/**
 * adminrpc HTTP REST client
 *
 * Calls the adminrpc HTTP server (default: http://adminrpc.admin.svc.cluster.local:9091)
 * which exposes the same session management and metrics APIs as the gRPC service.
 *
 * Usage:
 *   import { listWorkspaceSessions, kickUser } from "@/lib/admin-rpc";
 */

import { ADMIN_RPC_URL } from "./env";

// Default to k8s internal service address; override via ADMIN_RPC_URL env var
const BASE_URL = ADMIN_RPC_URL || "http://adminrpc.admin.svc.cluster.local:9091";

async function rpc<T>(path: string, options?: RequestInit): Promise<T> {
  const url = `${BASE_URL}${path}`;
  const res = await fetch(url, {
    ...options,
    headers: {
      "Content-Type": "application/json",
      ...options?.headers,
    },
  });
  if (!res.ok) {
    const body = await res.text();
    throw new Error(`adminrpc ${options?.method ?? "GET"} ${path} failed (${res.status}): ${body}`);
  }
  return res.json() as Promise<T>;
}

// ─── Types ────────────────────────────────────────────────────────────────────

export interface UserSession {
  session_id: string;
  user_id: string;
  workspace_id: string;
  ip_address: string;
  user_agent: string;
  connected_at: string;
  last_heartbeat: string;
}

export interface SessionInfo {
  user_id: string;
  session_count: number;
  workspaces: string[];
  latest_session: UserSession | null;
}

// ─── Sessions API ─────────────────────────────────────────────────────────────

/** List all active sessions for a workspace. */
export async function listWorkspaceSessions(workspaceId: string): Promise<UserSession[]> {
  return rpc<UserSession[]>(`/api/admin/sessions/workspace/${encodeURIComponent(workspaceId)}`);
}

/** List all active sessions for a specific user. */
export async function listUserSessions(userId: string): Promise<UserSession[]> {
  return rpc<UserSession[]>(`/api/admin/sessions/user/${encodeURIComponent(userId)}`);
}

/** Get the online status of a specific user. */
export async function getUserStatus(userId: string): Promise<{ status: string }> {
  return rpc<{ status: string }>(`/api/admin/sessions/user/${encodeURIComponent(userId)}/status`);
}

/** Get detailed info for a user (session count, workspaces, latest session). */
export async function getUserInfo(userId: string): Promise<SessionInfo | null> {
  return rpc<SessionInfo | null>(`/api/admin/sessions/user/${encodeURIComponent(userId)}/info`);
}

/** List all online user IDs in a workspace. */
export async function getWorkspaceOnlineUsers(workspaceId: string): Promise<{ user_ids: string[] }> {
  return rpc<{ user_ids: string[] }>(`/api/admin/sessions/workspace/${encodeURIComponent(workspaceId)}/online-users`);
}

/** Check if a user is currently online. */
export async function isUserOnline(userId: string): Promise<{ online: boolean }> {
  return rpc<{ online: boolean }>(`/api/admin/sessions/user/${encodeURIComponent(userId)}/online`);
}

/** Kick all sessions for a user. Returns the number of sessions kicked. */
export async function kickUser(userId: string): Promise<{ kicked_count: number }> {
  return rpc<{ kicked_count: number }>("/api/admin/sessions/kick", {
    method: "POST",
    body: JSON.stringify({ user_id: userId }),
  });
}

/** Kick all sessions for a user in a specific workspace. */
export async function kickUserFromWorkspace(
  userId: string,
  workspaceId: string
): Promise<{ kicked_count: number }> {
  return rpc<{ kicked_count: number }>("/api/admin/sessions/kick-workspace", {
    method: "POST",
    body: JSON.stringify({ user_id: userId, workspace_id: workspaceId }),
  });
}

// ─── Metrics API ─────────────────────────────────────────────────────────────

export interface InstanceMetrics {
  instance_id: string;
  timestamp_secs: number;
  http: Record<string, string>;
  room: Record<string, string>;
}

/** Get metrics across all app instances. */
export async function getMetrics(instanceFilter = ""): Promise<InstanceMetrics[]> {
  const qs = instanceFilter ? `?instance_filter=${encodeURIComponent(instanceFilter)}` : "";
  return rpc<InstanceMetrics[]>(`/api/admin/metrics${qs}`);
}

/** Export all metrics as CSV string. */
export async function exportMetricsCsv(instanceFilter = ""): Promise<string> {
  const qs = instanceFilter ? `?instance_filter=${encodeURIComponent(instanceFilter)}` : "";
  const res = await fetch(`${BASE_URL}/api/admin/metrics/export${qs}`);
  if (!res.ok) {
    throw new Error(`adminrpc GET /metrics/export failed (${res.status})`);
  }
  return res.text();
}

/** Get adminrpc health status. */
export async function adminRpcHealth(): Promise<{ ok: boolean }> {
  return rpc<{ ok: boolean }>("/health");
}