"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: [] });
  },
}));