package org.gcube.informationsystem.resourceregistry.schema;

import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.gcube.common.gxhttp.reference.GXConnection;
import org.gcube.common.gxhttp.request.GXHTTPStringRequest;
import org.gcube.common.http.GXHTTPUtility;
import org.gcube.informationsystem.model.knowledge.ModelKnowledge;
import org.gcube.informationsystem.model.reference.ModelElement;
import org.gcube.informationsystem.model.reference.properties.Metadata;
import org.gcube.informationsystem.resourceregistry.api.exceptions.NotFoundException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.ResourceRegistryException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.contexts.ContextAlreadyPresentException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.contexts.ContextNotFoundException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.types.SchemaException;
import org.gcube.informationsystem.resourceregistry.api.exceptions.types.SchemaNotFoundException;
import org.gcube.informationsystem.resourceregistry.api.rest.AccessPath;
import org.gcube.informationsystem.resourceregistry.api.rest.TypePath;
import org.gcube.informationsystem.resourceregistry.api.rest.httputils.HTTPUtility;
import org.gcube.informationsystem.tree.Node;
import org.gcube.informationsystem.types.TypeMapper;
import org.gcube.informationsystem.types.knowledge.TypeInformation;
import org.gcube.informationsystem.types.knowledge.TypesKnowledge;
import org.gcube.informationsystem.types.reference.Type;
import org.gcube.informationsystem.utils.TypeUtility;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * @author Luca Frosini (ISTI - CNR)
 */
public class ResourceRegistrySchemaClientImpl implements ResourceRegistrySchemaClient {
	
	private static final Logger logger = LoggerFactory.getLogger(ResourceRegistrySchemaClientImpl.class);
	
	private static final String ACCEPT_HTTP_HEADER_KEY = "Accept";
	private static final String CONTENT_TYPE_HTTP_HEADER_KEY = "Content-Type";
	
	protected final String address;
	
	protected Map<String, String> headers;
	
	protected TypesKnowledge typesKnowledge;
	
	/**
	 * Track if the client must request to include {@link Metadata} 
	 */
	protected boolean includeMeta;
	
	public boolean includeMeta() {
		return includeMeta;
	}

	public void setIncludeMeta(boolean includeMeta) {
		this.includeMeta = includeMeta;
	}

	private void addOptionalQueryParameters(Map<String,String> queryParams) throws UnsupportedEncodingException {
		addIncludeMeta(queryParams);
	}
	
	private GXHTTPStringRequest includeAdditionalQueryParameters(GXHTTPStringRequest gxHTTPStringRequest) throws UnsupportedEncodingException{
		Map<String,String> queryParams = new HashMap<>();
		return includeAdditionalQueryParameters(gxHTTPStringRequest, queryParams);
	}
	
	private GXHTTPStringRequest includeAdditionalQueryParameters(GXHTTPStringRequest gxHTTPStringRequest, Map<String,String> queryParams) throws UnsupportedEncodingException{
		if(queryParams==null) {
			queryParams = new HashMap<>();
		}
		addOptionalQueryParameters(queryParams);
		return gxHTTPStringRequest.queryParams(queryParams);
	}
	
	private void addIncludeMeta(Map<String,String> queryParams) throws UnsupportedEncodingException{
		if(includeMeta) {
			queryParams.put(AccessPath.INCLUDE_META_QUERY_PARAMETER, Boolean.toString(includeMeta));
		}
	}
	
	@Override
	public void addHeader(String name, String value) {
		headers.put(name, value);
	}
	
	protected GXHTTPStringRequest getGXHTTPStringRequest() {
		GXHTTPStringRequest gxHTTPStringRequest = GXHTTPUtility.getGXHTTPStringRequest(address);
		gxHTTPStringRequest.from(this.getClass().getSimpleName());
		for(String name : headers.keySet()) {
			gxHTTPStringRequest.header(name, headers.get(name));
		}
		return gxHTTPStringRequest;
	}
	
	public ResourceRegistrySchemaClientImpl(String address) {
		this(address, true);
		
	}
	
	public ResourceRegistrySchemaClientImpl(String address, boolean sharedModelKnowledge) {
		this.address = address;
		this.headers = new HashMap<>();
		this.includeMeta = false;
		
		if(sharedModelKnowledge) {
			this.typesKnowledge = TypesKnowledge.getInstance();
		}else {
			this.typesKnowledge = new TypesKnowledge();
		}
		typesKnowledge.setTypesDiscoverer(new RRCCTypesDiscoverer(this));
	}
	
	@Override
	public ModelKnowledge<Type, TypeInformation> getModelKnowledge() {
		return typesKnowledge.getModelKnowledge();
	}
	
	@Override
	public void renewModelKnowledge() {
		typesKnowledge.renew();
	}
	
	@Override
	public <ME extends ModelElement> Type create(Class<ME> clz)
			throws SchemaException, ResourceRegistryException {
		try {
			String typeDefinition = TypeMapper.serializeType(clz);
			// String type = AccessType.getAccessType(clz).getName();
			String res = create(typeDefinition);
			return TypeMapper.deserializeTypeDefinition(res);
		} catch(ResourceRegistryException e) {
			throw e;
		} catch(Exception e) {
			throw new RuntimeException(e);
		}
	}
	
	@Override
	public String create(String typeDefinitition) throws ContextAlreadyPresentException, ResourceRegistryException {
		try {
			logger.trace("Going to create: {}", typeDefinitition);
			Type typeDefinitionObj = TypeMapper.deserializeTypeDefinition(typeDefinitition);
			
			GXHTTPStringRequest gxHTTPStringRequest = getGXHTTPStringRequest();
			gxHTTPStringRequest.header(ACCEPT_HTTP_HEADER_KEY, GXConnection.APPLICATION_JSON_CHARSET_UTF_8);
			gxHTTPStringRequest.header(CONTENT_TYPE_HTTP_HEADER_KEY, GXConnection.APPLICATION_JSON_CHARSET_UTF_8);
			gxHTTPStringRequest.path(TypePath.TYPES_PATH_PART);
			gxHTTPStringRequest.path(typeDefinitionObj.getName());
			
			includeAdditionalQueryParameters(gxHTTPStringRequest);
			
			HttpURLConnection httpURLConnection = gxHTTPStringRequest.put(typeDefinitition);
			String c = HTTPUtility.getResponse(String.class, httpURLConnection);
			
			Type t = TypeMapper.deserializeTypeDefinition(c);
			typesKnowledge.getModelKnowledge().addType(t);
			
			logger.trace("{} successfully created", c);
			return c;
			
		} catch(ResourceRegistryException e) {
			throw e;
		} catch(Exception e) {
			throw new RuntimeException(e);
		}
	}
	
	@Override
	public <ME extends ModelElement> boolean exist(Class<ME> clazz) throws ResourceRegistryException {
		return exist(TypeUtility.getTypeName(clazz));
	}	
	
	@Override
	public boolean exist(String typeName) throws ResourceRegistryException {
		try {
			return typesKnowledge.getModelKnowledge().getTypeByName(typeName) != null;
		}catch (RuntimeException e) {
			return false;
		}
	}
	
	public List<Type> getTypeFromTypesKnowledge(String typeName, Boolean polymorphic)
			throws SchemaNotFoundException, ResourceRegistryException {
		return getTypeFromTypesKnowledge(typeName, polymorphic, -1);
	}
	
	
	public List<Type> getTypeFromTypesKnowledge(String typeName, int level)
			throws SchemaNotFoundException, ResourceRegistryException {
		return getTypeFromTypesKnowledge(typeName, true, level);
	}
	
	protected List<Type> addChildren(Node<Type> node, List<Type> types, int currentLevel, int maxLevel) {
		if(maxLevel>=0 && maxLevel <= currentLevel) {
			return types;
		}
		
		Set<Node<Type>> children = node.getChildrenNodes();
		if(children!=null && children.size()>0) {
			for(Node<Type> child : children) {
				types.add(child.getNodeElement());
				types = addChildren(child, types, ++currentLevel, maxLevel);
			}
		}
		
		return types;
	}
	
	public List<Type> getTypeFromTypesKnowledge(String typeName, Boolean polymorphic, int level)
			throws SchemaNotFoundException, ResourceRegistryException {
		
		Node<Type> node = getTypeTreeNode(typeName);
		
		List<Type> types = new ArrayList<>();
		types.add(node.getNodeElement());
		
		if (polymorphic) {
			addChildren(node, types, 0, level);
		} 
		
		return types;
	}
	
	@Override
	public String read(String typeName, Boolean polymorphic) throws SchemaNotFoundException, ResourceRegistryException {
		try { 
			List<Type> types = getTypeFromTypesKnowledge(typeName, polymorphic);
			return TypeMapper.serializeTypeDefinitions(types);
		} catch(ResourceRegistryException e) {
			throw e;
		} catch(Exception e) {
			throw new ResourceRegistryException(e);
		}
	}

	@Override
	public <ME extends ModelElement> List<Type> read(Class<ME> clazz, Boolean polymorphic)
			throws SchemaNotFoundException, ResourceRegistryException {
		try {
			String typeName = TypeUtility.getTypeName(clazz);
			return getTypeFromTypesKnowledge(typeName, polymorphic);
		} catch (Exception e) {
			throw new ResourceRegistryException(e);
		}
	}
	
	@Override
	public String read(String typeName, int level) throws SchemaNotFoundException, ResourceRegistryException {
		try { 
			List<Type> types = getTypeFromTypesKnowledge(typeName, level);
			return TypeMapper.serializeTypeDefinitions(types);
		} catch(ResourceRegistryException e) {
			throw e;
		} catch(Exception e) {
			throw new ResourceRegistryException(e);
		}
	}

	@Override
	public <ME extends ModelElement> List<Type> read(Class<ME> clazz, int level)
			throws SchemaNotFoundException, ResourceRegistryException {
		try {
			String typeName = TypeUtility.getTypeName(clazz);
			return getTypeFromTypesKnowledge(typeName, level);
		} catch (Exception e) {
			throw new ResourceRegistryException(e);
		}
	}
	
	@Override
	public Node<Type> getTypeTreeNode(String typeName) throws SchemaNotFoundException, ResourceRegistryException {
		try { 
			Node<Type> node = null;
			try {
				node = typesKnowledge.getModelKnowledge().getNodeByName(typeName);
			} catch (RuntimeException e) {
				throw new SchemaNotFoundException(e);
			}
			return node;
		} catch(ResourceRegistryException e) {
			throw e;
		} catch(Exception e) {
			throw new ResourceRegistryException(e);
		}
	}

	@Override
	public <ME extends ModelElement> Node<Type> getTypeTreeNode(Class<ME> clazz)
			throws SchemaNotFoundException, ResourceRegistryException {
		try {
			String typeName = TypeUtility.getTypeName(clazz);
			return getTypeTreeNode(typeName);
		} catch (Exception e) {
			throw new ResourceRegistryException(e);
		}
	}
	
	public boolean existTypeFromServer(String typeName) throws ResourceRegistryException {
		try {
			logger.info("Going to get {} schema", typeName);
			GXHTTPStringRequest gxHTTPStringRequest = getGXHTTPStringRequest();
			gxHTTPStringRequest.header(ACCEPT_HTTP_HEADER_KEY, GXConnection.APPLICATION_JSON_CHARSET_UTF_8);
			gxHTTPStringRequest.path(TypePath.TYPES_PATH_PART);
			gxHTTPStringRequest.path(typeName);
			
			Map<String,String> parameters = new HashMap<>();
			parameters.put(TypePath.POLYMORPHIC_QUERY_PARAMETER, Boolean.FALSE.toString());
			gxHTTPStringRequest.queryParams(parameters);
			
			HttpURLConnection httpURLConnection = gxHTTPStringRequest.head();
			HTTPUtility.getResponse(String.class, httpURLConnection);
			
			return true;
		} catch (NotFoundException e) {
			return false;
		} catch(ResourceRegistryException e) {
			throw e;
		} catch(Exception e) {
			throw new RuntimeException(e);
		}
	}
	
	public <ME extends ModelElement> List<Type> getTypeFromServer(Class<ME> clz, Boolean polymorphic)
			throws SchemaNotFoundException, ResourceRegistryException {
		try {
			String typeName = TypeUtility.getTypeName(clz);
			String json = getTypeFromServer(typeName, polymorphic);
			return TypeMapper.deserializeTypeDefinitions(json);
		} catch(ResourceRegistryException e) {
			throw e;
		} catch(Exception e) {
			throw new ResourceRegistryException(e);
		}
	}
	
	public String getTypeFromServer(String typeName, Boolean polymorphic) throws ContextNotFoundException, ResourceRegistryException {
		try {
			logger.info("Going to get {} schema", typeName);
			GXHTTPStringRequest gxHTTPStringRequest = getGXHTTPStringRequest();
			gxHTTPStringRequest.header(ACCEPT_HTTP_HEADER_KEY, GXConnection.APPLICATION_JSON_CHARSET_UTF_8);
			gxHTTPStringRequest.path(TypePath.TYPES_PATH_PART);
			gxHTTPStringRequest.path(typeName);
			
			Map<String,String> parameters = new HashMap<>();
			if(polymorphic != null) {
				parameters.put(TypePath.POLYMORPHIC_QUERY_PARAMETER, polymorphic.toString());
			}
			includeAdditionalQueryParameters(gxHTTPStringRequest, parameters);
			
			HttpURLConnection httpURLConnection = gxHTTPStringRequest.get();
			String json = HTTPUtility.getResponse(String.class, httpURLConnection);
			
			logger.debug("Got schema for {} is {}", typeName, json);
			return json;
		} catch(ResourceRegistryException e) {
			throw e;
		} catch(Exception e) {
			throw new RuntimeException(e);
		}
	}
	
}