feat: add embed resolver with async resolution and batch fetching

packages/server/src/utils/embedResolver.ts

@@ -0,0 +1,217 @@
+import { eq, inArray } from 'drizzle-orm';
+import type { Embed } from '@backspace/shared';
+import { getDb, schema } from '../db/index.js';
+import { generateSnowflake } from './snowflake.js';
+import { classifyUrl } from './embedClassifier.js';
+import { fetchUrlMetadata } from './metadataFetcher.js';
+import { connectionManager } from '../ws/handler.js';
+
+const MAX_EMBEDS_PER_MESSAGE = 5;
+
+// ─── URL Extraction ────────────────────────────────────────────────────────
+
+export function extractUrls(content: string | null): string[] {
+  if (!content) return [];
+
+  const matches = content.match(/https?:\/\/[^\s<>"{}|\\^`[\]]+/g);
+  if (!matches) return [];
+
+  // Deduplicate while preserving order
+  const seen = new Set<string>();
+  const unique: string[] = [];
+  for (const url of matches) {
+    if (!seen.has(url)) {
+      seen.add(url);
+      unique.push(url);
+    }
+  }
+
+  return unique.slice(0, MAX_EMBEDS_PER_MESSAGE);
+}
+
+// ─── Row → Embed Conversion ────────────────────────────────────────────────
+
+export function embedRowToEmbed(row: typeof schema.embeds.$inferSelect): Embed {
+  return {
+    id: row.id,
+    messageId: row.messageId,
+    dmMessageId: row.dmMessageId,
+    url: row.url,
+    embedType: row.embedType as Embed['embedType'],
+    provider: (row.provider ?? null) as Embed['provider'],
+    title: row.title ?? null,
+    description: row.description ?? null,
+    image: row.image ?? null,
+    embedUrl: row.embedUrl ?? null,
+    width: row.width ?? null,
+    height: row.height ?? null,
+    color: row.color ?? null,
+    createdAt: row.createdAt,
+  };
+}
+
+// ─── Embed Resolution ─────────────────────────────────────────────────────
+
+export async function resolveEmbeds(
+  messageId: string,
+  content: string | null,
+  channelId: string,
+  isDm: boolean,
+  spaceId: string | null,
+): Promise<void> {
+  const urls = extractUrls(content);
+  if (urls.length === 0) return;
+
+  const db = getDb();
+  const now = Date.now();
+  const resolvedEmbeds: Embed[] = [];
+
+  for (const url of urls) {
+    try {
+      const classification = classifyUrl(url);
+
+      let title: string | null = null;
+      let description: string | null = null;
+      let image: string | null = null;
+      let siteName: string | null = null;
+
+      if (classification.embedType === 'image') {
+        // Direct image URL — no fetch needed, use the URL as the image source
+        image = url;
+      } else if (classification.needsMetadataFetch) {
+        const metadata = await fetchUrlMetadata(url);
+        if (metadata) {
+          title = metadata.title;
+          description = metadata.description;
+          image = metadata.image;
+          siteName = metadata.siteName;
+        }
+
+        // For generic embeds, skip if we couldn't extract a title
+        if (classification.embedType === 'generic' && !title) {
+          continue;
+        }
+      }
+
+      const embedId = generateSnowflake();
+      const row: typeof schema.embeds.$inferInsert = {
+        id: embedId,
+        messageId: isDm ? null : messageId,
+        dmMessageId: isDm ? messageId : null,
+        url,
+        embedType: classification.embedType,
+        provider: classification.provider,
+        title,
+        description,
+        image,
+        embedUrl: classification.embedUrl,
+        width: null,
+        height: null,
+        color: null,
+        createdAt: now,
+      };
+
+      db.insert(schema.embeds).values(row).run();
+
+      resolvedEmbeds.push(embedRowToEmbed(row as typeof schema.embeds.$inferSelect));
+    } catch {
+      // One URL failure must not block the rest
+      continue;
+    }
+  }
+
+  if (resolvedEmbeds.length === 0) return;
+
+  if (isDm) {
+    connectionManager.sendToDmMembers(channelId, {
+      type: 'dm_embeds_resolved',
+      messageId,
+      dmChannelId: channelId,
+      embeds: resolvedEmbeds,
+    });
+  } else {
+    if (!spaceId) return;
+    connectionManager.sendToChannel(spaceId, channelId, {
+      type: 'embeds_resolved',
+      messageId,
+      channelId,
+      embeds: resolvedEmbeds,
+    });
+  }
+}
+
+// ─── Re-resolution (on message edit) ──────────────────────────────────────
+
+export async function reResolveEmbeds(
+  messageId: string,
+  content: string | null,
+  channelId: string,
+  isDm: boolean,
+  spaceId: string | null,
+): Promise<void> {
+  const db = getDb();
+
+  if (isDm) {
+    db.delete(schema.embeds)
+      .where(eq(schema.embeds.dmMessageId, messageId))
+      .run();
+  } else {
+    db.delete(schema.embeds)
+      .where(eq(schema.embeds.messageId, messageId))
+      .run();
+  }
+
+  await resolveEmbeds(messageId, content, channelId, isDm, spaceId);
+}
+
+// ─── Batch Fetching ────────────────────────────────────────────────────────
+
+export function fetchEmbedsForMessages(
+  messageIds: string[],
+): Map<string, (typeof schema.embeds.$inferSelect)[]> {
+  const result = new Map<string, (typeof schema.embeds.$inferSelect)[]>();
+  if (messageIds.length === 0) return result;
+
+  const db = getDb();
+  const rows = db.select()
+    .from(schema.embeds)
+    .where(inArray(schema.embeds.messageId, messageIds))
+    .all();
+
+  for (const row of rows) {
+    if (!row.messageId) continue;
+    const existing = result.get(row.messageId);
+    if (existing) {
+      existing.push(row);
+    } else {
+      result.set(row.messageId, [row]);
+    }
+  }
+
+  return result;
+}
+
+export function fetchDmEmbedsForMessages(
+  dmMessageIds: string[],
+): Map<string, (typeof schema.embeds.$inferSelect)[]> {
+  const result = new Map<string, (typeof schema.embeds.$inferSelect)[]>();
+  if (dmMessageIds.length === 0) return result;
+
+  const db = getDb();
+  const rows = db.select()
+    .from(schema.embeds)
+    .where(inArray(schema.embeds.dmMessageId, dmMessageIds))
+    .all();
+
+  for (const row of rows) {
+    if (!row.dmMessageId) continue;
+    const existing = result.get(row.dmMessageId);
+    if (existing) {
+      existing.push(row);
+    } else {
+      result.set(row.dmMessageId, [row]);
+    }
+  }
+
+  return result;
+}