import type { RequestOptions } from './instance'

type NoStringIndex<T> = { [K in keyof T as string extends K ? never : K]: T[K] }

export type Method = 'get' | 'delete' | 'post' | 'put' | 'patch'

export interface IRequestHandler<ResponseWrapper> {
  (path?: string | number): IRequestHandler<ResponseWrapper>
  // @ts-ignore
  get<P = unknown>(
    options?: Omit<NoStringIndex<RequestOptions>, 'data'>,
  ): RequestProxyResult<P, ResponseWrapper>
  // @ts-ignore
  post<P = unknown>(
    options?: RequestOptions,
  ): RequestProxyResult<P, ResponseWrapper>
  // @ts-ignore
  patch<P = unknown>(
    options?: RequestOptions,
  ): RequestProxyResult<P, ResponseWrapper>
  // @ts-ignore
  delete<P = unknown>(
    options?: Omit<NoStringIndex<RequestOptions>, 'data'>,
  ): RequestProxyResult<P, ResponseWrapper>
  // @ts-ignore
  put<P = unknown>(
    options?: RequestOptions,
  ): RequestProxyResult<P, ResponseWrapper>
  // @ts-ignore
  toString(withBase?: boolean): string
  // @ts-ignore
  valueOf(withBase?: boolean): string
  [key: string]: IRequestHandler<ResponseWrapper>
}

export type RequestProxyResult<
  T,
  ResponseWrapper,
  R = ResponseWrapper extends unknown
    ? { data: T; [key: string]: any }
    : ResponseWrapper extends { data: T }
    ? ResponseWrapper
    : Omit<ResponseWrapper, 'data'> & { data: T },
> = Promise<ResponseProxyExtraRaw<T, R, ResponseWrapper>>

type CamelToSnake<T extends string, P extends string = ''> = string extends T
  ? string
  : T extends `${infer C0}${infer R}`
  ? CamelToSnake<
      R,
      `${P}${C0 extends Lowercase<C0> ? '' : '_'}${Lowercase<C0>}`
    >
  : P

type CamelKeysToSnake<T> = {
  [K in keyof T as CamelToSnake<Extract<K, string>>]: T[K]
}

type ResponseWrapperType<Response, RawData, T> = {
  $raw: Response extends { data: infer T }
    ? Response
    : Response extends unknown
    ? {
        [i: string]: any
        data: RawData extends unknown ? CamelKeysToSnake<T> : RawData
      }
    : Response
  $request: {
    path: string
    method: string
    [k: string]: string
  }

  $serialized: T
}

export type ResponseProxyExtraRaw<
  T,
  RawData = unknown,
  Response = unknown,
> = T extends object
  ? T & ResponseWrapperType<Response, RawData, T>
  : T extends unknown
  ? T & ResponseWrapperType<Response, RawData, T>
  : unknown