fix(canvas): Agent 会话 - 刷新后恢复后台任务结果

web/src/lib/canvas/canvas-agent-session.ts

@@ -0,0 +1,73 @@
+import {
+    agentSessionFailureMessage,
+    createAgentSession,
+    queryAgentSession,
+    type AgentSessionDetail,
+    type CreateSessionInput,
+} from "@/services/api/task-center";
+
+const CINEMATIC_SESSION_POLL_INTERVAL_MS = 2000;
+const CINEMATIC_SESSION_MAX_POLLS = 120;
+
+type CinematicSessionWaitOptions = {
+    signal?: AbortSignal;
+};
+
+type CreateCinematicSessionOptions = CinematicSessionWaitOptions & {
+    onCreated?: (detail: AgentSessionDetail) => void;
+};
+
+export async function createCinematicAgentSession(input: CreateSessionInput, options: CreateCinematicSessionOptions = {}) {
+    const created = await createAgentSession(input);
+    throwIfAborted(options.signal);
+    options.onCreated?.(created);
+    return waitForCinematicAgentSession(created, options);
+}
+
+export async function resumeCinematicAgentSession(id: string, options: CinematicSessionWaitOptions = {}) {
+    throwIfAborted(options.signal);
+    const detail = await queryAgentSession(id);
+    return waitForCinematicAgentSession(detail, options);
+}
+
+export function cinematicAgentSessionOpsJson(detail: AgentSessionDetail) {
+    if (detail.session.status !== "completed") throw new Error("后端影视 Agent 会话尚未完成");
+    if (!detail.session.canvasOpsJson) throw new Error("后端影视 Agent 没有返回画布操作");
+    return detail.session.canvasOpsJson;
+}
+
+export function isAgentSessionPollingAbort(error: unknown) {
+    return error instanceof Error && error.name === "AbortError";
+}
+
+async function waitForCinematicAgentSession(initialDetail: AgentSessionDetail, options: CinematicSessionWaitOptions) {
+    let detail = initialDetail;
+    for (let attempt = 0; attempt < CINEMATIC_SESSION_MAX_POLLS; attempt += 1) {
+        throwIfAborted(options.signal);
+        if (detail.session.status === "completed") return detail;
+        if (detail.session.status === "failed") throw new Error(agentSessionFailureMessage(detail));
+        await abortableDelay(CINEMATIC_SESSION_POLL_INTERVAL_MS, options.signal);
+        detail = await queryAgentSession(initialDetail.session.id);
+    }
+    throw new Error("后端影视 Agent 会话超时");
+}
+
+function abortableDelay(ms: number, signal?: AbortSignal) {
+    return new Promise<void>((resolve, reject) => {
+        throwIfAborted(signal);
+        const finish = () => {
+            signal?.removeEventListener("abort", abort);
+            resolve();
+        };
+        const abort = () => {
+            window.clearTimeout(timer);
+            reject(new DOMException("Aborted", "AbortError"));
+        };
+        const timer = window.setTimeout(finish, ms);
+        signal?.addEventListener("abort", abort, { once: true });
+    });
+}
+
+function throwIfAborted(signal?: AbortSignal) {
+    if (signal?.aborted) throw new DOMException("Aborted", "AbortError");
+}