import {Record} from './Record'
import {Key} from '../Any/Key'
import {IntersectOf} from '../Union/IntersectOf'
import {ComputeRaw} from '../Any/Compute'

/**
@hidden
*/
export type _Invert<O extends Record<Key, Key>> =
  ComputeRaw<IntersectOf<
    { // swaps the key and the value
      [K in keyof O]: Record<O[K], K>
    }[keyof O]
  >>

/**
Swaps the keys and values of an [[Object]] (if applicable)
@param O
@returns [[Object]]
@example
```ts
import {O} from 'ts-toolbelt'

enum E {
    A = 'Av',
    B = 'Bv',
    C = 'Cv',
    D = 'Dv',
    X = 1
}

type O = {
    A: 'Av'
    B: 'Bv'
    C: 'Cv'
    D: 'Dv'
    X: 1
}

type test0 = O.Invert<typeof E>
type test1 = O.Invert<O>
```
*/
export type Invert<O extends Record<Key, Key>> =
    O extends unknown
    ? _Invert<O>
    : never