feat: implement EmbeddingProvider

src/openrouter/embedding.ts

@@ -0,0 +1,57 @@
+import { config } from "@/config";
+import { OpenRouter } from "@openrouter/sdk";
+import type { EmbeddingProvider } from "identitydb";
+
+export const QWEN_EMBEDDING_MODEL = "qwen/qwen3-embedding-8b" as const;
+export const QWEN_EMBEDDING_DIMENSIONS = 512 as const;
+
+export class OpenRouterEmbeddingProvider implements EmbeddingProvider {
+  readonly model: string = QWEN_EMBEDDING_MODEL;
+  readonly dimensions: number = QWEN_EMBEDDING_DIMENSIONS;
+
+  private client: OpenRouter;
+
+  constructor(apiKey: string = config.openrouterApiKey) {
+    this.client = new OpenRouter({ apiKey, appTitle: "boxbrain" });
+  }
+
+  async embed(input: string): Promise<number[]> {
+    const result = await this.embedBatch([input]);
+    return result[0]!;
+  }
+
+  async embedMany(inputs: string[]): Promise<number[][]> {
+    if (inputs.length === 0) return [];
+    return await this.embedBatch(inputs);
+  }
+
+  private async embedBatch(inputs: string[]): Promise<number[][]> {
+    const response = await this.client.embeddings.generate({
+      requestBody: {
+        model: this.model,
+        input: inputs,
+        dimensions: this.dimensions,
+        encodingFormat: "float",
+      },
+    });
+    if (typeof response === "string") {
+      throw new Error("OpenRouter returned a non-JSON embeddings response");
+    }
+    const ordered = new Array<number[]>(inputs.length);
+    for (const item of response.data) {
+      if (typeof item.embedding === "string") {
+        throw new Error(
+          "OpenRouter returned a base64 embedding but float was requested",
+        );
+      }
+      const index = item.index ?? 0;
+      ordered[index] = item.embedding;
+    }
+    for (let i = 0; i < ordered.length; i += 1) {
+      if (!ordered[i]) {
+        throw new Error(`OpenRouter omitted embedding for input index ${i}`);
+      }
+    }
+    return ordered;
+  }
+}