1 files changed, 64 insertions, 0 deletions
diff --git a/src/features/chat/model-select.ts b/src/features/chat/model-select.ts
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+++ b/src/features/chat/model-select.ts
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+import type { ModelMetadata } from "@dispatch/transport-contract";
+
+/**
+ * Pure helpers for the two-step model picker.
+ *
+ * Models arrive from `GET /models` as `<key>/<model>` strings, where `key` is
+ * the credential name (the part before the FIRST slash) and `model` is the rest.
+ * These pure functions split that into a key selector + a model selector and
+ * recombine the choice — zero DOM, zero Svelte.
+ */
+
+export interface SplitModel {
+  readonly key: string;
+  readonly model: string;
+}
+
+/** Split `<key>/<model>` on the first slash. A slashless name is all-key. */
+export function splitModelName(full: string): SplitModel {
+  const i = full.indexOf("/");
+  if (i === -1) return { key: full, model: "" };
+  return { key: full.slice(0, i), model: full.slice(i + 1) };
+}
+
+/** Recombine a key + model into a `<key>/<model>` name (key-only if no model). */
+export function joinModelName(key: string, model: string): string {
+  return model === "" ? key : `${key}/${model}`;
+}
+
+/** Distinct keys across all models, in first-seen order. */
+export function modelKeys(models: readonly string[]): string[] {
+  const seen = new Set<string>();
+  const out: string[] = [];
+  for (const full of models) {
+    const { key } = splitModelName(full);
+    if (!seen.has(key)) {
+      seen.add(key);
+      out.push(key);
+    }
+  }
+  return out;
+}
+
+/** The model suffixes available under a given key, in order. */
+export function modelsForKey(models: readonly string[], key: string): string[] {
+  const out: string[] = [];
+  for (const full of models) {
+    const split = splitModelName(full);
+    if (split.key === key) out.push(split.model);
+  }
+  return out;
+}
+
+/**
+ * Whether a given full model name (`<key>/<model>`) is vision-capable — i.e.
+ * `GET /models` `modelInfo[name].vision === true`. Absent/`false`/unknown →
+ * `false` (the server's vision handoff transcribes images to text for it).
+ * Pure lookup against the catalog metadata; zero DOM.
+ */
+export function isVisionModel(
+  modelInfo: Readonly<Record<string, ModelMetadata>>,
+  fullName: string,
+): boolean {
+  return modelInfo[fullName]?.vision === true;
+}