feat(gemini): support mid-session model change (#379)

web/src/components/AssistantChat/modelOptions.ts

@@ -0,0 +1,40 @@
+import { MODEL_OPTIONS } from '@/components/NewSession/types'
+import { getClaudeComposerModelOptions, getNextClaudeComposerModel } from './claudeModelOptions'
+import type { ClaudeComposerModelOption } from './claudeModelOptions'
+
+export type ModelOption = ClaudeComposerModelOption
+
+function getGeminiModelOptions(currentModel?: string | null): ModelOption[] {
+    const options = MODEL_OPTIONS.gemini.map((m) => ({
+        value: m.value === 'auto' ? null : m.value,
+        label: m.label
+    }))
+    const normalized = currentModel?.trim() || null
+    if (normalized && !options.some((o) => o.value === normalized)) {
+        options.splice(1, 0, { value: normalized, label: normalized })
+    }
+    return options
+}
+
+function getNextGeminiModel(currentModel?: string | null): string | null {
+    const options = getGeminiModelOptions(currentModel)
+    const currentIndex = options.findIndex((o) => o.value === (currentModel ?? null))
+    if (currentIndex === -1) {
+        return options[0]?.value ?? null
+    }
+    return options[(currentIndex + 1) % options.length]?.value ?? null
+}
+
+export function getModelOptionsForFlavor(flavor: string | undefined | null, currentModel?: string | null): ModelOption[] {
+    if (flavor === 'gemini') {
+        return getGeminiModelOptions(currentModel)
+    }
+    return getClaudeComposerModelOptions(currentModel)
+}
+
+export function getNextModelForFlavor(flavor: string | undefined | null, currentModel?: string | null): string | null {
+    if (flavor === 'gemini') {
+        return getNextGeminiModel(currentModel)
+    }
+    return getNextClaudeComposerModel(currentModel)
+}