feat(zustand): add zustand stores for exam, timer and auth

stores/examStore.ts

@@ -0,0 +1,90 @@
+"use client";
+
+import { create } from "zustand";
+import { Test, Answer } from "@/types/exam";
+import { API_URL, getToken } from "@/lib/auth";
+
+interface ExamState {
+  test: Test | null;
+  answers: Answer[];
+
+  startExam: (testType: string, testId: string) => Promise<void>;
+  setAnswer: (questionIndex: number, answer: Answer) => void;
+  submitExam: (testType: string) => Promise<void>;
+  cancelExam: () => void;
+}
+
+export const useExamStore = create<ExamState>((set, get) => ({
+  test: null,
+  answers: [],
+
+  // start exam
+  startExam: async (testType: string, testId: string) => {
+    try {
+      const token = await getToken();
+      const res = await fetch(`${API_URL}/tests/${testType}/${testId}`, {
+        method: "GET",
+        headers: {
+          Authorization: `Bearer ${token}`,
+        },
+      });
+
+      if (!res.ok) throw new Error(`Failed to fetch test: ${res.status}`);
+      const data: Test = await res.json();
+
+      set({
+        test: data,
+        answers: Array(data.questions.length).fill(null),
+      });
+    } catch (err) {
+      console.error("startExam error:", err);
+    }
+  },
+
+  // set an answer
+  setAnswer: (questionIndex: number, answer: Answer) => {
+    set((state) => {
+      const updated = [...state.answers];
+      updated[questionIndex] = answer;
+      return { answers: updated };
+    });
+  },
+
+  // submit exam
+  submitExam: async (testType: string) => {
+    const { test, answers } = get();
+    if (!test) return;
+
+    const token = await getToken();
+
+    try {
+      const { test_id, attempt_id } = test.metadata;
+      console.log(answers);
+      const res = await fetch(
+        `${API_URL}/tests/${testType}/${test_id}/${attempt_id}`,
+        {
+          method: "POST",
+          headers: {
+            "Content-Type": "application/json",
+            Authorization: `Bearer ${token}`,
+          },
+          body: JSON.stringify({ answers }),
+        }
+      );
+
+      console.log(res);
+
+      if (!res.ok) throw new Error("Failed to submit exam");
+
+      // reset store
+      set({ test: null, answers: [] });
+    } catch (err) {
+      console.error("Failed to submit exam. Reason:", err);
+    }
+  },
+
+  // cancel exam
+  cancelExam: () => {
+    set({ test: null, answers: [] });
+  },
+}));