<?php
/**
 * api/artwork.php
 * ---------------
 * Optional album-art lookup. The browser calls this only when the stream
 * provider itself did not supply artwork and ARTWORK_SOURCE allows a lookup.
 * Tries dumb (if USE_DUMB is on), then the official Genius API (if a token
 * is configured), then Last.fm — each tier only runs if the previous one
 * found nothing, so dumb and Genius can both be configured at once. Returns:
 *
 *   { "art": "https://…" | "", "album": "…", "url": "…" }
 *
 * With nothing configured it returns empty fields and the front-end falls back
 * to the placeholder image.
 */

require_once __DIR__ . '/_bootstrap.php';

$empty = ['art' => '', 'album' => '', 'url' => ''];

$source = cfg('artwork.source');
if ($source === 'none' || $source === 'provider') {
    json_out($empty);
}

[$artist, $title] = request_track();
if ($artist === '' && $title === '') {
    json_out($empty);
}

/* -- Operator-defined overrides (config/overrides.json) -------------------- */
$overrides = [];
$overridesFile = __DIR__ . '/../config/overrides.json';
if (is_file($overridesFile)) {
    $ov = json_decode((string) file_get_contents($overridesFile), true);
    if (is_array($ov)) $overrides = $ov['artwork'] ?? [];
}

/**
 * Does an override rule match this track? A rule may set any of artist / title
 * / album (all case-insensitive). artist & title are exact matches; album is a
 * substring match, so "Because the Internet" also catches "...(Deluxe)". An
 * album rule can only match once $album is known (after the provider lookup),
 * which is what lets you target one album without hitting the artist's others.
 */
function override_matches($rule, $artist, $title, $album) {
    if (isset($rule['artist']) && strcasecmp($rule['artist'], $artist) !== 0) return false;
    if (isset($rule['title'])  && strcasecmp($rule['title'],  $title)  !== 0) return false;
    if (isset($rule['album'])) {
        if ($album === '' || stripos($album, (string) $rule['album']) === false) return false;
    }
    return true;
}

// Fast path: artist/title-only rules match before any API call. (Rules that
// target an album can't match yet — the album is still unknown.)
foreach ($overrides as $rule) {
    if (!empty($rule['art']) && !isset($rule['album'])
        && override_matches($rule, $artist, $title, '')) {
        json_out(['art' => $rule['art'], 'album' => '', 'url' => '']);
    }
}

/* -- dumb (Genius-API-free) ------------------------------------------------ */
function dumb_artwork($artist, $title) {
    $path = dumb_search($artist, $title, 5);
    if ($path === '') return null;
    $song = dumb_song($path, 5);
    if ($song === null) return null;

    $art = $song['art'] !== '' ? $song['art'] : $song['song_art'];
    if ($art === '' && $song['album'] === '') return null;
    return ['art' => $art, 'album' => $song['album'], 'url' => cfg('dumb.url') . $path];
}

/* -- Genius --------------------------------------------------------------- */
function genius_artwork($artist, $title) {
    if (cfg('dumb.enabled')) {
        $res = dumb_artwork($artist, $title);
        if ($res !== null) return $res;
        // Nothing on dumb — fall through to the official API below.
    }

    $token = cfg('genius.token');
    if ($token === '') return null;
    $headers = ['Authorization: Bearer ' . $token];

    $query  = rawurlencode(trim($artist . ' - ' . strip_feature_credit($title), ' -'));
    $search = http_get('https://api.genius.com/search?q=' . $query, 5, $headers);
    if ($search === null) return null;

    $hits = dot_get(json_decode($search, true), 'response.hits', []);
    if (!is_array($hits) || count($hits) === 0) return null;

    // Same artist-attribution scan as api/lyrics.php — skip translation-page
    // hits filed under a pseudo-artist account, falling back to the raw top
    // hit if nothing in the first 5 matches.
    $hit = null;
    $checked = 0;
    foreach ($hits as $h) {
        if ($checked++ >= 5) break;
        $r = dot_get($h, 'result', null);
        if ($r && artist_loosely_matches((string) ($r['artist_names'] ?? ''), $artist)) { $hit = $r; break; }
    }
    if ($hit === null) $hit = dot_get($hits, '0.result', null);
    if (!$hit) return null;

    $out = [
        'art'   => (string) ($hit['song_art_image_url'] ?? $hit['header_image_url'] ?? ''),
        'album' => '',
        'url'   => (string) ($hit['url'] ?? ''),
    ];
    if (!empty($hit['id'])) {
        $songRaw = http_get('https://api.genius.com/songs/' . rawurlencode((string) $hit['id']), 5, $headers);
        if ($songRaw !== null) {
            $s = dot_get(json_decode($songRaw, true), 'response.song', null);
            if ($s) {
                $out['album'] = (string) dot_get($s, 'album.name', '');
                $better = (string) ($s['song_art_image_url'] ?? $s['header_image_url'] ?? '');
                if ($better !== '') $out['art'] = $better;
            }
        }
    }
    // Genius' generic default cover counts as "no art".
    if (strpos($out['art'], 'default_cover_image') !== false) $out['art'] = '';
    return ($out['art'] === '' && $out['album'] === '') ? null : $out;
}

/* -- Last.fm -------------------------------------------------------------- */
function lastfm_artwork($artist, $title) {
    $key = cfg('artwork.lastfm_key');
    if ($key === '' || $artist === '') return null;

    $url = 'https://ws.audioscrobbler.com/2.0/?method=track.getInfo&format=json&autocorrect=1'
         . '&api_key=' . rawurlencode($key)
         . '&artist=' . rawurlencode($artist)
         . '&track='  . rawurlencode($title);
    $raw = http_get($url, 5);
    if ($raw === null) return null;

    $data = json_decode($raw, true);
    $images = dot_get($data, 'track.album.image', []);
    $art = '';
    if (is_array($images)) {
        foreach ($images as $img) {                 // last non-empty = largest
            if (!empty($img['#text'])) $art = $img['#text'];
        }
    }
    if ($art === '') return null;
    return ['art' => $art, 'album' => (string) dot_get($data, 'track.album.title', ''), 'url' => ''];
}

/* -- Try providers in the configured order -------------------------------- */
$order = $source === 'lastfm' ? ['lastfm']
       : ($source === 'genius' ? ['genius'] : ['genius', 'lastfm']);

$art = ''; $album = ''; $url = '';
foreach ($order as $provider) {
    $res = ($provider === 'genius') ? genius_artwork($artist, $title) : lastfm_artwork($artist, $title);
    if ($res === null) continue;
    if ($album === '' && $res['album'] !== '') $album = $res['album'];
    if ($res['art'] !== '') { $art = $res['art']; $url = $res['url']; break; }
}

// Album-level overrides: now that the album is known, swap the art if a rule
// targets this album (e.g. a special animated cover for one album only). This
// replaces whatever the provider returned, but only for the matching album.
foreach ($overrides as $rule) {
    if (!empty($rule['art']) && isset($rule['album'])
        && override_matches($rule, $artist, $title, $album)) {
        $art = $rule['art'];
        break;
    }
}

json_out(['art' => $art, 'album' => $album, 'url' => $url]);