import axios from "axios";
import {
  authApi,
  handleApiError,
  tunnelApi,
  getRemoteTunnelApi,
  isElectron,
} from "@/main-axios";
import type {
  C2STunnelPreset,
  TunnelConfig,
  TunnelConnection,
  TunnelStatus,
} from "@/types/index";
import { streamServerSentEvents } from "./sse-stream";
import { runAdaptivePolling } from "@/lib/adaptive-polling";

// TUNNEL MANAGEMENT
// ============================================================================
//
// Tunnel status is a process-local, in-memory view (no DB lookup) so it's
// safe to read from both the embedded backend and a connected remote server
// and merge the results. connectTunnel/disconnectTunnel/cancelTunnel are
// NOT origin-routed: they resolve the target host by numeric database id
// against whichever backend receives the request, and a synced host has a
// different numeric id in each database (only its syncId matches across
// them) -- routing those calls to a remote backend would need a
// local-id-to-remote-id resolution step that doesn't exist yet. They always
// target the embedded local backend for now.

async function isRemoteSyncConnected(): Promise<boolean> {
  if (!isElectron()) return false;
  try {
    const config = (await window.electronAPI?.invoke?.(
      "get-remote-sync-config",
    )) as { serverUrl?: string } | null;
    return !!config?.serverUrl;
  } catch {
    return false;
  }
}

export async function getTunnelStatuses(): Promise<
  Record<string, TunnelStatus>
> {
  try {
    const [localResult, remoteConnected] = await Promise.all([
      tunnelApi.get("/tunnel/status"),
      isRemoteSyncConnected(),
    ]);
    const localStatuses = localResult.data || {};
    if (!remoteConnected) return localStatuses;

    try {
      const remoteResult = await getRemoteTunnelApi().get("/tunnel/status");
      return { ...(remoteResult.data || {}), ...localStatuses };
    } catch {
      return localStatuses;
    }
  } catch (error) {
    handleApiError(error, "fetch tunnel statuses");
  }
}

export function subscribeTunnelStatuses(
  onStatuses: (statuses: Record<string, TunnelStatus>) => void,
  onError?: () => void,
): () => void {
  const baseURL = (tunnelApi.defaults.baseURL || "").replace(/\/$/, "");
  const controller = new AbortController();

  let latestLocal: Record<string, TunnelStatus> = {};
  let latestRemote: Record<string, TunnelStatus> = {};
  let stopRemotePolling: (() => void) | null = null;

  const emitMerged = () => {
    // Controls target the local backend, so its state wins name collisions.
    onStatuses({ ...latestRemote, ...latestLocal });
  };

  const waitToReconnect = () =>
    new Promise<void>((resolve) => {
      const onAbort = () => {
        clearTimeout(timeout);
        resolve();
      };
      const timeout = setTimeout(() => {
        controller.signal.removeEventListener("abort", onAbort);
        resolve();
      }, 1000);
      controller.signal.addEventListener("abort", onAbort, { once: true });
    });

  void (async () => {
    while (!controller.signal.aborted) {
      const headers = new Headers({ Accept: "text/event-stream" });
      if (isElectron()) {
        headers.set("X-Electron-App", "true");
        const jwt = localStorage.getItem("jwt");
        if (jwt) headers.set("Authorization", `Bearer ${jwt}`);
      }
      try {
        await streamServerSentEvents(
          `${baseURL}/tunnel/status/stream`,
          { credentials: "include", headers, signal: controller.signal },
          (event) => {
            if (event.event !== "statuses") return;
            try {
              latestLocal = JSON.parse(event.data) as Record<
                string,
                TunnelStatus
              >;
              emitMerged();
            } catch {
              onError?.();
            }
          },
        );
        if (!controller.signal.aborted) onError?.();
      } catch (error) {
        const aborted =
          controller.signal.aborted ||
          (error instanceof DOMException && error.name === "AbortError");
        if (!aborted) onError?.();
      }
      if (!controller.signal.aborted) await waitToReconnect();
    }
  })();

  // Remote tunnel status has no SSE stream exposed to the desktop app yet,
  // so poll it at a modest interval when a remote server is connected.
  isRemoteSyncConnected().then((connected) => {
    if (!connected || controller.signal.aborted) return;
    let signature = "";
    stopRemotePolling = runAdaptivePolling(
      async () => {
        const result = await getRemoteTunnelApi().get("/tunnel/status");
        const next = result.data || {};
        const nextSignature = JSON.stringify(next);
        const changed = nextSignature !== signature;
        signature = nextSignature;
        latestRemote = next;
        emitMerged();
        return changed;
      },
      {
        minIntervalMs: 5000,
        maxIntervalMs: 30000,
        stablePollsPerStep: 3,
      },
      { enabled: () => !controller.signal.aborted },
    );
  });

  return () => {
    controller.abort();
    stopRemotePolling?.();
  };
}

export async function getTunnelStatusByName(
  tunnelName: string,
): Promise<TunnelStatus | undefined> {
  const statuses = await getTunnelStatuses();
  return statuses[tunnelName];
}

export async function connectTunnel(
  tunnelConfig: TunnelConfig,
): Promise<Record<string, unknown>> {
  try {
    const response = await tunnelApi.post("/tunnel/connect", tunnelConfig);
    return response.data;
  } catch (error) {
    handleApiError(error, "connect tunnel");
  }
}

export async function disconnectTunnel(
  tunnelName: string,
): Promise<Record<string, unknown>> {
  try {
    const response = await tunnelApi.post("/tunnel/disconnect", { tunnelName });
    return response.data;
  } catch (error) {
    handleApiError(error, "disconnect tunnel");
  }
}

export async function cancelTunnel(
  tunnelName: string,
): Promise<Record<string, unknown>> {
  try {
    const response = await tunnelApi.post("/tunnel/cancel", { tunnelName });
    return response.data;
  } catch (error) {
    handleApiError(error, "cancel tunnel");
  }
}

export async function getC2STunnelPresets(): Promise<C2STunnelPreset[]> {
  try {
    const response = await authApi.get("/c2s-tunnel-presets");
    return response.data || [];
  } catch (error) {
    if (axios.isAxiosError(error) && error.response?.status === 404) {
      return [];
    }
    handleApiError(error, "fetch client tunnel presets");
  }
}

export async function createC2STunnelPreset(data: {
  name: string;
  config: TunnelConnection[];
  platform?: string;
  computerName?: string;
}): Promise<C2STunnelPreset> {
  try {
    const response = await authApi.post("/c2s-tunnel-presets", data);
    return response.data;
  } catch (error) {
    handleApiError(error, "create client tunnel preset");
  }
}

export async function updateC2STunnelPreset(
  id: number,
  data: Partial<{
    name: string;
    config: TunnelConnection[];
    platform: string;
    computerName: string;
  }>,
): Promise<C2STunnelPreset> {
  try {
    const response = await authApi.put(`/c2s-tunnel-presets/${id}`, data);
    return response.data;
  } catch (error) {
    handleApiError(error, "update client tunnel preset");
  }
}

export async function deleteC2STunnelPreset(
  id: number,
): Promise<Record<string, unknown>> {
  try {
    const response = await authApi.delete(`/c2s-tunnel-presets/${id}`);
    return response.data;
  } catch (error) {
    handleApiError(error, "delete client tunnel preset");
  }
}

// ============================================================================