module ecs {


    interface EntityBindingState {

        decoratorGenerators:Array<DecoratorGenerator>
    }

    export interface Component {

        activate();

    }

    export interface Entity {

        addDecorator(decorator: Decorator): void;

        getDecorator(): Decorator

    }



    export function createMemberDecorator(decoratorGenerator: DecoratorGenerator) {

        let propertyDecorator: PropertyDecorator = (entityPrototype: eui.Component, key: string) => {


            bindDecoratorWithEntity(entityPrototype, decoratorGenerator)

        }



        return propertyDecorator;
    }

    function bindDecoratorWithEntity(entityPrototype: eui.Component, decoratorGenerator: DecoratorGenerator) {

        let state: EntityBindingState = entityPrototype["__ecs__state"];
        if (!state) {
            let rawPartAdd = entityPrototype["partAdded"];
            let overridePartAdd = function (partName, instance) {

                let entity: eui.Component = this;
                rawPartAdd.call(entity, partName, instance);
                for (let decorator of state.decoratorGenerators){
                    let handler = decorator(entity,instance);
                    handler.activate();
                }
            }
            entityPrototype["partAdded"] = overridePartAdd;
            state = {
                decoratorGenerators:[]
            };
            entityPrototype["__ecs__state"] = state;

        }
        state.decoratorGenerators.push(decoratorGenerator);


    }


}




type Class<T> = { new (...arg): T, prototype: T };

type DecoratorGenerator = (entity: any, component: any) => ecs.Component;

interface Entity {

    addDecorator(d: Decorator)
}

interface Decorator {

}