window.App = window.App || {};
App.enhance = App.enhance || {};

// Progressive UI enhancements layered on top of the core app. Everything here
// is non-essential polish: cursor-tracking card spotlight, a scroll-progress
// bar, a back-to-top button, a ⌘K command palette, and hover video previews.
// None of it is required for the app to function, so each piece fails soft.
(function() {
    const fineHover = window.matchMedia('(hover: hover) and (pointer: fine)').matches;
    const reduceMotion = () => window.matchMedia('(prefers-reduced-motion: reduce)').matches;

    // ---- Cursor-tracking spotlight border on grid cards ----------------------
    // One delegated listener keeps per-card vars (--mx/--my) updated; the brass
    // border gradient that reads them lives in CSS (.video-card::after).
    function initSpotlight() {
        const grid = document.getElementById('video-grid');
        if (!grid || !fineHover) return;
        grid.addEventListener('pointermove', (e) => {
            const card = e.target.closest('.video-card');
            if (!card) return;
            const r = card.getBoundingClientRect();
            card.style.setProperty('--mx', (e.clientX - r.left) + 'px');
            card.style.setProperty('--my', (e.clientY - r.top) + 'px');
        }, { passive: true });
    }

    // ---- Scroll progress bar + back-to-top FAB -------------------------------
    function initScrollAffordances() {
        const bar = document.getElementById('scroll-progress');
        const fab = document.getElementById('back-to-top');
        let ticking = false;
        const onScroll = () => {
            if (ticking) return;
            ticking = true;
            requestAnimationFrame(() => {
                ticking = false;
                const doc = document.documentElement;
                const max = doc.scrollHeight - window.innerHeight;
                const pct = max > 0 ? (window.scrollY / max) * 100 : 0;
                if (bar) bar.style.width = pct.toFixed(2) + '%';
                if (fab) fab.classList.toggle('is-visible', window.scrollY > 700);
            });
        };
        window.addEventListener('scroll', onScroll, { passive: true });
        onScroll();
        if (fab) {
            fab.addEventListener('click', () => {
                window.scrollTo({ top: 0, behavior: reduceMotion() ? 'auto' : 'smooth' });
            });
        }
    }

    // ---- Hover video preview --------------------------------------------------
    // After a short dwell over a card, play a muted inline clip in place of the
    // poster — but only if the video's real formats are already resolved (the
    // grid resolves them lazily on hover/scroll anyway), so we never block or
    // hammer the backend just to preview.
    function initHoverPreview() {
        const grid = document.getElementById('video-grid');
        if (!grid || !fineHover) return;
        let dwellTimer = null;
        let activeCard = null;
        // The card element alone doesn't identify what is being previewed: the
        // grid pools its cards, so the same element can come back showing a
        // different video (via relayout or a new search, neither of which
        // scrolls, so clearPreview never runs). Remembering the video too keeps
        // the "already previewing this" check honest.
        let activeVideo = null;

        const isActive = (card) => card === activeCard &&
            (!App.videos.getVideoForCard || App.videos.getVideoForCard(card) === activeVideo);

        const clearPreview = () => {
            if (dwellTimer) { clearTimeout(dwellTimer); dwellTimer = null; }
            if (activeCard) {
                const vid = activeCard.querySelector('.card-preview');
                if (vid) { try { vid.pause(); } catch (e) {} vid.remove(); }
                activeCard.classList.remove('is-previewing');
                activeCard = null;
                activeVideo = null;
            }
        };

        const startPreview = (card) => {
            if (!App.videos || typeof App.videos.getVideoForCard !== 'function') return;
            const v = App.videos.getVideoForCard(card);
            if (!v) return;
            const meta = v.meta;
            const ready = meta && Array.isArray(meta.formats) && meta.formats.length;
            if (!ready) {
                // Not resolved yet: kick it off so the *next* hover can preview.
                if (typeof App.videos.ensureFormats === 'function') App.videos.ensureFormats(v);
                return;
            }
            let url = '';
            try { url = App.videos.buildStreamUrl(v); } catch (e) { return; }
            if (!url) return;
            const img = card.querySelector('img');
            const vid = document.createElement('video');
            vid.className = 'card-preview';
            vid.muted = true;
            vid.loop = true;
            vid.playsInline = true;
            vid.setAttribute('playsinline', '');
            vid.setAttribute('webkit-playsinline', '');
            vid.preload = 'auto';
            if (img) vid.style.height = img.getBoundingClientRect().height + 'px';
            vid.src = url;
            vid.addEventListener('error', () => { if (vid.isConnected) vid.remove(); }, { once: true });
            card.appendChild(vid);
            card.classList.add('is-previewing');
            const p = vid.play();
            if (p && p.catch) p.catch(() => {});
        };

        grid.addEventListener('pointerover', (e) => {
            const card = e.target.closest('.video-card');
            if (!card || isActive(card)) return;
            clearPreview();
            activeCard = card;
            activeVideo = App.videos.getVideoForCard ? App.videos.getVideoForCard(card) : null;
            dwellTimer = setTimeout(() => {
                dwellTimer = null;
                if (isActive(card)) startPreview(card);
            }, 600);
        });
        grid.addEventListener('pointerout', (e) => {
            const card = e.target.closest('.video-card');
            if (!card) return;
            const to = e.relatedTarget;
            if (to && card.contains(to)) return; // still inside the same card
            if (card === activeCard) clearPreview();
        });
        window.addEventListener('scroll', clearPreview, { passive: true });
    }

    // ---- Command palette (⌘K / Ctrl+K) ---------------------------------------
    function initCommandPalette() {
        const palette = document.getElementById('command-palette');
        const input = document.getElementById('cmdk-input');
        const list = document.getElementById('cmdk-list');
        if (!palette || !input || !list) return;

        let actions = [];
        let filtered = [];
        let activeIndex = 0;

        const fireChange = (el) => el && el.dispatchEvent(new Event('change'));

        const buildActions = () => {
            const out = [];
            out.push({ label: 'Search videos', hint: 'Focus the search box', run: () => {
                const s = document.getElementById('search-input'); if (s) { s.focus(); s.select(); }
            }});
            const theme = (localStorage.getItem('theme') || 'dark');
            out.push({ label: `Switch to ${theme === 'light' ? 'dark' : 'light'} theme`, hint: 'Appearance', run: () => {
                localStorage.setItem('theme', theme === 'light' ? 'dark' : 'light');
                if (App.ui && App.ui.applyTheme) App.ui.applyTheme();
            }});
            const density = (App.storage && App.storage.getDensity) ? App.storage.getDensity() : 'comfortable';
            out.push({ label: `Grid density: ${density === 'compact' ? 'comfortable' : 'compact'}`, hint: 'Layout', run: () => {
                if (!App.storage) return;
                App.storage.setDensity(density === 'compact' ? 'comfortable' : 'compact');
                if (App.ui && App.ui.applyDensity) App.ui.applyDensity();
                if (App.virtualGrid && App.virtualGrid.relayout) App.virtualGrid.relayout();
            }});
            out.push({ label: 'Toggle Reels view', hint: 'Playback', run: () => { if (App.feed) App.feed.toggle(); } });

            // The favorites bar carries these controls, but it can be switched
            // off in settings -- in which case the palette is the way in.
            if (App.favoritesView && App.favorites) {
                const browsing = App.favoritesView.isActive();
                out.push({
                    label: browsing ? 'Back to videos' : 'Browse favorites',
                    hint: browsing ? 'Leave the favorites grid' : 'All favorites as a grid',
                    run: () => App.favoritesView.toggle()
                });
                const currentSort = App.favorites.getSort();
                App.favorites.SORTS.forEach((sort) => {
                    if (sort.id === currentSort) return;
                    out.push({
                        label: `Sort favorites: ${sort.label}`,
                        hint: 'Favorites',
                        run: () => App.favoritesView.applySort(sort.id)
                    });
                });
            }
            out.push({ label: 'Reload channel', hint: 'Refresh the current feed', run: () => { if (App.videos) App.videos.resetAndReload(); } });
            out.push({ label: 'Open Menu', hint: 'Source · channel · filters', run: () => { if (App.ui) App.ui.toggleDrawer('menu'); } });
            out.push({ label: 'Open Settings', hint: 'Preferences', run: () => { if (App.ui) App.ui.toggleDrawer('settings'); } });

            const sourceSelect = document.getElementById('source-select');
            if (sourceSelect) {
                Array.from(sourceSelect.options).forEach((opt) => {
                    if (opt.value === sourceSelect.value) return;
                    out.push({ label: opt.textContent, hint: 'Source', run: () => { sourceSelect.value = opt.value; fireChange(sourceSelect); } });
                });
            }
            // The channel list is the picker's (App.ui.channels), not a
            // <select>'s -- same entries, drawn as palette rows.
            if (App.ui && App.ui.channels) {
                const current = App.storage && App.storage.getSession ?
                    App.storage.getSession() : null;
                const currentId = (current && current.channel) ? current.channel.id : '';
                App.ui.channels.entries().forEach((entry) => {
                    if (entry.id === currentId) return;
                    out.push({
                        label: entry.label,
                        hint: entry.group || 'Channel',
                        run: () => App.ui.channels.choose(entry.id)
                    });
                });
            }
            return out;
        };

        const render = () => {
            list.innerHTML = '';
            filtered.forEach((a, i) => {
                const li = document.createElement('button');
                li.type = 'button';
                li.className = 'cmdk-item' + (i === activeIndex ? ' is-active' : '');
                li.innerHTML = `<span class="cmdk-label"></span><span class="cmdk-hint"></span>`;
                li.querySelector('.cmdk-label').textContent = a.label;
                li.querySelector('.cmdk-hint').textContent = a.hint || '';
                li.addEventListener('click', () => choose(i));
                li.addEventListener('pointermove', () => { if (activeIndex !== i) { activeIndex = i; render(); } });
                list.appendChild(li);
            });
        };

        const applyFilter = () => {
            const q = input.value.trim().toLowerCase();
            filtered = q
                ? actions.filter((a) => (a.label + ' ' + (a.hint || '')).toLowerCase().includes(q))
                : actions.slice();
            activeIndex = 0;
            render();
        };

        const choose = (i) => {
            const a = filtered[i];
            close();
            if (a && a.run) a.run();
        };

        const open = () => {
            actions = buildActions();
            input.value = '';
            applyFilter();
            palette.classList.add('open');
            palette.setAttribute('aria-hidden', 'false');
            requestAnimationFrame(() => input.focus());
        };
        const close = () => {
            palette.classList.remove('open');
            palette.setAttribute('aria-hidden', 'true');
        };
        App.enhance.openPalette = open;

        input.addEventListener('input', applyFilter);
        input.addEventListener('keydown', (e) => {
            if (e.key === 'ArrowDown') { e.preventDefault(); activeIndex = Math.min(activeIndex + 1, filtered.length - 1); render(); scrollActive(); }
            else if (e.key === 'ArrowUp') { e.preventDefault(); activeIndex = Math.max(activeIndex - 1, 0); render(); scrollActive(); }
            else if (e.key === 'Enter') { e.preventDefault(); choose(activeIndex); }
            else if (e.key === 'Escape') { e.preventDefault(); close(); }
        });
        const scrollActive = () => {
            const el = list.children[activeIndex];
            if (el) el.scrollIntoView({ block: 'nearest' });
        };
        palette.addEventListener('click', (e) => { if (e.target === palette) close(); });

        document.addEventListener('keydown', (e) => {
            if ((e.metaKey || e.ctrlKey) && (e.key === 'k' || e.key === 'K')) {
                e.preventDefault();
                if (palette.classList.contains('open')) close(); else open();
            }
        });
    }

    function init() {
        initSpotlight();
        initScrollAffordances();
        initHoverPreview();
        initCommandPalette();
    }

    if (document.readyState === 'loading') {
        document.addEventListener('DOMContentLoaded', init);
    } else {
        init();
    }
})();