app.js

import express from "express";
import connectDB from "./server/config/db.config.js";
import { config } from "./server/constants.js";
import cors from "cors";
import morgan from "morgan";
import helmet from "helmet";
import CookieParser from "cookie-parser";
import path from "path";
import fs from "fs";

const app = express();

// Create logs directory if it doesn't exist
const logDirectory = path.join(process.cwd(), "logs");
if (!fs.existsSync(logDirectory)) {
    fs.mkdirSync(logDirectory, { recursive: true });
}

// Create a write stream (append mode) for logging requests
const accessLogStream = fs.createWriteStream(
    path.join(logDirectory, "access.log"),
    { flags: "a" }
);

app.use(morgan("combined", { stream: accessLogStream }));

app.use(express.json());
app.use(express.urlencoded({ extended: true }));

// Allowed domains
const allowedDomains = [
    "https://expense-tracker.therahul.xyz", // production
    "https://expense-tracker-mu-wheat.vercel.app", // production
    "http://localhost:5173", // for development
    "http://localhost:5174", // for development
];

app.use(
    cors({
        origin: function (origin, callback) {
            if (!origin) return callback(null, true); // allow non-browser requests like Postman

            if (allowedDomains.includes(origin)) {
                callback(null, true); // ✅ allow request
            } else {
                callback(new Error("Not allowed by CORS")); // ❌ block request
            }
        },
        methods: ["GET", "POST", "PATCH", "DELETE"],
        credentials: true,
    })
);
app.use(morgan("dev"));
app.use(helmet());
app.use(CookieParser());

connectDB()
    .then(() => {
        app.listen(config.port, () =>
            console.log(`Server running on port ${config.port}`)
        );
        app.on("error", (error) => {
            console.log("Error on the server: ", error);
            throw error;
        });
    })
    .catch((error) => console.log("MongoDB Connection Failed: ", error));

// Route to check if server is running
app.get("/", (req, res) => {
    return res.status(200).json({
        success: true,
        message: "Server is running- v-1.0.0",
    });
});

// Route to fetch last 100 lines of logs
app.get("/logs", (req, res) => {
    const logFilePath = path.join(logDirectory, "access.log");

    // Read last 100 lines from the log file
    fs.readFile(logFilePath, "utf8", (err, data) => {
        if (err) {
            return res
                .status(500)
                .json({ success: false, message: "Error reading log file" });
        }

        const lines = data.trim().split("\n");
        const last100Lines = lines.slice(-100).join("\n");

        res.setHeader("Content-Type", "text/plain");
        res.send(last100Lines);
    });
});

// Import routes
import userRoutes from "./server/routes/user.routes.js";
import transactionRoutes from "./server/routes/transaction.routes.js";
import budgetRoutes from "./server/routes/budget.routes.js";

app.use("/api/v1/user", userRoutes);
app.use("/api/v1/transaction", transactionRoutes);
app.use("/api/v1/budget", budgetRoutes);