console.log("loading transform system");

const transform = (engine) => (
    entity,
    transformData = { x: {x: 1, y:0}, y: {x:0, y:1}, o: {x:0,y:0}}
) => {
    let {x, y, o} = transformData;
    let transform = [x.x, x.y, y.x, y.y, o.x, o.y];
    const updateEntity = () => {
        entity.dataset.transform = JSON.stringify (transform);
    };

    // these may be pulled out in the future into a separate renderer
    const setEntityStyleFromTransform = (entity) => {
        entity.style.transform =
            `matrix(${entity.dataset.transform.replace(/\[|\]/g,'')})`;
    };
    const renderEntity = () => setEntityStyleFromTransform (entity);

    return (message, ...messageArgs) => {
        switch (message) {
        case "origin": {
            return [transform[4], transform[5]];
        }
        case "x": {
            return [transform[0], transform[1]];
        }
        case "y": {
            return [transform[2], transform [3]];
        }
        case "translate": {
            let [xTranslation, yTranslation] = messageArgs [0];
            transform [4] += xTranslation;
            transform [5] += yTranslation;
            break;
        }
        }
        updateEntity ();
        renderEntity ();
    };
};

const initTransformSystem = (engine) => {
    engine("registerComponentType", "transform", transform);
};


// transform needs to actually provide transformation utilities