shitton of the ai changes

src/ai/user-request-pipeline/fallback-executor.ts

@@ -0,0 +1,61 @@
+import type {
+    PipelineFallbackAction,
+    PipelineFallbackPolicy,
+    PipelineStageName,
+    PipelineStageStatus,
+} from "./types.js";
+
+export type PipelineFallbackReason = "unavailable" | "failed";
+
+export type PipelineFallbackDecision = {
+    stage: PipelineStageName;
+    reason: PipelineFallbackReason;
+    action: PipelineFallbackAction;
+    shouldContinue: boolean;
+    shouldNotifyUser: boolean;
+    shouldFailRequest: boolean;
+};
+
+const DEFAULT_ACTION_BY_REASON: Record<PipelineFallbackReason, PipelineFallbackAction> = {
+    unavailable: "continue_without_stage",
+    failed: "fail_request",
+};
+
+export function resolvePipelineFallbackAction(params: {
+    stage: PipelineStageName;
+    reason: PipelineFallbackReason;
+    policies: readonly PipelineFallbackPolicy[];
+}): PipelineFallbackAction {
+    const policy = params.policies.find(item => item.stage === params.stage);
+    if (!policy) return DEFAULT_ACTION_BY_REASON[params.reason];
+
+    return params.reason === "unavailable"
+        ? policy.onUnavailable
+        : policy.onFailed;
+}
+
+export function decidePipelineFallback(params: {
+    stage: PipelineStageName;
+    reason: PipelineFallbackReason;
+    policies: readonly PipelineFallbackPolicy[];
+}): PipelineFallbackDecision {
+    const action = resolvePipelineFallbackAction(params);
+
+    return {
+        stage: params.stage,
+        reason: params.reason,
+        action,
+        shouldContinue: action === "ignore"
+            || action === "continue_without_stage"
+            || action === "notify_user"
+            || action === "use_alternate_target",
+        shouldNotifyUser: action === "notify_user",
+        shouldFailRequest: action === "fail_request",
+    };
+}
+
+export function fallbackReasonFromStageStatus(status: PipelineStageStatus): PipelineFallbackReason | undefined {
+    if (status === "skipped") return "unavailable";
+    if (status === "failed") return "failed";
+    return undefined;
+}