first commit for the leave management system. built a Leave Management System with role-based access:

Employees can apply for leave and track balance, status, and history.
Managers can view all requests and approve/reject them.
Login with separate dashboards for employees and managers with the dummy json.
Tables with filters (All, Pending, Approved, Rejected) for easy management.

lib/leavesStore.ts

@@ -0,0 +1,149 @@
+export interface LeaveRequest {
+  id: number;
+  userId: number;
+  userName?: string;
+  type: "Sick" | "Casual" | "Annual" | "Unpaid";
+  fromDate: string;
+  toDate: string;
+  reason: string;
+  status: "Pending" | "Approved" | "Rejected";
+  appliedAt: string;
+}
+
+export interface UserRecord {
+  id: number;
+  username: string;
+  name: string;
+  role: "employee" | "manager";
+  leaveBalance?: number;
+}
+
+const LEAVES_KEY = "lms_leaves";
+const USERS_KEY = "lms_users";
+
+// Seed from JSON on first load
+async function seedIfNeeded() {
+  if (typeof window === "undefined") return;
+  if (!localStorage.getItem(LEAVES_KEY)) {
+    const mod = await import("@/data/leaves.json");
+    const raw = mod.default ?? mod;
+    const leaves = Array.isArray(raw) ? raw : ((raw as any).leaves ?? []);
+    localStorage.setItem(LEAVES_KEY, JSON.stringify(leaves));
+  }
+  if (!localStorage.getItem(USERS_KEY)) {
+    const mod = await import("@/data/users.json");
+    const raw = mod.default ?? mod;
+    const users = Array.isArray(raw) ? raw : ((raw as any).users ?? []);
+    localStorage.setItem(USERS_KEY, JSON.stringify(users));
+  }
+}
+
+export async function getLeaves(): Promise<LeaveRequest[]> {
+  await seedIfNeeded();
+  const raw = localStorage.getItem(LEAVES_KEY) ?? "[]";
+  const leaves: LeaveRequest[] = JSON.parse(raw);
+  // Attach userName from users
+  const users = getUsers();
+  return leaves.map((l) => {
+    const u = users.find((u) => u.id === l.userId);
+    return { ...l, userName: u?.name ?? "Unknown" };
+  });
+}
+
+export function getUsers(): UserRecord[] {
+  const raw = localStorage.getItem(USERS_KEY) ?? "[]";
+  return JSON.parse(raw);
+}
+
+export async function getLeavesForUser(userId: number): Promise<LeaveRequest[]> {
+  const all = await getLeaves();
+  return all.filter((l) => l.userId === userId);
+}
+
+export async function applyLeave(
+  userId: number,
+  data: { type: LeaveRequest["type"]; fromDate: string; toDate: string; reason: string }
+): Promise<{ ok: boolean; error?: string }> {
+  await seedIfNeeded();
+
+  // Calculate days
+  const from = new Date(data.fromDate);
+  const to = new Date(data.toDate);
+  const days = Math.ceil((to.getTime() - from.getTime()) / 86400000) + 1;
+
+  // Check balance
+  const users = getUsers();
+  const user = users.find((u) => u.id === userId);
+  if (!user) return { ok: false, error: "User not found" };
+  if ((user.leaveBalance ?? 0) < days)
+    return { ok: false, error: `Insufficient balance. You have ${user.leaveBalance} days left.` };
+
+  const leaves: LeaveRequest[] = JSON.parse(localStorage.getItem(LEAVES_KEY) ?? "[]");
+  const newLeave: LeaveRequest = {
+    id: Date.now(),
+    userId,
+    type: data.type,
+    fromDate: data.fromDate,
+    toDate: data.toDate,
+    reason: data.reason,
+    status: "Pending",
+    appliedAt: new Date().toISOString().split("T")[0],
+  };
+  leaves.push(newLeave);
+  localStorage.setItem(LEAVES_KEY, JSON.stringify(leaves));
+  return { ok: true };
+}
+
+export async function updateLeaveStatus(
+  leaveId: number,
+  status: "Approved" | "Rejected"
+): Promise<void> {
+  await seedIfNeeded();
+  const leaves: LeaveRequest[] = JSON.parse(localStorage.getItem(LEAVES_KEY) ?? "[]");
+  const idx = leaves.findIndex((l) => l.id === leaveId);
+  if (idx === -1) return;
+
+  const leave = leaves[idx];
+  const wasApproved = leave.status === "Approved";
+  leaves[idx] = { ...leave, status };
+  localStorage.setItem(LEAVES_KEY, JSON.stringify(leaves));
+
+  // Adjust balance
+  const users = getUsers();
+  const user = users.find((u) => u.id === leave.userId);
+  if (!user || user.role !== "employee") return;
+
+  const from = new Date(leave.fromDate);
+  const to = new Date(leave.toDate);
+  const days = Math.ceil((to.getTime() - from.getTime()) / 86400000) + 1;
+
+  if (status === "Approved" && !wasApproved) {
+    user.leaveBalance = (user.leaveBalance ?? 0) - days;
+  } else if (status === "Rejected" && wasApproved) {
+    user.leaveBalance = (user.leaveBalance ?? 0) + days;
+  }
+
+  localStorage.setItem(USERS_KEY, JSON.stringify(users));
+
+  // Also update session user if it's the same person
+  const sessionUser = localStorage.getItem("lms_user");
+  if (sessionUser) {
+    const su = JSON.parse(sessionUser);
+    if (su.id === user.id) {
+      su.leaveBalance = user.leaveBalance;
+      localStorage.setItem("lms_user", JSON.stringify(su));
+    }
+  }
+}
+
+export function getUserBalance(userId: number): number {
+  const users = getUsers();
+  const u = users.find((u) => u.id === userId);
+  return u?.leaveBalance ?? 0;
+}
+
+export function daysBetween(from: string, to: string): number {
+  const f = new Date(from);
+  const t = new Date(to);
+  return Math.ceil((t.getTime() - f.getTime()) / 86400000) + 1;
+}