function initUuidGenerator() {
    const statusEl = document.getElementById("uuidStatus");
    const countEl = document.getElementById("uuidCount");
    const uppercaseEl = document.getElementById("uuidUppercase");
    const noHyphenEl = document.getElementById("uuidNoHyphen");
    const outputEl = document.getElementById("uuidOutput");
    const metaEl = document.getElementById("uuidMeta");
    const generateBtn = document.getElementById("uuidGenerateBtn");
    const copyBtn = document.getElementById("uuidCopyBtn");
    const downloadBtn = document.getElementById("uuidDownloadBtn");
    const clearBtn = document.getElementById("uuidClearBtn");

    if (!outputEl || !generateBtn) return;

    function setStatus(text, isError) {
        if (!statusEl) return;
        statusEl.textContent = text;
        statusEl.classList.toggle("status-error", !!isError);
        statusEl.classList.toggle("status-success", !isError);
    }

    function updateUiState() {
        const rows = outputEl.value.trim() ? outputEl.value.trim().split("\n") : [];
        if (metaEl) metaEl.textContent = `Count: ${rows.length}`;
        if (copyBtn) copyBtn.disabled = rows.length === 0;
        if (downloadBtn) downloadBtn.disabled = rows.length === 0;
        if (clearBtn) clearBtn.disabled = rows.length === 0;
    }

    function createUuid() {
        if (window.crypto && typeof window.crypto.randomUUID === "function") {
            return window.crypto.randomUUID();
        }
        // Fallback for older browsers.
        return "xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx".replace(/[xy]/g, (char) => {
            const rand = Math.random() * 16 | 0;
            const value = char === "x" ? rand : (rand & 0x3 | 0x8);
            return value.toString(16);
        });
    }

    function applyFormat(uuid) {
        let value = uuid;
        if (noHyphenEl && noHyphenEl.checked) value = value.replace(/-/g, "");
        if (uppercaseEl && uppercaseEl.checked) value = value.toUpperCase();
        return value;
    }

    function generateAction() {
        const rawCount = Number(countEl?.value || 1);
        const count = Math.min(1000, Math.max(1, Number.isFinite(rawCount) ? rawCount : 1));
        if (countEl) countEl.value = String(count);
        const items = [];
        for (let i = 0; i < count; i += 1) {
            items.push(applyFormat(createUuid()));
        }
        outputEl.value = items.join("\n");
        setStatus(`Generated ${count} UUID${count > 1 ? "s" : ""}.`);
        updateUiState();
    }

    async function copyAction() {
        if (!outputEl.value.trim()) return;
        await navigator.clipboard.writeText(outputEl.value);
        const label = copyBtn.textContent;
        copyBtn.textContent = "Copied";
        setStatus("UUID list copied.");
        setTimeout(() => {
            copyBtn.textContent = label;
        }, 1200);
    }

    function downloadAction() {
        if (!outputEl.value.trim()) return;
        const blob = new Blob([outputEl.value], { type: "text/plain;charset=utf-8" });
        const link = document.createElement("a");
        link.href = URL.createObjectURL(blob);
        link.download = "uuid-list.txt";
        link.click();
        URL.revokeObjectURL(link.href);
        setStatus("UUID list downloaded.");
    }

    function clearAction() {
        outputEl.value = "";
        setStatus("Configure options and generate UUIDs.");
        updateUiState();
    }

    generateBtn.addEventListener("click", generateAction);
    if (copyBtn) copyBtn.addEventListener("click", copyAction);
    if (downloadBtn) downloadBtn.addEventListener("click", downloadAction);
    if (clearBtn) clearBtn.addEventListener("click", clearAction);

    updateUiState();
}

if (document.readyState === "loading") {
    document.addEventListener("DOMContentLoaded", initUuidGenerator);
} else {
    initUuidGenerator();
}