import { CommonKeys } from "."


// type ExtendReducer<Super, Self> = (
//     Pick<Self, CommonKeys<Self, Super>> extends Pick<Super, CommonKeys<Self, Super>>
//         ? Omit<Super, CommonKeys<Self, Super>> & Self
//         : never
// )
// interface ExtendReducerFn extends Fn {
//     return: ExtendReducer<this["arg0"], this["arg1"]>
// }
// export type ExtendFn = Tuples.Reduce<ExtendReducerFn, {}>

// export type ExtendableFn = ComposeLeft<[
//     ExtendFn,
//     Match<[
//         Match.With<never, false>,
//         Match.With<any, true>,
//     ]>
// ]>


// TODO: use OverrideProperties from type-fest?
export type Extend<T extends readonly object[]> = (
    T extends readonly [
        infer Super,
        infer Self,
        ...infer Rest extends readonly object[],
    ]
        ? Pick<Self, CommonKeys<Self, Super>> extends Pick<Super, CommonKeys<Self, Super>>
            ? Extend<readonly [
                Omit<Super, CommonKeys<Self, Super>> & Self,
                ...Rest,
            ]>
            : never
        : T extends readonly [infer Self]
            ? Self
            : {}
)

export type Extendable<T extends readonly object[]> = (
    T extends readonly [
        infer Super,
        infer Self,
        ...infer Rest extends readonly object[],
    ]
        ? Pick<Self, CommonKeys<Self, Super>> extends Pick<Super, CommonKeys<Self, Super>>
            ? Extendable<readonly [
                Omit<Super, CommonKeys<Self, Super>> & Self,
                ...Rest,
            ]>
            : false
        : true
)

export type NonExtendableKeys<T extends readonly object[]> = (
    T extends readonly [
        infer Super   extends object,
        infer Self    extends object,
        ...infer Rest extends readonly object[],
    ]
        ? {[K in keyof Super & keyof Self]: Self[K] extends Super[K]
            ? never
            : K
        }[keyof Super & keyof Self]
        | NonExtendableKeys<readonly [
            Super & Self,
            ...Rest,
        ]>
        : void
)