datasouce sling model

package datasources.staticstyles.v1;

import com.adobe.granite.ui.components.ds.DataSource;
import com.adobe.granite.ui.components.ds.SimpleDataSource;
import com.adobe.granite.ui.components.ds.ValueMapResource;
import com.day.cq.commons.jcr.JcrConstants;
import com.day.cq.wcm.api.designer.Designer;
import org.apache.commons.collections.iterators.TransformIterator;
import org.apache.sling.api.SlingHttpServletRequest;
import org.apache.sling.api.resource.Resource;
import org.apache.sling.api.resource.ResourceMetadata;
import org.apache.sling.api.resource.ValueMap;
import org.apache.sling.api.wrappers.ValueMapDecorator;
import org.apache.sling.models.annotations.DefaultInjectionStrategy;
import org.apache.sling.models.annotations.Model;
import org.apache.sling.models.annotations.injectorspecific.Self;
import org.osgi.service.component.annotations.Component;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.annotation.PostConstruct;

import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Optional;
import java.util.stream.StreamSupport;

/**
 * This datasource sling model provides style classes for static templates as static templates are not compatible with the ootb style system
 */

@Model(
        adaptables = {SlingHttpServletRequest.class},
        defaultInjectionStrategy = DefaultInjectionStrategy.OPTIONAL
)
public class StaticStylesDatasourceModel {

    private static final Logger log = LoggerFactory.getLogger(StaticStylesDatasourceModel.class);

    public static final String NN_STATIC_STYLES = "staticStyles";
    public static final String PN_STATIC_STYLE_LABEL = "staticStyleLabel";
    public static final String PN_STATIC_STYLE_CLASS = "staticStyleClass";
    public static final String VALUE = "value";
    public static final String TEXT = "text";

    @Self
    private SlingHttpServletRequest request;

    @PostConstruct
    public void init() {
        final Map<String, String> stylesMap = new LinkedHashMap<>();
        try{
            Resource suffixResource = request.getRequestPathInfo().getSuffixResource();
            if(suffixResource != null){
                //This is getting the values of the static style system through the ootb Design API
                final Designer designer = request.getResourceResolver().adaptTo(Designer.class);
                Optional.ofNullable(designer)
                        .map(designer1 -> designer.getStyle(suffixResource))
                        .map(style -> request.getResourceResolver().getResource(style.getPath()))
                        .map(designResource -> designResource.getChild(NN_STATIC_STYLES))
                        .map(Resource::getChildren)
                        .map(iterable -> StreamSupport.stream(iterable.spliterator(), false))
                        .ifPresent(s -> {
                            s.map(Resource::getValueMap).forEach(
                                    valueMap -> {
                                        stylesMap.put(
                                                valueMap.get(PN_STATIC_STYLE_LABEL, String.class),
                                                valueMap.get(PN_STATIC_STYLE_CLASS, String.class));
                                    }
                            );
                        });
            }
        }catch (Exception e){
            log.error("Problem with getting the datasource for the static styles tab", e);
        }
        if(!stylesMap.isEmpty()){
            DataSource dataSource = new SimpleDataSource(new TransformIterator(stylesMap.keySet().iterator(), transformer -> {
                final String key = (String) transformer;
                ValueMap valueMap = new ValueMapDecorator(new HashMap<>());
                valueMap.put(TEXT, key);
                valueMap.put(VALUE, stylesMap.get(key));
                return new ValueMapResource(request.getResourceResolver(), new ResourceMetadata(), JcrConstants.NT_UNSTRUCTURED, valueMap);
            }));
            request.setAttribute(DataSource.class.getName(), dataSource);
        }
    }

}