/**
 * alexa-api/server.js
 * Windmill から Echo デバイスに TTS を送る API サーバー
 * 直接 Alexa API を叩く実装（alexa-remote2 不使用）
 *
 * Endpoints:
 *   POST /speak   { device: "デバイス名 or serial", text: "しゃべる内容" }
 *   GET  /devices デバイス一覧取得
 *   GET  /health  ヘルスチェック
 */

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

const app = express();
app.use(express.json());

const PORT = process.env.PORT || 3500;
const ALEXA_HOST = 'alexa.amazon.co.jp';
const ALEXA_COOKIE = process.env.ALEXA_COOKIE;

if (!ALEXA_COOKIE) {
  console.error('[ERROR] ALEXA_COOKIE 環境変数が設定されていません。');
  process.exit(1);
}

// ---- キャッシュ ----

let cachedDevices = null;
let cachedCustomerId = null;
let deviceCacheExpires = 0;

// ---- HTTP ヘルパー ----

function httpsRequest(path, options, extraCookies) {
  options = options || {};
  extraCookies = extraCookies || '';
  return new Promise(function(resolve, reject) {
    var allCookies = ALEXA_COOKIE + (extraCookies ? '; ' + extraCookies : '');
    var reqOpts = {
      hostname: ALEXA_HOST,
      path: path,
      method: options.method || 'GET',
      headers: Object.assign({
        'User-Agent': 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36',
        'Accept': 'application/json, text/plain, */*',
        'Accept-Language': 'ja-JP,ja;q=0.9',
        'Cookie': allCookies,
      }, options.headers || {}),
    };
    var req = https.request(reqOpts, function(res) {
      var body = '';
      res.on('data', function(d) { body += d; });
      res.on('end', function() { resolve({ status: res.statusCode, headers: res.headers, body: body }); });
    });
    req.on('error', reject);
    if (options.body) req.write(options.body);
    req.end();
  });
}

// ---- Alexa API ヘルパー ----

async function getCsrfToken() {
  var res = await httpsRequest('/api/language');
  var setCookies = res.headers['set-cookie'] || [];
  var csrfCookieStr = setCookies.find(function(c) { return c.startsWith('csrf='); });
  if (!csrfCookieStr) throw new Error('CSRF token not found');
  return csrfCookieStr.split('=')[1].split(';')[0];
}

async function getCustomerId() {
  if (cachedCustomerId) return cachedCustomerId;
  var res = await httpsRequest('/api/bootstrap');
  if (res.status !== 200) throw new Error('Bootstrap API failed: ' + res.status);
  var data = JSON.parse(res.body);
  cachedCustomerId = data.authentication && data.authentication.customerId;
  if (!cachedCustomerId) throw new Error('customerId not found');
  return cachedCustomerId;
}

async function getDevices(force) {
  var now = Date.now();
  if (!force && cachedDevices && now < deviceCacheExpires) return cachedDevices;
  var res = await httpsRequest('/api/devices-v2/device?cached=false');
  if (res.status !== 200) throw new Error('Devices API failed: ' + res.status);
  var data = JSON.parse(res.body);
  cachedDevices = data.devices || [];
  deviceCacheExpires = now + 5 * 60 * 1000;
  return cachedDevices;
}

function findDevice(devices, nameOrSerial) {
  var bySerial = devices.find(function(d) { return d.serialNumber === nameOrSerial; });
  if (bySerial) return bySerial;
  var lower = nameOrSerial.toLowerCase();
  var byName = devices.find(function(d) { return d.accountName && d.accountName.toLowerCase() === lower; });
  if (byName) return byName;
  return devices.find(function(d) { return d.accountName && d.accountName.toLowerCase().includes(lower); });
}

// ---- API エンドポイント ----

// POST /speak
app.post('/speak', async function(req, res) {
  var body = req.body || {};
  var device = body.device;
  var text = body.text;

  if (!device || !text) {
    return res.status(400).json({ error: 'device と text は必須です' });
  }

  console.log('[SPEAK] device="' + device + '" text="' + text + '"');

  try {
    var results = await Promise.all([getCsrfToken(), getCustomerId(), getDevices()]);
    var csrfToken = results[0];
    var customerId = results[1];
    var devices = results[2];

    var target = findDevice(devices, device);
    if (!target) {
      var names = devices.map(function(d) { return d.accountName; }).join(', ');
      return res.status(404).json({ error: 'デバイス "' + device + '" が見つかりません', available: names });
    }

    console.log('    -> ' + target.accountName + ' (type=' + target.deviceType + ', serial=' + target.serialNumber + ')');

    var sequenceObj = {
      '@type': 'com.amazon.alexa.behaviors.model.Sequence',
      startNode: {
        '@type': 'com.amazon.alexa.behaviors.model.OpaquePayloadOperationNode',
        type: 'Alexa.Speak',
        operationPayload: {
          deviceType: target.deviceType,
          deviceSerialNumber: target.serialNumber,
          customerId: customerId,
          locale: 'ja-JP',
          textToSpeak: text,
        },
      },
    };

    var bodyStr = JSON.stringify({
      behaviorId: 'PREVIEW',
      sequenceJson: JSON.stringify(sequenceObj),
      status: 'ENABLED',
    });

    var ttsRes = await httpsRequest('/api/behaviors/preview', {
      method: 'POST',
      headers: {
        'Content-Type': 'application/json',
        'csrf': csrfToken,
        'Referer': 'https://alexa.amazon.co.jp/spa/index.html',
        'Origin': 'https://alexa.amazon.co.jp',
      },
      body: bodyStr,
    }, 'csrf=' + csrfToken);

    if (ttsRes.status === 200 || ttsRes.status === 202) {
      console.log('    [OK] TTS sent to ' + target.accountName);
      res.json({ ok: true, device: target.accountName, text: text });
    } else {
      console.error('    [ERROR] TTS failed: ' + ttsRes.status + ' ' + ttsRes.body);
      res.status(502).json({ error: 'Alexa API error: ' + ttsRes.status, body: ttsRes.body });
    }
  } catch (err) {
    console.error('[ERROR] /speak:', err.message);
    res.status(500).json({ error: err.message });
  }
});

// GET /devices
app.get('/devices', async function(req, res) {
  try {
    var devices = await getDevices(true);
    res.json(devices.map(function(d) {
      return { name: d.accountName, type: d.deviceType, serial: d.serialNumber, online: d.online, family: d.deviceFamily };
    }));
  } catch (err) {
    console.error('[ERROR] /devices:', err.message);
    res.status(500).json({ error: err.message });
  }
});

// GET /health
app.get('/health', function(req, res) {
  res.json({ ok: true, cookieLength: ALEXA_COOKIE.length });
});

// ---- 起動 ----

app.listen(PORT, '0.0.0.0', async function() {
  console.log('[INFO] alexa-api server listening on port ' + PORT);
  try {
    var customerId = await getCustomerId();
    console.log('[INFO] Customer ID: ' + customerId);
    var devices = await getDevices();
    var echoDevices = devices.filter(function(d) {
      return (d.deviceType && (d.deviceType.startsWith('A4ZXE') || d.deviceType.startsWith('ASQZWP')));
    });
    console.log('[INFO] Echo devices: ' + echoDevices.map(function(d) { return d.accountName; }).join(', '));
  } catch (err) {
    console.error('[WARN] Startup init failed:', err.message);
  }
});