import type {
  BridgeBindMode,
  GatewayAuthConfig,
  GatewayTailscaleConfig,
  loadConfig,
} from "../config/config.js";
import {
  assertGatewayAuthConfigured,
  type ResolvedGatewayAuth,
  resolveGatewayAuth,
} from "./auth.js";
import { normalizeControlUiBasePath } from "./control-ui.js";
import { resolveHooksConfig } from "./hooks.js";
import { isLoopbackHost, resolveGatewayBindHost } from "./net.js";

export type GatewayRuntimeConfig = {
  bindHost: string;
  controlUiEnabled: boolean;
  openAiChatCompletionsEnabled: boolean;
  controlUiBasePath: string;
  resolvedAuth: ResolvedGatewayAuth;
  authMode: ResolvedGatewayAuth["mode"];
  tailscaleConfig: GatewayTailscaleConfig;
  tailscaleMode: "off" | "serve" | "funnel";
  hooksConfig: ReturnType<typeof resolveHooksConfig>;
  canvasHostEnabled: boolean;
};

export async function resolveGatewayRuntimeConfig(params: {
  cfg: ReturnType<typeof loadConfig>;
  port: number;
  bind?: BridgeBindMode;
  host?: string;
  controlUiEnabled?: boolean;
  openAiChatCompletionsEnabled?: boolean;
  auth?: GatewayAuthConfig;
  tailscale?: GatewayTailscaleConfig;
}): Promise<GatewayRuntimeConfig> {
  const bindMode = params.bind ?? params.cfg.gateway?.bind ?? "loopback";
  const customBindHost = params.cfg.gateway?.customBindHost;
  const bindHost = params.host ?? (await resolveGatewayBindHost(bindMode, customBindHost));
  const controlUiEnabled =
    params.controlUiEnabled ?? params.cfg.gateway?.controlUi?.enabled ?? true;
  const openAiChatCompletionsEnabled =
    params.openAiChatCompletionsEnabled ??
    params.cfg.gateway?.http?.endpoints?.chatCompletions?.enabled ??
    false;
  const controlUiBasePath = normalizeControlUiBasePath(params.cfg.gateway?.controlUi?.basePath);
  const authBase = params.cfg.gateway?.auth ?? {};
  const authOverrides = params.auth ?? {};
  const authConfig = {
    ...authBase,
    ...authOverrides,
  };
  const tailscaleBase = params.cfg.gateway?.tailscale ?? {};
  const tailscaleOverrides = params.tailscale ?? {};
  const tailscaleConfig = {
    ...tailscaleBase,
    ...tailscaleOverrides,
  };
  const tailscaleMode = tailscaleConfig.mode ?? "off";
  const resolvedAuth = resolveGatewayAuth({
    authConfig,
    env: process.env,
    tailscaleMode,
  });
  const authMode: ResolvedGatewayAuth["mode"] = resolvedAuth.mode;
  const hooksConfig = resolveHooksConfig(params.cfg);
  const canvasHostEnabled =
    process.env.CLAWDBOT_SKIP_CANVAS_HOST !== "1" && params.cfg.canvasHost?.enabled !== false;

  assertGatewayAuthConfigured(resolvedAuth);
  if (tailscaleMode === "funnel" && authMode !== "password") {
    throw new Error(
      "tailscale funnel requires gateway auth mode=password (set gateway.auth.password or CLAWDBOT_GATEWAY_PASSWORD)",
    );
  }
  if (tailscaleMode !== "off" && !isLoopbackHost(bindHost)) {
    throw new Error("tailscale serve/funnel requires gateway bind=loopback (127.0.0.1)");
  }
  if (!isLoopbackHost(bindHost) && authMode === "none") {
    throw new Error(
      `refusing to bind gateway to ${bindHost}:${params.port} without auth (set gateway.auth.token or CLAWDBOT_GATEWAY_TOKEN, or pass --token)`,
    );
  }

  return {
    bindHost,
    controlUiEnabled,
    openAiChatCompletionsEnabled,
    controlUiBasePath,
    resolvedAuth,
    authMode,
    tailscaleConfig,
    tailscaleMode,
    hooksConfig,
    canvasHostEnabled,
  };
}
