// Master display: owns the audio output for a room. Connects to the WS as
// kind='display', advertises a (fake) device list, plays the active station
// locally, and emits authoritative `state` events so other panels mirror.
//
// In production this same page is loaded inside an Electron window. The
// `window.oradioNative` bridge — when present — replaces the fake device
// enumerator below with the real OS one. The bridge contract is:
//
//   window.oradioNative = {
//     listOutputs(): Promise<{id, label, kind}[]>,
//     setOutput(id):  Promise<void>,
//     getCurrent():   Promise<string>,
//     onCurrentChanged(cb): unsubscribe
//   };

import { api } from '../shared/api.js';
import { connectWs } from '../shared/ws.js';
import { el, clear } from '../shared/dom.js';
import { Player } from '../player.js';

// Fake list mirrors what a typical desktop sees. Used only when no native
// bridge is present (i.e. running in a normal browser tab, not Electron).
const FAKE_DEVICES = [
    { id: 'default', label: 'System default', kind: 'speakers' },
    { id: 'speakers-internal', label: 'Built-in speakers', kind: 'speakers' },
    { id: 'headphones-jack', label: 'Headphones (3.5mm)', kind: 'headphones' },
    { id: 'hdmi-tv', label: 'HDMI – Living-room TV', kind: 'hdmi' },
    { id: 'bt-marshall', label: 'Bluetooth – Marshall Stanmore', kind: 'bluetooth' },
    { id: 'usb-audient', label: 'USB – Audient EVO 4', kind: 'usb' }
];

const app = document.getElementById('app');
const state = {
    user: null,
    rooms: [],
    roomSlug: null,
    room: null,
    peers: [],
    devices: { list: [], current: 'default' },
    np: {
        stationId: null, station: null, playing: false,
        loading: false, volume: 0.7, error: null
    },
    voteStats: null,
    favorites: [],
    favGenre: '',           // active genre filter for favorites browser
    showOutputs: false,     // output picker is hidden behind a button
    session: null           // { id, stationId, startedAt } for the open play_history row
};

const native = window.oradioNative || null;
let ws = null;
let player = null;

async function bootstrap() {
    try { state.user = await api.get('/api/auth/me'); }
    catch { return showLogin(); }

    // Pick the room: ?room=<slug> wins, else first server-side room, else personal.
    const params = new URLSearchParams(location.search);
    const wanted = params.get('room');
    try {
        state.rooms = await api.get('/api/rooms');
    } catch { state.rooms = []; }
    state.roomSlug = wanted
        || (state.rooms[0] && state.rooms[0].slug)
        || `u-${state.user.id}`;

    // Initial device list.
    if (native?.listOutputs) {
        state.devices.list = await native.listOutputs();
        state.devices.current = (await native.getCurrent()) || state.devices.list[0]?.id;
        native.onCurrentChanged?.((id) => { state.devices.current = id; advertiseDevices(); render(); });
    } else {
        state.devices.list = FAKE_DEVICES;
        state.devices.current = 'default';
    }

    player = new Player({
        onState: (s) => {
            Object.assign(state.np, s);
            // Push display truth out to the room.
            sendState();
            render();
        }
    });

    // Load favorites so the touch browser + heart indicator work.
    try { state.favorites = await api.get('/api/me/favorites'); }
    catch { state.favorites = []; }

    openWs();
    render();
}

// Best-effort session flush on tab close so total_play_ms stays honest.
if (typeof window !== 'undefined') {
    window.addEventListener('pagehide', () => endCurrentSession({ beacon: true }));
    window.addEventListener('beforeunload', () => endCurrentSession({ beacon: true }));
}

function openWs() {
    if (ws) { try { ws.close(); } catch { } }
    ws = connectWs(handleWs, {
        room: state.roomSlug,
        kind: 'display',
        onOpen: () => advertiseDevices()
    });
}

function handleWs(msg) {
    if (!msg || !msg.type) return;
    switch (msg.type) {
        case 'hello': {
            state.room = msg.room;
            state.peers = msg.peers || [];
            // If the server thinks another display already owns this room we
            // were demoted to 'panel' — surface that.
            if (msg.you?.kind && msg.you.kind !== 'display') {
                state.np.error = `This room already has a display (${countDisplays(msg.peers)} active). You were joined as ${msg.you.kind}.`;
            }
            // Resume room state when (re-)connecting: play whatever the room
            // thinks is current, unless we're already on it.
            const rs = msg.state;
            if (rs?.station_id && rs.station && rs.station_id !== state.np.stationId) {
                playStation(rs.station, { silent: true });
            }
            if (typeof rs?.volume === 'number') {
                player.setVolume(rs.volume);
            }
            render();
            return;
        }
        case 'presence':
            state.peers = msg.peers || [];
            render();
            return;
        case 'command':
            handleCommand(msg);
            return;
        case 'vote':
        case 'plays':
            if (msg.stationId === state.np.stationId) {
                state.voteStats = { ...(state.voteStats || {}), ...(msg.stats || {}) };
                if (msg.type === 'plays') state.voteStats.plays = msg.plays;
                render();
            }
            return;
        default:
            return;
    }
}

function handleCommand(msg) {
    switch (msg.action) {
        case 'play': {
            const id = Number(msg.stationId);
            if (!Number.isFinite(id)) return;
            api.get(`/api/stations/${id}`).then((st) => playStation(st)).catch(() => { });
            return;
        }
        case 'pause':
            player.togglePause();
            return;
        case 'stop':
            player.stop();
            endCurrentSession();
            state.np.playing = false;
            state.np.stationId = null;
            sendState();
            render();
            return;
        case 'volume':
            if (typeof msg.value === 'number') player.setVolume(msg.value);
            return;
        case 'setSink':
            setSink(String(msg.deviceId || ''));
            return;
        default:
            return;
    }
}

async function playStation(station, { silent } = {}) {
    if (!station) return;
    // Close any previous session before swapping. We compute the duration
    // locally so resumes-after-suspend don't get charged the whole gap.
    endCurrentSession();
    state.np.station = station;
    state.np.stationId = station.id;
    state.voteStats = {
        up: station.up || 0, down: station.down || 0,
        plays: station.plays || 0, score: station.score || 0
    };
    render();
    await player.play(station);
    if (!silent) {
        try {
            const stats = await api.post(`/api/stations/${station.id}/play`);
            // The same station may have been swapped out while the POST was in
            // flight — only retain the session id when it's still current.
            if (state.np.stationId === station.id) {
                state.session = { id: stats.sessionId, stationId: station.id, startedAt: Date.now() };
                state.voteStats = { ...state.voteStats, ...stats };
            } else if (stats.sessionId) {
                // We've already moved on; close the just-opened session immediately.
                api.post(`/api/stations/${station.id}/play/end`, {
                    sessionId: stats.sessionId, duration_ms: 0
                }).catch(() => { });
            }
        } catch { /* network blip — best-effort counter */ }
    }
}

// Close whichever session is currently open. Idempotent.
function endCurrentSession({ beacon = false } = {}) {
    const s = state.session;
    if (!s || !s.id) return;
    state.session = null;
    const body = { sessionId: s.id, duration_ms: Math.max(0, Date.now() - s.startedAt) };
    const url = `/api/stations/${s.stationId}/play/end`;
    if (beacon && typeof navigator !== 'undefined' && navigator.sendBeacon) {
        try {
            navigator.sendBeacon(url, new Blob([JSON.stringify(body)], { type: 'application/json' }));
            return;
        } catch { /* fall through */ }
    }
    api.post(url, body).catch(() => { });
}

function sendState() {
    if (!ws || !state.np.stationId) {
        ws?.send({
            type: 'state',
            stationId: state.np.stationId,
            playing: !!state.np.playing,
            volume: state.np.volume
        });
        return;
    }
    ws.send({
        type: 'state',
        stationId: state.np.stationId,
        playing: !!state.np.playing,
        volume: state.np.volume
    });
}

function advertiseDevices() {
    ws?.send({
        type: 'devices',
        list: state.devices.list,
        current: state.devices.current
    });
}

async function setSink(deviceId) {
    if (!deviceId) return;
    if (native?.setOutput) {
        try { await native.setOutput(deviceId); }
        catch (err) { console.warn('[master] setOutput failed', err); return; }
    }
    state.devices.current = deviceId;
    // Browser-only fallback: try `audio.setSinkId` if the device id maps to a
    // real MediaDevices id. For the fake list this is a no-op visualisation.
    if (player?.audio?.setSinkId && /^[a-f0-9]{16,}$/.test(deviceId)) {
        try { await player.audio.setSinkId(deviceId); } catch { }
    }
    advertiseDevices();
    state.showOutputs = false;
    render();
}

function countDisplays(peers) {
    return (peers || []).filter((p) => p.kind === 'display').length;
}

// ---------- Favorites ----------

function isFavorite(stationId) {
    return !!stationId && state.favorites.some((f) => f.id === stationId);
}

async function toggleFavorite(stationId) {
    if (!stationId) return;
    const has = isFavorite(stationId);
    try {
        if (has) await api.del(`/api/me/favorites/${stationId}`);
        else await api.put(`/api/me/favorites/${stationId}`, { position: state.favorites.length });
        state.favorites = await api.get('/api/me/favorites');
        render();
    } catch (err) {
        console.warn('[master] toggleFavorite failed', err);
    }
}

function favoriteGenres() {
    const counts = new Map();
    for (const s of state.favorites) {
        for (const g of (s.genres || [])) counts.set(g, (counts.get(g) || 0) + 1);
    }
    return [...counts.entries()]
        .sort((a, b) => b[1] - a[1] || a[0].localeCompare(b[0]))
        .map(([g, n]) => ({ genre: g, count: n }));
}

function filteredFavorites() {
    if (!state.favGenre) return state.favorites;
    return state.favorites.filter((s) => (s.genres || []).includes(state.favGenre));
}

// ---------- Render ----------

function render() {
    // Preserve scroll position of the favorites grid across re-renders so that
    // tapping a tile (which triggers a full re-render) does not jump back to top.
    const prevFavScroll = app.querySelector('.favs-grid')?.scrollLeft ?? 0;
    clear(app);
    const np = state.np;
    const st = np.station;
    const artUrl = st?.image_display_url || st?.image_url || null;
    const fav = isFavorite(st?.id);

    const shell = el('div', { class: 'master' },
        // Topbar
        el('header', { class: 'topbar' },
            el('h1', {}, '◉ MASTER'),
            el('div', { class: 'pill' },
                el('span', {}, 'Room:'),
                el('select', {
                    onChange: (e) => {
                        state.roomSlug = e.target.value;
                        history.replaceState(null, '', `?room=${encodeURIComponent(state.roomSlug)}`);
                        openWs();
                    }
                }, ...state.rooms.map((r) =>
                    el('option', { value: r.slug, selected: r.slug === state.roomSlug }, r.name)))
            ),
            el('div', { class: 'pill peers' }, `${state.peers.length} peer${state.peers.length === 1 ? '' : 's'}`),
            np.error ? el('div', { class: 'err-banner' }, np.error) : null,
            el('div', { class: 'grow' }),
            el('button', {
                class: 'pill out-btn' + (state.showOutputs ? ' active' : ''),
                title: 'Audio output',
                onClick: () => { state.showOutputs = !state.showOutputs; render(); }
            }, '🔊 ', currentDeviceLabel()),
            el('div', { class: 'pill' }, native ? 'native' : 'browser'),
            el('div', { class: 'pill' }, state.user.username),
        ),

        // Stage: now-playing block (with transport + volume embedded)
        el('section', { class: 'stage' },
            el('div', { class: 'np' },
                el('div', { class: 'art' + (artUrl ? '' : ' empty') },
                    artUrl ? el('img', {
                        class: 'art-img',
                        src: artUrl,
                        alt: '',
                        referrerpolicy: 'no-referrer',
                        onError: (e) => {
                            // Fall back to the empty glyph if the image fails to load.
                            const parent = e.target.parentNode;
                            e.target.remove();
                            if (parent) parent.classList.add('empty');
                        }
                    }) : null
                ),
                el('div', { class: 'meta' },
                    el('div', { class: 'tiny' }, np.loading ? 'Loading…' : np.playing ? 'Now playing' : st ? 'Paused' : 'Idle'),
                    el('div', { class: 'title-row' },
                        el('h2', {}, st?.name || '—'),
                        st ? el('button', {
                            class: 'fav-toggle' + (fav ? ' on' : ''),
                            title: fav ? 'Remove favorite' : 'Add favorite',
                            onClick: () => toggleFavorite(st.id)
                        }, fav ? '★' : '☆') : null
                    ),
                    el('div', { class: 'genres' }, ...(st?.genres || []).slice(0, 6).map((g) => el('span', { class: 'tag' }, g))),
                    state.voteStats ? el('div', { class: 'stats' },
                        el('span', {}, '▲ ', el('b', {}, String(state.voteStats.up || 0))),
                        el('span', {}, '▼ ', el('b', {}, String(state.voteStats.down || 0))),
                        el('span', {}, '▶ ', el('b', {}, String(state.voteStats.plays || 0)))
                    ) : null,
                    st?.country ? el('div', { class: 'stats' }, el('span', {}, st.country)) : null,
                    // Transport + volume embedded inside the now-playing block
                    el('div', { class: 'transport' },
                        el('button', {
                            class: 'ctrl primary',
                            title: 'Play / pause',
                            disabled: !st,
                            onClick: () => player.togglePause()
                        }, np.playing ? '❚❚' : '▶'),
                        el('button', {
                            class: 'ctrl',
                            title: 'Stop',
                            disabled: !st,
                            onClick: () => {
                                player.stop();
                                endCurrentSession();
                                state.np.playing = false;
                                sendState();
                                render();
                            }
                        }, '■'),
                        el('div', { class: 'vol' },
                            el('span', { class: 'vol-icon' }, '🔊'),
                            el('input', {
                                type: 'range', min: 0, max: 1, step: 0.01, value: np.volume,
                                onInput: (e) => player.setVolume(Number(e.target.value))
                            }),
                            el('span', { class: 'val' }, Math.round(np.volume * 100) + '%')
                        )
                    ),
                    el('div', { class: 'peer-line' },
                        el('span', { class: 'peer-line-label' }, 'In room:'),
                        ...(state.peers.length
                            ? state.peers.map((p) => el('span', { class: 'peer role-' + p.kind },
                                el('span', { class: 'role-tag' }, p.kind),
                                el('span', {}, p.user?.username || '?')
                            ))
                            : [el('span', { class: 'peer' }, 'Just you.')])
                    )
                )
            )
        ),

        // Bottom: stations grid (2 rows of the viewport)
        el('section', { class: 'stations-bar' },
            renderFavoritesCard()
        ),

        // Output picker popover (hidden by default; toggled by topbar button).
        state.showOutputs ? renderOutputPopover() : null
    );
    app.appendChild(shell);
    // Restore favorites grid scroll position after the DOM swap.
    const favGrid = app.querySelector('.favs-grid');
    if (favGrid) {
        if (prevFavScroll) favGrid.scrollLeft = prevFavScroll;
        attachDragScroll(favGrid);
    }
}

// Pointer-drag horizontal scrolling for the favorites strip. Mouse users can
// click and drag like a touch surface; we suppress the click on the tile that
// was the drag origin so a drag doesn't fire a station change.
function attachDragScroll(el) {
    if (el.dataset.dragBound === '1') return;
    el.dataset.dragBound = '1';
    let down = false;
    let moved = false;
    let startX = 0;
    let startScroll = 0;
    let pointerId = -1;

    el.addEventListener('pointerdown', (e) => {
        // Only left-button mouse / touch / pen; ignore wheel buttons.
        if (e.pointerType === 'mouse' && e.button !== 0) return;
        down = true;
        moved = false;
        startX = e.clientX;
        startScroll = el.scrollLeft;
        pointerId = e.pointerId;
    });
    el.addEventListener('pointermove', (e) => {
        if (!down) return;
        const dx = e.clientX - startX;
        if (!moved && Math.abs(dx) > 5) {
            moved = true;
            try { el.setPointerCapture(pointerId); } catch { }
            el.classList.add('dragging');
        }
        if (moved) {
            el.scrollLeft = startScroll - dx;
            e.preventDefault();
        }
    });
    const endDrag = () => {
        down = false;
        if (moved) {
            // Swallow the click that follows the drag-up so tiles aren't activated.
            const swallow = (ev) => { ev.stopPropagation(); ev.preventDefault(); };
            el.addEventListener('click', swallow, { capture: true, once: true });
            setTimeout(() => el.removeEventListener('click', swallow, true), 0);
        }
        moved = false;
        el.classList.remove('dragging');
        try { el.releasePointerCapture(pointerId); } catch { }
    };
    el.addEventListener('pointerup', endDrag);
    el.addEventListener('pointercancel', endDrag);
    el.addEventListener('pointerleave', () => { if (down && !moved) down = false; });
}

function scrollFavs(direction) {
    const grid = app.querySelector('.favs-grid');
    if (!grid) return;
    // Page by ~80% of the visible width, snapping feels natural with scroll-snap.
    const delta = Math.max(160, Math.round(grid.clientWidth * 0.8));
    grid.scrollBy({ left: direction * delta, behavior: 'smooth' });
}

function renderFavoritesCard() {
    const genres = favoriteGenres();
    const favs = filteredFavorites();
    return el('div', { class: 'card favs-card' },
        el('div', { class: 'favs-header' },
            el('h3', {}, `Favorites (${favs.length}${state.favGenre ? `/${state.favorites.length}` : ''})`),
            genres.length ? el('select', {
                class: 'genre-filter',
                title: 'Filter by genre',
                onChange: (e) => { state.favGenre = e.target.value; render(); }
            },
                el('option', { value: '' }, 'All genres'),
                ...genres.map(({ genre, count }) =>
                    el('option', { value: genre, selected: state.favGenre === genre }, `${genre} (${count})`))
            ) : null,
            el('button', {
                class: 'favs-nav',
                title: 'Scroll left',
                onClick: () => scrollFavs(-1)
            }, '‹'),
            el('button', {
                class: 'favs-nav',
                title: 'Scroll right',
                onClick: () => scrollFavs(1)
            }, '›')
        ),
        el('div', { class: 'favs-grid' }, ...(favs.length ? favs.map((s) => {
            const art = s.image_display_url || s.image_url;
            const active = state.np.stationId === s.id;
            return el('button', {
                class: 'fav-tile' + (active ? ' active' : ''),
                title: s.name,
                onClick: () => playStation(s)
            },
                el('div', {
                    class: 'fav-art' + (art ? '' : ' empty'),
                    style: art ? { backgroundImage: `url("${art}")` } : {}
                }),
                el('div', { class: 'fav-name' }, s.name)
            );
        }) : [el('div', { class: 'favs-empty' },
            state.favGenre ? 'No favorites in this genre.' : 'No favorites yet. Star a station to add it.')]))
    );
}

function renderOutputPopover() {
    return el('div', {
        class: 'out-popover-wrap',
        onClick: (e) => { if (e.target === e.currentTarget) { state.showOutputs = false; render(); } }
    },
        el('div', { class: 'out-popover card' },
            el('div', { class: 'out-popover-head' },
                el('h3', {}, 'Audio output'),
                el('button', {
                    class: 'close', title: 'Close',
                    onClick: () => { state.showOutputs = false; render(); }
                }, '×')
            ),
            el('div', { class: 'device-list' }, ...state.devices.list.map((d) =>
                el('button', {
                    class: 'device' + (d.id === state.devices.current ? ' active' : ''),
                    onClick: () => { setSink(d.id); }
                },
                    el('span', { class: 'dot' }),
                    el('span', { class: 'name' }, d.label),
                    el('span', { class: 'kind' }, d.kind)
                )))
        )
    );
}

function currentDeviceLabel() {
    const d = state.devices.list.find((d) => d.id === state.devices.current);
    return d ? d.label : '—';
}

function showLogin() {
    clear(app);
    app.appendChild(el('div', { class: 'login' },
        el('form', {
            onSubmit: async (e) => {
                e.preventDefault();
                const fd = new FormData(e.target);
                try {
                    state.user = await api.post('/api/auth/login', {
                        username: fd.get('username'), password: fd.get('password')
                    });
                    await bootstrap();
                } catch (err) { e.target.querySelector('.err').textContent = err.message; }
            }
        },
            el('h1', {}, 'Master sign in'),
            el('input', { name: 'username', placeholder: 'Username', required: true }),
            el('input', { name: 'password', type: 'password', placeholder: 'Password', required: true }),
            el('div', { class: 'err' }),
            el('button', { type: 'submit' }, 'Sign in')
        )));
}

bootstrap();