import type { CanvasCapabilityClientCommand } from "@/lib/canvas/capabilities/client-command";
import { mergeCanvasSnapshots } from "@/lib/video-canvas/merge-snapshot";
import { useCanvasStore } from "@/store/canvas";
import { formatRequestFailure, getRequestFailureDetails } from "@/lib/request-error";

async function requestCapabilityResult(command: CanvasCapabilityClientCommand) {
  const endpoint = `/api/canvas/${command.projectId}/capabilities`;
  let payload: any = null;
  try {
    const response = await fetch(endpoint, {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify(command),
    });
    payload = await response.json().catch(() => null);
    if (payload?.success === false || (!response.ok && ![502, 503, 504, 524].includes(response.status))) {
      throw Object.assign(new Error(payload?.error || "图片处理请求未通过"), { confirmedRejection: true });
    }
    if (!response.ok) payload = null;
  } catch (error) {
    if ((error as { confirmedRejection?: boolean })?.confirmedRejection) throw error;
  }
  const deadline = Date.now() + 20 * 60 * 1000;
  while (Date.now() < deadline) {
    const task = payload?.task;
    if (task?.status === "succeeded") return payload;
    if (task?.status === "failed") throw new Error(task.error || "图片处理失败，请联系管理员核对任务结果");
    await new Promise(resolve => setTimeout(resolve, 1500));
    try {
      const response = await fetch(`${endpoint}?requestId=${encodeURIComponent(command.requestId)}`, { cache: "no-store", signal: AbortSignal.timeout(12_000) });
      payload = response.ok ? await response.json() : null;
    } catch {
      payload = null;
    }
  }
  throw new Error(formatRequestFailure(getRequestFailureDetails({ providerOutcomeUnknown: true }), command.requestId));
}

/** Runs after the editor has saved and while its save queue is reserved. */
export async function executeCanvasToolbarCapability(
  command: CanvasCapabilityClientCommand,
) {
  const projectId = command.projectId!;
  const before = useCanvasStore.getState();
  if (before.projectId !== projectId) throw new Error("画布已切换，请重新选择图片");
  const base = JSON.stringify({ canvasData: before.getCanvasState() });
  await requestCapabilityResult(command);

  const projectResponse = await fetch(`/api/canvas/${projectId}`);
  const result = await projectResponse.json();
  if (!projectResponse.ok || !result.success || !result.data?.canvasData) {
    throw new Error(result.error || "结果已生成，但画布同步失败");
  }
  const current = useCanvasStore.getState();
  if (current.projectId !== projectId) return;
  const merged = mergeCanvasSnapshots(
    base,
    JSON.stringify({ canvasData: current.getCanvasState() }),
    JSON.stringify({ canvasData: result.data.canvasData }),
  );
  if (merged.conflicts.length > 0) {
    throw new Error("结果已生成，但画布有冲突；请保留本地改动后刷新查看结果");
  }
  current.loadCanvas(JSON.parse(merged.snapshot).canvasData);
  current.setCanvasRevision(String(result.data.updatedAt), String(result.data.updatedAt));
}