const fs    = require('fs');
const https = require('https');
const path  = require('path');
const express = require('express');

const service = require('../server/RobotConfigService');

const DATA_DIR   = path.join(__dirname, '..', 'data', 'robot');
const ROBOT_JSON = path.join(DATA_DIR, 'robot.json');
const TEST_KEY   = 'test-api-key-12345';

const SAMPLE_ROBOT = {
  links: {
    Arm1:   { size: [70, 250, 70] },
    Arm2:   { size: [70, 250, 70] },
    Ellbow: { size: [90, 0, 0] }
  }
};

// ── HTTPS-Test-Server ─────────────────────────────────────────────────────────

function makeServer(apiKey) {
  const app  = express();
  service.register(app, { apiKey });
  const key  = fs.readFileSync('https/localhost.key');
  const cert = fs.readFileSync('https/localhost.pem');
  return https.createServer({ key, cert, passphrase: 'abcd' }, app);
}

function listen(server) {
  return new Promise((resolve, reject) => {
    server.listen(0, () => {
      const addr = server.address();
      addr ? resolve(addr.port) : reject(new Error('no port'));
    });
    server.on('error', reject);
  });
}

function closeServer(server) {
  return new Promise(resolve => { server.close(resolve); });
}

function request(method, url, { body, token } = {}) {
  return new Promise((resolve, reject) => {
    const agent   = new https.Agent({ rejectUnauthorized: false });
    const payload = body ? JSON.stringify(body) : undefined;
    const headers = {
      ...(payload ? { 'Content-Type': 'application/json', 'Content-Length': Buffer.byteLength(payload) } : {}),
      ...(token   ? { 'Authorization': `Bearer ${token}` } : {})
    };
    const req = https.request(url, { method, agent, headers }, (res) => {
      let data = '';
      res.on('data', chunk => { data += chunk; });
      res.on('end',  () => resolve({ statusCode: res.statusCode, body: data }));
    });
    req.on('error', reject);
    if (payload) req.write(payload);
    req.end();
  });
}

// ── Setup / Teardown ──────────────────────────────────────────────────────────

function cleanupTestFiles() {
  for (const f of fs.readdirSync(DATA_DIR)) {
    if (f === '.gitkeep' || f === '.apikey') continue;
    fs.unlinkSync(path.join(DATA_DIR, f));
  }
}

// robot.json gehört zur Betriebskonfiguration und darf durch Tests NICHT dauerhaft
// gelöscht werden. Wir sichern den Inhalt vor der Suite und stellen ihn danach exakt
// wieder her — inklusive aller Snapshot-Dateien, die schon vorher da waren.
let _savedRobotJson    = null;   // null = Datei existierte nicht
let _savedSnapshotFiles = {};    // filename → content (nur Dateien, die VOR den Tests da waren)

beforeAll(() => {
  fs.mkdirSync(DATA_DIR, { recursive: true });
  // robot.json sichern
  try { _savedRobotJson = fs.readFileSync(ROBOT_JSON, 'utf8'); } catch { _savedRobotJson = null; }
  // Snapshot-Dateien sichern (robot_YYYYMMDD_HHmmss.json)
  for (const f of fs.readdirSync(DATA_DIR)) {
    if (/^robot_\d{8}_\d{6}\.json$/.test(f)) {
      _savedSnapshotFiles[f] = fs.readFileSync(path.join(DATA_DIR, f), 'utf8');
    }
  }
});

afterAll(() => {
  // Testdateien bereinigen
  cleanupTestFiles();
  // robot.json wiederherstellen
  if (_savedRobotJson !== null) {
    fs.writeFileSync(ROBOT_JSON, _savedRobotJson, 'utf8');
  }
  // Vor-Test-Snapshots wiederherstellen
  for (const [f, content] of Object.entries(_savedSnapshotFiles)) {
    fs.writeFileSync(path.join(DATA_DIR, f), content, 'utf8');
  }
});

beforeEach(() => {
  fs.mkdirSync(DATA_DIR, { recursive: true });
  cleanupTestFiles();
});

afterEach(() => {
  cleanupTestFiles();
});

// ── Einzel-Funktionen ─────────────────────────────────────────────────────────

describe('readRobotJson / writeRobotJson', () => {
  test('writeRobotJson schreibt Datei und legt Snapshot an', async () => {
    fs.writeFileSync(ROBOT_JSON, JSON.stringify({ version: 1 }), 'utf8');
    const { snapshotFile } = await service.writeRobotJson({ version: 2 });

    expect(snapshotFile).toMatch(/^robot_\d{8}_\d{6}\.json$/);
    expect(fs.existsSync(path.join(DATA_DIR, snapshotFile))).toBe(true);

    const written  = JSON.parse(fs.readFileSync(ROBOT_JSON, 'utf8'));
    expect(written).toEqual({ version: 2 });

    const snapshot = JSON.parse(fs.readFileSync(path.join(DATA_DIR, snapshotFile), 'utf8'));
    expect(snapshot).toEqual({ version: 1 });
  });

  test('kein Snapshot wenn robot.json noch nicht existiert', async () => {
    const { snapshotFile } = await service.writeRobotJson({ fresh: true });
    expect(fs.existsSync(path.join(DATA_DIR, snapshotFile))).toBe(false);
  });

  test('readRobotJson liest die aktuelle Datei', async () => {
    fs.writeFileSync(ROBOT_JSON, JSON.stringify(SAMPLE_ROBOT), 'utf8');
    const data = await service.readRobotJson();
    expect(data).toEqual(SAMPLE_ROBOT);
  });

  test('readRobotJson wirft, wenn robot.json fehlt', async () => {
    await expect(service.readRobotJson()).rejects.toThrow();
  });
});

describe('listHistory / readSnapshot', () => {
  test('listHistory gibt leere Liste zurück wenn kein Snapshot', async () => {
    const list = await service.listHistory();
    expect(list).toEqual([]);
  });

  test('listHistory listet vorhandene Snapshots, neueste zuerst', async () => {
    fs.writeFileSync(path.join(DATA_DIR, 'robot_20260101_120000.json'), '{}', 'utf8');
    fs.writeFileSync(path.join(DATA_DIR, 'robot_20260102_083000.json'), '{}', 'utf8');

    const list = await service.listHistory();
    expect(list.map(e => e.filename)).toEqual([
      'robot_20260102_083000.json',
      'robot_20260101_120000.json'
    ]);
    expect(list[0]).toEqual({ filename: 'robot_20260102_083000.json', day: '20260102', timestamp: '083000' });
  });

  test('readSnapshot liest einen bestimmten Snapshot', async () => {
    const ts = '20260101_120000';
    fs.writeFileSync(path.join(DATA_DIR, `robot_${ts}.json`), JSON.stringify({ x: 42 }), 'utf8');
    const data = await service.readSnapshot(ts);
    expect(data).toEqual({ x: 42 });
  });

  test('readSnapshot wirft bei unbekanntem Timestamp', async () => {
    await expect(service.readSnapshot('99999999_999999')).rejects.toThrow();
  });
});

describe('Pruning', () => {
  test('≤ 100 Snapshots pro Tag bleiben alle erhalten', async () => {
    for (let i = 1; i <= 5; i++) {
      fs.writeFileSync(path.join(DATA_DIR, `robot_2026061${i}_120000.json`), '{}', 'utf8');
    }
    fs.writeFileSync(ROBOT_JSON, '{}', 'utf8');
    await service.writeRobotJson({ pruned: true });

    const list = await service.listHistory();
    // 5 bestehende (verschiedene Tage) + 1 neuer Snapshot = 6
    expect(list.length).toBe(6);
  });

  test('> 100 Snapshots eines Tages: nur neuester bleibt', async () => {
    const day = '20260101';
    for (let i = 0; i < 102; i++) {
      const hh = String(Math.floor(i / 3600)).padStart(2, '0');
      const mm = String(Math.floor((i % 3600) / 60)).padStart(2, '0');
      const ss = String(i % 60).padStart(2, '0');
      fs.writeFileSync(path.join(DATA_DIR, `robot_${day}_${hh}${mm}${ss}.json`), `{"i":${i}}`, 'utf8');
    }
    // Neuester (lexikographisch letzter) vorher anlegen
    const newest = `robot_${day}_235959.json`;
    fs.writeFileSync(path.join(DATA_DIR, newest), '{"newest":true}', 'utf8');

    fs.writeFileSync(ROBOT_JSON, '{}', 'utf8');
    await service.writeRobotJson({ trigger: true });

    const list = await service.listHistory();
    const daySnapshots = list.filter(e => e.day === day);
    expect(daySnapshots.length).toBe(1);
    expect(daySnapshots[0].filename).toBe(newest);
  });
});

// ── HTTP-Routen ───────────────────────────────────────────────────────────────

describe('HTTP GET /api/robot', () => {
  let server, port;

  beforeEach(async () => { server = makeServer(TEST_KEY); port = await listen(server); });
  afterEach(async () => { await closeServer(server); });

  test('404 wenn robot.json nicht existiert', async () => {
    const { statusCode } = await request('GET', `https://127.0.0.1:${port}/api/robot`);
    expect(statusCode).toBe(404);
  });

  test('200 mit robot.json-Inhalt', async () => {
    fs.writeFileSync(ROBOT_JSON, JSON.stringify(SAMPLE_ROBOT), 'utf8');
    const { statusCode, body } = await request('GET', `https://127.0.0.1:${port}/api/robot`);
    expect(statusCode).toBe(200);
    expect(JSON.parse(body)).toEqual(SAMPLE_ROBOT);
  });
});

describe('HTTP PUT /api/robot', () => {
  let server, port;

  beforeEach(async () => { server = makeServer(TEST_KEY); port = await listen(server); });
  afterEach(async () => { await closeServer(server); });

  test('401 ohne Authorization-Header', async () => {
    const { statusCode } = await request('PUT', `https://127.0.0.1:${port}/api/robot`, { body: SAMPLE_ROBOT });
    expect(statusCode).toBe(401);
  });

  test('401 mit falschem Key', async () => {
    const { statusCode } = await request('PUT', `https://127.0.0.1:${port}/api/robot`, {
      body: SAMPLE_ROBOT, token: 'wrong-key'
    });
    expect(statusCode).toBe(401);
  });

  test('200 mit korrektem Key — schreibt Datei', async () => {
    const { statusCode, body } = await request('PUT', `https://127.0.0.1:${port}/api/robot`, {
      body: SAMPLE_ROBOT, token: TEST_KEY
    });
    expect(statusCode).toBe(200);
    const result = JSON.parse(body);
    expect(result.ok).toBe(true);
    expect(result.snapshotFile).toMatch(/^robot_\d{8}_\d{6}\.json$/);

    const written = JSON.parse(fs.readFileSync(ROBOT_JSON, 'utf8'));
    expect(written).toEqual(SAMPLE_ROBOT);
  });
});

describe('HTTP GET /api/robot/history', () => {
  let server, port;

  beforeEach(async () => { server = makeServer(TEST_KEY); port = await listen(server); });
  afterEach(async () => { await closeServer(server); });

  test('200 mit leerer History', async () => {
    const { statusCode, body } = await request('GET', `https://127.0.0.1:${port}/api/robot/history`);
    expect(statusCode).toBe(200);
    expect(JSON.parse(body)).toEqual({ history: [] });
  });

  test('200 listet vorhandene Snapshots', async () => {
    fs.writeFileSync(path.join(DATA_DIR, 'robot_20260611_100000.json'), '{}', 'utf8');
    const { statusCode, body } = await request('GET', `https://127.0.0.1:${port}/api/robot/history`);
    expect(statusCode).toBe(200);
    const { history } = JSON.parse(body);
    expect(history).toHaveLength(1);
    expect(history[0].filename).toBe('robot_20260611_100000.json');
  });
});

describe('HTTP GET /api/robot/history/:ts', () => {
  let server, port;

  beforeEach(async () => { server = makeServer(TEST_KEY); port = await listen(server); });
  afterEach(async () => { await closeServer(server); });

  test('200 für vorhandenen Snapshot', async () => {
    const ts = '20260611_100000';
    fs.writeFileSync(path.join(DATA_DIR, `robot_${ts}.json`), JSON.stringify({ snap: true }), 'utf8');
    const { statusCode, body } = await request('GET', `https://127.0.0.1:${port}/api/robot/history/${ts}`);
    expect(statusCode).toBe(200);
    expect(JSON.parse(body)).toEqual({ snap: true });
  });

  test('404 für unbekannten Snapshot', async () => {
    const { statusCode } = await request('GET', `https://127.0.0.1:${port}/api/robot/history/99991231_235959`);
    expect(statusCode).toBe(404);
  });
});