feat: multi-provider support — Anthropic + Ollama (P2-002) (#74)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

apps/gateway/src/agent/agent.service.ts

@@ -5,9 +5,17 @@ import {
   type AgentSession as PiAgentSession,
   type AgentSessionEvent,
 } from '@mariozechner/pi-coding-agent';
+import { ProviderService } from './provider.service.js';
+
+export interface AgentSessionOptions {
+  provider?: string;
+  modelId?: string;
+}
 
 export interface AgentSession {
   id: string;
+  provider: string;
+  modelId: string;
   piSession: PiAgentSession;
   listeners: Set<(event: AgentSessionEvent) => void>;
   unsubscribe: () => void;
@@ -19,33 +27,46 @@ export class AgentService implements OnModuleDestroy {
   private readonly sessions = new Map<string, AgentSession>();
   private readonly creating = new Map<string, Promise<AgentSession>>();
 
-  async createSession(sessionId: string): Promise<AgentSession> {
+  constructor(private readonly providerService: ProviderService) {}
+
+  async createSession(sessionId: string, options?: AgentSessionOptions): Promise<AgentSession> {
     const existing = this.sessions.get(sessionId);
     if (existing) return existing;
 
     const inflight = this.creating.get(sessionId);
     if (inflight) return inflight;
 
-    const promise = this.doCreateSession(sessionId).finally(() => {
+    const promise = this.doCreateSession(sessionId, options).finally(() => {
       this.creating.delete(sessionId);
     });
     this.creating.set(sessionId, promise);
     return promise;
   }
 
-  private async doCreateSession(sessionId: string): Promise<AgentSession> {
-    this.logger.log(`Creating agent session: ${sessionId}`);
+  private async doCreateSession(
+    sessionId: string,
+    options?: AgentSessionOptions,
+  ): Promise<AgentSession> {
+    const model = this.resolveModel(options);
+    const providerName = model?.provider ?? 'default';
+    const modelId = model?.id ?? 'default';
+
+    this.logger.log(
+      `Creating agent session: ${sessionId} (provider=${providerName}, model=${modelId})`,
+    );
 
     let piSession: PiAgentSession;
     try {
       const result = await createAgentSession({
         sessionManager: SessionManager.inMemory(),
+        modelRegistry: this.providerService.getRegistry(),
+        model: model ?? undefined,
         tools: [],
       });
       piSession = result.session;
     } catch (err) {
       this.logger.error(
-        `Failed to create Pi SDK session for ${sessionId}`,
+        `Failed to create agent session for ${sessionId}`,
         err instanceof Error ? err.stack : String(err),
       );
       throw new Error(`Agent session creation failed for ${sessionId}: ${String(err)}`);
@@ -65,17 +86,43 @@ export class AgentService implements OnModuleDestroy {
 
     const session: AgentSession = {
       id: sessionId,
+      provider: providerName,
+      modelId,
       piSession,
       listeners,
       unsubscribe,
     };
 
     this.sessions.set(sessionId, session);
-    this.logger.log(`Agent session ${sessionId} ready`);
+    this.logger.log(`Agent session ${sessionId} ready (${providerName}/${modelId})`);
 
     return session;
   }
 
+  private resolveModel(options?: AgentSessionOptions) {
+    if (!options?.provider && !options?.modelId) {
+      return this.providerService.getDefaultModel() ?? null;
+    }
+
+    if (options.provider && options.modelId) {
+      const model = this.providerService.findModel(options.provider, options.modelId);
+      if (!model) {
+        throw new Error(`Model not found: ${options.provider}/${options.modelId}`);
+      }
+      return model;
+    }
+
+    if (options.modelId) {
+      const available = this.providerService.listAvailableModels();
+      const match = available.find((m) => m.id === options.modelId);
+      if (match) {
+        return this.providerService.findModel(match.provider, match.id) ?? null;
+      }
+    }
+
+    return this.providerService.getDefaultModel() ?? null;
+  }
+
   getSession(sessionId: string): AgentSession | undefined {
     return this.sessions.get(sessionId);
   }
@@ -89,7 +136,7 @@ export class AgentService implements OnModuleDestroy {
       await session.piSession.prompt(message);
     } catch (err) {
       this.logger.error(
-        `Pi SDK prompt failed for session=${sessionId}, messageLength=${message.length}`,
+        `Prompt failed for session=${sessionId}, messageLength=${message.length}`,
         err instanceof Error ? err.stack : String(err),
       );
       throw err;
@@ -112,7 +159,7 @@ export class AgentService implements OnModuleDestroy {
     try {
       session.unsubscribe();
     } catch (err) {
-      this.logger.error(`Failed to unsubscribe Pi session ${sessionId}`, String(err));
+      this.logger.error(`Failed to unsubscribe session ${sessionId}`, String(err));
     }
     session.listeners.clear();
     this.sessions.delete(sessionId);