/* eslint-disable @next/next/no-img-element */
import {Module} from "@/interfaces";
import {useEffect, useState} from "react";

import AbandonPopup from "@/components/AbandonPopup";
import Layout from "@/components/High/Layout";
import Finish from "@/exams/Finish";
import Level from "@/exams/Level";
import Listening from "@/exams/Listening";
import Reading from "@/exams/Reading";
import Selection from "@/exams/Selection";
import Speaking from "@/exams/Speaking";
import Writing from "@/exams/Writing";
import useUser from "@/hooks/useUser";
import {Exam, UserSolution, Variant} from "@/interfaces/exam";
import {Stat} from "@/interfaces/user";
import useExamStore from "@/stores/examStore";
import {evaluateSpeakingAnswer, evaluateWritingAnswer} from "@/utils/evaluation";
import {defaultExamUserSolutions, getExam} from "@/utils/exams";
import axios from "axios";
import {useRouter} from "next/router";
import {toast, ToastContainer} from "react-toastify";
import {v4 as uuidv4} from "uuid";
import useSessions from "@/hooks/useSessions";
import ShortUniqueId from "short-unique-id";

interface Props {
	page: "exams" | "exercises";
}

export default function ExamPage({page}: Props) {
	const [variant, setVariant] = useState<Variant>("full");
	const [avoidRepeated, setAvoidRepeated] = useState(false);
	const [hasBeenUploaded, setHasBeenUploaded] = useState(false);
	const [showAbandonPopup, setShowAbandonPopup] = useState(false);
	const [isEvaluationLoading, setIsEvaluationLoading] = useState(false);
	const [statsAwaitingEvaluation, setStatsAwaitingEvaluation] = useState<string[]>([]);
	const [timeSpent, setTimeSpent] = useState(0);

	const resetStore = useExamStore((state) => state.reset);
	const assignment = useExamStore((state) => state.assignment);
	const initialTimeSpent = useExamStore((state) => state.timeSpent);

	const examStore = useExamStore;

	const {exam, setExam} = useExamStore((state) => state);
	const {exams, setExams} = useExamStore((state) => state);
	const {sessionId, setSessionId} = useExamStore((state) => state);
	const {partIndex, setPartIndex} = useExamStore((state) => state);
	const {moduleIndex, setModuleIndex} = useExamStore((state) => state);
	const {questionIndex, setQuestionIndex} = useExamStore((state) => state);
	const {exerciseIndex, setExerciseIndex} = useExamStore((state) => state);
	const {userSolutions, setUserSolutions} = useExamStore((state) => state);
	const {showSolutions, setShowSolutions} = useExamStore((state) => state);
	const {selectedModules, setSelectedModules} = useExamStore((state) => state);

	const {user} = useUser({redirectTo: "/login"});
	const router = useRouter();

	const reset = () => {
		resetStore();
		setVariant("full");
		setAvoidRepeated(false);
		setHasBeenUploaded(false);
		setShowAbandonPopup(false);
		setIsEvaluationLoading(false);
		setStatsAwaitingEvaluation([]);
		setTimeSpent(0);
	};

	// eslint-disable-next-line react-hooks/exhaustive-deps
	const saveSession = async () => {
		console.log("Saving your session...");

		await axios.post("/api/sessions", {
			id: sessionId,
			sessionId,
			date: new Date().toISOString(),
			userSolutions,
			moduleIndex,
			selectedModules,
			assignment,
			timeSpent,
			exams,
			exam,
			partIndex,
			exerciseIndex,
			questionIndex,
			user: user?.id,
		});
	};

	useEffect(() => setTimeSpent((prev) => prev + initialTimeSpent), [initialTimeSpent]);

	useEffect(() => {
		if (userSolutions.length === 0 && exams.length > 0) {
			const defaultSolutions = exams.map(defaultExamUserSolutions).flat();
			setUserSolutions(defaultSolutions);
		}
	}, [exams, setUserSolutions, userSolutions]);

	useEffect(() => {
		if (
			sessionId.length > 0 &&
			userSolutions.length > 0 &&
			selectedModules.length > 0 &&
			exams.length > 0 &&
			!!exam &&
			timeSpent > 0 &&
			!showSolutions &&
			moduleIndex < selectedModules.length
		)
			saveSession();
		// eslint-disable-next-line react-hooks/exhaustive-deps
	}, [assignment, exam, exams, moduleIndex, selectedModules, sessionId, userSolutions, user, exerciseIndex, partIndex, questionIndex]);

	useEffect(() => {
		if (timeSpent % 20 === 0 && timeSpent > 0 && moduleIndex < selectedModules.length && !showSolutions) saveSession();
		// eslint-disable-next-line react-hooks/exhaustive-deps
	}, [timeSpent]);

	useEffect(() => {
		if (selectedModules.length > 0 && sessionId.length === 0) {
			const shortUID = new ShortUniqueId();
			setSessionId(shortUID.randomUUID(8));
		}
	}, [setSessionId, selectedModules, sessionId]);

	useEffect(() => {
		if (user?.type === "developer") console.log(exam);
	}, [exam, user]);

	useEffect(() => {
		if (selectedModules.length > 0 && timeSpent === 0 && !showSolutions) {
			const timerInterval = setInterval(() => {
				setTimeSpent((prev) => prev + 1);
			}, 1000);

			return () => {
				clearInterval(timerInterval);
			};
		}
		// eslint-disable-next-line react-hooks/exhaustive-deps
	}, [selectedModules.length]);

	useEffect(() => {
		if (showSolutions) setModuleIndex(-1);
	}, [setModuleIndex, showSolutions]);

	useEffect(() => {
		(async () => {
			if (selectedModules.length > 0 && exams.length > 0 && moduleIndex < selectedModules.length) {
				const nextExam = exams[moduleIndex];

				if (partIndex === -1 && nextExam.module !== "listening") setPartIndex(0);
				if (exerciseIndex === -1 && !["reading", "listening"].includes(nextExam.module)) setExerciseIndex(0);
				setExam(nextExam ? updateExamWithUserSolutions(nextExam) : undefined);
			}
		})();
		// eslint-disable-next-line react-hooks/exhaustive-deps
	}, [selectedModules, moduleIndex, exams]);

	useEffect(() => {
		(async () => {
			if (selectedModules.length > 0 && exams.length === 0) {
				const examPromises = selectedModules.map((module) =>
					getExam(
						module,
						avoidRepeated,
						variant,
						user?.type === "student" || user?.type === "developer" ? user.preferredGender : undefined,
					),
				);
				Promise.all(examPromises).then((values) => {
					if (values.every((x) => !!x)) {
						setExams(values.map((x) => x!));
					} else {
						toast.error("Something went wrong, please try again");
						setTimeout(router.reload, 500);
					}
				});
			}
		})();
		// eslint-disable-next-line react-hooks/exhaustive-deps
	}, [selectedModules, setExams, exams]);

	useEffect(() => {
		if (selectedModules.length > 0 && exams.length !== 0 && moduleIndex >= selectedModules.length && !hasBeenUploaded && !showSolutions) {
			const newStats: Stat[] = userSolutions.map((solution) => ({
				...solution,
				id: solution.id || uuidv4(),
				timeSpent,
				session: sessionId,
				exam: solution.exam!,
				module: solution.module!,
				user: user?.id || "",
				date: new Date().getTime(),
				isDisabled: solution.isDisabled,
				...(assignment ? {assignment: assignment.id} : {}),
			}));

			axios
				.post<{ok: boolean}>("/api/stats", newStats)
				.then((response) => setHasBeenUploaded(response.data.ok))
				.catch(() => setHasBeenUploaded(false));
		}
		// eslint-disable-next-line react-hooks/exhaustive-deps
	}, [selectedModules, moduleIndex, hasBeenUploaded]);

	useEffect(() => {
		setIsEvaluationLoading(statsAwaitingEvaluation.length !== 0);
	}, [statsAwaitingEvaluation]);

	useEffect(() => {
		if (statsAwaitingEvaluation.length > 0) {
			checkIfStatsHaveBeenEvaluated(statsAwaitingEvaluation);
		}
		// eslint-disable-next-line react-hooks/exhaustive-deps
	}, [statsAwaitingEvaluation]);

	const checkIfStatsHaveBeenEvaluated = (ids: string[]) => {
		setTimeout(async () => {
			try {
				const awaitedStats = await Promise.all(ids.map(async (id) => (await axios.get<Stat>(`/api/stats/${id}`)).data));
				const solutionsEvaluated = awaitedStats.every((stat) => stat.solutions.every((x) => x.evaluation !== null));
				if (solutionsEvaluated) {
					const statsUserSolutions: UserSolution[] = awaitedStats.map((stat) => ({
						id: stat.id,
						exercise: stat.exercise,
						score: stat.score,
						solutions: stat.solutions,
						type: stat.type,
						exam: stat.exam,
						module: stat.module,
					}));

					const updatedUserSolutions = userSolutions.map((x) => {
						const respectiveSolution = statsUserSolutions.find((y) => y.exercise === x.exercise);
						return respectiveSolution ? respectiveSolution : x;
					});

					setUserSolutions(updatedUserSolutions);
					return setStatsAwaitingEvaluation((prev) => prev.filter((x) => !ids.includes(x)));
				}

				return checkIfStatsHaveBeenEvaluated(ids);
			} catch {
				return checkIfStatsHaveBeenEvaluated(ids);
			}
		}, 5 * 1000);
	};

	const updateExamWithUserSolutions = (exam: Exam): Exam => {
		if (exam.module === "reading" || exam.module === "listening") {
			const parts = exam.parts.map((p) =>
				Object.assign(p, {
					exercises: p.exercises.map((x) =>
						Object.assign(x, {
							userSolutions: userSolutions.find((y) => x.id === y.exercise)?.solutions,
						}),
					),
				}),
			);
			return Object.assign(exam, {parts});
		}

		const exercises = exam.exercises.map((x) =>
			Object.assign(x, {
				userSolutions: userSolutions.find((y) => x.id === y.exercise)?.solutions,
			}),
		);
		return Object.assign(exam, {exercises});
	};

	const onFinish = async (solutions: UserSolution[]) => {
		const solutionIds = solutions.map((x) => x.exercise);
		const solutionExams = solutions.map((x) => x.exam);

		if (exam && !solutionExams.includes(exam.id)) return;

		if (exam && (exam.module === "writing" || exam.module === "speaking") && solutions.length > 0 && !showSolutions) {
			setHasBeenUploaded(true);
			setIsEvaluationLoading(true);

			Promise.all(
				exam.exercises.map(async (exercise) => {
					const evaluationID = uuidv4();
					if (exercise.type === "writing")
						return await evaluateWritingAnswer(exercise, solutions.find((x) => x.exercise === exercise.id)!, evaluationID);

					if (exercise.type === "interactiveSpeaking" || exercise.type === "speaking")
						return await evaluateSpeakingAnswer(exercise, solutions.find((x) => x.exercise === exercise.id)!, evaluationID);
				}),
			)
				.then((responses) => {
					examStore.setState((prev) => {
						return {
							userSolutions: [
								...prev.userSolutions.filter(
									(x) =>
										!responses
											.filter((r) => !!r)
											.map((r) => r!.id)
											.includes(x.id),
								),
								...responses.filter((x) => !!x),
							] as any,
						};
					});
					setStatsAwaitingEvaluation((prev) => [...prev, ...responses.filter((x) => !!x).map((r) => (r as any).id)]);
				})
				.finally(() => {
					setHasBeenUploaded(false);
				});
		}

		axios.get("/api/stats/update");

		setUserSolutions([...userSolutions.filter((x) => !solutionIds.includes(x.exercise)), ...solutions]);
		setModuleIndex(moduleIndex + 1);

		setPartIndex(-1);
		setExerciseIndex(-1);
		setQuestionIndex(0);
	};

	const aggregateScoresByModule = (): {module: Module; total: number; missing: number; correct: number}[] => {
		const scores: {
			[key in Module]: {total: number; missing: number; correct: number};
		} = {
			reading: {
				total: 0,
				correct: 0,
				missing: 0,
			},
			listening: {
				total: 0,
				correct: 0,
				missing: 0,
			},
			writing: {
				total: 0,
				correct: 0,
				missing: 0,
			},
			speaking: {
				total: 0,
				correct: 0,
				missing: 0,
			},
			level: {
				total: 0,
				correct: 0,
				missing: 0,
			},
		};

		userSolutions.forEach((x) => {
			const examModule =
				x.module || (x.type === "writing" ? "writing" : x.type === "speaking" || x.type === "interactiveSpeaking" ? "speaking" : undefined);

			scores[examModule!] = {
				total: scores[examModule!].total + x.score.total,
				correct: scores[examModule!].correct + x.score.correct,
				missing: scores[examModule!].missing + x.score.missing,
			};
		});

		return Object.keys(scores)
			.filter((x) => scores[x as Module].total > 0)
			.map((x) => ({module: x as Module, ...scores[x as Module]}));
	};

	const renderScreen = () => {
		if (selectedModules.length === 0) {
			return (
				<Selection
					page={page}
					user={user!}
					disableSelection={page === "exams"}
					onStart={(modules: Module[], avoid: boolean, variant: Variant) => {
						setModuleIndex(0);
						setAvoidRepeated(avoid);
						setSelectedModules(modules);
						setVariant(variant);
					}}
				/>
			);
		}

		if (moduleIndex >= selectedModules.length || moduleIndex === -1) {
			return (
				<Finish
					isLoading={isEvaluationLoading}
					user={user!}
					modules={selectedModules}
					onViewResults={() => {
						setShowSolutions(true);
						setModuleIndex(0);
						setExerciseIndex(["reading", "listening"].includes(exams[0].module) ? -1 : 0);
						setPartIndex(exams[0].module === "listening" ? -1 : 0);
						setExam(exams[0]);
					}}
					scores={aggregateScoresByModule()}
				/>
			);
		}

		if (exam && exam.module === "reading") {
			return <Reading exam={exam} onFinish={onFinish} showSolutions={showSolutions} />;
		}

		if (exam && exam.module === "listening") {
			return <Listening exam={exam} onFinish={onFinish} showSolutions={showSolutions} />;
		}

		if (exam && exam.module === "writing") {
			return <Writing exam={exam} onFinish={onFinish} showSolutions={showSolutions} />;
		}

		if (exam && exam.module === "speaking") {
			return <Speaking exam={exam} onFinish={onFinish} showSolutions={showSolutions} />;
		}

		if (exam && exam.module === "level") {
			return <Level exam={exam} onFinish={onFinish} showSolutions={showSolutions} />;
		}

		return <>Loading...</>;
	};

	return (
		<>
			<ToastContainer />
			{user && (
				<Layout
					user={user}
					className="justify-between"
					focusMode={selectedModules.length !== 0 && !showSolutions && moduleIndex < selectedModules.length}
					onFocusLayerMouseEnter={() => setShowAbandonPopup(true)}>
					<>
						{renderScreen()}
						{!showSolutions && moduleIndex < selectedModules.length && (
							<AbandonPopup
								isOpen={showAbandonPopup}
								abandonPopupTitle="Leave Exercise"
								abandonPopupDescription="Are you sure you want to leave the exercise? Your progress will be saved and this exam can be resumed on the Dashboard."
								abandonConfirmButtonText="Confirm"
								onAbandon={() => {
									reset();
								}}
								onCancel={() => setShowAbandonPopup(false)}
							/>
						)}
					</>
				</Layout>
			)}
		</>
	);
}