require("dotenv").config();

const express = require("express");
const cors = require("cors");
const admin = require("firebase-admin");
const fs = require("fs");

const app = express();

app.use(cors());
app.use(express.json());

admin.initializeApp({
  credential: admin.credential.cert(
    require("./serviceAccountKey.json")
  ),
});

const API_KEY = process.env.API_KEY;

const TOKEN_FILE = "./tokens.json";

function loadTokens() {
  try {
    if (!fs.existsSync(TOKEN_FILE)) return [];
    const data = fs.readFileSync(TOKEN_FILE, "utf8");
    return JSON.parse(data || "[]");
  } catch (err) {
    console.error("[ERROR] Failed to load tokens:", err);
    return [];
  }
}

function saveTokens(tokens) {
  try {
    fs.writeFileSync(TOKEN_FILE, JSON.stringify(tokens, null, 2));
  } catch (err) {
    console.error("[ERROR] Failed to save tokens:", err);
  }
}

let deviceTokens = new Set(loadTokens());

function authMiddleware(req, res, next) {
  console.log("[INFO] Incoming request to /push");
  const authHeader = req.headers.authorization;

  if (!authHeader) {
    return res.status(401).json({
      error: "Missing Authorization Header",
    });
  }

  const token = authHeader.replace("Bearer ", "");

  if (token !== API_KEY) {
    return res.status(403).json({
      error: "Invalid API Key",
    });
  }

  next();
}

app.post("/register-token", (req, res) => {
  console.log("[INFO] /register-token called");

  const { token, platform } = req.body;

  if (!token) {
    return res.status(400).json({
      error: "token required",
    });
  }

  deviceTokens.add(token);

  saveTokens([...deviceTokens]);

  console.log("[INFO] Token registered");
  console.log("[DEBUG] Token:", token);
  console.log("[DEBUG] Platform:", platform || "unknown");
  console.log("[INFO] Total tokens:", deviceTokens.size);

  res.json({
    success: true,
    count: deviceTokens.size,
  });
});

app.post("/push", authMiddleware, async (req, res) => {
  console.log("[INFO] /push called");

  try {
    const { type = "none", title, message } = req.body;

    if (!title || !message) {
      return res.status(400).json({
        error: "title and message required",
      });
    }

    if (deviceTokens.size === 0) {
      return res.status(400).json({
        error: "No registered device tokens",
      });
    }

    let color = "#9e9e9e";

    switch (type) {
      case "info":
        color = "#2196f3";
        break;
      case "warning":
        color = "#ff9800";
        break;
      case "danger":
        color = "#f44336";
        break;
    }

    const messages = [];

    for (const token of deviceTokens) {
      messages.push({
        token,
        notification: {
          title,
          body: message,
        },
        data: {
          type,
          color,
        },
        android: {
          priority: "high",
          notification: { color },
        },
        apns: {
          payload: {
            aps: { sound: "default" },
          },
        },
        webpush: {
          notification: {
            icon: "/icon-192.png",
          },
        },
      });
    }

    console.log("[INFO] Sending messages...");
    const response = await admin.messaging().sendEach(messages);

    console.log("[INFO]:", response.successCount);
    console.log("[ERROR]:", response.failureCount);

    res.json({
      success: true,
      successCount: response.successCount,
      failureCount: response.failureCount,
    });
  } catch (err) {
    console.error("[ERROR] PUSH:", err);

    res.status(500).json({
      error: err.message,
    });
  }
});

const PORT = process.env.PORT || 3000;

app.listen(PORT, () => {
  console.log("=================================");
  console.log("Push Server started");
  console.log("Port:", PORT);
  console.log("Tokens:", TOKEN_FILE);
  console.log("=================================");
});