"use client";

import React, { useEffect, useState } from "react";
import { usePathname, useRouter, useSearchParams } from "next/navigation";
import Header from "@/components/Header";
import QuestionItem from "@/components/QuestionItem";
import BackgroundWrapper from "@/components/BackgroundWrapper";
import { useExamStore } from "@/stores/examStore";
import { useTimerStore } from "@/stores/timerStore";

export default function ExamPage() {
  const router = useRouter();
  const pathname = usePathname();
  const searchParams = useSearchParams();
  const test_id = searchParams.get("test_id") || "";
  const type = searchParams.get("type") || "";

  const { setStatus, test, answers, startExam, setAnswer, submitExam } =
    useExamStore();
  const { resetTimer, stopTimer } = useTimerStore();

  const [isSubmitting, setIsSubmitting] = useState(false);

  // Start exam + timer automatically
  useEffect(() => {
    if (type && test_id) {
      startExam(type, test_id).then((fetchedTest) => {
        if (fetchedTest?.metadata.time_limit_minutes) {
          setStatus("in-progress"); // ✅ make sure exam status is set here
          resetTimer(fetchedTest.metadata.time_limit_minutes * 60, () => {
            // Timer ended → auto-submit
            setStatus("finished");
            stopTimer();
            submitExam(type);
            router.replace(`/exam/results`);
          });
        }
      });
    }
  }, [
    type,
    test_id,
    startExam,
    resetTimer,
    submitExam,
    router,
    setStatus,
    stopTimer,
  ]);

  // useEffect(() => {
  //   const handlePopState = (event: PopStateEvent) => {
  //     if (status === "in-progress") {
  //       const confirmExit = window.confirm(
  //         "Are you sure you want to quit the exam?"
  //       );

  //       if (confirmExit) {
  //         setStatus("finished");
  //         stopTimer();
  //         cancelExam();
  //         router.replace(`/categories/${type}s`);
  //       } else {
  //         // User canceled → push them back to current page
  //         router.replace(pathname, { scroll: false });
  //       }
  //     } else {
  //       router.replace(`/categories/${type}s`);
  //     }
  //   };

  //   window.addEventListener("popstate", handlePopState);
  //   return () => window.removeEventListener("popstate", handlePopState);
  // }, [status, router, pathname, type, setStatus, stopTimer, cancelExam]);

  if (!test) {
    return (
      <div className="min-h-screen bg-gray-50 flex items-center justify-center">
        <div className="flex flex-col items-center justify-center">
          <div className="animate-spin rounded-full h-12 w-12 border-b-2 border-blue-900 mb-4"></div>
          <p className="text-lg font-medium text-gray-900">Loading exam...</p>
        </div>
      </div>
    );
  }

  const handleSubmitExam = async (type: string) => {
    try {
      setStatus("finished"); // ✅ mark exam finished
      stopTimer();
      setIsSubmitting(true);
      await submitExam(type);
      router.replace(`/exam/results`); // ✅ replace to prevent back nav
    } finally {
      setIsSubmitting(false);
    }
  };

  return (
    <div className="min-h-screen bg-gray-50">
      {/* Header with live timer */}
      <Header />

      {/* Questions */}
      <BackgroundWrapper>
        <div className="container mx-auto px-6 py-8 mb-20">
          {test.questions.map((q, idx) => (
            <div id={`question-${idx}`} key={q.question_id}>
              <QuestionItem
                question={q}
                index={idx}
                selectedAnswer={answers[idx]}
                onSelect={(answer) => setAnswer(idx, answer)}
              />
            </div>
          ))}

          {/* Bottom submit bar */}
          <div className="fixed bottom-0 left-0 right-0 bg-white border-t border-gray-200 flex">
            <button
              onClick={() => handleSubmitExam(type)}
              disabled={isSubmitting}
              className="flex-1 bg-blue-900 text-white p-6 font-bold text-lg disabled:opacity-50 disabled:cursor-not-allowed hover:bg-blue-800 transition-colors flex justify-center items-center gap-2"
            >
              {isSubmitting ? (
                <>
                  <span className="animate-spin rounded-full h-5 w-5 border-b-2 border-white"></span>
                  Submitting...
                </>
              ) : (
                "Submit"
              )}
            </button>
          </div>
        </div>
      </BackgroundWrapper>
    </div>
  );
}
function cancelExam() {
  throw new Error("Function not implemented.");
}