
  const findings = [];
  const dirs = ['events', 'decisions', 'missions'];

  for (const dirName of dirs) {
    const files = await walkTxtFiles(join(MOD_ROOT, dirName));
    for (const path of files) {
      const { tree } = await parseFile(path);
      const fileRel = rel(path);

      walkItems(tree.items, (item) => {
        if (item.kind !== 'pair') return;
        const key = item.keyToken.value;
        const line = item.keyToken.line;

        // Check province-id fields with scalar numeric values
        if (PROVINCE_ID_FIELDS.has(key) && item.value.type === 'scalar' && item.value.token) {
          const val = item.value.token.value;
          if (PURE_NUMBER.test(val)) {
            const id = Number(val);
            if (!mapSets.provinces.has(id)) {
              findings.push({
                id: 'scope-province-ref', level: 'warn', file: fileRel, line,
                message: `province_id ${val} (field "${key}") is not a valid province in definition.csv`,
              });
            }
          }
        }

        // Check bare-number scopes: "1234 = { ... }" - verify it's a valid province
        if (item.value.type === 'block' && PURE_NUMBER.test(key) && !DATE_LIKE.test(key)) {
          const id = Number(key);
          if (!mapSets.provinces.has(id)) {
            findings.push({
              id: 'scope-province-scope', level: 'warn', file: fileRel, line,
              message: `province scope "${key}" is not a valid province in definition.csv`,
            });
          }
        }

        // Check _area scopes
        if (item.value.type === 'block' && key.endsWith('_area') && !ENGINE_AREA_KEYWORDS.has(key) && !isNonScopeKey(key)) {
          if (!mapSets.areas.has(key)) {
            findings.push({
              id: 'scope-area-ref', level: 'warn', file: fileRel, line,
              message: `area "${key}" is not defined in map/area.txt`,
            });
          }
        }

        // Check _region scopes
        if (item.value.type === 'block' && key.endsWith('_region') && !ENGINE_REGION_KEYWORDS.has(key) && !isNonScopeKey(key)) {
          if (!mapSets.regions.has(key)) {
            findings.push({
              id: 'scope-region-ref', level: 'warn', file: fileRel, line,
              message: `region "${key}" is not defined in map/region.txt`,
            });
          }
        }

        // Check _node scopes
        if (item.value.type === 'block' && key.endsWith('_node') && !ENGINE_TRADE_NODE_KEYWORDS.has(key) && !isNonScopeKey(key) && key === key.toLowerCase() && !key.includes('_best_')) {
          if (!mapSets.tradeNodes.has(key)) {
            findings.push({
              id: 'scope-tradenode-ref', level: 'warn', file: fileRel, line,
              message: `trade node "${key}" is not defined in common/tradenodes/`,
            });
          }
        }
      });
    }
  }

  return findings;
}

// ===========================================================================
// Phase 8: Manifest consistency (from build_history_english.mjs check)
// ===========================================================================

async function runManifestCheck() {
  const findings = [];
  const started = Date.now();
  try {
    const manifest = await loadManifest(MANIFEST_PATH);
    const summary = await validateManifestAgainstRoot(manifest, root);
    if (summary.stale.length) {
      const sample = summary.stale.slice(0, 5).join(', ');
      findings.push({
        id: 'manifest-stale', level: 'error',
        message: `${summary.stale.length} file(s) changed since last manifest stamp (e.g. ${sample}${summary.stale.length > 5 ? ', ...' : ''}); run: node tools/history_language_manifest.mjs stamp`,
      });
    }
  } catch (error) {
    findings.push({
      id: 'manifest-consistency', level: 'error',
      message: error.message,
    });
  }
  console.log(`Manifest check took ${((Date.now() - started) / 1000).toFixed(1)}s`);
  return findings;
}

// ===========================================================================
// Phase 9: Localisation source vs built (from localisation.mjs check)
// ===========================================================================

function sha256(buffer) {
  return createHash('sha256').update(buffer).digest('hex');
}

async function listLocalisationFiles(dirRoot) {
  const files = [];
  async function visit(directory) {
    const entries = await readdir(directory, { withFileTypes: true });
    for (const entry of entries) {
      const path = join(directory, entry.name);
      if (entry.isDirectory()) await visit(path);
      else if (entry.isFile() && entry.name.endsWith('.yml')) {
        files.push(relative(dirRoot, path).replaceAll('\\', '/'));
      }
    }
  }
  await visit(dirRoot);
  return files.sort();
}

async function runLocalisationCheck() {
  const findings = [];

  const [sourceFiles, encodedFiles] = await Promise.all([
    listLocalisationFiles(LOC_SOURCE_ROOT),
    listLocalisationFiles(LOC_ENCODED_ROOT),
  ]);

  const sourceSet = new Set(sourceFiles);
  const encodedSet = new Set(encodedFiles);

  for (const path of sourceFiles) {
    if (!encodedSet.has(path)) {
      findings.push({ id: 'loc-file-set', level: 'error', message: `missing encoded file: ${path}` });
    }
  }
  for (const path of encodedFiles) {
    if (!sourceSet.has(path)) {
      findings.push({ id: 'loc-file-set', level: 'error', message: `missing source file: ${path}` });
    }
  }

  // Check manifest currency + hash comparison
  let manifest = null;
  try {
    manifest = JSON.parse(await readFile(LOC_MANIFEST_PATH, 'utf8'));
  } catch {
    // no manifest - will fall through to re-encode check
  }

  const codecSha256 = sha256(await readFile(CODEC_PATH));
  const manifestCurrent = manifest
    && manifest.version === 1
    && manifest.profile === 'compatible'
    && manifest.codecSha256 === codecSha256;

  let outOfDate = false;

  for (const path of sourceFiles) {
    if (!encodedSet.has(path)) continue;
    const sourceBuffer = await readFile(join(LOC_SOURCE_ROOT, path));
    const encodedBuffer = await readFile(join(LOC_ENCODED_ROOT, path));

    if (!hasUtf8Bom(encodedBuffer)) {
      findings.push({ id: 'loc-bom', level: 'error', message: `missing UTF-8 BOM: ${path}` });
    }

    const sourceSha256 = sha256(sourceBuffer);
    const encodedSha256 = sha256(encodedBuffer);
    const entry = manifestCurrent ? manifest.files?.[path] : null;

    if (entry && entry.sourceSha256 === sourceSha256 && entry.encodedSha256 === encodedSha256) {
      continue; // verified via manifest
    }

    // Fall back to re-encode-and-compare
    let expected;
    try {
      expected = encodeBuffer(new TextDecoder('utf-8', { fatal: true }).decode(
        sourceBuffer.subarray(0, 3).equals(Buffer.from([0xef, 0xbb, 0xbf])) ? sourceBuffer.subarray(3) : sourceBuffer,
      ), { profile: 'compatible' });
    } catch (error) {
      findings.push({ id: 'loc-encode', level: 'error', message: `failed to encode ${path}: ${error.message}` });
      outOfDate = true;
      continue;
    }

    if (!encodedBuffer.equals(expected)) {
      findings.push({ id: 'loc-stale', level: 'error', message: `encoded localisation is out of date: ${path}` });
      outOfDate = true;
    }
  }

  if (!manifestCurrent || outOfDate) {
    findings.push({ id: 'loc-manifest', level: 'error', message: 'localisation_manifest.json is out of date; run the build command' });
  }

  return findings;
}

// ===========================================================================
// Phase 10: English overlay (from build_variants.mjs validateEnglishOverlay)
// ===========================================================================

async function listEnglishFiles(directory, englishOnly = false) {
  const files = [];
  async function visit(current) {
    for (const entry of await readdir(current, { withFileTypes: true })) {
      const path = join(current, entry.name);
      if (entry.isDirectory()) await visit(path);
      else if (entry.isFile() && entry.name.endsWith('.yml') && (!englishOnly || entry.name.endsWith('_l_english.yml'))) {
        files.push(relative(directory, path).replaceAll('\\', '/'));
      }
    }
  }
  await visit(directory);
  return files.sort();
}

function parseLocEntries(content) {
  return [...content.split(/\r?\n/)].flatMap((line) => {
    const match = line.match(/^\s*([^\s:#]+):(?:\d+)?\s+".*"/);
    return match ? [[match[1], line.trimEnd()]] : [];
  });
}

async function readKeyLineIndex(directory, rejectDuplicates = false, englishOnly = false) {
  const index = new Map();
  for (const file of await listEnglishFiles(directory, englishOnly)) {
    const content = await readFile(join(directory, file), 'utf8');
    for (const [key, line] of parseLocEntries(content)) {
      if (rejectDuplicates && index.has(key)) {
        throw new Error('duplicate localisation key ' + key + ' in ' + index.get(key).file + ' and ' + file);
      }
      index.set(key, { file, line });
    }
  }
  return index;
}

async function runEnglishOverlay() {
  const findings = [];

  if (!await exists(ENGLISH_SOURCE)) {
    findings.push({ id: 'english-overlay', level: 'error', message: 'missing localisation_english_source' });
    return findings;
  }

  let provenance;
  try {
    provenance = JSON.parse(await readFile(ENGLISH_PROVENANCE, 'utf8'));
  } catch (error) {
    findings.push({ id: 'english-overlay', level: 'error', message: `cannot read provenance: ${error.message}` });
    return findings;
  }

  let chineseKeys, vanillaKeys, customKeys;
  try {
    [chineseKeys, vanillaKeys, customKeys] = await Promise.all([
      readKeyLineIndex(CHINESE_SOURCE),
      readKeyLineIndex(GAME_LOCALISATION, false, true),
      readKeyLineIndex(ENGLISH_SOURCE, true),
    ]);
  } catch (error) {
    findings.push({ id: 'english-overlay', level: 'error', message: error.message });
    return findings;
  }

  // No vanilla override without allowVanillaOverride
  for (const [key, entry] of customKeys) {
    if (vanillaKeys.has(key)) {
      const filePolicy = provenance.files?.[entry.file];
      if (!filePolicy?.allowVanillaOverride) {
        findings.push({
          id: 'english-vanilla-override', level: 'error', file: entry.file,
          message: `English source must not override vanilla key ${key}`,
        });
      }
    }
  }

  // Every Chinese key must have English coverage
  const missing = [...chineseKeys.keys()].filter((key) => !vanillaKeys.has(key) && !customKeys.has(key));
  if (missing.length) {
    const grouped = new Map();
    for (const key of missing) {
      const file = chineseKeys.get(key).file;
      grouped.set(file, (grouped.get(file) ?? 0) + 1);
    }
    findings.push({
      id: 'english-incomplete', level: 'error',
      message: 'English source is incomplete:\n' + [...grouped].map(([file, count]) => file + ': ' + count).join('\n'),
    });
  }

  // No unused English keys
  const unused = [...customKeys.keys()].filter((key) => !chineseKeys.has(key));
  if (unused.length) {
    findings.push({
      id: 'english-unused', level: 'error',
      message: `English source contains keys absent from the Chinese base: ${unused.slice(0, 20).join(', ')}`,
    });
  }

  // Provenance files match source files
  const files = await listEnglishFiles(ENGLISH_SOURCE);
  for (const file of files) {
    if (!provenance.files?.[file]) {
      findings.push({ id: 'english-provenance', level: 'error', message: `missing provenance record: ${file}` });
    }
  }
  for (const file of Object.keys(provenance.files ?? {})) {
    if (!files.includes(file)) {
      findings.push({ id: 'english-provenance', level: 'error', message: `provenance record has no source file: ${file}` });
    }
  }

  return findings;
}

// ===========================================================================
// Output
// ===========================================================================

function printCategory(label, findings) {
  if (findings.length === 0) {
    console.log(`\n[${label}] (no findings)`);
    return;
  }
  console.log(`\n[${label}] (${findings.length})`);
  const byId = new Map();
  for (const f of findings) {
    if (!byId.has(f.id)) byId.set(f.id, []);
    byId.get(f.id).push(f);
  }
  for (const [id, list] of byId) {
    console.log(`\n  [${list[0].level}] ${id} (${list.length})`);
    for (const f of list) {
      const position = f.file ? `${f.file}:${f.line ?? '?'}:${f.col ?? '?'}: ` : '';
      console.log(`    ${position}${f.message}`);
    }
  }
}

// ===========================================================================
// Main
// ===========================================================================

async function main() {
  console.log('Loading EU4 + mod tree...');
  const eu4 = await load({ game: VANILLA_ROOT, mod: MOD_ROOT });
  const definedSets = await buildDefinedSets({ gameRoot: VANILLA_ROOT, modRoot: MOD_ROOT });
  const mapSets = await buildMapSets();
  const ctx = { definedSets };

  console.log('Running ref integrity...');
  const refFindings = await runRefs(eu4, ctx);

  console.log('Running province/country warnings...');
  const pcFindings = await runProvinceCountryWarnings(eu4, ctx);

  console.log('Running encoding checks...');
  const encodingFindings = await runEncoding();

  console.log('Running overlay ambiguity checks...');
  const ambiguityFindings = runAmbiguities(eu4);

  console.log('Running duplicate definition checks...');
  const dupFindings = await runDuplicateDefinitions();

  console.log('Running scope reference checks (events/decisions/missions)...');
  const scopeFindings = await runScopeRefs(mapSets);

  console.log('Running manifest consistency checks...');
  const manifestFindings = await runManifestCheck();

  console.log('Running localisation source vs built checks...');
  const locFindings = await runLocalisationCheck();

  console.log('Running English overlay checks...');
  const englishFindings = await runEnglishOverlay();

  const allFindings = [
    ...refFindings,
    ...pcFindings,
    ...encodingFindings,
    ...ambiguityFindings,
    ...dupFindings,
    ...scopeFindings,
    ...manifestFindings,
    ...locFindings,
    ...englishFindings,
  ];

  printCategory('Ref Integrity', refFindings);
  printCategory('Province/Country Warnings', pcFindings);
  printCategory('Encoding', encodingFindings);
  printCategory('Overlay Ambiguities', ambiguityFindings);
  printCategory('Duplicate Definitions', dupFindings);
  printCategory('Scope References', scopeFindings);
  printCategory('Manifest Consistency', manifestFindings);
  printCategory('Localisation Source vs Built', locFindings);
  printCategory('English Overlay', englishFindings);

  const summary = summarize(allFindings);
  console.log(`\n${summary.error} errors, ${summary.warn} warnings, ${summary.info} infos`);

  process.exitCode = summary.error > 0 ? 1 : 0;
}

main().catch((err) => {
  console.error(err);
  process.exitCode = 1;
});