/**
 * Radio — vanilla JS audio controller.
 *
 * Binds to every `.radio-player` element on the page (dashboard widget
 * + main page can co-exist; both share one logical audio session per
 * surface). Persists station + volume changes via AJAX so they survive
 * page reloads.
 *
 * v0.3.0 additions:
 *  - Mute toggle on the speaker icon (preserves prior volume).
 *  - MediaSession API integration — OS media keys (F8 on Mac, headphone
 *    buttons, lock-screen widget) control the player.
 *  - SomaFM current-track polling (every 30s while playing). Best-effort:
 *    silently hidden if the API is unavailable / CORS-blocked.
 *  - Save errors surface to the user as a transient notice rather than
 *    being swallowed silently.
 *  - Settings-page volume slider live-label is wired here (no inline
 *    `oninput` in settings.php).
 *
 * No build step. No dependencies.
 */
(function () {
    'use strict';

    if (typeof window.RadioPlugin === 'undefined') { return; }

    var cfg      = window.RadioPlugin;
    var stations = Array.isArray(cfg.stations) ? cfg.stations : [];

    /** Look up a station by id. */
    function findStation(stationId) {
        for (var i = 0; i < stations.length; i++) {
            if (stations[i].id === stationId) { return stations[i]; }
        }
        return null;
    }

    /** Extract the SomaFM short-code from a stream URL.
     *  e.g. https://ice1.somafm.com/groovesalad-128-mp3 → "groovesalad".
     *  Used for the current-track JSON endpoint. */
    function getSomaCode(station) {
        if (!station || !station.url) { return null; }
        var m = station.url.match(/somafm\.com\/([^/]+?)-\d+-mp3/);
        return m ? m[1] : null;
    }

    /** Persist a state patch back to the server. On failure, surface a
     *  transient notice on the originating player surface (if given) so
     *  the user knows their preference didn't save. */
    function saveState(patch, surface) {
        if (!cfg.ajaxUrl || !cfg.nonce) { return; }
        var fd = new FormData();
        fd.append('action', 'radio_save_state');
        fd.append('nonce', cfg.nonce);
        Object.keys(patch).forEach(function (k) { fd.append(k, patch[k]); });
        fetch(cfg.ajaxUrl, {
            method:      'POST',
            credentials: 'same-origin',
            body:        fd
        }).then(function (r) {
            if (!r.ok) { throw new Error('save failed: HTTP ' + r.status); }
        }).catch(function (err) {
            if (window.console && console.warn) { console.warn('Radio:', err); }
            if (surface) {
                showError(surface, cfg.strings.saveError || 'Preferences not saved.');
                setTimeout(function () { showError(surface, null); }, 3500);
            }
        });
    }

    /** Update play/pause button glyph + label to reflect current audio state.
     *  v0.3.2: switched from .dashicons to a Unicode glyph so the symbol sits
     *  on the text baseline instead of below it. */
    function setPlayIcon(btn, playing) {
        var glyph = btn.querySelector('[data-radio-play-glyph]');
        var label = btn.querySelector('[data-radio-play-label]');
        if (glyph) { glyph.textContent = playing ? '‖' : '▶'; } // ‖ or ▶
        if (label) { label.textContent = playing ? (cfg.strings.pause || 'Pause') : (cfg.strings.play || 'Play'); }
        btn.setAttribute('title', playing ? (cfg.strings.pause || 'Pause') : (cfg.strings.play || 'Play'));
    }

    /** Show an error message inside a given .radio-player surface. */
    function showError(player, msg) {
        var err = player.querySelector('[data-radio-error]');
        if (!err) { return; }
        if (msg) {
            err.textContent = msg;
            err.hidden = false;
        } else {
            err.textContent = '';
            err.hidden = true;
        }
    }

    /** Update the MediaSession metadata + handlers so OS media keys work. */
    function updateMediaSession(audio, station) {
        if (!('mediaSession' in navigator) || !station) { return; }
        try {
            if (typeof window.MediaMetadata === 'function') {
                navigator.mediaSession.metadata = new window.MediaMetadata({
                    title:  station.name,
                    artist: 'SomaFM',
                    album:  station.genre || ''
                });
            }
            navigator.mediaSession.setActionHandler('play',  function () { audio.play(); });
            navigator.mediaSession.setActionHandler('pause', function () { audio.pause(); });
        } catch (e) { /* ignore — older browsers / locked-down contexts */ }
    }

    /** SomaFM current-track polling. Best-effort: stays hidden if the API
     *  is unreachable / CORS-blocked (the plugin keeps working regardless). */
    function startTrackPolling(player, station) {
        stopTrackPolling(player);
        var trackEl = player.querySelector('[data-radio-track]');
        if (!trackEl) { return; }
        var code = getSomaCode(station);
        if (!code) { trackEl.hidden = true; return; }
        var url = 'https://somafm.com/songs/' + code + '.json';

        function fetchTrack() {
            fetch(url, { credentials: 'omit', cache: 'no-store' })
                .then(function (r) { return r.ok ? r.json() : null; })
                .then(function (data) {
                    if (!data || !data.songs || !data.songs.length) { trackEl.hidden = true; return; }
                    var s      = data.songs[0];
                    var title  = (s.title  || '').trim();
                    var artist = (s.artist || '').trim();
                    if (!title && !artist) { trackEl.hidden = true; return; }
                    trackEl.textContent = artist ? (title + ' — ' + artist) : title;
                    trackEl.hidden = false;
                })
                .catch(function () { trackEl.hidden = true; });
        }
        fetchTrack();
        player._trackTimer = setInterval(fetchTrack, 30000);
    }

    function stopTrackPolling(player) {
        if (player._trackTimer) {
            clearInterval(player._trackTimer);
            player._trackTimer = null;
        }
        var trackEl = player.querySelector('[data-radio-track]');
        if (trackEl) { trackEl.hidden = true; trackEl.textContent = ''; }
    }

    /** Mute toggle. Remembers the volume at mute-time so unmute restores it. */
    function bindMute(player, audio, volumeIn, volPctEl) {
        var muteBtn = player.querySelector('[data-radio-mute]');
        if (!muteBtn) { return; }
        muteBtn.addEventListener('click', function () {
            var icon = muteBtn.querySelector('.dashicons');
            if (audio.muted || audio.volume === 0) {
                // Unmute → restore stored prior volume (default 0.6 if we never had one)
                var prev = parseFloat(muteBtn.dataset.prevVolume || '0.6');
                audio.muted = false;
                audio.volume = prev;
                if (volumeIn)  { volumeIn.value = Math.round(prev * 100); }
                if (volPctEl)  { volPctEl.textContent = Math.round(prev * 100) + '%'; }
                muteBtn.classList.remove('radio-player__mute--muted');
                muteBtn.setAttribute('aria-label', cfg.strings.mute || 'Mute');
                if (icon) { icon.className = 'dashicons dashicons-controls-volumeon'; }
            } else {
                // Mute → store current volume, drop to 0
                muteBtn.dataset.prevVolume = String(audio.volume);
                audio.muted = true;
                muteBtn.classList.add('radio-player__mute--muted');
                muteBtn.setAttribute('aria-label', cfg.strings.unmute || 'Unmute');
                if (icon) { icon.className = 'dashicons dashicons-controls-volumeoff'; }
            }
        });
    }

    /** Wire up one .radio-player surface (widget or main). */
    function bindPlayer(player) {
        var audio      = player.querySelector('[data-radio-audio]');
        var playBtn    = player.querySelector('[data-radio-play]');
        var stationSel = player.querySelector('[data-radio-station]');
        var volumeIn   = player.querySelector('[data-radio-volume]');
        var nameEl     = player.querySelector('[data-radio-name]');
        var descEl     = player.querySelector('[data-radio-desc]');
        var volPctEl   = player.querySelector('[data-radio-volume-pct]');

        if (!audio || !playBtn || !stationSel) { return; }

        var currentId  = stationSel.value;
        var station    = findStation(currentId);
        if (station) {
            audio.src    = station.url;
            audio.volume = parseFloat(cfg.state && cfg.state.volume != null ? cfg.state.volume : 0.6);
            updateMediaSession(audio, station);
        }
        if (volumeIn) { volumeIn.value = Math.round(audio.volume * 100); }

        playBtn.addEventListener('click', function () {
            showError(player, null);
            if (audio.paused) {
                var p = audio.play();
                if (p && p.catch) {
                    p.catch(function (err) {
                        if (err && err.name === 'NotAllowedError') {
                            showError(player, cfg.strings.error || 'Click play again to start.');
                        } else {
                            showError(player, cfg.strings.error || 'Stream error.');
                        }
                    });
                }
            } else {
                audio.pause();
            }
        });

        audio.addEventListener('play',  function () {
            setPlayIcon(playBtn, true);
            startTrackPolling(player, findStation(stationSel.value));
        });
        audio.addEventListener('pause', function () {
            setPlayIcon(playBtn, false);
            stopTrackPolling(player);
        });
        audio.addEventListener('error', function () {
            showError(player, cfg.strings.error || 'Stream error.');
            setPlayIcon(playBtn, false);
            stopTrackPolling(player);
        });
        audio.addEventListener('canplay', function () { showError(player, null); });

        stationSel.addEventListener('change', function () {
            var newId = stationSel.value;
            var s     = findStation(newId);
            if (!s) { return; }
            var wasPlaying = !audio.paused;
            audio.pause();
            audio.src = s.url;
            audio.load();
            if (nameEl) { nameEl.textContent = s.name; }
            if (descEl) { descEl.textContent = s.description || ''; }
            var genreEl = player.querySelector('[data-radio-genre]');
            if (genreEl) { genreEl.textContent = s.genre || ''; }
            stopTrackPolling(player);                       // clear last station's track
            updateMediaSession(audio, s);
            mirrorSelection(player, newId);
            saveState({ station_id: newId }, player);
            if (wasPlaying) {
                audio.play().catch(function () { showError(player, cfg.strings.error || 'Stream error.'); });
            }
        });

        if (volumeIn) {
            volumeIn.addEventListener('input', function () {
                var pct = parseInt(volumeIn.value, 10) || 0;
                var vol = Math.max(0, Math.min(100, pct)) / 100;
                audio.muted  = false;
                audio.volume = vol;
                if (volPctEl) { volPctEl.textContent = pct + '%'; }
                // Manual volume change exits mute state visibly.
                var muteBtn = player.querySelector('[data-radio-mute]');
                if (muteBtn) {
                    muteBtn.classList.remove('radio-player__mute--muted');
                    var icon = muteBtn.querySelector('.dashicons');
                    if (icon) { icon.className = 'dashicons dashicons-controls-volumeon'; }
                }
                mirrorVolume(player, pct);
                clearTimeout(volumeIn._saveTimer);
                volumeIn._saveTimer = setTimeout(function () {
                    saveState({ volume: vol }, player);
                }, 400);
            });
        }

        bindMute(player, audio, volumeIn, volPctEl);
    }

    /** Keep all .radio-player surfaces on the same station. */
    function mirrorSelection(originPlayer, stationId) {
        document.querySelectorAll('.radio-player').forEach(function (other) {
            if (other === originPlayer) { return; }
            var sel = other.querySelector('[data-radio-station]');
            if (sel && sel.value !== stationId) {
                sel.value = stationId;
                var s = findStation(stationId);
                if (s) {
                    var nm = other.querySelector('[data-radio-name]');
                    var dc = other.querySelector('[data-radio-desc]');
                    var gn = other.querySelector('[data-radio-genre]');
                    if (nm) { nm.textContent = s.name; }
                    if (dc) { dc.textContent = s.description || ''; }
                    if (gn) { gn.textContent = s.genre || ''; }
                }
            }
        });
    }

    /** Keep volume sliders in sync across surfaces. */
    function mirrorVolume(originPlayer, pct) {
        document.querySelectorAll('.radio-player').forEach(function (other) {
            if (other === originPlayer) { return; }
            var vol = other.querySelector('[data-radio-volume]');
            if (vol && parseInt(vol.value, 10) !== pct) {
                vol.value = pct;
                var label = other.querySelector('[data-radio-volume-pct]');
                if (label) { label.textContent = pct + '%'; }
                var au = other.querySelector('[data-radio-audio]');
                if (au) { au.volume = pct / 100; au.muted = false; }
            }
        });
    }

    /** Wire the Settings page volume slider's live percentage label.
     *  Replaces the inline `oninput` attribute removed in v0.3.0. */
    function bindSettingsSlider() {
        var slider = document.getElementById('default_volume');
        var label  = document.getElementById('default_volume_label');
        if (!slider || !label) { return; }
        slider.addEventListener('input', function () {
            label.textContent = slider.value + '%';
        });
    }

    function init() {
        var players = document.querySelectorAll('.radio-player');
        for (var i = 0; i < players.length; i++) { bindPlayer(players[i]); }
        bindSettingsSlider();
    }

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