import type { IncomingMessage, ServerResponse } from 'http';
import type { AnyRouter, inferRouterContext } from '../../core';
import type { HTTPBaseHandlerOptions } from '../../http';
import type { MaybePromise } from '../../types';
import type { NodeHTTPContentTypeHandler } from './internals/contentType';

interface ParsedQs {
  [key: string]: ParsedQs | ParsedQs[] | string[] | string | undefined;
}

export type NodeHTTPRequest = IncomingMessage & {
  query?: ParsedQs;
  body?: unknown;
};
export type NodeHTTPResponse = ServerResponse & {
  /**
   * Force the partially-compressed response to be flushed to the client.
   *
   * Added by compression middleware
   * (depending on the environment,
   * e.g. Next <= 12,
   * e.g. Express w/ `compression()`)
   */
  flush?: () => void;
};

export type NodeHTTPCreateContextOption<
  TRouter extends AnyRouter,
  TRequest,
  TResponse,
> = object extends inferRouterContext<TRouter>
  ? {
      /**
       * @link https://trpc.io/docs/context
       **/
      createContext?: NodeHTTPCreateContextFn<TRouter, TRequest, TResponse>;
    }
  : {
      /**
       * @link https://trpc.io/docs/context
       **/
      createContext: NodeHTTPCreateContextFn<TRouter, TRequest, TResponse>;
    };

/**
 * @internal
 */
type ConnectMiddleware<
  TRequest extends NodeHTTPRequest = NodeHTTPRequest,
  TResponse extends NodeHTTPResponse = NodeHTTPResponse,
> = (req: TRequest, res: TResponse, next: (err?: any) => any) => void;

export type NodeHTTPHandlerOptions<
  TRouter extends AnyRouter,
  TRequest extends NodeHTTPRequest,
  TResponse extends NodeHTTPResponse,
> = HTTPBaseHandlerOptions<TRouter, TRequest> &
  NodeHTTPCreateContextOption<TRouter, TRequest, TResponse> & {
    /**
     * By default, http `OPTIONS` requests are not handled, and CORS headers are not returned.
     *
     * This can be used to handle them manually or via the `cors` npm package: https://www.npmjs.com/package/cors
     *
     * ```ts
     * import cors from 'cors'
     *
     * nodeHTTPRequestHandler({
     *   cors: cors()
     * })
     * ```
     *
     * You can also use it for other needs which a connect/node.js compatible middleware can solve,
     *  though you might wish to consider an alternative solution like the Express adapter if your needs are complex.
     */
    middleware?: ConnectMiddleware;
    maxBodySize?: number;
    experimental_contentTypeHandlers?: NodeHTTPContentTypeHandler<
      TRequest,
      TResponse
    >[];
  };

export type NodeHTTPRequestHandlerOptions<
  TRouter extends AnyRouter,
  TRequest extends NodeHTTPRequest,
  TResponse extends NodeHTTPResponse,
> = {
  req: TRequest;
  res: TResponse;
  path: string;
} & NodeHTTPHandlerOptions<TRouter, TRequest, TResponse>;

export type NodeHTTPCreateContextFnOptions<TRequest, TResponse> = {
  req: TRequest;
  res: TResponse;
};
export type NodeHTTPCreateContextFn<
  TRouter extends AnyRouter,
  TRequest,
  TResponse,
> = (
  opts: NodeHTTPCreateContextFnOptions<TRequest, TResponse>,
) => MaybePromise<inferRouterContext<TRouter>>;