import {Injectable} from 'angular2/src/core/di';

import {ViewMetadata} from '../metadata/view';

import {Type, stringify, isBlank, BaseException} from 'angular2/src/core/facade/lang';

import {Map, MapWrapper, ListWrapper} from 'angular2/src/core/facade/collection';

import {reflector} from 'angular2/src/core/reflection/reflection';

@Injectable()

export class ViewResolver {

_cache: Map<Type, /*node*/ any> = new Map();

resolve(component: Type): ViewMetadata {

var view = this._cache.get(component);

if (isBlank(view)) {

view = this._resolve(component);

this._cache.set(component, view);

}

return view;

}

_resolve(component: Type): ViewMetadata {

var annotations = reflector.annotations(component);

for (var i = 0; i < annotations.length; i++) {

var annotation = annotations[i];

if (annotation instanceof ViewMetadata) {

return annotation;

}

}

throw new BaseException(`No View annotation found on component ${stringify(component)}`);

}

}