fix(ai): 保留拆解生成结果

apps/web/lib/ai-decompose-session.ts

@@ -0,0 +1,92 @@
+import type { AgentDecomposeResponse, AgentDecomposeTarget } from '@ftb/shared';
+
+export interface AiDecomposeCompletedPayload {
+  result: AgentDecomposeResponse;
+  dedupeSummary: { removedDevTaskCount: number; removedTestCaseCount: number };
+}
+
+export type AiDecomposeButtonMode = 'generate' | 'generating' | 'view_result' | 'retry';
+
+export type AiDecomposeSessionState =
+  | { status: 'idle' }
+  | { status: 'generating'; startedAt: number; promise: Promise<AiDecomposeCompletedPayload> }
+  | { status: 'completed'; completedAt: number; payload: AiDecomposeCompletedPayload }
+  | { status: 'error'; failedAt: number; error: string };
+
+type Listener = () => void;
+
+export interface AiDecomposeSessionStore {
+  get: (planId: string, target: AgentDecomposeTarget) => AiDecomposeSessionState;
+  start: (
+    planId: string,
+    target: AgentDecomposeTarget,
+    run: () => Promise<AiDecomposeCompletedPayload>,
+  ) => Promise<AiDecomposeCompletedPayload>;
+  markReviewed: (planId: string, target: AgentDecomposeTarget) => void;
+  subscribe: (listener: Listener) => () => void;
+}
+
+function getSessionKey(planId: string, target: AgentDecomposeTarget): string {
+  return `${planId}::${target}`;
+}
+
+function normalizeError(error: unknown): string {
+  return error instanceof Error ? error.message : String(error || 'AI 生成失败');
+}
+
+export function createAiDecomposeSessionStore(): AiDecomposeSessionStore {
+  const sessions = new Map<string, AiDecomposeSessionState>();
+  const listeners = new Set<Listener>();
+
+  const notify = () => {
+    for (const listener of listeners) listener();
+  };
+
+  return {
+    get(planId, target) {
+      return sessions.get(getSessionKey(planId, target)) ?? { status: 'idle' };
+    },
+
+    start(planId, target, run) {
+      const key = getSessionKey(planId, target);
+      const existing = sessions.get(key);
+      if (existing?.status === 'generating') return existing.promise;
+
+      const promise = run().then(
+        (payload) => {
+          sessions.set(key, { status: 'completed', completedAt: Date.now(), payload });
+          notify();
+          return payload;
+        },
+        (error) => {
+          sessions.set(key, { status: 'error', failedAt: Date.now(), error: normalizeError(error) });
+          notify();
+          throw error;
+        },
+      );
+
+      sessions.set(key, { status: 'generating', startedAt: Date.now(), promise });
+      notify();
+      return promise;
+    },
+
+    markReviewed(planId, target) {
+      sessions.delete(getSessionKey(planId, target));
+      notify();
+    },
+
+    subscribe(listener) {
+      listeners.add(listener);
+      return () => listeners.delete(listener);
+    },
+  };
+}
+
+export function getAiDecomposeButtonMode(session: AiDecomposeSessionState): AiDecomposeButtonMode {
+  if (session.status === 'generating') return 'generating';
+  if (session.status === 'completed') return 'view_result';
+  if (session.status === 'error') return 'retry';
+  return 'generate';
+}
+
+export const aiDecomposeSessionStore = createAiDecomposeSessionStore();