feat: Ollama models command, with load/pull/delete and unload (#16)

src/lib/hooks/useChat.ts

@@ -3,11 +3,12 @@ import { runAgent } from "../agent";
 import { toStoredAttachment } from "../attachments";
 import { ipPlace } from "../geo";
 import { buildMessages, composeSystemPrompt } from "../history";
+import { isSelfHosted } from "../ollama";
 import { OllamaError } from "../ollama";
 import type { ResolvedPreferences } from "../preferences";
 import { createSession, createTurn, saveSession, withTitleFromFirstTurn } from "../sessions";
 import { toolsFor } from "../tools";
-import type { PendingAttachment, Session } from "../types";
+import type { PendingAttachment, Session, VisionSupport } from "../types";
 import { errorMessage, isAbortError } from "../utils";
 
 /**
@@ -33,6 +34,14 @@ export interface UseChatOptions {
   preferences: ResolvedPreferences;
   /** Restores an existing conversation, e.g. when reopening from the sessions command. */
   initialSession?: Session;
+  /**
+   * Whether the model can read images, for the system prompt.
+   *
+   * Passed in rather than checked here because the answer is already known to the
+   * view: the snip action is gated on the same value, and asking twice would mean
+   * two capability requests per model change.
+   */
+  vision?: VisionSupport;
 }
 
 /** Which tool is running right now, and how stale it is getting. */
@@ -85,6 +94,11 @@ export function useChat(options: UseChatOptions): UseChat {
 
   const sessionRef = useRef(session);
   const preferencesRef = useRef(options.preferences);
+  /**
+   * Read through a ref for the same reason as the preferences: `ask` is a stable
+   * callback, and the capability check lands after the first render.
+   */
+  const visionRef = useRef<VisionSupport>(options.vision ?? "unknown");
   const abortRef = useRef<AbortController | null>(null);
   const liveRef = useRef(false);
   const responseRef = useRef("");
@@ -93,6 +107,9 @@ export function useChat(options: UseChatOptions): UseChat {
   const flushTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
 
   preferencesRef.current = options.preferences;
+  // Only ever forwards. The check starts as "unknown", and a value arriving is
+  // news; going back to "unknown" would be the view telling us less than before.
+  if (options.vision) visionRef.current = options.vision;
 
   /** Updates state and the ref together, so `ask` never reads a stale session. */
   const commit = useCallback((next: Session) => {
@@ -181,7 +198,13 @@ export function useChat(options: UseChatOptions): UseChat {
       abortRef.current = controller;
 
       const messages = buildMessages(
-        composeSystemPrompt(preferences.systemPrompt, preferences.webEnabled),
+        composeSystemPrompt(preferences.systemPrompt, {
+          model: preferences.model,
+          host: preferences.host,
+          selfHosted: isSelfHosted(preferences.host),
+          webTools: preferences.webEnabled,
+          vision: visionRef.current,
+        }),
         base.turns,
         prompt,
         attachment ? [attachment.base64] : undefined,