'use client';

import { useEffect, useState } from 'react';
import { useParams, useRouter } from 'next/navigation';
import Image from 'next/image';
import apiService from '../../lib/apiService';
import BackCircleSvg from '../../svgs/backcirclesvg';

const imgPlay = '/imgs/play.svg';
const imgMusicAudioPlay = '/imgs/music-audio-play.svg';

type Lesson = {
	id: string;
	title: string;
	duration: string; // "12:46" 형식
	state: "제출완료" | "제출대기";
	action: "복습하기" | "이어서 수강하기" | "수강하기";
};

type CourseDetail = {
	id: string;
	status: "수강 중" | "수강 예정" | "수강 완료";
	title: string;
	goal: string;
	method: string;
	summary: string; // VOD · 총 n강 · n시간 n분
	submitSummary: string; // 학습 제출 n/n
	thumbnail: string;
	lessons: Lesson[];
};

export default function CourseDetailPage() {
	const params = useParams();
	const router = useRouter();
	const [course, setCourse] = useState<CourseDetail | null>(null);
	const [loading, setLoading] = useState(true);
	const [error, setError] = useState<string | null>(null);

	useEffect(() => {
		const fetchCourse = async () => {
			if (!params?.id) return;

			try {
				setLoading(true);
				setError(null);
				
				let data: any = null;
				
				// 먼저 getLecture 시도
				try {
					const response = await apiService.getLecture(params.id as string);
					data = response.data;
				} catch (lectureErr) {
					console.warn('getLecture 실패, getSubjects로 재시도:', lectureErr);
					
					// getLecture 실패 시 getSubjects로 폴백
					try {
						const subjectsResponse = await apiService.getSubjects();
						let subjectsData: any[] = [];
						
						if (Array.isArray(subjectsResponse.data)) {
							subjectsData = subjectsResponse.data;
						} else if (subjectsResponse.data && typeof subjectsResponse.data === 'object') {
							subjectsData = subjectsResponse.data.items || 
										subjectsResponse.data.courses || 
										subjectsResponse.data.data || 
										subjectsResponse.data.list || 
										subjectsResponse.data.subjects || 
										subjectsResponse.data.subjectList || 
										[];
						}
						
						// ID로 과목 찾기
						data = subjectsData.find((s: any) => String(s.id || s.subjectId) === String(params.id));
						
						if (!data) {
							// getLectures로도 시도
							try {
								const lecturesResponse = await apiService.getLectures();
								const lectures = Array.isArray(lecturesResponse.data) 
									? lecturesResponse.data 
									: lecturesResponse.data?.items || lecturesResponse.data?.lectures || lecturesResponse.data?.data || [];
								
								data = lectures.find((l: any) => String(l.id || l.lectureId) === String(params.id));
							} catch (lecturesErr) {
								console.error('getLectures 실패:', lecturesErr);
							}
						}
					} catch (subjectsErr) {
						console.error('getSubjects 실패:', subjectsErr);
					}
				}
				
				if (!data) {
					throw new Error('강좌를 찾을 수 없습니다.');
				}
				
				// 썸네일 이미지 가져오기
				let thumbnail = '/imgs/talk.png';
				if (data.imageKey) {
					try {
						const imageUrl = await apiService.getFile(data.imageKey);
						if (imageUrl) {
							thumbnail = imageUrl;
						}
					} catch (imgErr) {
						console.error('이미지 다운로드 실패:', imgErr);
					}
				}
				
				// 강좌의 차시(lessons) 정보 가져오기
				let lessons: any[] = [];
				if (data.lessons && Array.isArray(data.lessons)) {
					lessons = data.lessons;
				} else if (data.lectureId) {
					// lectureId가 있으면 해당 강좌의 차시 정보 가져오기 시도
					try {
						const lectureResponse = await apiService.getLecture(data.lectureId);
						if (lectureResponse.data?.lessons) {
							lessons = lectureResponse.data.lessons;
						}
					} catch (err) {
						console.warn('차시 정보 가져오기 실패:', err);
					}
				}
				
				// API 응답 데이터를 CourseDetail 타입으로 변환
				const courseDetail: CourseDetail = {
					id: String(data.id || params.id),
					status: data.status || "수강 예정",
					title: data.title || data.lectureName || data.subjectName || '',
					goal: data.objective || data.goal || '',
					method: data.method || '',
					summary: data.summary || `VOD · 총 ${lessons.length || 0}강`,
					submitSummary: data.submitSummary || '',
					thumbnail: thumbnail,
					lessons: lessons.map((lesson: any, index: number) => ({
						id: String(lesson.id || lesson.lessonId || index + 1),
						title: `${index + 1}. ${lesson.title || lesson.lessonName || ''}`,
						duration: lesson.duration || '00:00',
						state: lesson.isCompleted ? "제출완료" : "제출대기",
						action: lesson.isCompleted ? "복습하기" : (index === 0 ? "수강하기" : "이어서 수강하기"),
					})),
				};

				setCourse(courseDetail);
			} catch (err) {
				console.error('강좌 조회 실패:', err);
				setError(err instanceof Error ? err.message : '강좌를 불러오는데 실패했습니다.');
			} finally {
				setLoading(false);
			}
		};

		fetchCourse();
	}, [params?.id]);

	if (loading) {
		return (
			<main className="flex w-full flex-col items-center">
				<div className="flex h-[100px] w-full max-w-[1440px] items-center gap-[12px] px-8">
					<button
						type="button"
						onClick={() => router.back()}
						aria-label="뒤로 가기"
						className="size-8 rounded-full inline-flex items-center justify-center text-[#8C95A1] hover:bg-black/5 no-underline cursor-pointer"
					>
						<BackCircleSvg width={32} height={32} />
					</button>
					<h1 className="text-[24px] font-bold leading-[1.5] text-[#1b2027]">교육 과정 상세보기</h1>
				</div>
				<section className="w-full max-w-[1440px] px-8 pb-20">
					<div className="flex items-center justify-center py-20">
						<p className="text-[16px] text-[#8c95a1]">로딩 중...</p>
					</div>
				</section>
			</main>
		);
	}

	if (error || !course) {
		return (
			<main className="flex w-full flex-col items-center">
				<div className="flex h-[100px] w-full max-w-[1440px] items-center gap-[12px] px-8">
					<button
						type="button"
						onClick={() => router.back()}
						aria-label="뒤로 가기"
						className="size-8 rounded-full inline-flex items-center justify-center text-[#8C95A1] hover:bg-black/5 no-underline cursor-pointer"
					>
						<BackCircleSvg width={32} height={32} />
					</button>
					<h1 className="text-[24px] font-bold leading-[1.5] text-[#1b2027]">교육 과정 상세보기</h1>
				</div>
				<section className="w-full max-w-[1440px] px-8 pb-20">
					<div className="flex flex-col items-center justify-center py-20">
						<p className="text-[16px] text-red-500 mb-4">{error || '강좌를 찾을 수 없습니다.'}</p>
						<button
							type="button"
							onClick={() => router.push('/course-list')}
							className="px-4 py-2 rounded-[6px] bg-primary text-white text-[14px] font-medium"
						>
							강좌 목록으로 돌아가기
						</button>
					</div>
				</section>
			</main>
		);
	}

	return (
		<main className="flex w-full flex-col items-center">
			{/* 헤더 */}
			<div className="flex h-[100px] w-full max-w-[1440px] items-center gap-[12px] px-8">
				<button
					type="button"
					onClick={() => router.back()}
					aria-label="뒤로 가기"
					className="size-8 rounded-full inline-flex items-center justify-center text-[#8C95A1] hover:bg-black/5 no-underline cursor-pointer"
				>
					<BackCircleSvg width={32} height={32} />
				</button>
				<h1 className="text-[24px] font-bold leading-[1.5] text-[#1b2027]">교육 과정 상세보기</h1>
			</div>

			{/* 메인 콘텐츠 */}
			<section className="w-full max-w-[1440px] px-8 pb-[80px] pt-[24px]">
				{/* 상단 정보 카드 */}
				<div className="bg-[#f8f9fa] box-border flex gap-[24px] items-start p-[24px] rounded-[8px] w-full">
					{/* 이미지 컨테이너 */}
					<div className="overflow-clip relative rounded-[4px] shrink-0 w-[220.5px] h-[159px]">
						<Image 
							src={course.thumbnail} 
							alt={course.title} 
							fill
							sizes="220.5px"
							className="object-cover"
							unoptimized
						/>
					</div>

					{/* 교육과정 정보 */}
					<div className="basis-0 flex flex-col gap-[12px] grow items-start min-h-px min-w-px relative shrink-0">
						{/* 제목 영역 */}
						<div className="flex gap-[8px] h-[27px] items-center w-full">
							<div className="bg-[#e5f5ec] box-border flex h-[20px] items-center justify-center px-[4px] py-0 rounded-[4px] shrink-0">
								<p className="font-['Pretendard:SemiBold',sans-serif] text-[#0c9d61] text-[13px] leading-[1.4]">{course.status}</p>
							</div>
							<h2 className="font-['Pretendard:SemiBold',sans-serif] text-[#333c47] text-[18px] leading-[1.5]">{course.title}</h2>
						</div>

						{/* 학습 목표 및 방법 */}
						<div className="flex flex-col gap-[4px] items-start w-full">
							<p className="font-['Pretendard:Regular',sans-serif] text-[#333c47] text-[15px] leading-[1.5] mb-0">
								<span className="font-['Pretendard:Medium',sans-serif]">학습 목표:</span>
								<span>{` ${course.goal}`}</span>
							</p>
							<p className="font-['Pretendard:Regular',sans-serif] text-[#333c47] text-[15px] leading-[1.5]">
								<span className="font-['Pretendard:Medium',sans-serif]">학습 방법:</span>
								<span>{` ${course.method}`}</span>
							</p>
						</div>

						{/* 통계 정보 */}
						<div className="flex gap-[4px] items-center w-full">
							<div className="flex gap-[20px] items-center">
								{/* VOD 정보 */}
								<div className="flex gap-[4px] items-center">
									<div className="relative shrink-0 size-[16px]">
										<img src={imgPlay} alt="" className="block max-w-none size-full" />
									</div>
									<p className="font-['Pretendard:Medium',sans-serif] text-[#8c95a1] text-[13px] leading-[1.4]">{course.summary}</p>
								</div>

								{/* 학습 제출 정보 */}
								{course.submitSummary && (
									<div className="flex gap-[4px] items-center">
										<div className="relative shrink-0 size-[16px]">
											<img src={imgMusicAudioPlay} alt="" className="block max-w-none size-full" />
										</div>
										<p className="font-['Pretendard:Medium',sans-serif] text-[#8c95a1] text-[13px] leading-[1.4]">{course.submitSummary}</p>
									</div>
								)}
							</div>
						</div>
					</div>
				</div>

				{/* 차시 리스트 */}
				<div className="flex flex-col gap-[8px] items-start mt-[24px] w-full">
					{course.lessons.map((l) => {
						const isSubmitted = l.state === "제출완료";
						const submitBtnBorder = isSubmitted 
							? "border-transparent" 
							: (l.action === "이어서 수강하기" || l.action === "수강하기" ? "border-[#b1b8c0]" : "border-[#8c95a1]");
						const submitBtnText = isSubmitted ? "text-[#384fbf]" : (l.action === "이어서 수강하기" || l.action === "수강하기" ? "text-[#b1b8c0]" : "text-[#4c5561]");
						const rightBtnStyle =
							l.action === "이어서 수강하기" || l.action === "수강하기"
								? "bg-[#ecf0ff] text-[#384fbf]"
								: "bg-[#f1f3f5] text-[#4c5561]";
						
						return (
							<div key={l.id} className="bg-white border border-[#dee1e6] border-solid relative rounded-[8px] w-full">
								<div className="box-border flex gap-[16px] items-center overflow-clip px-[24px] py-[16px] rounded-[inherit] w-full">
									<div className="basis-0 flex grow h-[46px] items-center justify-between min-h-px min-w-px relative shrink-0">
										{/* 차시 정보 */}
										<div className="basis-0 grow min-h-px min-w-px relative shrink-0">
											<div className="flex flex-col gap-[4px] items-start w-full">
												<p className="font-['Pretendard:SemiBold',sans-serif] text-[#333c47] text-[16px] leading-[1.5]">{l.title}</p>
												<div className="flex gap-[12px] items-center w-full">
													<p className="font-['Pretendard:Medium',sans-serif] text-[#8c95a1] text-[13px] leading-[1.4] w-[40px]">{l.duration}</p>
												</div>
											</div>
										</div>

										{/* 버튼 영역 */}
										<div className="relative shrink-0">
											<div className="flex gap-[8px] items-center">
												{/* 학습 제출 버튼 */}
												<button
													type="button"
													className={[
														"bg-white box-border flex flex-col h-[32px] items-center justify-center px-[16px] py-[3px] rounded-[6px] shrink-0",
														"border border-solid",
														submitBtnBorder,
														submitBtnText,
													].join(" ")}
												>
													{isSubmitted ? (
														<div className="flex gap-[4px] h-[18px] items-center">
															<div className="relative shrink-0 size-[12px]">
																<svg width="12" height="12" viewBox="0 0 12 12" fill="none" xmlns="http://www.w3.org/2000/svg">
																	<path d="M10 3L4.5 8.5L2 6" stroke="#384fbf" strokeWidth="1.5" strokeLinecap="round" strokeLinejoin="round"/>
																</svg>
															</div>
															<p className="font-['Pretendard:Medium',sans-serif] text-[#384fbf] text-[13px] leading-[1.4]">학습 제출 완료</p>
														</div>
													) : (
														<p className={[
															"font-['Pretendard:Medium',sans-serif] text-[14px] leading-[1.5] text-center",
															submitBtnText,
														].join(" ")}>학습 제출 하기</p>
													)}
												</button>

												{/* 수강/복습 버튼 */}
												<button
													type="button"
													className={[
														"box-border flex flex-col h-[32px] items-center justify-center px-[16px] py-[3px] rounded-[6px] shrink-0",
														rightBtnStyle,
													].join(" ")}
												>
													<p className={[
														"font-['Pretendard:Medium',sans-serif] text-[14px] leading-[1.5] text-center",
														l.action === "이어서 수강하기" || l.action === "수강하기" ? "text-[#384fbf]" : "text-[#4c5561]",
													].join(" ")}>{l.action}</p>
												</button>
											</div>
										</div>
									</div>
								</div>
							</div>
						);
					})}
				</div>
			</section>
		</main>
	);
}