package org.gcube.informationsystem.resourceregistry.context;

import java.io.IOException;
import java.net.HttpURLConnection;
import java.util.List;
import java.util.UUID;

import org.gcube.com.fasterxml.jackson.core.JsonProcessingException;
import org.gcube.common.gxhttp.reference.GXConnection;
import org.gcube.common.gxhttp.request.GXHTTPStringRequest;
import org.gcube.informationsystem.context.reference.entities.Context;
import org.gcube.informationsystem.model.impl.properties.HeaderImpl;
import org.gcube.informationsystem.model.reference.properties.Header;
import org.gcube.informationsystem.resourceregistry.api.contexts.ContextCache;
import org.gcube.informationsystem.resourceregistry.api.contexts.ContextCacheRenewal;
import org.gcube.informationsystem.resourceregistry.api.exceptions.ResourceRegistryException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.context.ContextAlreadyPresentException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.context.ContextNotFoundException;
import org.gcube.informationsystem.resourceregistry.api.rest.AccessPath;
import org.gcube.informationsystem.resourceregistry.api.rest.ContextPath;
import org.gcube.informationsystem.resourceregistry.api.rest.httputils.HTTPUtility;
import org.gcube.informationsystem.utils.ElementMapper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @author Luca Frosini (ISTI - CNR)
 */
public class ResourceRegistryContextClientImpl implements ResourceRegistryContextClient {
	
	private static final Logger logger = LoggerFactory.getLogger(ResourceRegistryContextClientImpl.class);
	
	protected final String address;
	
	protected ContextCacheRenewal contextCacheRenewal = new ContextCacheRenewal() {
		
		@Override
		public List<Context> renew() throws ResourceRegistryException {
			return getAllContextFromServer();
		}
		
	};
	
	public ResourceRegistryContextClientImpl(String address) {
		this.address = address;
		ContextCache contextCache = ContextCache.getInstance();
		contextCache.setContextCacheRenewal(contextCacheRenewal);
	}
	
	private void forceCacheRefresh() {
		try {
			ContextCache contextCache = ContextCache.getInstance();
			contextCache.cleanCache();
			contextCache.refreshContextsIfNeeded();
		}catch (Exception e) {
			logger.warn("Unable to force cache refresh.", e);
		}
	}
	
	protected String internalCreate(Context context) throws ContextAlreadyPresentException, ResourceRegistryException {
		try {
			Header header = context.getHeader();
			if(header == null) {
				header = new HeaderImpl(UUID.randomUUID());
				context.setHeader(header);
			}
			UUID uuid = context.getHeader().getUUID();
			
			String contextString = ElementMapper.marshal(context);
			
			logger.trace("Going to create {}", contextString);
			
			GXHTTPStringRequest gxHTTPStringRequest = GXHTTPStringRequest.newRequest(address);
			gxHTTPStringRequest.from(ResourceRegistryContextClient.class.getSimpleName());
			gxHTTPStringRequest.header("Accept", GXConnection.APPLICATION_JSON_CHARSET_UTF_8);
			gxHTTPStringRequest.header("Content-type", GXConnection.APPLICATION_JSON_CHARSET_UTF_8);
			gxHTTPStringRequest.path(ContextPath.CONTEXTS_PATH_PART);
			gxHTTPStringRequest.path(uuid.toString());
			
			HttpURLConnection httpURLConnection = gxHTTPStringRequest.put(contextString);
			String c = HTTPUtility.getResponse(String.class, httpURLConnection);
			
			forceCacheRefresh();
			
			logger.trace("{} successfully created", c);
			return c;
			
		} catch(ResourceRegistryException e) {
			// logger.trace("Error Creating {}", facet, e);
			throw e;
		} catch(Exception e) {
			// logger.trace("Error Creating {}", facet, e);
			throw new RuntimeException(e);
		}
	}
	
	@Override
	public Context create(Context context) throws ContextAlreadyPresentException, ResourceRegistryException {
		try {
			String res = internalCreate(context);
			return ElementMapper.unmarshal(Context.class, res);
		} catch(ResourceRegistryException e) {
			// logger.trace("Error Creating {}", facet, e);
			throw e;
		} catch(Exception e) {
			// logger.trace("Error Creating {}", facet, e);
			throw new RuntimeException(e);
		}
	}
	
	@Override
	public String create(String context) throws ContextAlreadyPresentException, ResourceRegistryException {
		try {
			Context c = ElementMapper.unmarshal(Context.class, context);
			return internalCreate(c);
		} catch(ResourceRegistryException e) {
			// logger.trace("Error Creating {}", facet, e);
			throw e;
		} catch(Exception e) {
			// logger.trace("Error Creating {}", facet, e);
			throw new RuntimeException(e);
		}
	}
	
	@Override
	public Context read(Context context) throws ContextNotFoundException, ResourceRegistryException {
		return read(context.getHeader().getUUID());
	}
	
	@Override
	public Context read(UUID uuid) throws ContextNotFoundException, ResourceRegistryException {
		ContextCache contextCache = ContextCache.getInstance();
		Context context = ContextCache.getInstance().getContextByUUID(uuid);;
		if(context == null) {
			String contextJson = readFromServer(uuid.toString());
			try {
				context = ElementMapper.unmarshal(Context.class, contextJson);
			} catch (IOException e) {
				throw new RuntimeException(e);
			}
			forceCacheRefresh();
			Context c = contextCache.getContextByUUID(context.getHeader().getUUID());
			if(c!=null){
				context = c;
			}else {
				logger.error("Context with UUID {} is {}. It is possibile to get it from the server but not from the cache. This is very strange and should not occur.", uuid, context);
			}
		}
		return context;
	}
	
	@Override
	public Context readCurrentContext() throws ContextNotFoundException, ResourceRegistryException {
		String contextFullName = ResourceRegistryContextClientFactory.getCurrentContextFullName();
		ContextCache contextCache = ContextCache.getInstance();
		UUID uuid = contextCache.getUUIDByFullName(contextFullName);
		Context context = null;
		if(uuid == null) {
			String contextJson = readFromServer(AccessPath.CURRENT_CONTEXT);
			try {
				context = ElementMapper.unmarshal(Context.class, contextJson);
			} catch (IOException e) {
				throw new RuntimeException(e);
			}
			contextCache.cleanCache();
			contextCache.refreshContextsIfNeeded();
			Context c = contextCache.getContextByUUID(context.getHeader().getUUID());
			if(c!=null){
				context = c;
			}else {
				logger.error("Current Context is {}. It is possibile to get it from the server but not from the cache. This is very strange and should not occur.", contextFullName);
			}
		}else {
			context = contextCache.getContextByUUID(uuid);
		}
		return context;
	}
	
	@Override
	public String read(String uuid) throws ContextNotFoundException, ResourceRegistryException {
		try {
			return ElementMapper.marshal(read(UUID.fromString(uuid)));
		} catch (ContextNotFoundException e) {
			throw e;
		} catch (JsonProcessingException e) {
			throw new RuntimeException(e);
		} catch (ResourceRegistryException e) {
			throw e;
		}
	}
	
	public String readFromServer(String uuid) throws ContextNotFoundException, ResourceRegistryException {
		try {
			logger.trace("Going to read {} with UUID {}", Context.NAME, uuid);
			GXHTTPStringRequest gxHTTPStringRequest = GXHTTPStringRequest.newRequest(address);
			gxHTTPStringRequest.from(ResourceRegistryContextClient.class.getSimpleName());
			gxHTTPStringRequest.header("Accept", GXConnection.APPLICATION_JSON_CHARSET_UTF_8);
			gxHTTPStringRequest.path(ContextPath.CONTEXTS_PATH_PART);
			gxHTTPStringRequest.path(uuid);
			
			HttpURLConnection httpURLConnection = gxHTTPStringRequest.get();
			String c = HTTPUtility.getResponse(String.class, httpURLConnection);
			
			logger.debug("Got {} is {}", Context.NAME, c);
			return c;
		} catch(ResourceRegistryException e) {
			// logger.trace("Error Creating {}", facet, e);
			throw e;
		} catch(Exception e) {
			// logger.trace("Error Creating {}", facet, e);
			throw new RuntimeException(e);
		}
	}
	
	public String internalUpdate(Context context) throws ContextNotFoundException, ResourceRegistryException {
		try {
			String contextString = ElementMapper.marshal(context);
			logger.trace("Going to update {}", contextString);
			
			UUID uuid = context.getHeader().getUUID();
			
			GXHTTPStringRequest gxHTTPStringRequest = GXHTTPStringRequest.newRequest(address);
			gxHTTPStringRequest.from(ResourceRegistryContextClient.class.getSimpleName());
			gxHTTPStringRequest.header("Accept", GXConnection.APPLICATION_JSON_CHARSET_UTF_8);
			gxHTTPStringRequest.header("Content-type", GXConnection.APPLICATION_JSON_CHARSET_UTF_8);
			gxHTTPStringRequest.path(ContextPath.CONTEXTS_PATH_PART);
			gxHTTPStringRequest.path(uuid.toString());
			
			HttpURLConnection httpURLConnection = gxHTTPStringRequest.put(contextString);
			String c = HTTPUtility.getResponse(String.class, httpURLConnection);
			
			forceCacheRefresh();
			
			logger.trace("{} successfully updated", c);
			return c;
			
		} catch(ResourceRegistryException e) {
			// logger.trace("Error Creating {}", facet, e);
			throw e;
		} catch(Exception e) {
			// logger.trace("Error Creating {}", facet, e);
			throw new RuntimeException(e);
		}
	}
	
	@Override
	public Context update(Context context) throws ContextNotFoundException, ResourceRegistryException {
		try {
			String res = internalUpdate(context);
			return ElementMapper.unmarshal(Context.class, res);
		} catch(ResourceRegistryException e) {
			// logger.trace("Error Updating {}", facet, e);
			throw e;
		} catch(Exception e) {
			// logger.trace("Error Updating {}", facet, e);
			throw new RuntimeException(e);
		}
	}
	
	@Override
	public String update(String context) throws ContextNotFoundException, ResourceRegistryException {
		try {
			Context c = ElementMapper.unmarshal(Context.class, context);
			return internalUpdate(c);
		} catch(ResourceRegistryException e) {
			// logger.trace("Error Updating {}", facet, e);
			throw e;
		} catch(Exception e) {
			// logger.trace("Error Updating {}", facet, e);
			throw new RuntimeException(e);
		}
	}
	
	@Override
	public boolean delete(Context context) throws ContextNotFoundException, ResourceRegistryException {
		return delete(context.getHeader().getUUID());
	}
	
	@Override
	public boolean delete(UUID uuid) throws ContextNotFoundException, ResourceRegistryException {
		return delete(uuid.toString());
	}
	
	@Override
	public boolean delete(String uuid) throws ContextNotFoundException, ResourceRegistryException {
		try {
			logger.trace("Going to delete {} with UUID {}", Context.NAME, uuid);
			GXHTTPStringRequest gxHTTPStringRequest = GXHTTPStringRequest.newRequest(address);
			gxHTTPStringRequest.from(ResourceRegistryContextClient.class.getSimpleName());
			gxHTTPStringRequest.header("Accept", GXConnection.APPLICATION_JSON_CHARSET_UTF_8);
			gxHTTPStringRequest.path(ContextPath.CONTEXTS_PATH_PART);
			gxHTTPStringRequest.path(uuid);
			
			HttpURLConnection httpURLConnection = gxHTTPStringRequest.delete();
			HTTPUtility.getResponse(String.class, httpURLConnection);
			
			boolean deleted = true;
			
			
			
			logger.info("{} with UUID {} {}", Context.NAME, uuid,
					deleted ? " successfully deleted" : "was NOT deleted");
			return deleted;
		} catch(ResourceRegistryException e) {
			// logger.trace("Error Creating {}", facet, e);
			throw e;
		} catch(Exception e) {
			// logger.trace("Error Creating {}", facet, e);
			throw new RuntimeException(e);
		}finally {
			try {
				ContextCache contextCache = ContextCache.getInstance();
				contextCache.cleanCache();
				contextCache.refreshContextsIfNeeded();
			}catch (Exception e) {
				
			}
		}
	}
	
	protected List<Context> getAllContextFromServer() throws ResourceRegistryException {
		try {
			logger.trace("Going to read {} with UUID {}", Context.NAME);
			GXHTTPStringRequest gxHTTPStringRequest = GXHTTPStringRequest.newRequest(address);
			gxHTTPStringRequest.from(ResourceRegistryContextClient.class.getSimpleName());
			gxHTTPStringRequest.header("Accept", GXConnection.APPLICATION_JSON_CHARSET_UTF_8);
			gxHTTPStringRequest.path(ContextPath.CONTEXTS_PATH_PART);
			
			HttpURLConnection httpURLConnection = gxHTTPStringRequest.get();
			String all = HTTPUtility.getResponse(String.class, httpURLConnection);
			
			logger.debug("Got contexts are {}", Context.NAME, all);
			return ElementMapper.unmarshalList(Context.class, all);
			
		} catch(ResourceRegistryException e) {
			// logger.trace("Error Creating {}", facet, e);
			throw e;
		} catch(Exception e) {
			// logger.trace("Error Creating {}", facet, e);
			throw new RuntimeException(e);
		}
	}
	
	@Override
	public List<Context> all() throws ResourceRegistryException {
		ContextCache contextCache = ContextCache.getInstance();
		return contextCache.getContexts();
	}
	
}