package org.gcube.gcat.rest;

import java.util.ArrayList;
import java.util.List;

import javax.cache.Cache;
import javax.ws.rs.DefaultValue;
import javax.ws.rs.GET;
import javax.ws.rs.HeaderParam;
import javax.ws.rs.InternalServerErrorException;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;

import org.gcube.common.scope.api.ScopeProvider;
import org.gcube.datacatalogue.metadatadiscovery.DataCalogueMetadataFormatReader;
import org.gcube.datacatalogue.metadatadiscovery.bean.MetadataProfile;
import org.gcube.gcat.ResourceInitializer;
import org.gcube.gcat.oldutils.CachesManager;
import org.json.JSONObject;
import org.json.XML;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ArrayNode;


/**
 * @author Luca Frosini (ISTI - CNR)
 */
@Path(BaseREST.PROFILES)
public class Profile extends BaseREST {
	
	public static final String PROFILE_NAME_PARAMETER = "PROFILE_NAME";

	public static DataCalogueMetadataFormatReader getDataCalogueMetadataFormatReader() throws Exception {
		Cache<String,DataCalogueMetadataFormatReader> readerCache = CachesManager.getReaderCache();
		String context = ScopeProvider.instance.get();
		DataCalogueMetadataFormatReader reader;
		if(readerCache.containsKey(context))
			reader = (DataCalogueMetadataFormatReader) readerCache.get(context);
		else {
			reader = new DataCalogueMetadataFormatReader();
			readerCache.put(context, reader);
		}
		return reader;
	}
	
	/**
	 * Returns the names of the metadata profiles in a given context
	 * @param context
	 * @return
	 * @throws Exception 
	 */
	public static List<String> getProfilesNames() throws Exception {
		
		DataCalogueMetadataFormatReader reader = getDataCalogueMetadataFormatReader();
		
		List<String> toReturn = new ArrayList<String>();
		List<MetadataProfile> listProfiles = reader.getListOfMetadataProfiles();
		
		if(listProfiles != null && !listProfiles.isEmpty()) {
			for(MetadataProfile profile : listProfiles) {
				toReturn.add(profile.getName());
			}
		}
		
		return toReturn;
	}
	
	/**
	 * Returns the source xml of the metadata profile (specified via name) in a given context
	 * @param context
	 * @return
	 * @throws Exception 
	 */
	public static String getProfileSource(String profileName) throws Exception {
		
		DataCalogueMetadataFormatReader reader = Profile.getDataCalogueMetadataFormatReader();
		
		List<MetadataProfile> listProfiles = reader.getListOfMetadataProfiles();
		String xmlToReturn = null;
		
		if(listProfiles != null && !listProfiles.isEmpty()) {
			for(MetadataProfile profile : listProfiles) {
				if(profile.getName().equals(profileName)) {
					xmlToReturn = reader.getMetadataFormatForMetadataProfile(profile).getMetadataSource();
					break;
				}
			}
		}
		
		return xmlToReturn;
	}
	
	@GET
	@Produces(ResourceInitializer.APPLICATION_JSON_CHARSET_UTF_8)
	public String list() {
		setCalledMethod("GET /" + BaseREST.PROFILES);
		
		ObjectMapper mapper = new ObjectMapper();
		ArrayNode arrayNode = mapper.createArrayNode();
		
		try {
			List<String> names = getProfilesNames();
			for(String name : names) {
				arrayNode.add(name);
			}
			return mapper.writeValueAsString(arrayNode);
		} catch(Exception e) {
			throw new InternalServerErrorException(e.getMessage());
		}
	}
	
	public static int PRETTY_PRINT_INDENT_FACTOR = 4;
	
	@GET
	@Path("/{" + PROFILE_NAME_PARAMETER + "}")
	@Produces({MediaType.APPLICATION_XML, ResourceInitializer.APPLICATION_JSON_CHARSET_UTF_8})
	public String read(@PathParam(PROFILE_NAME_PARAMETER) String id, 
			@DefaultValue(MediaType.APPLICATION_JSON) @HeaderParam("Accept") String accept) {
		setCalledMethod("GET /" + BaseREST.PROFILES + "/{" + PROFILE_NAME_PARAMETER + "}");
		try {
			String profile = Profile.getProfileSource(id);
			if(accept.startsWith(MediaType.APPLICATION_XML)){
				return profile;
			}else {
				 JSONObject xmlJSONObj = XML.toJSONObject(profile);
		         String jsonString = xmlJSONObj.toString(PRETTY_PRINT_INDENT_FACTOR);
		         return jsonString;
			} 
		} catch(Exception e) {
			throw new InternalServerErrorException(e.getMessage());
		}
	}
	
}