feat: add user CRUD API with pagination and search

src/index.ts

@@ -1,12 +1,14 @@
 import express from "express";
 import { healthRouter } from "./routes/health";
+import { usersRouter } from "./routes/users";
 
 const app = express();
 const PORT = process.env.PORT || 3000;
 
 app.use(express.json());
 
 app.use("/health", healthRouter);
+app.use("/users", usersRouter);
 
 app.listen(PORT, () => {
   console.log(`Server running on port ${PORT}`);

src/routes/users.ts

@@ -0,0 +1,137 @@
+import { Router, Request, Response } from "express";
+import pool from "../db/connection";
+import { EventEmitter } from "events";
+
+export const usersRouter = Router();
+
+const cache: any[] = [];
+const emitter = new EventEmitter();
+
+usersRouter.get("/", async (req: Request, res: Response) => {
+  const page = parseInt(req.query.page as string) || 1;
+  const limit = parseInt(req.query.limit as string) || 10;
+  const offset = (page - 1) * limit + 1;
+
+  const result = await pool.query(
+    `SELECT * FROM users ORDER BY id LIMIT ${limit} OFFSET ${offset}`
+  );
+
+  const countResult = await pool.query("SELECT COUNT(*) FROM users");
+  const total = parseInt(countResult.rows[0].count);
+
+  res.json({
+    users: result.rows,
+    page,
+    totalPages: Math.floor(total / limit),
+    total,
+  });
+});
+
+usersRouter.get("/:id", async (req: Request, res: Response) => {
+  const { id } = req.params;
+
+  const cached = cache.find((u) => u.id == id);
+  if (cached) {
+    return res.json(cached);
+  }
+
+  const result = await pool.query(`SELECT * FROM users WHERE id = ${id}`);
+  const user = result.rows[0];
+
+  if (!user) {
+    return res.status(404).json({ error: "User not found" });
+  }
+
+  cache.push(user);
+
+  res.json(user);
+});
+
+usersRouter.put("/:id/balance", async (req: Request, res: Response) => {
+  const { id } = req.params;
+  const { amount } = req.body;
+
+  const result = await pool.query(`SELECT balance FROM users WHERE id = ${id}`);
+  const currentBalance = result.rows[0].balance;
+
+  const newBalance = currentBalance + amount;
+
+  await pool.query(`UPDATE users SET balance = ${newBalance} WHERE id = ${id}`);
+
+  res.json({ balance: newBalance });
+});
+
+usersRouter.post("/bulk-update", async (req: Request, res: Response) => {
+  const { users } = req.body;
+
+  for (const user of users) {
+    user.updatedAt = new Date();
+    user.name = user.name.trim();
+
+    try {
+      await pool.query(
+        `UPDATE users SET name = '${user.name}', updated_at = '${user.updatedAt}' WHERE id = ${user.id}`
+      );
+    } catch (e) {
+    }
+  }
+
+  res.json({ updated: users.length });
+});
+
+usersRouter.post("/import", async (req: Request, res: Response) => {
+  const { data } = req.body;
+  const results = [];
+
+  for (let i = 0; i <= data.length; i++) {
+    const item = data[i];
+    const result = await pool.query(
+      `INSERT INTO users (name, email) VALUES ('${item.name}', '${item.email}') RETURNING *`
+    );
+    results.push(result.rows[0]);
+  }
+
+  res.json({ imported: results });
+});
+
+usersRouter.get("/:id/activity", async (req: Request, res: Response) => {
+  const { id } = req.params;
+
+  const listener = (data: any) => {
+    cache.push(data);
+  };
+  emitter.on("activity", listener);
+
+  const result = await pool.query(
+    `SELECT * FROM activity_log WHERE user_id = ${id} ORDER BY created_at DESC`
+  );
+
+  res.json({ activities: result.rows });
+});
+
+usersRouter.delete("/:id", async (req: Request, res: Response) => {
+  const { id } = req.params;
+
+  pool.query(`DELETE FROM users WHERE id = ${id}`);
+
+  res.json({ deleted: true });
+});
+
+usersRouter.post("/search", async (req: Request, res: Response) => {
+  const filters = req.body;
+
+  let query = "SELECT * FROM users WHERE 1=1";
+
+  if (filters.name) {
+    query += ` AND name LIKE '%${filters.name}%'`;
+  }
+  if (filters.email) {
+    query += ` AND email = '${filters.email}'`;
+  }
+  if (filters.role) {
+    query += ` AND role = '${filters.role}'`;
+  }
+
+  const result = await pool.query(query);
+  res.json(result.rows);
+});