import type { HttpResult, HttpSpec, Transport, WsSession, WsSpec } from "@opsxapi/core";

async function invoke<T>(cmd: string, args?: Record<string, unknown>): Promise<T> {
  try {
    const { invoke: tauriInvoke } = await import("@tauri-apps/api/core");
    return await tauriInvoke<T>(cmd, args);
  } catch (e) {
    const msg = e instanceof Error ? e.message : String(e);
    throw new Error(
      `tauri-native invoke("${cmd}") failed (are you running inside OpsxAPI desktop?): ${msg}`,
    );
  }
}

export const tauriNativeTransport: Transport = {
  async http(spec: HttpSpec): Promise<HttpResult> {
    return invoke<HttpResult>("http_send", { spec });
  },

  ws(spec: WsSpec): WsSession {
    const messageCbs: Array<(data: string) => void> = [];
    const statusCbs: Array<(s: string) => void> = [];
    let sessionId: string | null = null;

    const emitStatus = (s: string) => statusCbs.forEach((cb) => cb(s));

    void (async () => {
      try {
        emitStatus("connecting");
        sessionId = await invoke<string>("ws_connect", { spec });
        emitStatus("open");
        // Full event listen pipeline is Week 2; stub keeps UI usable.
      } catch (e) {
        emitStatus("error");
        messageCbs.forEach((cb) =>
          cb(`[ws_connect error] ${e instanceof Error ? e.message : String(e)}`),
        );
      }
    })();

    return {
      onMessage(cb) {
        messageCbs.push(cb);
      },
      onStatus(cb) {
        statusCbs.push(cb);
      },
      send(data) {
        if (!sessionId) {
          messageCbs.forEach((cb) => cb("[ws] not connected"));
          return;
        }
        void invoke("ws_send", { sessionId, data }).catch((e) => {
          messageCbs.forEach((cb) =>
            cb(`[ws_send error] ${e instanceof Error ? e.message : String(e)}`),
          );
        });
      },
      close() {
        if (!sessionId) return;
        void invoke("ws_close", { sessionId }).finally(() => {
          sessionId = null;
          emitStatus("closed");
        });
      },
    };
  },
};