import type { VisualTaskQueryResponse, VisualTaskSubmitResponse } from "@/lib/types";
import { signVolcengineRequest } from "@/lib/volcengine/signature";

export type VisualClientConfig = {
  accessKeyId: string;
  secretAccessKey: string;
  region: string;
  service: string;
  endpoint: string;
};

export function getVisualClientConfig(): VisualClientConfig | null {
  const accessKeyId = process.env.VOLCENGINE_ACCESS_KEY_ID;
  const secretAccessKey = process.env.VOLCENGINE_SECRET_ACCESS_KEY;
  if (!accessKeyId || !secretAccessKey) return null;
  return {
    accessKeyId,
    secretAccessKey,
    region: process.env.VOLCENGINE_REGION || "cn-north-1",
    service: process.env.VOLCENGINE_SERVICE || "cv",
    endpoint: process.env.VOLCENGINE_VISUAL_ENDPOINT || "https://visual.volcengineapi.com"
  };
}

export function shouldMockVisualApi(): boolean {
  const flag = process.env.JIMENG_VISUAL_MOCK || "auto";
  if (flag === "1" || flag === "true") return true;
  if (flag === "0" || flag === "false") return false;
  return getVisualClientConfig() === null;
}

export async function submitVisualTask(
  payload: Record<string, unknown>,
  config = getVisualClientConfig()
): Promise<VisualTaskSubmitResponse> {
  if (!config) throw new Error("Volcengine Visual credentials are not configured.");
  return callVisualApi<VisualTaskSubmitResponse>("CVSync2AsyncSubmitTask", payload, config);
}

export async function queryVisualTask(
  payload: Record<string, unknown>,
  config = getVisualClientConfig()
): Promise<VisualTaskQueryResponse> {
  if (!config) throw new Error("Volcengine Visual credentials are not configured.");
  return callVisualApi<VisualTaskQueryResponse>("CVSync2AsyncGetResult", payload, config);
}

async function callVisualApi<T>(
  action: "CVSync2AsyncSubmitTask" | "CVSync2AsyncGetResult",
  payload: Record<string, unknown>,
  config: VisualClientConfig
): Promise<T> {
  const body = JSON.stringify(payload);
  const signed = signVolcengineRequest({
    method: "POST",
    endpoint: config.endpoint,
    query: {
      Action: action,
      Version: "2022-08-31"
    },
    body,
    accessKeyId: config.accessKeyId,
    secretAccessKey: config.secretAccessKey,
    region: config.region,
    service: config.service
  });
  const response = await fetch(signed.url, {
    method: "POST",
    headers: signed.headers,
    body
  });
  const text = await response.text();
  let json: unknown;
  try {
    json = JSON.parse(text);
  } catch {
    throw new Error(`Volcengine Visual returned non-JSON response: ${response.status} ${text.slice(0, 240)}`);
  }
  if (!response.ok) {
    const message = typeof json === "object" && json && "message" in json ? String(json.message) : text;
    throw new Error(`Volcengine Visual HTTP ${response.status}: ${message}`);
  }
  return json as T;
}