// Gateway HTTP/SSE 客户端：提交 DSL 任务、订阅 Token 流、登记偏好记忆。
import type { TaskDsl } from "./dsl";

// 开发期直连 Gateway；Wails 打包后可改为本地后端地址或经 Go 绑定。
export const GATEWAY: string =
  (import.meta.env.VITE_GATEWAY as string | undefined) ?? "http://localhost:8080";

export interface Identity {
  userId: string;
  sessionId: string;
}

// submitTask: POST /api/v1/tasks，返回 task_id。
export async function submitTask(dsl: TaskDsl, id: Identity): Promise<string> {
  const res = await fetch(`${GATEWAY}/api/v1/tasks`, {
    method: "POST",
    headers: {
      "Content-Type": "application/json",
      "X-User-ID": id.userId,
      "X-Session-ID": id.sessionId,
    },
    body: JSON.stringify(dsl),
  });
  if (!res.ok) throw new Error(`submit failed: ${res.status} ${await res.text()}`);
  const data = (await res.json()) as { task_id: string };
  return data.task_id;
}

// streamTokens: 订阅 SSE /api/v1/tasks/:id/stream，逐 token 回调，done 收尾。
// 返回关闭函数。注意 EventSource 无法带请求头，但流按 task_id 寻址，无需身份头。
export function streamTokens(
  taskId: string,
  onToken: (t: string) => void,
  onDone: () => void,
  onError?: (e: unknown) => void,
): () => void {
  const es = new EventSource(`${GATEWAY}/api/v1/tasks/${taskId}/stream`);
  es.addEventListener("token", (e) => onToken((e as MessageEvent).data));
  es.addEventListener("done", () => {
    es.close();
    onDone();
  });
  es.onerror = (e) => {
    es.close();
    onError?.(e);
  };
  return () => es.close();
}

// ingestKb: POST /api/v1/kb/ingest，把文本入库（→ mcp-go kb_ingest：切块/embedding/Milvus）。
export async function ingestKb(kb: string, text: string): Promise<string> {
  const res = await fetch(`${GATEWAY}/api/v1/kb/ingest`, {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ kb, text }),
  });
  const data = (await res.json()) as { message?: string; error?: string };
  if (!res.ok) throw new Error(data.error ?? `ingest failed: ${res.status}`);
  return data.message ?? "ok";
}

// ingestFile: POST /api/v1/kb/ingest_file（multipart）—— 上传文件入库（docx/xlsx/pdf… → mcp-py 解析）。
export async function ingestFile(kb: string, file: File): Promise<string> {
  const fd = new FormData();
  fd.append("kb", kb);
  fd.append("file", file);
  const res = await fetch(`${GATEWAY}/api/v1/kb/ingest_file`, { method: "POST", body: fd });
  const data = (await res.json()) as { message?: string; chars?: number; error?: string };
  if (!res.ok) throw new Error(data.error ?? `ingest file failed: ${res.status}`);
  return `${file.name}：解析 ${data.chars ?? 0} 字 → ${data.message ?? "ok"}`;
}

export interface KbHit {
  text: string;
  score: number;
}

// searchKb: POST /api/v1/kb/search，检索台查询（→ mcp-go kb_search，带分数）。
export async function searchKb(kb: string, q: string, topK = 5): Promise<KbHit[]> {
  const res = await fetch(`${GATEWAY}/api/v1/kb/search`, {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ kb, q, topK }),
  });
  const data = (await res.json()) as { hits?: KbHit[]; error?: string };
  if (!res.ok) throw new Error(data.error ?? `search failed: ${res.status}`);
  return data.hits ?? [];
}

// setMemory: PUT /api/v1/memory，登记一条用户偏好（→ mcp-go memory_upsert）。
export async function setMemory(
  id: Identity,
  key: string,
  value: string,
): Promise<string> {
  const res = await fetch(`${GATEWAY}/api/v1/memory`, {
    method: "PUT",
    headers: {
      "Content-Type": "application/json",
      "X-User-ID": id.userId,
      "X-Session-ID": id.sessionId,
    },
    body: JSON.stringify({ key, value }),
  });
  const data = (await res.json()) as { message?: string; error?: string };
  if (!res.ok) throw new Error(data.error ?? `memory failed: ${res.status}`);
  return data.message ?? "ok";
}