feat(epg): order EPG sources by priority (#24)

Add persistent EPG priority ordering, source reorder validation, and priority-aware EPG matching for live channels.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

server/services/epgMatchingService.js

@@ -0,0 +1,61 @@
+const { numericPriority, sortEpgSources } = require('./epgSourceOrdering');
+
+function normalize(value) {
+    return String(value || '').normalize('NFKD').replace(/[\u0300-\u036f]/g, '')
+        .toLowerCase().replace(/[^a-z0-9]+/g, ' ').trim();
+}
+
+function candidateScore(channel, epgChannel) {
+    const variantIds = new Set((channel.variants || []).flatMap(variant => [variant.tvgId, variant.epg_channel_id]).filter(Boolean).map(String));
+    if (variantIds.has(String(epgChannel.id))) return 100;
+    const wantedNames = new Set([channel.standardName, channel.displayName, ...(channel.variants || []).map(variant => variant.name)].map(normalize).filter(Boolean));
+    const candidateName = normalize(epgChannel.name);
+    if (wantedNames.has(candidateName)) return 90;
+    if (candidateName && [...wantedNames].some(name => name.includes(candidateName) || candidateName.includes(name))) return 50;
+    return 0;
+}
+
+function chooseBestMatch(channel, candidates, epgSources) {
+    const language = channel.language?.code;
+    const eligible = sortEpgSources(epgSources, { enabledOnly: true }).filter(source =>
+        !source.language || !language || language === 'und' || source.language === language
+    );
+    const priorities = new Map(eligible.map(source => [source.id, numericPriority(source)]));
+    return candidates
+        .filter(candidate => priorities.has(candidate.sourceId))
+        .map(candidate => ({ ...candidate, matchConfidence: candidateScore(channel, candidate) }))
+        .filter(candidate => candidate.matchConfidence > 0)
+        .sort((left, right) => right.matchConfidence - left.matchConfidence ||
+            priorities.get(left.sourceId) - priorities.get(right.sourceId) || left.sourceId - right.sourceId)[0] || null;
+}
+
+function findBestMatch(database, channel, epgSources, now = Date.now()) {
+    const language = channel.language?.code;
+    const enabled = sortEpgSources(epgSources, { enabledOnly: true }).filter(source =>
+        !source.language || !language || language === 'und' || source.language === language
+    );
+    if (!enabled.length) return null;
+    const ids = enabled.map(source => source.id);
+    const placeholders = ids.map(() => '?').join(',');
+    const epgChannels = database.prepare(`
+        SELECT source_id AS sourceId, item_id AS id, name
+        FROM playlist_items
+        WHERE type = 'epg_channel' AND source_id IN (${placeholders})
+    `).all(...ids);
+    const best = chooseBestMatch(channel, epgChannels, enabled);
+    if (!best) return null;
+    const current = database.prepare(`
+        SELECT title, description, start_time AS startTime, end_time AS endTime
+        FROM epg_programs
+        WHERE source_id = ? AND channel_id = ? AND start_time <= ? AND end_time > ?
+        ORDER BY start_time DESC LIMIT 1
+    `).get(best.sourceId, best.id, now, now);
+    return {
+        sourceId: best.sourceId,
+        channelId: best.id,
+        matchConfidence: best.matchConfidence,
+        currentProgram: current || undefined
+    };
+}
+
+module.exports = { candidateScore, chooseBestMatch, findBestMatch, normalize };