import { Resource } from 'resource-loader';
import url from 'url';
import { Spritesheet } from '../core';

export default function ()
{
    return function spritesheetParser(resource, next)
    {
        const imageResourceName = `${resource.name}_image`;

        // skip if no data, its not json, it isn't spritesheet data, or the image resource already exists
        if (!resource.data
            || resource.type !== Resource.TYPE.JSON
            || !resource.data.frames
            || this.resources[imageResourceName]
        )
        {
            next();

            return;
        }

        const loadOptions = {
            crossOrigin: resource.crossOrigin,
            metadata: resource.metadata.imageMetadata,
            parentResource: resource,
        };

        const resourcePath = getResourcePath(resource, this.baseUrl);

        // load the image for this sheet
        this.add(imageResourceName, resourcePath, loadOptions, function onImageLoad(res)
        {
            if (res.error)
            {
                next(res.error);

                return;
            }

            const spritesheet = new Spritesheet(
                res.texture.baseTexture,
                resource.data,
                resource.url
            );

            spritesheet.parse(() =>
            {
                resource.spritesheet = spritesheet;
                resource.textures = spritesheet.textures;
                next();
            });
        });
    };
}

export function getResourcePath(resource, baseUrl)
{
    // Prepend url path unless the resource image is a data url
    if (resource.isDataUrl)
    {
        return resource.data.meta.image;
    }

    return url.resolve(resource.url.replace(baseUrl, ''), resource.data.meta.image);
}