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

(function() {
    const { FAVORITES_KEY, FAVORITES_VISIBILITY_KEY } = App.constants;

    // Favorites storage helpers.
    App.favorites.getAll = function() {
        try {
            const raw = localStorage.getItem(FAVORITES_KEY);
            const parsed = raw ? JSON.parse(raw) : [];
            if (!Array.isArray(parsed)) return [];
            // Two things are repaired on the way in, and written back once if
            // anything changed, so the fix happens exactly one time:
            //
            // `meta`, from older versions, is a blob of resolved formats whose
            // URLs are signed and long expired -- dropped so no code path can
            // reach for one; everything re-resolves from `url` at play time.
            //
            // `favoriteDate` didn't exist before sorting needed it. There's no
            // way to recover when an old favorite was actually saved, so it
            // gets now: they sort together, as one batch, at the point the
            // client learned to keep dates.
            let repaired = false;
            const now = new Date().toISOString();
            const items = parsed.map((item) => {
                if (!item || typeof item !== 'object') return item;
                if (!item.meta && item.favoriteDate) return item;
                const clean = Object.assign({}, item);
                delete clean.meta;
                if (!clean.favoriteDate) clean.favoriteDate = now;
                repaired = true;
                return clean;
            });
            if (repaired) App.favorites.setAll(items);
            return items;
        } catch (err) {
            return [];
        }
    };

    // Sort orders offered for the favorites bar and the favorites grid.
    // `random` reshuffles on every read by design -- it's for rediscovering a
    // long list, so landing somewhere different each time is the point.
    App.favorites.SORTS = [
        { id: 'recent', label: 'Recently added' },
        { id: 'oldest', label: 'Oldest first' },
        { id: 'title', label: 'Title A-Z' },
        { id: 'longest', label: 'Longest' },
        { id: 'shortest', label: 'Shortest' },
        { id: 'random', label: 'Shuffle' }
    ];
    App.favorites.DEFAULT_SORT = 'recent';

    App.favorites.getSort = function() {
        const stored = localStorage.getItem(App.constants.FAVORITES_SORT_KEY);
        return App.favorites.SORTS.some((sort) => sort.id === stored) ? stored : App.favorites.DEFAULT_SORT;
    };

    App.favorites.setSort = function(sort) {
        localStorage.setItem(App.constants.FAVORITES_SORT_KEY, sort);
    };

    const dateValue = function(item) {
        const parsed = Date.parse((item && item.favoriteDate) || '');
        return isNaN(parsed) ? 0 : parsed;
    };

    App.favorites.sorted = function(sort) {
        const items = App.favorites.getAll();
        const mode = sort || App.favorites.getSort();
        if (mode === 'random') {
            for (let i = items.length - 1; i > 0; i--) {
                const j = Math.floor(Math.random() * (i + 1));
                [items[i], items[j]] = [items[j], items[i]];
            }
            return items;
        }
        const comparators = {
            recent: (a, b) => dateValue(b) - dateValue(a),
            oldest: (a, b) => dateValue(a) - dateValue(b),
            title: (a, b) => String(a.title || '').localeCompare(String(b.title || ''), undefined, { sensitivity: 'base' }),
            longest: (a, b) => (Number(b.duration) || 0) - (Number(a.duration) || 0),
            shortest: (a, b) => (Number(a.duration) || 0) - (Number(b.duration) || 0)
        };
        return items.sort(comparators[mode] || comparators.recent);
    };

    App.favorites.setAll = function(items) {
        localStorage.setItem(FAVORITES_KEY, JSON.stringify(items));
    };

    App.favorites.getKey = function(video) {
        if (!video) return null;
        const meta = video.meta || video;
        return video.key || meta.key || video.id || meta.id || video.url || meta.url || null;
    };

    App.favorites.normalize = function(video) {
        const key = App.favorites.getKey(video);
        if (!key) return null;
        const meta = video && video.meta ? video.meta : video;
        return {
            key,
            id: video.id || null,
            // The page/source URL (e.g. the YouTube watch URL), not a resolved
            // CDN media URL -- those expire, so favorites must always re-resolve
            // via the server at play time instead of caching a stream link.
            url: video.url || (meta && meta.url) || '',
            title: video.title || '',
            thumb: video.thumb || '',
            channel: video.channel || (meta && meta.channel) || '',
            uploader: video.uploader || (meta && meta.uploader) || '',
            duration: video.duration || (meta && meta.duration) || 0,
            isLive: !!(video.isLive || (meta && meta.isLive)),
            // When it was saved. An import carries the date the other client
            // recorded; anything saved here is saved now.
            favoriteDate: video.favoriteDate || new Date().toISOString()
            // No `meta` field: persisting resolved formats would freeze their
            // (expiring) CDN URLs into localStorage. Leaving it unset makes a
            // favorite look like a fresh, unresolved listing item again, so
            // playback/download/info all re-resolve through the backend from
            // `url` -- see resolveStreamSources' no-formats fallback, which the
            // backend resolves live via yt-dlp (main.py stream_video).
        };
    };

    // Identity across sources. Favorites added here are keyed by the server's
    // id; ones imported from a Hot Tub backup can only be keyed by URL (the app
    // keys videos by a hash of its own). Comparing normalized URLs is what
    // stops the same video being listed twice under two different keys.
    App.favorites.urlKey = function(url) {
        const raw = String(url || '').trim();
        if (!raw) return '';
        try {
            const parsed = new URL(raw, window.location.href);
            const host = parsed.host.replace(/^www\./i, '').toLowerCase();
            const path = parsed.pathname.replace(/\/+$/, '');
            return `${host}${path}${parsed.search}`;
        } catch (err) {
            return raw.toLowerCase();
        }
    };

    // Adds favorites from an import, skipping any this client already has.
    // Existing entries are left exactly as they are -- they carry the server id
    // that makes a listing card's heart light up, which an imported entry has
    // no way to know -- and new ones are appended after them.
    App.favorites.mergeImported = function(entries) {
        const incoming = Array.isArray(entries) ? entries : [];
        const favorites = App.favorites.getAll();
        const keys = new Set();
        const urls = new Set();
        favorites.forEach((item) => {
            if (!item) return;
            if (item.key) keys.add(item.key);
            const urlKey = App.favorites.urlKey(item.url);
            if (urlKey) urls.add(urlKey);
        });

        let added = 0;
        let skipped = 0;
        incoming.forEach((entry) => {
            if (!entry || !entry.key) return;
            const urlKey = App.favorites.urlKey(entry.url);
            if (keys.has(entry.key) || (urlKey && urls.has(urlKey))) {
                skipped++;
                return;
            }
            keys.add(entry.key);
            if (urlKey) urls.add(urlKey);
            favorites.push(entry);
            added++;
        });

        if (added) {
            App.favorites.setAll(favorites);
            App.favorites.renderBar();
            App.favorites.syncButtons();
        }
        return { added, skipped, total: favorites.length };
    };

    App.favorites.getSet = function() {
        return new Set(App.favorites.getAll().map((item) => item.key));
    };

    // Same set, addressed by URL. Imported favorites are keyed by URL rather
    // than by a server id, so a listing card can only recognise one this way.
    App.favorites.getUrlSet = function() {
        const urls = new Set();
        App.favorites.getAll().forEach((item) => {
            const urlKey = item && App.favorites.urlKey(item.url);
            if (urlKey) urls.add(urlKey);
        });
        return urls;
    };

    // Is this video already a favorite, whichever way it got saved? Checked by
    // key first, then by URL, so a card and an imported entry for the same
    // video are recognised as one thing.
    App.favorites.indexOfEntry = function(favorites, video) {
        const key = App.favorites.getKey(video);
        const byKey = key ? favorites.findIndex((item) => item && item.key === key) : -1;
        if (byKey >= 0) return byKey;
        const meta = (video && video.meta) || video || {};
        const urlKey = App.favorites.urlKey(video && (video.url || meta.url));
        if (!urlKey) return -1;
        return favorites.findIndex((item) => item && App.favorites.urlKey(item.url) === urlKey);
    };

    App.favorites.isVisible = function() {
        return localStorage.getItem(FAVORITES_VISIBILITY_KEY) !== 'false';
    };

    App.favorites.setVisible = function(isVisible) {
        localStorage.setItem(FAVORITES_VISIBILITY_KEY, isVisible ? 'true' : 'false');
    };

    // UI helpers for rendering and syncing heart states.
    App.favorites.setButtonState = function(button, isFavorite) {
        button.classList.toggle('is-favorite', isFavorite);
        button.textContent = isFavorite ? '♥' : '♡';
        button.setAttribute('aria-pressed', isFavorite ? 'true' : 'false');
        button.setAttribute('aria-label', isFavorite ? 'Remove from favorites' : 'Add to favorites');
    };

    App.favorites.syncButtons = function() {
        const favoritesSet = App.favorites.getSet();
        const favoriteUrls = App.favorites.getUrlSet();
        document.querySelectorAll('.favorite-btn[data-fav-key]').forEach((button) => {
            const key = button.dataset.favKey;
            const urlKey = App.favorites.urlKey(button.dataset.favUrl);
            if (!key && !urlKey) return;
            App.favorites.setButtonState(button, (key && favoritesSet.has(key)) || (urlKey && favoriteUrls.has(urlKey)));
        });
    };

    App.favorites.toggle = function(video) {
        const key = App.favorites.getKey(video);
        if (!key) return;
        const favorites = App.favorites.getAll();
        // By key or by URL: unfavoriting a card whose video came in from a
        // backup must remove that entry, not add a second one beside it.
        const existingIndex = App.favorites.indexOfEntry(favorites, video);
        const becameFavorite = existingIndex < 0;
        if (existingIndex >= 0) {
            favorites.splice(existingIndex, 1);
        } else {
            const entry = App.favorites.normalize(video);
            if (entry) favorites.unshift(entry);
        }
        App.favorites.setAll(favorites);
        App.favorites.renderBar();
        App.favorites.syncButtons();
        // Celebrate an add with a brass pop + ring on every button for this key.
        if (becameFavorite) {
            document.querySelectorAll(`.favorite-btn[data-fav-key="${(window.CSS && CSS.escape) ? CSS.escape(key) : key}"]`).forEach((btn) => {
                btn.classList.remove('just-favorited');
                void btn.offsetWidth; // restart the animation
                btn.classList.add('just-favorited');
                btn.addEventListener('animationend', () => btn.classList.remove('just-favorited'), { once: true });
            });
        }
    };

    // The bar is a horizontal strip, and a long favorites list is hundreds of
    // cards. Only a screenful or so is built up front; the rest arrives as the
    // strip is scrolled, which keeps opening the app cheap no matter how many
    // favorites are saved (an import can add hundreds at once).
    const BAR_PAGE_SIZE = 24;
    // How close to the right end the strip has to get before the next page is
    // appended -- roughly a screen's worth of cards ahead of the reader.
    const BAR_PAGE_AHEAD_PX = 800;
    const barPage = { items: [], rendered: 0 };

    // Bar titles are one line that scrolls when it doesn't fit, the same as the
    // grid card's. Which one scrolls follows the grid too: with a real pointer
    // it's the card under it, on touch the card nearest the middle of the strip.
    // Animating every overflowing title at once turns the bar into a wall of
    // moving text.
    const barTitleEnv = {
        useHoverFocus: window.matchMedia('(hover: hover) and (pointer: fine)').matches
    };

    const setBarTitleActive = function(card, active) {
        const title = card && card.querySelector('.favorite-title');
        if (!title) return;
        card.classList.toggle('is-title-active', !!active && title.classList.contains('has-marquee'));
    };

    // Touch: the card nearest the centre of the visible strip is the one being
    // read, so it is the one whose title scrolls.
    const syncBarTitleActive = function(list) {
        if (!list) return;
        const listRect = list.getBoundingClientRect();
        const centre = listRect.left + listRect.width / 2;
        let best = null;
        let bestDistance = Infinity;
        const cards = list.querySelectorAll('.favorite-card');
        cards.forEach((card) => {
            const rect = card.getBoundingClientRect();
            if (rect.right <= listRect.left || rect.left >= listRect.right) return;
            const distance = Math.abs((rect.left + rect.width / 2) - centre);
            if (distance < bestDistance) {
                bestDistance = distance;
                best = card;
            }
        });
        cards.forEach((card) => setBarTitleActive(card, card === best));
    };

    // Measures every card in the strip. Cheap enough to redo wholesale: a card's
    // width is fixed, so this only really runs when cards are added.
    const measureBarTitles = function(list) {
        const target = list || document.getElementById('favorites-list');
        if (!target) return;
        target.querySelectorAll('.favorite-card').forEach((card) => {
            App.marquee.measure(card.querySelector('.favorite-title'),
                card.querySelector('.favorite-title-text'));
        });
        if (!barTitleEnv.useHoverFocus) syncBarTitleActive(target);
    };

    // The display font arrives after the first render, and it changes how wide
    // every title is -- so whatever was measured against the fallback font has
    // to be measured again once the real one is in.
    if (document.fonts && document.fonts.ready) {
        document.fonts.ready.then(() => measureBarTitles()).catch(() => {});
    }

    App.favorites.renderBar = function() {
        const bar = document.getElementById('favorites-bar');
        const list = document.getElementById('favorites-list');
        const empty = document.getElementById('favorites-empty');
        if (!bar || !list) return;

        const favorites = App.favorites.sorted();
        // While the favorites grid is open the bar is kept mounted even if it's
        // switched off in settings: its header is what leads back out.
        const browsing = !!(App.favoritesView && App.favoritesView.isActive());
        bar.style.display = (App.favorites.isVisible() || browsing) ? 'block' : 'none';

        list.innerHTML = "";
        barPage.items = favorites;
        barPage.rendered = 0;
        // While the favorites grid is open the strip is hidden -- the grid is
        // the same list, larger -- so don't build cards nobody can see. The
        // header stays, because it carries the way back out.
        if (!browsing) appendBarPage(list);

        // Assignment rather than addEventListener: renderBar runs on every
        // favorite change, and this must not stack up handlers.
        let scrollRaf = null;
        list.onscroll = () => {
            // Which card is centred changes as the strip moves, but only once
            // per frame is worth measuring.
            if (!barTitleEnv.useHoverFocus && !scrollRaf) {
                scrollRaf = requestAnimationFrame(() => {
                    scrollRaf = null;
                    syncBarTitleActive(list);
                });
            }
            if (barPage.rendered >= barPage.items.length) return;
            const remaining = list.scrollWidth - (list.scrollLeft + list.clientWidth);
            if (remaining <= BAR_PAGE_AHEAD_PX) appendBarPage(list);
        };

        if (empty) {
            empty.style.display = favorites.length > 0 ? 'none' : 'block';
        }
    };

    function appendBarPage(list) {
        const slice = barPage.items.slice(barPage.rendered, barPage.rendered + BAR_PAGE_SIZE);
        barPage.rendered += slice.length;
        slice.forEach((item) => {
            const card = document.createElement('div');
            card.className = 'favorite-card';
            card.dataset.favKey = item.key;
            const uploaderText = item.uploader || '';
            const durationText = (!item.isLive && App.videos && typeof App.videos.formatDuration === 'function')
                ? App.videos.formatDuration(item.duration)
                : '';
            const liveBadge = item.isLive ? '<span class="live-badge">● LIVE</span>' : '';
            card.innerHTML = `
                ${liveBadge}
                <button class="favorite-btn is-favorite" type="button" aria-pressed="true" aria-label="Remove from favorites" data-fav-key="${item.key}" data-fav-url="${item.url || ''}">♥</button>
                <button class="video-menu-btn" type="button" aria-haspopup="true" aria-expanded="false" aria-label="More options">⋯</button>
                <div class="video-menu" role="menu">
                    <button class="video-menu-item" type="button" data-action="info" role="menuitem">Show info</button>
                    <button class="video-menu-item" type="button" data-action="download" role="menuitem">Download</button>
                </div>
                <div class="video-thumb">
                    <img src="${item.thumb}" alt="${item.title}" loading="lazy" decoding="async">
                    <div class="video-loading" aria-hidden="true">
                        <div class="video-loading-spinner"></div>
                    </div>
                    ${uploaderText ? `<button class="video-uploader uploader-link" type="button" data-uploader="${uploaderText}">${uploaderText}</button>` : ''}
                    ${durationText ? `<span class="video-duration">${durationText}</span>` : ''}
                </div>
                <div class="favorite-info">
                    <h4 class="favorite-title"><span class="favorite-title-text">${item.title}</span></h4>
                </div>
            `;
            const thumb = card.querySelector('img');
            if (App.videos && typeof App.videos.attachNoReferrerRetry === 'function') {
                App.videos.attachNoReferrerRetry(thumb);
            }
            card.onclick = () => {
                if (card.classList.contains('is-loading')) return;
                card.classList.add('is-loading');
                // Ignore any stale `meta` a favorite saved before this fix may
                // still carry in localStorage -- always re-resolve from `item`
                // (id/url) so playback never reuses an expired stream URL.
                App.player.open(item, { originEl: card });
            };
            const favoriteBtn = card.querySelector('.favorite-btn');
            if (favoriteBtn) {
                favoriteBtn.onclick = (event) => {
                    event.stopPropagation();
                    App.favorites.toggle(item);
                };
            }
            const menuBtn = card.querySelector('.video-menu-btn');
            const menu = card.querySelector('.video-menu');
            const showInfoBtn = card.querySelector('.video-menu-item[data-action="info"]');
            const downloadBtn = card.querySelector('.video-menu-item[data-action="download"]');
            if (menuBtn && menu) {
                menuBtn.onclick = (event) => {
                    event.stopPropagation();
                    App.videos.toggleMenu(menu, menuBtn);
                };
            }
            if (showInfoBtn) {
                showInfoBtn.onclick = (event) => {
                    event.stopPropagation();
                    App.videos.closeAllMenus();
                    // Favorites deliberately store no resolved metadata; the
                    // panel opens on what the entry holds and resolves the rest
                    // itself.
                    App.ui.openInfo(item);
                };
            }
            if (downloadBtn) {
                downloadBtn.onclick = (event) => {
                    event.stopPropagation();
                    App.videos.closeAllMenus();
                    // Same as playback: resolve a real media URL first rather
                    // than pointing the download at the page URL.
                    App.videos.ensureFormats(item).then(() => App.videos.downloadVideo(item));
                };
            }
            const uploaderBtn = card.querySelector('.uploader-link');
            if (uploaderBtn) {
                uploaderBtn.onclick = (event) => {
                    event.stopPropagation();
                    const uploader = uploaderBtn.dataset.uploader || uploaderBtn.textContent || '';
                    App.videos.handleSearch(uploader);
                };
            }
            if (barTitleEnv.useHoverFocus) {
                card.addEventListener('pointerenter', () => setBarTitleActive(card, true));
                card.addEventListener('pointerleave', () => setBarTitleActive(card, false));
            }
            // Keyboard: tabbing to a card's heart should reveal its whole title
            // too, on touch devices as much as on desktop.
            card.addEventListener('focusin', () => setBarTitleActive(card, true));
            card.addEventListener('focusout', () => setBarTitleActive(card, false));
            list.appendChild(card);
        });
        // Widths only exist once the cards are laid out.
        requestAnimationFrame(() => measureBarTitles(list));
    }
})();