import {
  ProviderTaskFailedError,
  type ProviderTaskLifecycle,
} from "@/lib/video-canvas/video-task-lifecycle";
import type { ExecuteDirectVideoGenerationParams } from "@/lib/ai/tools/generate-video";

// This adapter deliberately exposes only the official model whose contract we support.
export const ALIYUN_CANVAS_VIDEO_MODEL = "wan2.6-i2v-flash";

export function buildAliyunCanvasVideoRequest(params: ExecuteDirectVideoGenerationParams, modelId: string) {
  if (modelId !== ALIYUN_CANVAS_VIDEO_MODEL) throw new Error("当前阿里云视频模型尚未接入画布");
  if (params.mode !== "first-frame" || params.images?.length !== 1) throw new Error("万相首帧生视频需要一张参考图");
  if (params.audioUrls?.length) throw new Error("此画布接入暂不支持参考音频");
  const duration = params.duration ?? 5;
  const resolution = params.resolution ?? "720p";
  if (!Number.isInteger(duration) || duration < 2 || duration > 15) throw new Error("万相视频时长需为 2–15 秒整数");
  if (!["720p", "1080p"].includes(resolution)) throw new Error("万相视频仅支持 720P / 1080P");
  if (params.cameraFixed || params.returnLastFrame) throw new Error("此万相接入不支持固定镜头参数或返回尾帧参数");
  return {
    model: modelId,
    input: { prompt: params.prompt, img_url: params.images[0] },
    parameters: {
      resolution: resolution.toUpperCase(), duration,
      // The upstream derives aspect ratio from the input image, not a ratio parameter.
      audio: params.generateAudio ?? false,
      prompt_extend: false, watermark: params.watermark ?? false,
      ...(params.seed != null ? { seed: params.seed } : {}),
    },
  };
}

export async function executeAliyunCanvasVideo(
  params: ExecuteDirectVideoGenerationParams & {
    modelId: string;
    apiKey: string;
    baseURL: string;
    lifecycle?: ProviderTaskLifecycle;
  },
  runtime = {
    fetch: globalThis.fetch,
    sleep: (ms: number) => new Promise<void>((resolve) => setTimeout(resolve, ms)),
  },
) {
  const body = buildAliyunCanvasVideoRequest(params, params.modelId);
  const base = new URL(params.baseURL);
  base.pathname = "/api/v1";
  base.search = "";
  base.hash = "";
  const headers = { Authorization: `Bearer ${params.apiKey}`, "Content-Type": "application/json", "X-DashScope-Async": "enable" };
  const deadline = Date.now() + 275_000;
  let taskId = params.lifecycle?.resume?.taskId || "";
  const request = async (path: string, init: RequestInit = {}) => {
    const remaining = deadline - Date.now();
    if (remaining <= 0) throw new Error(`阿里云视频查询超时，任务 ${taskId}，请勿重复生成`);
    const response = await runtime.fetch(`${base.toString().replace(/\/$/, "")}${path}`, {
      ...init, headers, signal: AbortSignal.timeout(Math.min(30_000, remaining)),
    });
    const data = await response.json();
    if (!response.ok) throw new Error(`阿里云视频请求失败（${response.status}）：${data.code || data.error?.code || "UnknownError"}${taskId ? `，任务 ${taskId}` : ""}`);
    return data;
  };
  await params.lifecycle?.assertActive();
  if (!taskId) {
    const submitted = await request("/services/aigc/video-generation/video-synthesis", {
      method: "POST",
      body: JSON.stringify(body),
    });
    taskId = submitted.output?.task_id;
    if (!taskId) throw new Error("阿里云未返回视频任务 ID");
    await params.lifecycle?.accepted({ taskId });
  }
  await params.onProgress?.(`阿里云视频任务已提交：${taskId}`);
  while (Date.now() < deadline) {
    await runtime.sleep(Math.min(5_000, Math.max(0, deadline - Date.now())));
    await params.lifecycle?.assertActive();
    const result = await request(`/tasks/${encodeURIComponent(taskId)}`);
    const output = result.output || {};
    if (output.task_status === "SUCCEEDED") {
      if (!/^https?:\/\//i.test(output.video_url || "")) throw new Error("阿里云任务完成但没有返回视频");
      return { url: output.video_url as string, metadata: {
        provider: "aliyun", taskId, requestId: result.request_id,
        duration: body.parameters.duration, resolution: params.resolution ?? "720p",
        generateAudio: body.parameters.audio,
      } };
    }
    if (["FAILED", "CANCELED", "UNKNOWN"].includes(output.task_status)) {
      throw new ProviderTaskFailedError(
        `阿里云视频生成失败：${output.code || result.code || output.task_status}，任务 ${taskId}`,
      );
    }
  }
  throw new Error(`阿里云视频查询超时，任务 ${taskId}，请勿重复生成`);
}