let currentSessionId = null;
let currentQuestionNumber = 1;
let totalQuestions = 10;
let currentScore = 0;
let currentStreak = 0;
let attemptsUsed = 0;
const maxAttempts = 3;
let selectedDifficulty = "all";
let selectedCategory = "all";
let lastQuestionData = null;
let timerStartTime = null;
let timerInterval = null;
let elapsedSeconds = 0;

const CATEGORY_LABELS = {
    de: {
        all: "✨ Alle Kategorien",
        books: "📖 Buchwissen",
        movies: "🎬 Filmwissen",
        creatures: "🐉 Magische Geschöpfe",
        spells: "🪄 Zaubersprüche & Tränke",
        characters: "🧙‍♂️ Charaktere",
        hogwarts: "🏰 Hogwarts & Orte",
        quidditch: "🧹 Quidditch",
        lore: "🔮 Artefakte & Lore",
        general: "⚡ Allgemein",
        harry_potter: "⚡ Harry Potter"
    },
    en: {
        all: "✨ All Categories",
        books: "📖 Book Lore",
        movies: "🎬 Movie Trivia",
        creatures: "🐉 Magical Creatures",
        spells: "🪄 Spells & Potions",
        characters: "🧙‍♂️ Characters",
        hogwarts: "🏰 Hogwarts & Places",
        quidditch: "🧹 Quidditch",
        lore: "🔮 Artifacts & Lore",
        general: "⚡ General",
        harry_potter: "⚡ Harry Potter"
    }
};

const UI_TEXT = {
    de: {
        pageTitle: "Harry Potter Wissensquiz",
        pageSubtitle: "Teste dein Wissen über Bücher, Filme, Geschöpfe und Zaubersprüche – direkt & ohne Umwege.",
        diffLabel: "Schwierigkeitsgrad",
        diffAll: "Alle Stufen",
        diffEasy: "Leicht",
        diffMed: "Mittel",
        diffHard: "Schwer (Experte)",
        catLabel: "Themengebiet wählen",
        catAll: "Alle Kategorien",
        catBooks: "Buchwissen",
        catMovies: "Filmwissen",
        catCreatures: "Magische Geschöpfe",
        catSpells: "Zaubersprüche & Tränke",
        catChars: "Charaktere",
        catHogwarts: "Hogwarts & Orte",
        catQuidditch: "Quidditch",
        catLore: "Artefakte & Lore",
        dashboardRules: "<span>🎯 10 Fragen pro Runde</span><span>·</span><span>🔥 Streak-Zähler</span><span>·</span><span>💡 Bis zu 3 Versuche je Frage</span>",
        startQuizBtn: "⚡ Quiz jetzt starten ➔",
        startBtnCasting: "⚡ Runde wird geladen...",
        pointsLabel: "Pkt.",
        questionLabel: "Frage",
        ofLabel: "/",
        attemptLabel: "Versuch",
        checkBtn: "✓ Antwort prüfen",
        hintBtn: "💡 Tipp anzeigen",
        hintHeading: "💡 Hinweis:",
        placeholder: "Deine Antwort eingeben...",
        noHint: "Kein Tipp vorhanden.",
        hintFailed: "Tipp konnte nicht geladen werden.",
        wrongFeedback: "Nicht ganz! Noch {attempts} Versuch(e).",
        exhaustedWrong: "Leider nicht gelöst (3 Fehlversuche).",
        solutionLabel: "Richtige Antwort:",
        startError: "Fehler beim Starten des Quiz: ",
        networkError: "Netzwerkfehler: "
    },
    en: {
        pageTitle: "Harry Potter Trivia Quiz",
        pageSubtitle: "Test your knowledge across books, movies, creatures, and spells — straight to the action.",
        diffLabel: "Difficulty Level",
        diffAll: "All Levels",
        diffEasy: "Easy",
        diffMed: "Medium",
        diffHard: "Hard (Expert)",
        catLabel: "Select Topic",
        catAll: "All Categories",
        catBooks: "Book Lore",
        catMovies: "Movie Trivia",
        catCreatures: "Magical Creatures",
        catSpells: "Spells & Potions",
        catChars: "Characters",
        catHogwarts: "Hogwarts & Places",
        catQuidditch: "Quidditch",
        catLore: "Artifacts & Lore",
        dashboardRules: "<span>🎯 10 Questions per Round</span><span>·</span><span>🔥 Answer Streak</span><span>·</span><span>💡 Up to 3 Attempts</span>",
        startQuizBtn: "⚡ Start Quiz Now ➔",
        startBtnCasting: "⚡ Loading Round...",
        pointsLabel: "Pts",
        questionLabel: "Question",
        ofLabel: "/",
        attemptLabel: "Attempt",
        checkBtn: "✓ Check Answer",
        hintBtn: "💡 Show Hint",
        hintHeading: "💡 Hint:",
        placeholder: "Type your answer...",
        noHint: "No hint available.",
        hintFailed: "Could not load hint.",
        wrongFeedback: "Not quite! {attempts} attempt(s) left.",
        exhaustedWrong: "Out of attempts (3 failed tries).",
        solutionLabel: "Correct answer:",
        startError: "Error starting quiz: ",
        networkError: "Network error: "
    }
};

// Web Audio API Sound Generator for crisp trivia feedback
const audioCtx = new (window.AudioContext || window.webkitAudioContext)();

function playSound(type) {
    if (audioCtx.state === 'suspended') {
        audioCtx.resume();
    }
    if (type === 'magic') {
        const notes = [523.25, 659.25, 783.99, 1046.50]; // C5, E5, G5, C6
        notes.forEach((freq, index) => {
            const osc = audioCtx.createOscillator();
            const gain = audioCtx.createGain();
            osc.type = 'sine';
            osc.frequency.value = freq;
            gain.gain.setValueAtTime(0.12, audioCtx.currentTime + index * 0.07);
            gain.gain.exponentialRampToValueAtTime(0.001, audioCtx.currentTime + index * 0.07 + 0.3);
            osc.connect(gain);
            gain.connect(audioCtx.destination);
            osc.start(audioCtx.currentTime + index * 0.07);
            osc.stop(audioCtx.currentTime + index * 0.07 + 0.3);
        });
    } else if (type === 'wrong') {
        const osc = audioCtx.createOscillator();
        const gain = audioCtx.createGain();
        osc.type = 'triangle';
        osc.frequency.setValueAtTime(180, audioCtx.currentTime);
        osc.frequency.exponentialRampToValueAtTime(95, audioCtx.currentTime + 0.22);
        gain.gain.setValueAtTime(0.12, audioCtx.currentTime);
        gain.gain.exponentialRampToValueAtTime(0.001, audioCtx.currentTime + 0.22);
        osc.connect(gain);
        gain.connect(audioCtx.destination);
        osc.start();
        osc.stop(audioCtx.currentTime + 0.22);
    }
}

function selectDifficulty(diff) {
    selectedDifficulty = diff;
    document.querySelectorAll(".diff-chip").forEach(chip => {
        chip.classList.toggle("active", chip.getAttribute("data-diff") === diff);
    });
}

function selectCategory(cat) {
    selectedCategory = cat;
    document.querySelectorAll(".cat-chip").forEach(chip => {
        chip.classList.toggle("active", chip.getAttribute("data-cat") === cat);
    });
}

function updateStreakUI(animate = false) {
    const badge = document.getElementById("streakBadge");
    if (!badge) return;
    badge.innerText = currentStreak >= 2 ? `🔥 ${currentStreak} Streak` : `🔥 ${currentStreak}`;
    badge.classList.toggle("streak-hot", currentStreak >= 2);
    if (animate) {
        badge.classList.remove("streak-pop");
        void badge.offsetWidth;
        badge.classList.add("streak-pop");
    }
}

function onLanguageChange(lang) {
    applyQuizTranslations(lang);
}

function applyQuizTranslations(lang) {
    const t = UI_TEXT[lang] || UI_TEXT.de;
    const setTxt = (id, val) => {
        const el = document.getElementById(id);
        if (el && val) el.innerText = val;
    };

    setTxt("pageTitle", t.pageTitle);
    setTxt("pageSubtitle", t.pageSubtitle);
    setTxt("diffLabel", t.diffLabel);
    setTxt("diffAllText", t.diffAll);
    setTxt("diffEasyText", t.diffEasy);
    setTxt("diffMedText", t.diffMed);
    setTxt("diffHardText", t.diffHard);
    setTxt("catLabel", t.catLabel);
    setTxt("catAllText", t.catAll);
    setTxt("catBooksText", t.catBooks);
    setTxt("catMoviesText", t.catMovies);
    setTxt("catCreaturesText", t.catCreatures);
    setTxt("catSpellsText", t.catSpells);
    setTxt("catCharsText", t.catChars);
    setTxt("catHogwartsText", t.catHogwarts);
    setTxt("catQuidditchText", t.catQuidditch);
    setTxt("catLoreText", t.catLore);

    const rulesEl = document.getElementById("dashboardRules");
    if (rulesEl) rulesEl.innerHTML = t.dashboardRules;

    const startQuizBtn = document.getElementById("startQuizBtn");
    if (startQuizBtn && !startQuizBtn.disabled) startQuizBtn.innerText = t.startQuizBtn;

    setTxt("checkBtn", t.checkBtn);
    setTxt("hintBtn", t.hintBtn);
    setTxt("hintBtnMC", t.hintBtn);
    setTxt("hintHeading", t.hintHeading);

    const answerInput = document.getElementById("answerInput");
    if (answerInput) answerInput.placeholder = t.placeholder;

    if (lastQuestionData) {
        renderQuestion(lastQuestionData);
    }
}

let sessionQuestionIds = [];

function getRecentQuestionIds() {
    try {
        const stored = localStorage.getItem("quiz_recent_qids");
        return stored ? JSON.parse(stored) : [];
    } catch(e) {
        return [];
    }
}

function getWrongQuestionIds() {
    try {
        const stored = localStorage.getItem("quiz_wrong_qids");
        return stored ? JSON.parse(stored) : [];
    } catch(e) {
        return [];
    }
}

function recordQuestionWrong(qid) {
    if (!qid) return;
    try {
        const wrong = getWrongQuestionIds();
        if (!wrong.includes(qid)) {
            wrong.push(qid);
            if (wrong.length > 30) wrong.shift();
            localStorage.setItem("quiz_wrong_qids", JSON.stringify(wrong));
        }
    } catch(e) {}
}

function recordQuestionMastered(qid) {
    if (!qid) return;
    try {
        let wrong = getWrongQuestionIds();
        if (wrong.includes(qid)) {
            wrong = wrong.filter(id => id !== qid);
            localStorage.setItem("quiz_wrong_qids", JSON.stringify(wrong));
        }
    } catch(e) {}
}

function saveRecentQuestions(ids) {
    if (!ids || ids.length === 0) return;
    try {
        let recent = getRecentQuestionIds();
        recent = Array.from(new Set([...ids, ...recent])).slice(0, 20);
        localStorage.setItem("quiz_recent_qids", JSON.stringify(recent));
    } catch(e) {}
}

async function startGame() {
    const startQuizBtn = document.getElementById("startQuizBtn");
    const t = UI_TEXT[currentLang] || UI_TEXT.de;

    if (startQuizBtn) {
        startQuizBtn.disabled = true;
        startQuizBtn.innerText = t.startBtnCasting;
    }

    playSound('magic');
    sessionQuestionIds = [];
    currentStreak = 0;
    updateStreakUI(false);

    try {
        const recentIds = getRecentQuestionIds();
        const wrongIds = getWrongQuestionIds();

        const res = await fetch("/api/game/start", {
            method: "POST",
            headers: { "Content-Type": "application/json" },
            body: JSON.stringify({
                lang: currentLang,
                difficulty: selectedDifficulty,
                category: selectedCategory,
                recent_ids: recentIds,
                wrong_ids: wrongIds
            })
        });

        if (!res.ok) {
            throw new Error(currentLang === "en" ? "Could not start game session." : "Konnte Spiel nicht starten.");
        }

        const data = await res.json();
        currentSessionId = data.session_id;
        currentQuestionNumber = data.question_number;
        totalQuestions = data.total_questions;
        currentScore = data.score;
        attemptsUsed = data.attempts_used;

        const introCard = document.getElementById("introCard");
        if (introCard) {
            introCard.classList.add("hidden");
        }
        document.getElementById("gameCard").classList.remove("hidden");
        startTimer();
        renderQuestion(data);

    } catch (err) {
        alert(t.startError + err.message);
        if (startQuizBtn) {
            startQuizBtn.disabled = false;
            startQuizBtn.innerText = t.startQuizBtn;
        }
    }
}

function startTimer() {
    timerStartTime = Date.now();
    elapsedSeconds = 0;
    if (timerInterval) clearInterval(timerInterval);
    timerInterval = setInterval(updateTimer, 1000);
    updateTimer();
}

function updateTimer() {
    if (!timerStartTime) return;
    elapsedSeconds = Math.floor((Date.now() - timerStartTime) / 1000);
    const m = Math.floor(elapsedSeconds / 60);
    const s = elapsedSeconds % 60;
    const badge = document.getElementById("timerBadge");
    if (badge) {
        badge.innerText = `⏱️ ${String(m).padStart(2, '0')}:${String(s).padStart(2, '0')}`;
    }
}

function renderQuestion(qData) {
    lastQuestionData = qData;
    if (qData.id && !sessionQuestionIds.includes(qData.id)) {
        sessionQuestionIds.push(qData.id);
    }
    const t = UI_TEXT[currentLang] || UI_TEXT.de;
    const catMap = CATEGORY_LABELS[currentLang] || CATEGORY_LABELS.de;

    document.getElementById("questionCounter").innerText = `${t.questionLabel} ${qData.question_number} ${t.ofLabel} ${totalQuestions}`;
    document.getElementById("pointsCounter").innerText = `🏆 ${currentScore} ${t.pointsLabel}`;

    const rawCat = (qData.category || "general").toLowerCase();
    document.getElementById("badgeCategory").innerText = catMap[rawCat] || `⚡ ${rawCat.toUpperCase()}`;

    const badgeDiff = document.getElementById("badgeDifficulty");
    if (badgeDiff) {
        const diff = qData.difficulty || "medium";
        badgeDiff.className = `badge badge-diff badge-diff-${diff}`;
        let diffText = t.diffMed;
        let diffIcon = "🟡";
        if (diff === "easy") {
            diffText = t.diffEasy;
            diffIcon = "🟢";
        } else if (diff === "hard") {
            diffText = currentLang === "en" ? "Hard" : "Schwer";
            diffIcon = "🔴";
        }
        badgeDiff.innerText = `${diffIcon} ${diffText}`;
    }

    document.getElementById("attemptBadge").innerText = `${t.attemptLabel} ${attemptsUsed + 1} ${t.ofLabel} ${maxAttempts}`;
    document.getElementById("frageText").innerText = qData.question;

    const textGroup = document.getElementById("textAnswerGroup");
    const choiceGroup = document.getElementById("choiceAnswerGroup");
    const choiceContainer = document.getElementById("choiceOptionsContainer");
    const input = document.getElementById("answerInput");

    document.getElementById("hintBox").classList.add("hidden");
    document.getElementById("feedbackBox").innerHTML = "";

    if (qData.question_type === "multiple_choice" && qData.options && qData.options.length > 0) {
        textGroup.classList.add("hidden");
        choiceGroup.classList.remove("hidden");
        choiceContainer.innerHTML = "";

        const letters = ["A", "B", "C", "D", "E", "F"];
        qData.options.forEach((opt, idx) => {
            const btn = document.createElement("button");
            btn.className = "choice-btn";
            btn.type = "button";
            btn.innerHTML = `<span class="choice-letter">${letters[idx] || "•"}</span> <span class="choice-text">${opt}</span>`;
            btn.onclick = () => submitAnswer(opt, btn);
            choiceContainer.appendChild(btn);
        });
    } else {
        choiceGroup.classList.add("hidden");
        textGroup.classList.remove("hidden");
        input.value = "";
        input.placeholder = t.placeholder;
        input.disabled = false;
        document.getElementById("checkBtn").disabled = false;
        input.focus();
    }

    const hintBtn = document.getElementById("hintBtn");
    if (hintBtn) hintBtn.disabled = false;
    const hintBtnMC = document.getElementById("hintBtnMC");
    if (hintBtnMC) hintBtnMC.disabled = false;

    updateProgress();
}

function updateProgress() {
    const percent = ((currentQuestionNumber - 1) / totalQuestions) * 100;
    document.getElementById("progressBar").style.width = percent + "%";
}

function checkAnswer() {
    const input = document.getElementById("answerInput");
    const answer = input.value.trim();
    if (!answer) {
        input.focus();
        return;
    }
    submitAnswer(answer);
}

async function submitAnswer(answer, clickedBtn = null) {
    const checkBtn = document.getElementById("checkBtn");
    const input = document.getElementById("answerInput");
    const t = UI_TEXT[currentLang] || UI_TEXT.de;

    if (checkBtn) checkBtn.disabled = true;
    if (input) input.disabled = true;

    const choiceBtns = document.querySelectorAll(".choice-btn");
    choiceBtns.forEach(b => b.disabled = true);
    if (clickedBtn) {
        clickedBtn.classList.add("choice-selected");
    }

    try {
        const res = await fetch("/api/game/check", {
            method: "POST",
            headers: { "Content-Type": "application/json" },
            body: JSON.stringify({
                session_id: currentSessionId,
                answer: answer
            })
        });

        if (!res.ok) {
            throw new Error(currentLang === "en" ? "Answer check failed." : "Fehler bei der Antwortprüfung.");
        }

        const result = await res.json();
        currentScore = result.score;
        document.getElementById("pointsCounter").innerText = `🏆 ${currentScore} ${t.pointsLabel}`;

        const frageBox = document.getElementById("frageBox");
        const feedbackBox = document.getElementById("feedbackBox");

        if (result.correct) {
            playSound('magic');
            currentStreak += 1;
            updateStreakUI(true);

            if (clickedBtn) {
                clickedBtn.classList.remove("choice-selected");
                clickedBtn.classList.add("choice-correct");
            }
            frageBox.classList.add("sparkle-effect");

            if (result.question_id) {
                recordQuestionMastered(result.question_id);
            }

            const pts = result.points_earned || 100;
            const streakBonusText = currentStreak >= 3 ? ` · 🔥 ${currentStreak}er Serie!` : "";
            const ptsText = (currentLang === "en")
                ? `✓ Correct! +${pts} Points${currentStreak >= 3 ? ` · 🔥 ${currentStreak} Streak!` : ""}`
                : `✓ Richtig! +${pts} Punkte${streakBonusText}`;
            feedbackBox.innerHTML = `<span class="feedback-correct">${ptsText}</span>`;

            setTimeout(() => {
                frageBox.classList.remove("sparkle-effect");
                if (result.is_finished) {
                    finishGame();
                } else if (result.next_question) {
                    currentQuestionNumber = result.next_question.question_number;
                    attemptsUsed = 0;
                    renderQuestion(result.next_question);
                }
            }, 1100);

        } else {
            playSound('wrong');
            currentStreak = 0;
            updateStreakUI(false);

            if (clickedBtn) {
                clickedBtn.classList.remove("choice-selected");
                clickedBtn.classList.add("choice-wrong");
            }
            frageBox.classList.add("shake-effect");
            setTimeout(() => frageBox.classList.remove("shake-effect"), 500);

            attemptsUsed = result.attempts_used;
            document.getElementById("attemptBadge").innerText = `${t.attemptLabel} ${Math.min(attemptsUsed + 1, maxAttempts)} ${t.ofLabel} ${maxAttempts}`;

            if (result.attempts_left === 0) {
                if (result.question_id) {
                    recordQuestionWrong(result.question_id);
                }

                feedbackBox.innerHTML = `
                    <div class="feedback-wrong">${t.exhaustedWrong}</div>
                    <div class="feedback-revealed">${t.solutionLabel} <strong>${result.revealed_answer}</strong></div>
                `;

                setTimeout(() => {
                    if (result.is_finished) {
                        finishGame();
                    } else if (result.next_question) {
                        currentQuestionNumber = result.next_question.question_number;
                        attemptsUsed = 0;
                        renderQuestion(result.next_question);
                    }
                }, 2200);

            } else {
                const msg = t.wrongFeedback.replace("{attempts}", result.attempts_left);
                feedbackBox.innerHTML = `<span class="feedback-wrong">${msg}</span>`;
                if (checkBtn) checkBtn.disabled = false;
                if (input) {
                    input.disabled = false;
                    input.select();
                }
                choiceBtns.forEach(b => b.disabled = false);
            }
        }

    } catch (err) {
        alert(t.networkError + err.message);
        if (checkBtn) checkBtn.disabled = false;
        if (input) input.disabled = false;
        choiceBtns.forEach(b => b.disabled = false);
    }
}

async function requestHint() {
    if (!currentSessionId) return;
    const hintBox = document.getElementById("hintBox");
    const hintText = document.getElementById("hintText");
    const t = UI_TEXT[currentLang] || UI_TEXT.de;

    try {
        const res = await fetch(`/api/game/hint?session_id=${encodeURIComponent(currentSessionId)}`);
        const data = await res.json();
        hintText.innerText = data.hint || t.noHint;
        hintBox.classList.remove("hidden");
    } catch (err) {
        hintText.innerText = t.hintFailed;
        hintBox.classList.remove("hidden");
    }
}

function finishGame() {
    if (timerInterval) clearInterval(timerInterval);
    saveRecentQuestions(sessionQuestionIds);
    document.getElementById("progressBar").style.width = "100%";
    window.location.href = `/finale?score=${currentScore}&total=${totalQuestions}&time=${elapsedSeconds}&lang=${currentLang}&diff=${encodeURIComponent(selectedDifficulty)}`;
}

document.addEventListener("DOMContentLoaded", () => {
    const input = document.getElementById("answerInput");
    if (input) {
        input.addEventListener("keydown", (e) => {
            if (e.key === "Enter") {
                e.preventDefault();
                checkAnswer();
            }
        });
    }
    applyQuizTranslations(currentLang);
});