fix(source-control): preserve Pi configured default intent

src/shared/commit-message-plan-model.ts

@@ -0,0 +1,40 @@
+import {
+  getCommitMessageModel,
+  PI_DEFAULT_MODEL_ID,
+  PI_RETIRED_COPILOT_DEFAULT_MODEL_ID,
+  type CommitMessageModel
+} from './commit-message-agent-spec'
+import type { TuiAgent } from './tui-agent'
+
+type CommitMessagePlanModelInput = {
+  agentId: TuiAgent | 'custom'
+  model: string
+  thinkingLevel?: string
+  useConfiguredDefaultModel?: boolean
+}
+
+type CommitMessagePlanModelResult =
+  | { ok: true; model: CommitMessageModel; modelId: string }
+  | { ok: false; error: string }
+
+export function resolveCommitMessagePlanModel(
+  input: CommitMessagePlanModelInput,
+  agentLabel: string
+): CommitMessagePlanModelResult {
+  if (
+    input.useConfiguredDefaultModel &&
+    (input.agentId !== 'pi' ||
+      input.model !== PI_RETIRED_COPILOT_DEFAULT_MODEL_ID ||
+      input.thinkingLevel !== undefined)
+  ) {
+    return { ok: false, error: 'Configured-default model intent is invalid for this request.' }
+  }
+  const modelId = input.useConfiguredDefaultModel ? PI_DEFAULT_MODEL_ID : input.model
+  if (input.agentId === 'custom') {
+    return { ok: false, error: `Model "${input.model}" is not available for ${agentLabel}.` }
+  }
+  const model = getCommitMessageModel(input.agentId, modelId)
+  return model
+    ? { ok: true, model, modelId }
+    : { ok: false, error: `Model "${input.model}" is not available for ${agentLabel}.` }
+}