GameLib.D3.Entity = function(
    meshId,
    componentIds
) {
    this.meshId = meshId;

    if (typeof componentIds == 'undefined') {
        componentIds = [];
    }

    this.componentIds = componentIds;

    // constructed at runtime
    this.parentScene = null;
    this.mesh = null;

    // todo:
    // add position, rotation & scale properties to entity itself!

    this.permutate = {
        offset : {
            position : null,
            quaternion : null
        }
    };
};

/**
 * Updates the Entity and it's components
 * @param deltaTime Number
 */
GameLib.D3.Entity.prototype.update = function(
    deltaTime
) {
    for(var c in this.componentIds) {
        var componentId = this.componentIds[c];
        var component = this.parentScene.componentIdToComponent[componentId];
        if(component && component.onUpdate) {
            component.onUpdate(deltaTime, this);
        }
    }

    this.onUpdate(deltaTime);
};

/**
* Late updates the Entity and it's components
* @param deltaTime Number
*/
GameLib.D3.Entity.prototype.lateUpdate = function(
    deltaTime
) {
    for(var c in this.componentIds) {
        var componentId = this.componentIds[c];
        var component = this.parentScene.componentIdToComponent[componentId];
        if(component && component.onLateUpdate) {
            component.onLateUpdate(deltaTime, this);
        }
    }

    this.onLateUpdate(deltaTime);
};

/**
* Gets called when the entity was registered with it's parent scene
* @param parentScene GameLib.D3.Scene
*/
GameLib.D3.Entity.prototype.register = function(
    parentScene
) {
    this.parentScene = parentScene;

    if(this.meshId != null && parentScene.meshIdToMesh[this.meshId]) {
        parentScene.threeScene.add(parentScene.meshIdToMesh[this.meshId]);
        this.mesh = parentScene.meshIdToMesh[this.meshId];
    }

    this.onRegistered(parentScene);
};

/**
 * Add an already registered component to the entity
 * @param componentId Number
 */
GameLib.D3.Entity.prototype.addComponentId = function(
    componentId
) {
    this.componentIds.push(componentId);
};

/**
 * Adds a components to the entity and registers it with the entity's parent scene
 * @param component GameLib.D3.ComponentInterface
 */
GameLib.D3.Entity.prototype.addComponent = function(
    component
) {
    this.parentScene.registerComponent(component);

    this.componentIds.push(component.componentId);

    if(component.setParentEntity && typeof component.setParentEntity == 'function') {
        component.setParentEntity(this.parentScene, this);
    }
};


GameLib.D3.Entity.prototype.getComponent = function(
    componentType
) {
    for(var c in this.componentIds) {
        var componentId = this.componentIds[c];
        var component = this.parentScene.componentIdToComponent[componentId];
        if (component instanceof componentType) {
            return component;
        }
    }

    return null;
};

///////////////////////// Methods to override //////////////////////////

GameLib.D3.Entity.prototype.onUpdate = function(
    deltaTime
) {

};

GameLib.D3.Entity.prototype.onLateUpdate = function(
    deltaTime
) {

};

GameLib.D3.Entity.prototype.onRegistered = function(
    parentScene
) {

};