type AliyunVideoModel = "qwen3.8-max" | "qwen3.8-flash" | "qwen3.8-omni-flash";

export function isAliyunVideoModel(modelId: string, providerType: string) {
  return providerType === "alibaba" &&
    ["qwen3.8-max", "qwen3.8-flash", "qwen3.8-omni-flash"].includes(modelId);
}

export function supportsVideoSound(modelId: string) {
  return modelId === "qwen3.8-omni-flash";
}

function officialEndpoint(baseUrl: string) {
  const url = new URL(baseUrl);
  if (url.protocol !== "https:" ||
    !(url.hostname === "dashscope.aliyuncs.com" ||
      /^[-a-z0-9]+\.[-a-z0-9]+\.maas\.aliyuncs\.com$/.test(url.hostname))) {
    throw new Error("视频解析仅允许阿里云百炼官方地址");
  }
  return `${url.href.replace(/\/$/, "")}/chat/completions`;
}

function sseText(body: string) {
  let result = "";
  let finishReason: string | undefined;
  for (const line of body.split(/\r?\n/)) {
    if (!line.startsWith("data: ") || line === "data: [DONE]") continue;
    try {
      const event = JSON.parse(line.slice(6));
      result += event.choices?.[0]?.delta?.content || "";
      finishReason = event.choices?.[0]?.finish_reason || finishReason;
    } catch {
      // Ignore keep-alive and incomplete events; a missing result is rejected below.
    }
  }
  if (finishReason === "length") throw new Error("阿里云视频分析结果被截断，未提交成片合成");
  return result;
}

export async function analyzeAliyunVideo({
  apiKey,
  baseUrl,
  modelId,
  prompt,
  videoUrl,
  contextImages = [],
  fps = 1,
  jsonOutput = false,
  signal,
}: {
  apiKey: string;
  baseUrl: string;
  modelId: AliyunVideoModel;
  prompt: string;
  videoUrl: string;
  contextImages?: string[];
  fps?: number;
  jsonOutput?: boolean;
  signal?: AbortSignal;
}) {
  const video = new URL(videoUrl);
  if (video.protocol !== "https:") {
    throw new Error("阿里云视频解析需要可公网访问的 HTTPS 视频地址");
  }
  if (!Number.isFinite(fps) || fps < 0.1 || fps > 10 || contextImages.length > 2)
    throw new Error("视频分析采样或参考图片参数无效");
  const omni = supportsVideoSound(modelId);
  const response = await fetch(officialEndpoint(baseUrl), {
    method: "POST",
    headers: {
      Authorization: `Bearer ${apiKey}`,
      "Content-Type": "application/json",
    },
    body: JSON.stringify({
      model: modelId,
      messages: [{
        role: "user",
        content: [
          { type: "video_url", video_url: { url: video.href }, fps },
          ...contextImages.map(url => ({ type: "image_url", image_url: { url } })),
          { type: "text", text: prompt },
        ],
      }],
      stream: omni,
      ...(jsonOutput ? { response_format: { type: "json_object" } } : {}),
      ...(omni ? { modalities: ["text"], reasoning_effort: "none" } : {
        temperature: 0.2,
        max_tokens: 6000,
      }),
    }),
    signal,
  });
  if (!response.ok) {
    let code = "";
    try {
      const body = await response.json();
      code = String(body.error?.code || body.code || "").slice(0, 80);
    } catch {}
    throw new Error(`阿里云视频解析失败（HTTP ${response.status}${code ? `，${code}` : ""}）`);
  }
  let text: string;
  if (omni) text = sseText(await response.text());
  else {
    const choice = (await response.json()).choices?.[0];
    if (choice?.finish_reason === "length")
      throw new Error("阿里云视频分析结果被截断，未提交成片合成");
    text = String(choice?.message?.content || "");
  }
  if (!text.trim()) throw new Error("阿里云视频解析返回空结果");
  return text;
}