import { createModelInfo } from './model';

export enum Relationship {
    HasMany,
    BelongsTo,
    HasOne,
    HasAndBelongsToMany,
}

export interface RelationshipInfo {
    kind: Relationship;
    key: string;
    foreignKey?: string;
    model: (model: any) => any;
}

export function HasMany(
    model: (model: any) => any,
    foreignKey: string,
): PropertyDecorator {
    return RelationshipDecorator(Relationship.HasMany, model, foreignKey);
}

export function HasOne(
    model: (model: any) => any,
    foreignKey: string,
): PropertyDecorator {
    return RelationshipDecorator(Relationship.HasOne, model, foreignKey);
}

export function BelongsTo(
    model: (model: any) => any,
    localKey: string,
): PropertyDecorator {
    return RelationshipDecorator(Relationship.BelongsTo, model, localKey);
}

export function HasAndBelongsToMany(
    model: (model: any) => any,
): PropertyDecorator {
    return RelationshipDecorator(Relationship.HasAndBelongsToMany, model);
}

function RelationshipDecorator(
    kind: Relationship,
    model: (model: any) => any,
    foreignKey?: string,
): PropertyDecorator {
    return (target, key) => {
        const relationship: RelationshipInfo = {
            kind,
            model,
            key: <string>key,
            foreignKey,
        };

        createModelInfo(<any>target.constructor, {
            relationships: [relationship],
        });
    };
}