import type { Application, Id, Paginated, Params } from '@feathersjs/feathers'
import type { UnwrapArray } from '../internal.utils.js'

type AsArray<T> = T extends any[] ? T : [T]

// MARK: get
export type InferGetResult<S> = S extends {
  get: (id: any, params: any) => infer R
}
  ? Awaited<R>
  : never

export type InferGetResultFromPath<
  App extends Application,
  Path extends string,
> = InferGetResult<GetService<App, Path>>

// MARK: find

export type InferFindResult<S> = S extends {
  find: (params: any) => infer R
}
  ? Awaited<R>
  : never

export type InferFindResultFromPath<
  App extends Application,
  Path extends string,
> = InferFindResult<GetService<App, Path>>

export type InferFindResultSingle<
  S,
  R extends InferFindResult<S> = InferFindResult<S>,
> =
  R extends Paginated<infer D>
    ? UnwrapArray<D>
    : R extends any[]
      ? UnwrapArray<R>
      : R

export type InferFindParams<S> = S extends {
  find: (params: infer P) => any
}
  ? P extends Params
    ? P
    : Params
  : Params

// MARK: create

export type InferCreateData<S> = S extends {
  create: (data: infer D, params: any) => any
}
  ? D
  : never

export type InferCreateDataSingle<S> = UnwrapArray<InferCreateData<S>>

export type InferCreateResult<S, D = unknown> = S extends {
  create: (data: any, params: any) => infer R
}
  ? D extends any[]
    ? AsArray<Awaited<R>>
    : D extends InferCreateDataSingle<S>
      ? UnwrapArray<Awaited<R>>
      : Awaited<R>
  : never

export type InferCreateResultSingle<S> = UnwrapArray<InferCreateResult<S>>

export type InferCreateDataFromPath<
  App extends Application,
  Path extends string,
> = InferCreateData<GetService<App, Path>>
export type InferCreateDataSingleFromPath<
  App extends Application,
  Path extends string,
> = InferCreateDataSingle<GetService<App, Path>>

export type InferCreateResultFromPath<
  App extends Application,
  Path extends string,
  D = unknown,
> = InferCreateResult<GetService<App, Path>, D>
export type InferCreateResultSingleFromPath<
  App extends Application,
  Path extends string,
> = InferCreateResultSingle<GetService<App, Path>>

// MARK: update

export type InferUpdateData<S> = S extends {
  update: (id: any, data: infer D, params: any) => any
}
  ? D
  : never

export type InferUpdateResult<S> = S extends {
  update: (id: any, data: any, params: any) => infer R
}
  ? Awaited<R>
  : never

export type InferUpdateDataFromPath<
  App extends Application,
  Path extends string,
> = InferUpdateData<GetService<App, Path>>

export type InferUpdateResultFromPath<
  App extends Application,
  Path extends string,
> = InferUpdateResult<GetService<App, Path>>

// MARK: patch

export type InferPatchData<S> = S extends {
  patch: (id: any, data: infer D, params: any) => any
}
  ? D
  : never

export type InferPatchResult<S, IdOrNullable = any> = S extends {
  patch: (id: Id, data: any, params: any) => infer R
}
  ? IdOrNullable extends Id
    ? UnwrapArray<Awaited<R>>
    : IdOrNullable extends null
      ? AsArray<Awaited<R>>
      : Awaited<R>
  : never

export type InferPatchDataFromPath<
  App extends Application,
  Path extends string,
> = InferPatchData<GetService<App, Path>>

export type InferPatchResultFromPath<
  App extends Application,
  Path extends string,
  IdOrNullable = any,
> = InferPatchResult<GetService<App, Path>, IdOrNullable>

// MARK: remove

export type InferRemoveResult<S, IdOrNullable = any> = S extends {
  remove: (id: IdOrNullable, params: any) => infer R
}
  ? IdOrNullable extends Id
    ? UnwrapArray<Awaited<R>>
    : IdOrNullable extends null
      ? AsArray<Awaited<R>>
      : Awaited<R>
  : never

export type InferRemoveResultFromPath<
  App extends Application,
  Path extends string,
  IdOrNullable = any,
> = InferRemoveResult<GetService<App, Path>, IdOrNullable>

export type GetService<
  App extends Application,
  Path extends string,
> = App['services'][Path]

export type InferDataFromPath<
  App extends Application,
  Path extends string,
  Method extends 'create' | 'update' | 'patch',
> = Method extends 'create'
  ? InferCreateDataFromPath<App, Path>
  : Method extends 'update'
    ? InferUpdateDataFromPath<App, Path>
    : Method extends 'patch'
      ? InferPatchDataFromPath<App, Path>
      : never

export type InferResultFromPath<
  App extends Application,
  Path extends string,
  Method extends 'get' | 'find' | 'create' | 'update' | 'patch' | 'remove',
> = Method extends 'get'
  ? InferGetResultFromPath<App, Path>
  : Method extends 'find'
    ? InferFindResultFromPath<App, Path>
    : Method extends 'create'
      ? InferCreateResultFromPath<App, Path>
      : Method extends 'update'
        ? InferUpdateResultFromPath<App, Path>
        : Method extends 'patch'
          ? InferPatchResultFromPath<App, Path>
          : Method extends 'remove'
            ? InferRemoveResultFromPath<App, Path>
            : never