import { AnyType, ChainableAttributeSpec, Record } from '../record';

import { CollectionReference, parseReference } from './commons';

/********

* Reference to model by id.

*

* Untyped attribute. Holds model id, when unresolved. When resolved, is substituted

* with a real model.

*

* No model changes are detected and counted as owner's change. That's intentional.

*/

/** @private */

type RecordRefValue = Record | string;

/** @private */

class RecordRefType extends AnyType {

// It is always serialized as an id, whenever it's resolved or not.

toJSON( value : RecordRefValue ){

return value && typeof value === 'object' ? value.id : value;

}

// Wne

clone( value : RecordRefValue ){

return value && typeof value === 'object' ? value.id : value;

}

// Model refs by id are equal when their ids are equal.

isChanged( a : RecordRefValue, b : RecordRefValue){

var aId = a && ( (<Record>a).id == null ? a : (<Record>a).id ),

bId = b && ( (<Record>b).id == null ? b : (<Record>b).id );

return aId !== bId;

}

// Refs are always valid.

validate( model, value, name ){}

}

export function memberOf<R extends typeof Record>( this : void, masterCollection : CollectionReference, T? : R ) : ChainableAttributeSpec<R> {

const getMasterCollection = parseReference( masterCollection );

const typeSpec = new ChainableAttributeSpec<R>({

value : null,

_metatype : RecordRefType

});

return typeSpec

.get( function( objOrId : RecordRefValue, name : string ) : Record {

if( typeof objOrId === 'object' ) return objOrId;

// So, we're dealing with an id reference. Resolve it.

const collection = getMasterCollection( this );

let record : Record = null;

// If master collection exists and is not empty...

if( collection && collection.length ){

// Silently update attribute with record from this collection.

record = collection.get( objOrId ) || null;

this.attributes[ name ] = record;

// Subscribe for events manually. delegateEvents won't be invoked.

record && this._attributes[ name ].handleChange( record, null, this, {} );

}

return record;

});

}