import { afterAll, afterEach, beforeEach, describe, expect, it } from 'vitest';
import { fileURLToPath } from 'node:url';
import { copyFileSync, mkdirSync, mkdtempSync, rmSync } from 'node:fs';
import { tmpdir } from 'node:os';
import path from 'node:path';
import {
  allTerritoryKeys,
  expandCountriesToKeys,
  hasAdjacency,
  hasRegionData,
  loadRegions,
  neighboursOf,
  referenceForKeys,
  regionName,
  resetRegions,
  validKeys,
} from './regions';
import type { GameState } from '../shared/types';

// The repo root: this file lives in server/, so '..' is the directory holding
// public/region-keys.json and public/regions.geo.json. cwd-independent (mirrors
// how server/index.ts locates its root via import.meta.url).
const root = fileURLToPath(new URL('..', import.meta.url));

describe('regions (region-key loader, v0.19 #16 P1)', () => {
  beforeEach(() => {
    expect(loadRegions(root)).toBe(true);
  });

  it('loads the full manifest: 1,798 unique valid region keys', () => {
    expect(hasRegionData()).toBe(true);
    expect(validKeys().size).toBe(1798);
  });

  it('expands an ISO_A3 country to the region keys of all its sub-regions', () => {
    const fra = expandCountriesToKeys(['FRA']);
    // FRA has 42 sub-regions in the committed dataset.
    expect(fra).toHaveLength(42);
    // every expanded key is a real region key
    for (const k of fra) expect(validKeys().has(k)).toBe(true);
    // and the reference table labels each one with its parent country
    const ref = referenceForKeys(fra);
    expect(Object.keys(ref)).toHaveLength(42);
    for (const [k, label] of Object.entries(ref)) {
      expect(label.endsWith('(FRA)')).toBe(true);
      expect(regionName(k)).toBeTruthy();
    }
    // sample known FRA keys, and their exact reference strings
    expect(fra).toContain('ain-lqtt');
    expect(ref['ain-lqtt']).toBe('Ain (FRA)');
    expect(ref['aisne-gstu']).toBe('Aisne (FRA)');
  });

  it('expands RUS to all 82 sub-regions after the #31 Arkhangel split (no ownership gap at game init)', () => {
    // #31 split RU-ARK into mainland + New Earth + Severnaya Zemlya. A fresh
    // game's RUS territory (expanded from the preset's country list) must
    // contain all three sub-region keys — the main one (ownership-safe,
    // unchanged key) plus the two new island ones.
    const rus = expandCountriesToKeys(['RUS']);
    expect(rus).toHaveLength(82);
    expect(rus).toContain('arkhangel-sk-lhbk');
    expect(rus).toContain('new-earth-eikt');
    expect(rus).toContain('severnaya-zemlya-awqp');
  });

  it('referenceForKeys labels only known keys and omits unknown ones', () => {
    const ref = referenceForKeys(['ain-lqtt', 'not-a-real-key-xyz']);
    expect(ref['ain-lqtt']).toBe('Ain (FRA)');
    expect(ref['not-a-real-key-xyz']).toBeUndefined();
  });

  it('allTerritoryKeys unions every nation\'s territory keys (no overlap)', () => {
    const state: GameState = {
      id: 'g',
      presetId: 'p',
      presetTitle: 'P',
      playerNationId: 'uk',
      turn: 1,
      date: '1939-09-01',
      nations: {
        uk: {
          id: 'uk',
          name: 'UK',
          type: 'major',
          stats: { military: 80, economy: 70, stability: 60, population: 50 },
          territory: expandCountriesToKeys(['GBR']),
          relations: {},
        },
        fr: {
          id: 'fr',
          name: 'FR',
          type: 'major',
          stats: { military: 80, economy: 70, stability: 60, population: 50 },
          territory: expandCountriesToKeys(['FRA']),
          relations: {},
        },
      },
      events: [],
      pending: [],
      version: 1,
      unowned: [],
      pendingNationOps: [],
    };
    // 16 GBR sub-regions + 42 FRA sub-regions, no overlap between the two.
    expect(allTerritoryKeys(state).size).toBe(58);
  });

  it('hasAdjacency() is true: the region-adjacency manifest loaded (v0.21 #16 P2)', () => {
    expect(hasAdjacency()).toBe(true);
  });

  it('neighboursOf returns the union of bordering keys (deduped, sorted, queried excluded)', () => {
    // known mutual pairs from the manifest (verified in the Stage 1 spot checks)
    const moselle = neighboursOf(['moselle-rygy']);
    expect(moselle).toContain('baden-wurttemberg-oyje'); // FRA/DEU border
    expect(neighboursOf(['baden-wurttemberg-oyje'])).toContain('moselle-rygy'); // mutual
    expect(neighboursOf(['acre-ekzw'])).toContain('loreto-ipkx'); // BRA/PER border
    expect(neighboursOf(['loreto-ipkx'])).toContain('acre-ekzw'); // mutual

    // union + dedupe + sorted + the queried keys themselves excluded
    const union = neighboursOf(['moselle-rygy', 'baden-wurttemberg-oyje']);
    expect(union).toEqual([...union].sort());
    expect(new Set(union).size).toBe(union.length); // no duplicates
    expect(union).not.toContain('moselle-rygy');
    expect(union).not.toContain('baden-wurttemberg-oyje');
  });

  it('neighboursOf returns [] for unknown keys or an empty set', () => {
    expect(neighboursOf(['not-a-real-key-xyz'])).toEqual([]);
    expect(neighboursOf([])).toEqual([]);
  });

  describe('graceful degradation with no region data', () => {
    beforeEach(() => resetRegions());

    it('expands to the raw input, omits references, and reports no data', () => {
      expect(hasRegionData()).toBe(false);
      // no manifest -> the country list passes through unchanged (old model)
      expect(expandCountriesToKeys(['FRA', 'GBR'])).toEqual(['FRA', 'GBR']);
      expect(referenceForKeys(['FRA'])).toEqual({});
      expect(validKeys().size).toBe(0);
      expect(regionName('FRA')).toBeUndefined();
      // and no adjacency: the LLM tool / frontier field switch off
      expect(hasAdjacency()).toBe(false);
      expect(neighboursOf(['moselle-rygy'])).toEqual([]);
    });
  });

  afterAll(() => resetRegions());
});

describe('loadRegions resolves the manifest per environment (dev public/ vs prod dist/)', () => {
  const realRoot = root;
  // A root that mimics the prod Docker image: no public/, the region files live
  // in dist/ (where Vite copies public/* at build). This is the exact layout that
  // broke v0.19.0 in prod (the loader only looked in public/).
  const base = mkdtempSync(path.join(tmpdir(), 'history-regions-'));
  const prodRoot = path.join(base, 'prod');

  beforeEach(() => {
    mkdirSync(path.join(prodRoot, 'dist'), { recursive: true });
    copyFileSync(
      path.join(realRoot, 'public', 'region-keys.json'),
      path.join(prodRoot, 'dist', 'region-keys.json'),
    );
    copyFileSync(
      path.join(realRoot, 'public', 'regions.geo.json'),
      path.join(prodRoot, 'dist', 'regions.geo.json'),
    );
  });

  afterEach(() => resetRegions());

  afterAll(() => {
    rmSync(base, { recursive: true, force: true });
  });

  it('loads from dist/ when public/ is absent (the prod container layout)', () => {
    expect(loadRegions(prodRoot)).toBe(true);
    expect(hasRegionData()).toBe(true);
    expect(validKeys().size).toBe(1798);
    expect(expandCountriesToKeys(['FRA'])).toHaveLength(42);
  });

  it('still loads from public/ (the dev layout, the first candidate)', () => {
    expect(loadRegions(realRoot)).toBe(true);
    expect(validKeys().size).toBe(1798);
  });

  it('a dist/ WITHOUT the adjacency manifest degrades: hasAdjacency() false, neighboursOf []', () => {
    // this fixture copies only region-keys.json + regions.geo.json (no
    // region-adjacency.json) — the server must boot and serve turns with the
    // tool/frontier simply switched off.
    expect(loadRegions(prodRoot)).toBe(true);
    expect(hasAdjacency()).toBe(false);
    expect(neighboursOf(['moselle-rygy'])).toEqual([]);
  });

  it('returns false and no data when neither public/ nor dist/ holds the files', () => {
    const emptyRoot = path.join(base, 'empty');
    mkdirSync(emptyRoot, { recursive: true });
    expect(loadRegions(emptyRoot)).toBe(false);
    expect(hasRegionData()).toBe(false);
    expect(validKeys().size).toBe(0);
  });
});