import type { SchemaDeclaration } from '../../schema.js';
import type { MergeObjects, GetSingleType, Equals } from '../type-utils.js';
type GetCollectionName<TSchema extends SchemaDeclaration, TObj> = keyof {
    [K in keyof TSchema as Equals<TSchema[K]['type'], TObj> extends true ? K : never]: unknown;
};
/**
 * Returns the back-relation key if any column in `TCollectionName` points to `TypeToLookFor`
 *
 * @template TSchema - The schema declaration.
 * @template TCollectionName - The name of the collection to search for back-relation.
 * @template TypeToLookFor - The type to look for in the relation fields.
 */
type BackRelationKey<TSchema extends SchemaDeclaration, TCollectionName extends keyof TSchema, TypeToLookFor> = keyof {
    [K in keyof TSchema[TCollectionName]['relations'] as Equals<GetSingleType<TSchema[TCollectionName]['relations'][K]>, TypeToLookFor> extends true ? `${TCollectionName & string}_via_${K & string}` : never]: unknown;
};
/** Back-relations that are inferred from the schema */
type ImplicitRelations<TSchema extends SchemaDeclaration> = {
    [K1 in keyof TSchema]: {
        [K2 in keyof TSchema as BackRelationKey<TSchema, K2, TSchema[K1]['type']>]: {
            type: GetSingleType<TSchema[K2]['type']>;
            isOptional: true;
            isToMany: true;
            tableName: K2;
        };
    };
};
type RelationHelper<TSchema extends SchemaDeclaration, T> = {
    type: GetSingleType<T>;
    isOptional: undefined extends T ? true : false;
    isToMany: NonNullable<T> extends Array<any> ? true : false;
    tableName: GetCollectionName<TSchema, GetSingleType<T>>;
};
/** Relations that are explicitly defined in the schema */
type ExplicitRelations<TSchema extends SchemaDeclaration> = {
    [Collection in keyof TSchema]: {
        [Relation in keyof TSchema[Collection]['relations']]-?: RelationHelper<TSchema, TSchema[Collection]['relations'][Relation]>;
    };
};
/** parse relations from the schema */
export type SchemaParser<TSchema extends SchemaDeclaration> = {
    [K in keyof TSchema]: MergeObjects<ImplicitRelations<TSchema>[K], ExplicitRelations<TSchema>[K]>;
};
export {};