import {Model} from '../Model.ts'
import {HasOneOrMany} from './HasOneOrMany.ts'
import {Collection} from '../../../../lib/src/collection/Collection.ts'
import {Logging} from '../../../../lib/src/service/logging/Logging.ts'

/**
 * Relation class for one-to-one relations.
 * @extends HasOneOrMany
 */
export class HasOne<T extends Model<T>, T2 extends Model<T2>> extends HasOneOrMany<T, T2> {
    /**
     * The cached value of this relation.
     * @type Model
     */
    protected _value?: T2

    /**
     * True if the relation has been loaded.
     * @type boolean
     */
    protected _loaded = false

    public async get(): Promise<T2 | undefined> {
        return this.fetch().first()
    }

    public set_value(related: Collection<T2>) {
        this._value = related.first()
        this._loaded = true

        if ( related.length > 1 ) {
            this.make(Logging).warn(`HasOne relation result contained more than one value for ${this.qualified_local_key} -> ${this.qualified_local_key}`)
        }
    }

    public get_value(): T2 | undefined {
        return this._value
    }

    public is_loaded(): boolean {
        return this._loaded
    }
}