(() => {
    const qrInput = document.getElementById("qr-input");
    const statusCard = document.getElementById("status-card");
    const statusCenterCard = document.getElementById("status-center-card");
    const statusVisual = document.getElementById("status-visual");
    const statusMiniIcon = document.getElementById("status-mini-icon");
    const statusHeadline = document.getElementById("status-headline");
    const statusMiniHeadline = document.getElementById("status-mini-headline");
    const statusText = document.getElementById("status-text");
    const statusMiniMessage = document.getElementById("status-mini-message");
    const lastUpdatedTime = document.getElementById("last-updated-time");
    const historyBody = document.querySelector("#history-table tbody");
    const historyEmpty = document.getElementById("history-empty");

    const details = {
        model: document.getElementById("detail-model"),
        unique: document.getElementById("detail-unique"),
        exists: document.getElementById("detail-exists"),
        marked: document.getElementById("detail-marked"),
        time: document.getElementById("detail-time")
    };

    const antiForgeryToken = document.querySelector('input[name="__RequestVerificationToken"]')?.value;

    qrInput.addEventListener("keydown", async event => {
        if (event.key !== "Enter") {
            return;
        }

        event.preventDefault();
        const qrValue = qrInput.value.trim();
        if (!qrValue) {
            return;
        }

        await submitScan(qrValue);
        qrInput.value = "";
        qrInput.focus();
    });

    async function submitScan(qrValue) {
        try {
            const response = await fetch("/api/verification/scan", {
                method: "POST",
                headers: {
                    "Content-Type": "application/json",
                    "RequestVerificationToken": antiForgeryToken ?? ""
                },
                body: JSON.stringify({ qrValue })
            });

            const payload = await response.json();
            if (!response.ok) {
                const fallbackMessage = "Verification service is unavailable.";
                setFailedState(payload.message ?? fallbackMessage);
                triggerFailureAlarm();
                resetDetails();
                return;
            }

            const result = payload.result;
            renderDetails(result);
            renderStatus(result);
            renderHistory(payload.recentScans ?? []);
        } catch {
            setFailedState("Unexpected communication error.");
            triggerFailureAlarm();
            resetDetails();
        }
    }

    function renderStatus(result) {
        if (result.isSuccessful) {
            setStatusClasses("status-success");
            statusVisual.textContent = "\u2713";
            statusMiniIcon.textContent = "\u2713";
            statusHeadline.textContent = "VERIFIED";
            statusMiniHeadline.textContent = "VERIFIED";
            statusText.textContent = result.message;
            statusMiniMessage.textContent = result.message;
            lastUpdatedTime.textContent = formatDisplayTime(result.processedAtUtc);
            return;
        }

        setFailedState(result.message);
        triggerFailureAlarm();
    }

    function setFailedState(message) {
        setStatusClasses("status-failed");
        statusVisual.textContent = "!";
        statusMiniIcon.textContent = "!";
        statusHeadline.textContent = "FAILED";
        statusMiniHeadline.textContent = "FAILED";
        statusText.textContent = message;
        statusMiniMessage.textContent = message;
        lastUpdatedTime.textContent = "-";
    }

    function setStatusClasses(statusClass) {
        statusCard.className = `panel panel-status ${statusClass}`;
        statusCenterCard.className = `panel panel-center-status ${statusClass}`;
    }

    function renderDetails(result) {
        details.model.textContent = result.modelNumber || "-";
        details.unique.textContent = result.uniqueNumber || "-";
        details.exists.textContent = result.existsInSystem ? "YES" : "NO";
        details.marked.textContent = result.shipmentMarked ? "TRUE" : "FALSE";
        details.time.textContent = formatDisplayTime(result.processedAtUtc);
    }

    function resetDetails() {
        details.model.textContent = "-";
        details.unique.textContent = "-";
        details.exists.textContent = "-";
        details.marked.textContent = "-";
        details.time.textContent = "-";
    }

    function renderHistory(records) {
        historyBody.innerHTML = "";

        if (records.length === 0) {
            historyEmpty.classList.remove("is-hidden");
            return;
        }

        historyEmpty.classList.add("is-hidden");
        records.forEach((record, index) => {
            const row = document.createElement("tr");
            row.innerHTML = `
                <td>${index + 1}</td>
                <td>${sanitize(record.modelNumber)}</td>
                <td>${sanitize(record.uniqueNumber)}</td>
                <td><span class="status-pill ${record.shipmentMarked ? "status-true" : "status-false"}">${record.shipmentMarked ? "TRUE" : "FALSE"}</span></td>
                <td>${formatDisplayTime(record.processedAtUtc)}</td>
                <td>System</td>`;

            historyBody.appendChild(row);
        });
    }

    function sanitize(value) {
        return (value ?? "").replace(/[&<>\"']/g, char => ({
            "&": "&amp;",
            "<": "&lt;",
            ">": "&gt;",
            "\"": "&quot;",
            "'": "&#39;"
        }[char]));
    }

    function formatDisplayTime(utcValue) {
        if (!utcValue) {
            return "-";
        }

        const date = new Date(utcValue);
        if (Number.isNaN(date.getTime())) {
            return "-";
        }

        return date.toLocaleString("en-US", {
            day: "2-digit",
            month: "short",
            year: "numeric",
            hour: "numeric",
            minute: "2-digit",
            second: "2-digit",
            hour12: true
        });
    }

    function triggerFailureAlarm() {
        const context = new AudioContext();
        const oscillator = context.createOscillator();
        const gainNode = context.createGain();

        oscillator.type = "sawtooth";
        oscillator.frequency.setValueAtTime(740, context.currentTime);
        oscillator.frequency.exponentialRampToValueAtTime(320, context.currentTime + 0.4);
        oscillator.connect(gainNode);
        gainNode.connect(context.destination);

        gainNode.gain.setValueAtTime(0.0001, context.currentTime);
        gainNode.gain.exponentialRampToValueAtTime(0.5, context.currentTime + 0.05);
        gainNode.gain.exponentialRampToValueAtTime(0.0001, context.currentTime + 0.45);

        oscillator.start(context.currentTime);
        oscillator.stop(context.currentTime + 0.45);
        oscillator.onended = () => context.close();
    }
})();