let selectStreamerRequestId = 0;
let vodRenderTaskId = 0;
const VOD_RENDER_CHUNK_SIZE = 64;

// VOD filter state — persists across renderer reloads via localStorage so the
// user's search query survives an app restart. Cleared explicitly via Esc /
// the clear button. Shared across streamers (acts like a search bar).
let lastLoadedVods: VOD[] = [];
let lastLoadedStreamer: string | null = null;
let vodFilterQuery = '';
const VOD_FILTER_STORAGE_KEY = 'twitch-vod-manager:vod-filter';

// Bulk-select state — keyed by VOD URL since URL is unique per VOD. Cleared
// on streamer switch (selection is per-streamer mental model). NOT persisted
// because a stale selection across reloads is more confusing than helpful.
const selectedVodUrls = new Set<string>();
let vodGridDelegationInitialized = false;

// Hide-downloaded toggle: when enabled, the VOD grid skips entries whose
// vod.id is in config.downloaded_vod_ids. Persisted to localStorage so a
// power user who keeps it enabled doesn't have to re-flip it every launch.
const VOD_HIDE_DOWNLOADED_STORAGE_KEY = 'twitch-vod-manager:vod-hide-downloaded';
let vodHideDownloaded = false;

function loadPersistedHideDownloaded(): boolean {
    try { return localStorage.getItem(VOD_HIDE_DOWNLOADED_STORAGE_KEY) === '1'; } catch { return false; }
}

function persistHideDownloaded(value: boolean): void {
    try { localStorage.setItem(VOD_HIDE_DOWNLOADED_STORAGE_KEY, value ? '1' : '0'); } catch { /* ignore */ }
}

function onVodHideDownloadedChange(): void {
    const cb = byId<HTMLInputElement>('vodHideDownloadedToggle');
    vodHideDownloaded = cb.checked;
    persistHideDownloaded(vodHideDownloaded);
    if (lastLoadedStreamer) renderVodGridFromCurrentState();
}

function syncVodHideDownloadedToggle(): void {
    const cb = document.getElementById('vodHideDownloadedToggle') as HTMLInputElement | null;
    if (cb) cb.checked = vodHideDownloaded;
}

type VodSortKey = 'date_desc' | 'date_asc' | 'views_desc' | 'duration_desc' | 'duration_asc';
const VALID_VOD_SORTS: ReadonlyArray<VodSortKey> = ['date_desc', 'date_asc', 'views_desc', 'duration_desc', 'duration_asc'];
const VOD_SORT_STORAGE_KEY = 'twitch-vod-manager:vod-sort';
let vodSortKey: VodSortKey = 'date_desc';

function loadPersistedVodSort(): VodSortKey {
    try {
        const stored = localStorage.getItem(VOD_SORT_STORAGE_KEY);
        if (stored && (VALID_VOD_SORTS as readonly string[]).includes(stored)) {
            return stored as VodSortKey;
        }
    } catch { /* localStorage may be unavailable */ }
    return 'date_desc';
}

function persistVodSort(key: VodSortKey): void {
    try { localStorage.setItem(VOD_SORT_STORAGE_KEY, key); } catch { /* localStorage may be unavailable */ }
}

function vodDurationToSeconds(durationStr: string): number {
    let total = 0;
    const h = durationStr.match(/(\d+)h/);
    const m = durationStr.match(/(\d+)m/);
    const s = durationStr.match(/(\d+)s/);
    if (h) total += parseInt(h[1], 10) * 3600;
    if (m) total += parseInt(m[1], 10) * 60;
    if (s) total += parseInt(s[1], 10);
    return total;
}

function sortVods(vods: VOD[], key: VodSortKey): VOD[] {
    const sorted = [...vods];
    const ts = (s: string): number => {
        const n = new Date(s).getTime();
        return Number.isFinite(n) ? n : 0;
    };
    switch (key) {
        case 'date_desc':
            sorted.sort((a, b) => ts(b.created_at) - ts(a.created_at));
            break;
        case 'date_asc':
            sorted.sort((a, b) => ts(a.created_at) - ts(b.created_at));
            break;
        case 'views_desc':
            sorted.sort((a, b) => (b.view_count || 0) - (a.view_count || 0));
            break;
        case 'duration_desc':
            sorted.sort((a, b) => vodDurationToSeconds(b.duration) - vodDurationToSeconds(a.duration));
            break;
        case 'duration_asc':
            sorted.sort((a, b) => vodDurationToSeconds(a.duration) - vodDurationToSeconds(b.duration));
            break;
    }
    return sorted;
}

function onVodSortChange(): void {
    const select = byId<HTMLSelectElement>('vodSortSelect');
    const value = select.value;
    if ((VALID_VOD_SORTS as readonly string[]).includes(value)) {
        vodSortKey = value as VodSortKey;
        persistVodSort(vodSortKey);
        if (lastLoadedStreamer) {
            renderVodGridFromCurrentState();
        }
    }
}

function syncVodSortSelect(): void {
    const select = document.getElementById('vodSortSelect') as HTMLSelectElement | null;
    if (select) select.value = vodSortKey;
}

function refreshVodSortSelectLabels(): void {
    const select = document.getElementById('vodSortSelect') as HTMLSelectElement | null;
    if (!select) return;
    const labels: Record<VodSortKey, string> = {
        date_desc: UI_TEXT.vods.sortDateDesc,
        date_asc: UI_TEXT.vods.sortDateAsc,
        views_desc: UI_TEXT.vods.sortViewsDesc,
        duration_desc: UI_TEXT.vods.sortDurationDesc,
        duration_asc: UI_TEXT.vods.sortDurationAsc
    };
    for (const opt of Array.from(select.options)) {
        const k = opt.value as VodSortKey;
        if (labels[k]) opt.textContent = labels[k];
    }
}

function loadPersistedVodFilter(): string {
    try {
        return localStorage.getItem(VOD_FILTER_STORAGE_KEY) ?? '';
    } catch {
        return '';
    }
}

function persistVodFilter(query: string): void {
    try { localStorage.setItem(VOD_FILTER_STORAGE_KEY, query); } catch { /* localStorage may be unavailable */ }
}

function filterVodsByQuery(vods: VOD[], query: string): VOD[] {
    const q = query.trim().toLowerCase();
    if (!q) return vods;
    return vods.filter((vod) => (vod.title || '').toLowerCase().includes(q));
}

function updateVodFilterCount(filteredCount: number, totalCount: number): void {
    const node = document.getElementById('vodFilterCount');
    if (!node) return;
    if (!totalCount || !vodFilterQuery.trim()) {
        node.textContent = '';
        return;
    }
    node.textContent = UI_TEXT.vods.filterMatchCount
        .replace('{shown}', String(filteredCount))
        .replace('{total}', String(totalCount));
}

function syncVodFilterClearButton(): void {
    const btn = document.getElementById('vodFilterClearBtn') as HTMLButtonElement | null;
    if (!btn) return;
    btn.style.display = vodFilterQuery.trim() ? '' : 'none';
}

function onVodFilterInput(): void {
    const input = byId<HTMLInputElement>('vodFilterInput');
    vodFilterQuery = input.value;
    persistVodFilter(vodFilterQuery);
    syncVodFilterClearButton();
    if (lastLoadedStreamer) {
        renderVodGridFromCurrentState();
    }
}

function clearVodFilter(): void {
    vodFilterQuery = '';
    const input = byId<HTMLInputElement>('vodFilterInput');
    if (input) input.value = '';
    persistVodFilter('');
    syncVodFilterClearButton();
    if (lastLoadedStreamer) {
        renderVodGridFromCurrentState();
    }
}

function focusVodFilter(): void {
    const input = document.getElementById('vodFilterInput') as HTMLInputElement | null;
    if (input) {
        input.focus();
        input.select();
    }
}

function buildVodCardHtml(vod: VOD, streamer: string, downloadedIds?: Set<string>): string {
    const thumb = vod.thumbnail_url.replace('%{width}', '320').replace('%{height}', '180');
    const date = formatUiDate(vod.created_at);
    const escapedTitle = vod.title.replace(/'/g, "\\'").replace(/\"/g, '&quot;');
    const safeDisplayTitle = escapeHtml(vod.title || UI_TEXT.vods.untitled);
    const safeUrlAttr = escapeHtml(vod.url);
    const isChecked = selectedVodUrls.has(vod.url);
    const isAlreadyDownloaded = downloadedIds ? downloadedIds.has(vod.id) : false;
    const downloadedBadge = isAlreadyDownloaded
        ? `<div class="vod-downloaded-badge" title="${escapeHtml(UI_TEXT.vods.alreadyDownloaded)}">&#10003;</div>`
        : '';

    return `
        <div class="vod-card${isChecked ? ' selected' : ''}${isAlreadyDownloaded ? ' already-downloaded' : ''}">
            <input type="checkbox" class="vod-select-checkbox" data-vod-url="${safeUrlAttr}" ${isChecked ? 'checked' : ''} title="Select for bulk action" style="position:absolute; top:8px; left:8px; width:18px; height:18px; accent-color:#9146FF; cursor:pointer; z-index:2;">
            ${downloadedBadge}
            <img class="vod-thumbnail" loading="lazy" decoding="async" src="${thumb}" alt="" onerror="this.src='data:image/svg+xml,<svg xmlns=%22http://www.w3.org/2000/svg%22 viewBox=%220 0 320 180%22><rect fill=%22%23333%22 width=%22320%22 height=%22180%22/></svg>'">
            <div class="vod-info">
                <div class="vod-title">${safeDisplayTitle}</div>
                <div class="vod-meta">
                    <span>${date}</span>
                    <span>${vod.duration}</span>
                    <span>${formatUiNumber(vod.view_count)} ${UI_TEXT.vods.views}</span>
                </div>
            </div>
            <div class="vod-actions">
                <button class="vod-btn secondary" onclick="openClipDialog('${vod.url}', '${escapedTitle}', '${vod.created_at}', '${streamer}', '${vod.duration}')">${UI_TEXT.vods.trimButton}</button>
                <button class="vod-btn primary" onclick="addToQueue('${vod.url}', '${escapedTitle}', '${vod.created_at}', '${streamer}', '${vod.duration}')">${UI_TEXT.vods.addQueue}</button>
            </div>
        </div>
    `;
}

let streamerDragInitialized = false;
let draggedStreamerName: string | null = null;

function renderStreamers(): void {
    const list = byId('streamerList');
    list.replaceChildren();

    (config.streamers ?? []).forEach((streamer: string) => {
        const item = document.createElement('div');
        item.className = 'streamer-item' + (currentStreamer === streamer ? ' active' : '');
        item.setAttribute('draggable', 'true');
        item.dataset.streamerName = streamer;

        const nameSpan = document.createElement('span');
        nameSpan.textContent = streamer;
        const removeSpan = document.createElement('span');
        removeSpan.className = 'remove';
        removeSpan.textContent = 'x';
        removeSpan.addEventListener('click', (e) => {
            e.stopPropagation();
            void removeStreamer(streamer);
        });
        item.append(nameSpan, removeSpan);

        item.addEventListener('click', () => {
            // Skip click if drag was just released — drop fires after dragend
            if (draggedStreamerName === streamer) return;
            void selectStreamer(streamer);
        });
        list.appendChild(item);
    });

    initStreamerDragDrop();
}

function initStreamerDragDrop(): void {
    if (streamerDragInitialized) return;
    streamerDragInitialized = true;

    const list = byId('streamerList');

    list.addEventListener('dragstart', (e: DragEvent) => {
        const target = e.target as HTMLElement;
        const item = target.closest('.streamer-item') as HTMLElement | null;
        if (!item || !item.dataset.streamerName) return;
        draggedStreamerName = item.dataset.streamerName;
        item.classList.add('dragging');
        if (e.dataTransfer) {
            e.dataTransfer.effectAllowed = 'move';
            // Some browsers refuse the drag without setData
            e.dataTransfer.setData('text/plain', draggedStreamerName);
        }
    });

    list.addEventListener('dragover', (e: DragEvent) => {
        if (!draggedStreamerName) return;
        e.preventDefault();
        if (e.dataTransfer) e.dataTransfer.dropEffect = 'move';
    });

    list.addEventListener('drop', async (e: DragEvent) => {
        e.preventDefault();
        const target = (e.target as HTMLElement).closest('.streamer-item') as HTMLElement | null;
        if (!target || !draggedStreamerName) return;
        const targetName = target.dataset.streamerName;
        if (!targetName || targetName === draggedStreamerName) return;

        const streamers = [...(config.streamers ?? [])];
        const fromIdx = streamers.indexOf(draggedStreamerName);
        const toIdx = streamers.indexOf(targetName);
        if (fromIdx < 0 || toIdx < 0) return;
        const [moved] = streamers.splice(fromIdx, 1);
        streamers.splice(toIdx, 0, moved);

        config.streamers = streamers;
        renderStreamers();
        config = await window.api.saveConfig({ streamers });
    });

    list.addEventListener('dragend', () => {
        document.querySelectorAll('.streamer-item.dragging').forEach((el) => el.classList.remove('dragging'));
        // Defer clearing draggedStreamerName so the click handler that fires
        // after dragend can suppress the spurious select.
        const wasDragging = draggedStreamerName;
        window.setTimeout(() => {
            if (draggedStreamerName === wasDragging) draggedStreamerName = null;
        }, 50);
    });
}

async function addStreamer(): Promise<void> {
    const input = byId<HTMLInputElement>('newStreamer');
    const name = input.value.trim().toLowerCase();
    if (!name) {
        return;
    }

    // Twitch usernames: 4-25 characters, alphanumeric + underscore.
    // Catch typos / invalid input before it hits the API and silently
    // returns "streamer not found".
    if (!/^[a-zA-Z0-9_]{4,25}$/.test(name)) {
        showAppToast(UI_TEXT.static.streamerInvalid, 'warn');
        return;
    }

    if ((config.streamers ?? []).includes(name)) {
        return;
    }

    config.streamers = [...(config.streamers ?? []), name];
    config = await window.api.saveConfig({ streamers: config.streamers });
    input.value = '';
    renderStreamers();
    await selectStreamer(name);
}

async function removeStreamer(name: string): Promise<void> {
    config.streamers = (config.streamers ?? []).filter((s: string) => s !== name);
    config = await window.api.saveConfig({ streamers: config.streamers });
    renderStreamers();

    if (currentStreamer !== name) {
        return;
    }

    currentStreamer = null;
    byId('vodGrid').innerHTML = `
        <div class="empty-state">
            <svg viewBox="0 0 24 24" fill="currentColor"><path d="M21 3H3c-1.1 0-2 .9-2 2v14c0 1.1.9 2 2 2h18c1.1 0 2-.9 2-2V5c0-1.1-.9-2-2-2zm-9 14l-5-4 5-4v8zm2-8l5 4-5 4V9z"/></svg>
            <h3>${UI_TEXT.vods.noneTitle}</h3>
            <p>${UI_TEXT.vods.noneText}</p>
        </div>
    `;
}

async function selectStreamer(name: string, forceRefresh = false): Promise<void> {
    const requestId = ++selectStreamerRequestId;
    const isStaleRequest = () => requestId !== selectStreamerRequestId || currentStreamer !== name;

    currentStreamer = name;
    renderStreamers();
    byId('pageTitle').textContent = name;

    if (!isConnected) {
        await connect();
        if (isStaleRequest()) {
            return;
        }
    }

    if (!isConnected) {
        updateStatus(UI_TEXT.status.noLogin, false);
    }

    byId('vodGrid').innerHTML = `<div class="empty-state"><p>${UI_TEXT.vods.loading}</p></div>`;

    const userId = await window.api.getUserId(name);
    if (isStaleRequest()) {
        return;
    }

    if (!userId) {
        byId('vodGrid').innerHTML = `<div class="empty-state"><h3>${UI_TEXT.vods.notFound}</h3></div>`;
        return;
    }

    const vods = await window.api.getVODs(userId, forceRefresh);
    if (isStaleRequest()) {
        return;
    }

    renderVODs(vods, name);
}

function setVodGridEmptyState(grid: HTMLElement, title: string, text: string): void {
    // Build via DOM API so the (locale-only) strings can never escape into HTML.
    const wrap = document.createElement('div');
    wrap.className = 'empty-state';
    const h3 = document.createElement('h3');
    h3.textContent = title;
    const p = document.createElement('p');
    p.textContent = text;
    wrap.appendChild(h3);
    wrap.appendChild(p);
    grid.replaceChildren(wrap);
}

function renderVODs(vods: VOD[] | null | undefined, streamer: string): void {
    // Clear bulk-selection on streamer switch — selection is per-streamer
    if (lastLoadedStreamer && lastLoadedStreamer !== streamer && selectedVodUrls.size > 0) {
        selectedVodUrls.clear();
        updateVodBulkBar();
    }
    lastLoadedVods = Array.isArray(vods) ? vods : [];
    lastLoadedStreamer = streamer;
    initVodGridSelectionDelegation();
    renderVodGridFromCurrentState();
}

function initVodGridSelectionDelegation(): void {
    if (vodGridDelegationInitialized) return;
    vodGridDelegationInitialized = true;

    const grid = document.getElementById('vodGrid');
    if (!grid) return;
    grid.addEventListener('click', (e) => {
        const target = e.target as HTMLElement;
        if (!(target instanceof HTMLInputElement)) return;
        if (!target.classList.contains('vod-select-checkbox')) return;
        const url = target.dataset.vodUrl || '';
        if (!url) return;
        if (target.checked) selectedVodUrls.add(url);
        else selectedVodUrls.delete(url);
        // Keep card visual + bar in sync without a full re-render of all cards
        const card = target.closest('.vod-card') as HTMLElement | null;
        if (card) card.classList.toggle('selected', target.checked);
        updateVodBulkBar();
    });
}

function updateVodBulkBar(): void {
    const bar = document.getElementById('vodBulkBar');
    if (!bar) return;
    const count = selectedVodUrls.size;
    bar.style.display = count > 0 ? 'flex' : 'none';
    const countEl = document.getElementById('vodBulkCount');
    if (countEl) {
        countEl.textContent = UI_TEXT.vods.bulkSelectedCount.replace('{count}', String(count));
    }
}

function clearVodSelection(): void {
    if (selectedVodUrls.size === 0) return;
    selectedVodUrls.clear();
    updateVodBulkBar();
    if (lastLoadedStreamer) renderVodGridFromCurrentState();
}

async function bulkAddSelectedVodsToQueue(): Promise<void> {
    const urls = Array.from(selectedVodUrls);
    if (urls.length === 0 || !lastLoadedStreamer) return;
    const streamer = lastLoadedStreamer;

    const btn = document.getElementById('vodBulkAddBtn') as HTMLButtonElement | null;
    const originalText = btn?.textContent || '';
    if (btn) {
        btn.disabled = true;
        btn.textContent = UI_TEXT.vods.bulkAdding;
    }

    let added = 0;
    let skipped = 0;
    for (const url of urls) {
        const vod = lastLoadedVods.find((v) => v.url === url);
        if (!vod) { skipped++; continue; }
        try {
            queue = await window.api.addToQueue({
                url: vod.url,
                title: vod.title,
                date: vod.created_at,
                streamer,
                duration_str: vod.duration
            });
            added++;
        } catch {
            skipped++;
        }
    }

    selectedVodUrls.clear();
    if (btn) {
        btn.disabled = false;
        btn.textContent = originalText;
    }
    updateVodBulkBar();
    renderQueue();
    renderVodGridFromCurrentState();

    const toast = (window as unknown as { showAppToast?: (msg: string, kind?: 'info' | 'warn') => void }).showAppToast;
    if (toast && added > 0) {
        toast(UI_TEXT.vods.bulkAddedToQueue.replace('{count}', String(added)), 'info');
    } else if (toast && skipped > 0) {
        toast(UI_TEXT.vods.bulkAddSkipped, 'warn');
    }
}

function renderVodGridFromCurrentState(): void {
    if (!lastLoadedStreamer) return;

    const grid = byId('vodGrid');
    const renderTaskId = ++vodRenderTaskId;
    const total = lastLoadedVods.length;

    if (total === 0) {
        setVodGridEmptyState(grid, UI_TEXT.vods.noResultsTitle, UI_TEXT.vods.noResultsText);
        updateVodFilterCount(0, 0);
        return;
    }

    const sorted = sortVods(lastLoadedVods, vodSortKey);
    const downloadedIdsForFilter = new Set(
        Array.isArray(config.downloaded_vod_ids)
            ? (config.downloaded_vod_ids as string[]).filter((id) => typeof id === 'string')
            : []
    );
    const sortedAndHidden = vodHideDownloaded
        ? sorted.filter((vod) => !downloadedIdsForFilter.has(vod.id))
        : sorted;
    const filtered = filterVodsByQuery(sortedAndHidden, vodFilterQuery);

    if (filtered.length === 0 && vodFilterQuery.trim()) {
        setVodGridEmptyState(grid, UI_TEXT.vods.filterNoMatchTitle, UI_TEXT.vods.filterNoMatchText);
        updateVodFilterCount(0, total);
        return;
    }

    grid.replaceChildren();
    updateVodFilterCount(filtered.length, total);

    // Build the downloaded-ids lookup once per render — Set.has is O(1) vs
    // Array.includes which would be O(n*m) across all cards.
    const downloadedIds = new Set(
        Array.isArray(config.downloaded_vod_ids)
            ? (config.downloaded_vod_ids as string[]).filter((id) => typeof id === 'string')
            : []
    );

    const scheduleNextChunk = (nextStartIndex: number): void => {
        const delayMs = document.hidden ? 16 : 0;
        window.setTimeout(() => {
            renderChunk(nextStartIndex);
        }, delayMs);
    };

    const renderChunk = (startIndex: number): void => {
        if (renderTaskId !== vodRenderTaskId) {
            return;
        }

        const chunk = filtered.slice(startIndex, startIndex + VOD_RENDER_CHUNK_SIZE);
        if (!chunk.length) {
            return;
        }

        grid.insertAdjacentHTML('beforeend', chunk.map((vod) => buildVodCardHtml(vod, lastLoadedStreamer || '', downloadedIds)).join(''));

        if (startIndex + chunk.length < filtered.length) {
            scheduleNextChunk(startIndex + chunk.length);
        }
    };

    renderChunk(0);
}

async function refreshVODs(): Promise<void> {
    if (!currentStreamer) {
        return;
    }

    await selectStreamer(currentStreamer, true);
}