import React, { useState, useEffect } from "react";
import { useRouter } from "next/navigation";
import { ChevronLeft, Layers } from "lucide-react";
import { useTimer } from "@/context/TimerContext";
import styles from "@/css/Header.module.css";
import { useExam } from "@/context/ExamContext";
import { Avatar, AvatarFallback } from "@/components/ui/avatar";
import { useModal } from "@/context/ModalContext";
import { useAuth } from "@/context/AuthContext";

interface HeaderProps {
  displayUser?: boolean;
  displaySubject?: string;
  displayTabTitle?: string;
  examDuration?: string | null;
}

const Header = ({
  displayUser,
  displaySubject,
  displayTabTitle,
  examDuration,
}: HeaderProps) => {
  const router = useRouter();
  const { open } = useModal();
  const { clearExam } = useExam();
  const [totalSeconds, setTotalSeconds] = useState(
    examDuration ? parseInt(examDuration) * 60 : 0
  );
  const { stopTimer } = useTimer();
  const { user, isLoading } = useAuth();

  useEffect(() => {
    if (!examDuration) return;

    const timer = setInterval(() => {
      setTotalSeconds((prev) => {
        if (prev <= 0) {
          clearInterval(timer);
          return 0;
        }
        return prev - 1;
      });
    }, 1000);

    return () => clearInterval(timer);
  }, [examDuration]);

  const hours = Math.floor(totalSeconds / 3600);
  const minutes = Math.floor((totalSeconds % 3600) / 60);
  const seconds = totalSeconds % 60;

  const showExitDialog = () => {
    const confirmed = window.confirm("Are you sure you want to quit the exam?");

    if (confirmed) {
      if (stopTimer) {
        stopTimer();
      }
      clearExam();
      router.push("/unit");
    }
  };

  const handleBackClick = () => {
    router.back();
  };

  return (
    <header className={styles.header}>
      {displayUser && (
        <div className={styles.profile}>
          <Avatar className="bg-gray-200 w-10 h-10">
            <AvatarFallback className=" text-lg">
              {user?.username ? user.username.charAt(0).toUpperCase() : ""}
            </AvatarFallback>
          </Avatar>
          <span className={styles.text}>
            Hello, {user?.username ? user.username.split(" ")[0] : ""}
          </span>
        </div>
      )}

      {displayTabTitle && (
        <div className={styles.profile}>
          <button onClick={handleBackClick} className={styles.iconButton}>
            <ChevronLeft size={24} color="white" />
          </button>
          <span className={styles.text}>{displayTabTitle}</span>
        </div>
      )}

      {displaySubject && (
        <div className={styles.profile}>
          <span className={styles.text}>{displaySubject}</span>
        </div>
      )}

      {examDuration && (
        <div className={styles.examHeader}>
          <button onClick={showExitDialog} className={styles.iconButton}>
            <ChevronLeft size={30} color="white" />
          </button>

          <div className={styles.timer}>
            <div className={styles.timeUnit}>
              <span className={styles.timeValue}>
                {String(hours).padStart(2, "0")}
              </span>
              <span className={styles.timeLabel}>Hrs</span>
            </div>
            <div className={styles.timeUnit}>
              <span className={styles.timeValue}>
                {String(minutes).padStart(2, "0")}
              </span>
              <span className={styles.timeLabel}>Mins</span>
            </div>
            <div className={styles.timeUnit} style={{ borderRight: "none" }}>
              <span className={styles.timeValue}>
                {String(seconds).padStart(2, "0")}
              </span>
              <span className={styles.timeLabel}>Secs</span>
            </div>
          </div>

          <button
            onClick={open}
            className={`${styles.iconButton} ${styles.disabled}`}
          >
            <Layers size={30} color="white" />
          </button>
        </div>
      )}
    </header>
  );
};

export default Header;