// House Management backend
// Routes messages between household members (Au Pair <-> Child roles),
// persists an inbox history, and pushes APNs notifications to offline devices.

const fs = require("fs");
const path = require("path");
const http = require("http");
const http2 = require("http2");
const crypto = require("crypto");
const express = require("express");
const cors = require("cors");
const jwt = require("jsonwebtoken");
const { Server } = require("socket.io");

const PORT = process.env.PORT || 7860;
const DB_PATH = path.join(__dirname, "data", "db.json");

// ---------- Persistence ----------
function loadDB() {
  try {
    return JSON.parse(fs.readFileSync(DB_PATH, "utf8"));
  } catch {
    return { users: {}, messages: [] };
  }
}
function saveDB(db) {
  fs.mkdirSync(path.dirname(DB_PATH), { recursive: true });
  fs.writeFileSync(DB_PATH, JSON.stringify(db, null, 2));
}
let db = loadDB();

// ---------- App / Socket setup ----------
const app = express();
app.use(cors());
app.use(express.json());

const server = http.createServer(app);
const io = new Server(server, { cors: { origin: "*" } });

// userId -> socket.id (only while connected)
const liveSockets = new Map();

app.get("/health", (_req, res) => res.json({ ok: true }));

// ---------- User registration ----------
// body: { userId, role: "aupair"|"child", name, pushToken, language }
app.post("/register", (req, res) => {
  const { userId, role, name, pushToken, language } = req.body || {};
  if (!userId || !role) return res.status(400).json({ error: "userId and role required" });
  db.users[userId] = {
    ...(db.users[userId] || {}),
    userId,
    role,
    name: name || db.users[userId]?.name || role,
    pushToken: pushToken ?? db.users[userId]?.pushToken ?? null,
    language: language ?? db.users[userId]?.language ?? "en",
    updatedAt: Date.now(),
  };
  saveDB(db);
  res.json({ ok: true, user: db.users[userId] });
});

// ---------- Message send (REST fallback to socket) ----------
// body: { fromUserId, toRole? , toUserId?, text }
// Routing rule: if toUserId given, deliver directly. Else deliver to everyone
// with the opposite role of the sender (broadcast to household).
app.post("/message", async (req, res) => {
  const { fromUserId, toRole, toUserId, text } = req.body || {};
  const sender = db.users[fromUserId];
  if (!sender || !text) return res.status(400).json({ error: "fromUserId (registered) and text required" });

  const targets = resolveTargets(sender, toRole, toUserId);
  const message = {
    id: crypto.randomUUID(),
    fromUserId,
    fromName: sender.name,
    fromRole: sender.role,
    text,
    targets: targets.map((t) => t.userId),
    createdAt: Date.now(),
    readBy: [],
  };
  db.messages.push(message);
  saveDB(db);

  await deliver(message, targets);
  res.json({ ok: true, message });
});

// ---------- Inbox ----------
app.get("/inbox/:userId", (req, res) => {
  const { userId } = req.params;
  const msgs = db.messages.filter((m) => m.targets.includes(userId));
  res.json({ messages: msgs.sort((a, b) => b.createdAt - a.createdAt) });
});

app.post("/inbox/:userId/read/:messageId", (req, res) => {
  const { userId, messageId } = req.params;
  const msg = db.messages.find((m) => m.id === messageId);
  if (!msg) return res.status(404).json({ error: "not found" });
  if (!msg.readBy.includes(userId)) msg.readBy.push(userId);
  saveDB(db);
  res.json({ ok: true });
});

app.delete("/inbox/:userId/:messageId", (req, res) => {
  const { userId, messageId } = req.params;
  const msg = db.messages.find((m) => m.id === messageId);
  if (!msg) return res.status(404).json({ error: "not found" });
  msg.targets = msg.targets.filter((t) => t !== userId);
  db.messages = db.messages.filter((m) => m.id !== messageId || m.targets.length > 0);
  saveDB(db);
  res.json({ ok: true });
});

// ---------- Simple free-tier translation passthrough ----------
// body: { text, target, source? }
app.post("/translate", async (req, res) => {
  const { text, target, source = "auto" } = req.body || {};
  if (!text || !target) return res.status(400).json({ error: "text and target required" });
  try {
    const url = `https://api.mymemory.translated.net/get?q=${encodeURIComponent(text)}&langpair=${source}|${target}`;
    const r = await fetch(url);
    const data = await r.json();
    res.json({ translated: data?.responseData?.translatedText || text });
  } catch (e) {
    res.status(502).json({ error: "translation failed", detail: String(e) });
  }
});

// ---------- Routing helpers ----------
function resolveTargets(sender, toRole, toUserId) {
  if (toUserId) {
    const u = db.users[toUserId];
    return u ? [u] : [];
  }
  const targetRole = toRole || (sender.role === "aupair" ? "child" : "aupair");
  return Object.values(db.users).filter((u) => u.role === targetRole && u.userId !== sender.userId);
}

async function deliver(message, targets) {
  for (const target of targets) {
    const socketId = liveSockets.get(target.userId);
    if (socketId) {
      io.to(socketId).emit("message", message);
    }
    if (target.pushToken) {
      pushAPNs(target.pushToken, message).catch((e) => console.error("APNs push failed:", e.message));
    }
  }
}

// ---------- APNs push (token-based auth, .p8 key) ----------
// Configure via env: APNS_KEY (PEM contents), APNS_KEY_ID, APNS_TEAM_ID,
// APNS_BUNDLE_ID, APNS_PRODUCTION ("true"/"false")
let cachedAPNsJWT = null;
let cachedAPNsJWTExpiry = 0;

function getAPNsJWT() {
  const now = Math.floor(Date.now() / 1000);
  if (cachedAPNsJWT && now < cachedAPNsJWTExpiry - 60) return cachedAPNsJWT;
  const key = process.env.APNS_KEY;
  const keyId = process.env.APNS_KEY_ID;
  const teamId = process.env.APNS_TEAM_ID;
  if (!key || !keyId || !teamId) throw new Error("APNs env vars not configured");
  cachedAPNsJWT = jwt.sign({ iss: teamId, iat: now }, key.replace(/\\n/g, "\n"), {
    algorithm: "ES256",
    header: { alg: "ES256", kid: keyId },
  });
  cachedAPNsJWTExpiry = now + 3600;
  return cachedAPNsJWT;
}

function pushAPNs(deviceToken, message) {
  return new Promise((resolve, reject) => {
    const bundleId = process.env.APNS_BUNDLE_ID || "com.sebastienhall.HouseManagement";
    const production = process.env.APNS_PRODUCTION === "true";
    const host = production ? "api.push.apple.com" : "api.sandbox.push.apple.com";

    let token;
    try {
      token = getAPNsJWT();
    } catch (e) {
      return reject(e);
    }

    const client = http2.connect(`https://${host}`);
    client.on("error", reject);

    const payload = JSON.stringify({
      aps: {
        alert: { title: `${message.fromName} (${message.fromRole})`, body: message.text },
        sound: "default",
        category: "HOUSE_MESSAGE",
      },
      messageId: message.id,
      deepLink: "housemanagement://inbox",
    });

    const req = client.request({
      ":method": "POST",
      ":path": `/3/device/${deviceToken}`,
      authorization: `bearer ${token}`,
      "apns-topic": bundleId,
      "apns-push-type": "alert",
      "content-type": "application/json",
    });

    req.setEncoding("utf8");
    let data = "";
    req.on("data", (chunk) => (data += chunk));
    req.on("end", () => {
      client.close();
      resolve(data);
    });
    req.on("error", (e) => {
      client.close();
      reject(e);
    });
    req.end(payload);
  });
}

// ---------- Socket.io realtime ----------
io.on("connection", (socket) => {
  socket.on("identify", ({ userId, role, name }) => {
    if (!userId) return;
    liveSockets.set(userId, socket.id);
    socket.data.userId = userId;
    if (role) {
      db.users[userId] = {
        ...(db.users[userId] || {}),
        userId,
        role,
        name: name || db.users[userId]?.name || role,
        updatedAt: Date.now(),
      };
      saveDB(db);
    }
  });

  socket.on("message", async ({ fromUserId, toRole, toUserId, text }) => {
    const sender = db.users[fromUserId];
    if (!sender || !text) return;
    const targets = resolveTargets(sender, toRole, toUserId);
    const message = {
      id: crypto.randomUUID(),
      fromUserId,
      fromName: sender.name,
      fromRole: sender.role,
      text,
      targets: targets.map((t) => t.userId),
      createdAt: Date.now(),
      readBy: [],
    };
    db.messages.push(message);
    saveDB(db);
    await deliver(message, targets);
  });

  socket.on("disconnect", () => {
    if (socket.data.userId && liveSockets.get(socket.data.userId) === socket.id) {
      liveSockets.delete(socket.data.userId);
    }
  });
});

server.listen(PORT, () => {
  console.log(`House Management backend listening on :${PORT}`);
});