function formatCheckoutEuro(value) {
    return `${Number(value || 0).toFixed(2).replace(".", ",")} EUR`;
}

let selectedPaymentMethod = "";
let checkoutEventsBound = false;

function setCheckoutStep(step) {
    const step1 = document.getElementById("checkout-step-1");
    const step2 = document.getElementById("checkout-step-2");
    const step3 = document.getElementById("checkout-step-3");

    step1?.classList.toggle("hidden", step !== 1);
    step2?.classList.toggle("hidden", step !== 2);
    step3?.classList.toggle("hidden", step !== 3);

    const line1 = document.getElementById("line-1");
    const line2 = document.getElementById("line-2");
    const indicator1 = document.getElementById("step-1-indicator");
    const indicator2 = document.getElementById("step-2-indicator");
    const indicator3 = document.getElementById("step-3-indicator");

    indicator1?.classList.add("active");
    indicator2?.classList.toggle("active", step >= 2);
    indicator3?.classList.toggle("active", step >= 3);
    line1?.classList.toggle("active", step >= 2);
    line2?.classList.toggle("active", step >= 3);
}

function renderCheckout() {
    const summaryList = document.getElementById("checkout-summary-list");
    const totalDisplay = document.getElementById("checkout-total-display");
    const vatDisplay = document.getElementById("checkout-vat-display");
    const nextButton = document.getElementById("btn-next-step-2");

    if (!summaryList) {
        return;
    }

    summaryList.innerHTML = "";

    const safeCart = Array.isArray(cart) ? cart : [];
    const total = safeCart.reduce((sum, item) => sum + Number(item.price || 0), 0);
    const vat = total - total / 1.19;

    safeCart.forEach((item) => {
        const row = document.createElement("div");
        row.style.cssText = "display:flex; justify-content:space-between; gap:12px; margin-bottom:10px; font-size:0.95rem;";

        const infoText = item.category === "movie"
            ? `Sitz ${item.seatId || "-"} | ${item.hall || "-"} | ${item.time || "-"} Uhr`
            : `${item.time || "Standard"} | ${item.hall || "-"}`;

        row.innerHTML = `<span>${item.title} (${infoText})</span><span>${formatCheckoutEuro(item.price)}</span>`;
        summaryList.appendChild(row);
    });

    if (totalDisplay) {
        totalDisplay.innerText = `Gesamtbetrag: ${formatCheckoutEuro(total)}`;
    }

    if (vatDisplay) {
        vatDisplay.innerText = `inkl. 19% MwSt: ${formatCheckoutEuro(vat)}`;
    }

    selectedPaymentMethod = "";
    document.querySelectorAll(".payment-method").forEach((method) => {
        method.classList.remove("selected");
    });

    nextButton?.classList.add("hidden");
    setCheckoutStep(1);
}

function generateTicket() {
    const ticketContainer = document.getElementById("ticket-container");
    if (!ticketContainer) {
        return;
    }

    const moviesInCart = (Array.isArray(cart) ? cart : []).filter((item) => item.category === "movie");
    if (!moviesInCart.length) {
        ticketContainer.innerHTML = "<p>Danke fuer deinen Einkauf!</p>";
        return;
    }

    const mainMovie = moviesInCart[0];
    const matchingMovieSeats = moviesInCart
        .filter((item) => item.title === mainMovie.title && item.time === mainMovie.time)
        .map((item) => item.seatId)
        .join(", ");

    const qrData = encodeURIComponent(`EAGLE-IMAX|${mainMovie.title}|${mainMovie.hall}|${matchingMovieSeats}`);
    const qrUrl = `https://api.qrserver.com/v1/create-qr-code/?size=150x150&data=${qrData}&bgcolor=ffffff`;

    ticketContainer.innerHTML = `
        <div class="luxury-ticket">
            <div class="ticket-left">
                <img src="${mainMovie.img}" class="ticket-poster" alt="${mainMovie.title}">
            </div>
            <div class="ticket-right">
                <div class="ticket-brand">EAGLE'S IMAX PREMIUM</div>
                <h2 class="ticket-title">${mainMovie.title}</h2>
                <div class="ticket-details">
                    <p><span>SAAL</span> <strong>${mainMovie.hall}</strong></p>
                    <p><span>ZEIT</span> <strong>${mainMovie.time} Uhr</strong></p>
                    <p><span>SITZE</span> <strong>${matchingMovieSeats || "-"}</strong></p>
                </div>
                <div class="ticket-footer">
                    <img src="${qrUrl}" class="ticket-qr" alt="QR Code">
                    <div class="ticket-code">#${Math.floor(Math.random() * 90000) + 10000}</div>
                </div>
            </div>
        </div>
    `;
}

function saveOrderForCurrentUser(orderItems, orderTotal) {
    if (typeof currentUser === "undefined" || !currentUser) {
        return;
    }

    if (typeof users === "undefined" || !Array.isArray(users)) {
        return;
    }

    const order = {
        date: new Date().toLocaleString("de-DE"),
        items: orderItems,
        total: orderTotal,
        paymentMethod: selectedPaymentMethod || "-"
    };

    const userIndex = users.findIndex((entry) => entry.email === currentUser.email);
    if (userIndex === -1) {
        return;
    }

    if (!Array.isArray(users[userIndex].orders)) {
        users[userIndex].orders = [];
    }

    users[userIndex].orders.push(order);
    localStorage.setItem("eagleUsers", JSON.stringify(users));
}

function reserveSeatsAfterPayment(orderItems) {
    const movieItems = orderItems.filter((item) => item.category === "movie");

    movieItems.forEach((item) => {
        const key = `${item.hall}-${item.time}`;
        if (!occupiedSeatsData[key]) {
            occupiedSeatsData[key] = [];
        }

        occupiedSeatsData[key].push(item.seatId);
    });

    localStorage.setItem("eagleOccupied", JSON.stringify(occupiedSeatsData));
}

function completeCheckout() {
    const orderItems = Array.isArray(cart) ? [...cart] : [];
    const orderTotal = orderItems.reduce((sum, item) => sum + Number(item.price || 0), 0);

    saveOrderForCurrentUser(orderItems, orderTotal);
    reserveSeatsAfterPayment(orderItems);

    cart = [];
    saveCart?.();
    renderCart?.();
}

function bindCheckoutEvents() {
    if (checkoutEventsBound) {
        return;
    }

    checkoutEventsBound = true;

    const nextButton = document.getElementById("btn-next-step-2");
    const backButton = document.getElementById("btn-back-to-step1");
    const payNowButton = document.getElementById("btn-pay-now");

    document.querySelectorAll(".payment-method").forEach((method) => {
        method.addEventListener("click", () => {
            document.querySelectorAll(".payment-method").forEach((entry) => {
                entry.classList.remove("selected");
            });

            method.classList.add("selected");
            selectedPaymentMethod = method.dataset.method || "";
            nextButton?.classList.remove("hidden");
        });
    });

    nextButton?.addEventListener("click", () => {
        if (!selectedPaymentMethod) {
            alert("Bitte waehle zuerst eine Zahlungsmethode aus.");
            return;
        }

        setCheckoutStep(2);
    });

    backButton?.addEventListener("click", () => {
        setCheckoutStep(1);
    });

    payNowButton?.addEventListener("click", () => {
        if (!Array.isArray(cart) || !cart.length) {
            alert("Dein Warenkorb ist leer.");
            return;
        }

        payNowButton.disabled = true;
        payNowButton.innerText = "Verarbeite...";
        payNowButton.style.opacity = "0.7";

        setTimeout(() => {
            setCheckoutStep(3);
            generateTicket();
            completeCheckout();

            payNowButton.disabled = false;
            payNowButton.innerText = "Jetzt Bezahlen";
            payNowButton.style.opacity = "1";
        }, 1200);
    });
}

document.addEventListener("DOMContentLoaded", bindCheckoutEvents);