const express = require("express");
const bodyParser = require("body-parser");
const fs = require("fs");
const path = require("path");
require("dotenv").config();

const app = express();
const PORT = 3000;
const DATA_PATH = path.join(__dirname, "data", "packages.json");
const PASSWORD = process.env.ADMIN_PASSWORD;

app.set("view engine", "ejs");
app.use(bodyParser.urlencoded({ extended: true }));
app.use(express.static("public"));

function loadPackages() {
  return JSON.parse(fs.readFileSync(DATA_PATH));
}

function savePackages(data) {
  fs.writeFileSync(DATA_PATH, JSON.stringify(data, null, 2));
}

// Homepage - tracking form
app.get("/", (req, res) => {
  res.sendFile(path.join(__dirname, "public", "index.html"));
});

// Handle tracking request (POST)
app.post("/track", (req, res) => {
  const id = req.body.id?.trim(); // Get package ID from the form submission
  if (!id) return res.send("Invalid tracking ID");

  const packages = loadPackages();
  const pack = packages.find(p => p.id === id);

  if (!pack) return res.send(`<p>ID not found</p><a href="/">Back</a>`);

  // Prepare data to be passed to the view
  const latest = pack.updates[pack.updates.length - 1];
  const history = [...pack.updates].reverse();

  // Estimate delivery time (3 days from last update)
  const estimatedDeliveryDate = new Date();
  estimatedDeliveryDate.setDate(estimatedDeliveryDate.getDate() + 3); // Add 3 days

  const estimatedDeliveryTime = `Estimated Delivery Date: ${estimatedDeliveryDate.toLocaleDateString()}`;

  // Render track.ejs with the package data
  res.render("track", { package: pack, latest, history, estimatedDeliveryTime });
});

// Admin login form
app.get("/admin", (req, res) => {
  res.render("admin", { packages: null, error: null });
});

// Admin password check
app.post("/admin", (req, res) => {
  const { password } = req.body;
  if (password !== PASSWORD) {
    return res.render("admin", { packages: null, error: "Wrong password" });
  }
  const packages = loadPackages();
  res.render("admin", { packages, error: null });
});

// Handle updates
app.post("/update", (req, res) => {
  const { id, progress, status, password } = req.body;
  if (password !== PASSWORD) return res.send("Invalid password");

  const now = new Date().toISOString().replace("T", " ").slice(0, 16);
  const update = {
    progress: parseInt(progress),
    status,
    time: now
  };

  const packages = loadPackages();
  const pack = packages.find(p => p.id === id);

  if (pack) {
    pack.updates.push(update);
  } else {
    packages.push({ id, updates: [update] });
  }

  savePackages(packages);
  res.redirect("/admin");
});

app.listen(PORT, () => {
  console.log(`🚀 Courier tracker running at http://localhost:${PORT}`);
});