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

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

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

export default function ExamPage({page}: Props) {
	const [hasBeenUploaded, setHasBeenUploaded] = useState(false);
	const [moduleIndex, setModuleIndex] = useState(0);
	const [sessionId, setSessionId] = useState("");
	const [exam, setExam] = useState<Exam>();
	const [isEvaluationLoading, setIsEvaluationLoading] = useState(false);
	const [showAbandonPopup, setShowAbandonPopup] = useState(false);
	const [avoidRepeated, setAvoidRepeated] = useState(false);
	const [timeSpent, setTimeSpent] = useState(0);
	const [statsAwaitingEvaluation, setStatsAwaitingEvaluation] = useState<string[]>([]);

	const [exams, setExams] = useExamStore((state) => [state.exams, state.setExams]);
	const [userSolutions, setUserSolutions] = useExamStore((state) => [state.userSolutions, state.setUserSolutions]);
	const [showSolutions, setShowSolutions] = useExamStore((state) => [state.showSolutions, state.setShowSolutions]);
	const [selectedModules, setSelectedModules] = useExamStore((state) => [state.selectedModules, state.setSelectedModules]);
	const assignment = useExamStore((state) => state.assignment);

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

	useEffect(() => setSessionId(uuidv4()), []);

	useEffect(() => {
		selectedModules.length > 0 && timeSpent === 0 && !showSolutions;
		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(() => {
		(async () => {
			if (selectedModules.length > 0 && exams.length > 0 && moduleIndex < selectedModules.length) {
				const nextExam = exams[moduleIndex];
				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));
				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(),
				...(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(() => {
		if (statsAwaitingEvaluation.length === 0) return setIsEvaluationLoading(false);
		return setIsEvaluationLoading(true);
	}, [statsAwaitingEvaluation]);

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

	const checkIfStatHasBeenEvaluated = (id: string) => {
		setTimeout(async () => {
			const statRequest = await axios.get<Stat>(`/api/stats/${id}`);
			const stat = statRequest.data;
			if (stat.solutions.every((x) => x.evaluation !== null)) {
				const userSolution: UserSolution = {
					id,
					exercise: stat.exercise,
					score: stat.score,
					solutions: stat.solutions,
					type: stat.type,
					exam: stat.exam,
					module: stat.module,
				};

				setUserSolutions(userSolutions.map((x) => (x.exercise === userSolution.exercise ? userSolution : x)));
				return setStatsAwaitingEvaluation((prev) => prev.filter((x) => x !== id));
			}

			return checkIfStatHasBeenEvaluated(id);
		}, 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 = (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) => {
					setStatsAwaitingEvaluation((prev) => [...prev, ...responses.filter((x) => !!x).map((r) => (r as any).id)]);
					setUserSolutions([...userSolutions, ...responses.filter((x) => !!x)] as any);
				})
				.finally(() => {
					setHasBeenUploaded(false);
				});
		}

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

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

	const aggregateScoresByModule = (answers: UserSolution[]): {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,
			},
		};

		answers.forEach((x) => {
			scores[x.module!] = {
				total: scores[x.module!].total + x.score.total,
				correct: scores[x.module!].correct + x.score.correct,
				missing: scores[x.module!].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, avoid) => {
						setSelectedModules(modules);
						setAvoidRepeated(avoid);
					}}
				/>
			);
		}

		if (moduleIndex >= selectedModules.length) {
			return (
				<Finish
					isLoading={isEvaluationLoading}
					user={user!}
					modules={selectedModules}
					onViewResults={() => {
						setShowSolutions(true);
						setModuleIndex(0);
						setExam(exams[0]);
					}}
					scores={aggregateScoresByModule(userSolutions)}
				/>
			);
		}

		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? You will lose all your progress."
								abandonConfirmButtonText="Confirm"
								onAbandon={() => router.reload()}
								onCancel={() => setShowAbandonPopup(false)}
							/>
						)}
					</>
				</Layout>
			)}
		</>
	);
}