traitify-ts/src/TraitBuilder.ts

import { Pipe, Tuples } from "hotscript"
import { AbstractClass, Class } from "type-fest"
import { Trait, TraitClass, TraitConcreteClass } from "./Trait"
import { TraitExpression } from "./TraitExpression"
import { ExtendFn, SimplifyFn, StaticMembers } from "./util"


type ExtendAbstractSuper<SuperExpression, Abstract> = (
    Pipe<SuperExpression, [
        TraitExpression.TraitsFn,
        Tuples.Map<Trait.OwnAbstractFn>,
        Tuples.Append<Abstract>,
        ExtendFn,
        SimplifyFn,
    ]>
)

type ExtendStaticAbstractSuper<SuperExpression, StaticAbstract> = (
    Pipe<SuperExpression, [
        TraitExpression.TraitsFn,
        Tuples.Map<Trait.OwnStaticAbstractFn>,
        Tuples.Append<StaticAbstract>,
        ExtendFn,
        SimplifyFn,
    ]>
)


type TraitApplierSuperTag = "@thilawyn/traitify-ts/Super"

type RemoveAbstractFromImplClass<
    ImplClassWithAbstract extends AbstractClass<object>,
    Abstract              extends AbstractClass<object>,
> = (
    Class<
        Omit<
            InstanceType<ImplClassWithAbstract>,
            keyof InstanceType<Abstract>
        >,

        ConstructorParameters<ImplClassWithAbstract>
    > &
    Omit<
        StaticMembers<ImplClassWithAbstract>,
        keyof StaticMembers<Abstract> | "_tag"
    >
)


export class TraitBuilder<
    SuperExpression extends TraitExpression<
        typeof TraitExpression.NullSuperclass,
        Trait<any, any, any, any>[]
    >,
    Abstract        extends object,
    StaticAbstract  extends object,
    ImplClass       extends Class<object, []>,
> {
    constructor(
        private readonly traitSuperExpression:  SuperExpression,
        private readonly traitAbstract:         Abstract,
        private readonly traitStaticAbstract:   StaticAbstract,
        private readonly traitApply:            (Super: AbstractClass<object>) => ImplClass,
    ) {}

    abstract<A extends ExtendAbstractSuper<SuperExpression, Abstract>>() {
        return new TraitBuilder(
            this.traitSuperExpression,
            {} as A,
            this.traitStaticAbstract,
            this.traitApply,
        )
    }

    extendAbstract<A extends ExtendAbstractSuper<SuperExpression, Abstract>>(
        _: (
            Super: AbstractClass<
                ExtendAbstractSuper<SuperExpression, Abstract>
            >
        ) => AbstractClass<A, []>
    ) {
        return new TraitBuilder(
            this.traitSuperExpression,
            {} as A,
            this.traitStaticAbstract,
            this.traitApply,
        )
    }

    staticAbstract<A extends ExtendStaticAbstractSuper<SuperExpression, StaticAbstract>>() {
        return new TraitBuilder(
            this.traitSuperExpression,
            this.traitAbstract,
            {} as A,
            this.traitApply,
        )
    }

    extendStaticAbstract<A extends ExtendStaticAbstractSuper<SuperExpression, StaticAbstract>>(
        _: (
            Super: AbstractClass<
                ExtendStaticAbstractSuper<SuperExpression, StaticAbstract>
            >
        ) => AbstractClass<A, []>
    ) {
        return new TraitBuilder(
            this.traitSuperExpression,
            this.traitAbstract,
            {} as A,
            this.traitApply,
        )
    }

    implement<
        ImplClassWithAbstract extends (
            TraitConcreteClass<
                Trait<SuperExpression, Abstract, StaticAbstract, ImplClass>
            > &
            { _tag: TraitApplierSuperTag }
        )
    >(
        apply: (
            Super: (
                TraitClass<
                    Trait<SuperExpression, Abstract, StaticAbstract, ImplClass>
                > &
                { _tag: TraitApplierSuperTag }
            )
        ) => ImplClassWithAbstract
    ) {
        return new TraitBuilder(
            this.traitSuperExpression,
            this.traitAbstract,
            this.traitStaticAbstract,
            apply as unknown as (Super: AbstractClass<object>) => RemoveAbstractFromImplClass<
                ImplClassWithAbstract,
                TraitClass<
                    Trait<SuperExpression, Abstract, StaticAbstract, ImplClass>
                >
            >,
        )
    }

    build() {
        return new Trait(
            this.traitSuperExpression,
            this.traitAbstract,
            this.traitStaticAbstract,
            this.traitApply,
        )
    }
}

export const trait = new TraitBuilder(
    new TraitExpression(TraitExpression.NullSuperclass, []),
    {},
    {},
    Super => class extends Super {},
)