package org.simantics.db.layer0.variable;

import java.util.Collection;
import java.util.Collections;
import java.util.Map;
import java.util.Set;

import org.simantics.databoard.Bindings;
import org.simantics.datatypes.literal.GUID;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.common.procedure.adapter.TransientCacheAsyncListener;
import org.simantics.db.exception.AssumptionException;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.layer0.exception.InvalidVariableException;
import org.simantics.db.layer0.function.All;
import org.simantics.db.layer0.request.ClassificationsRequest;
import org.simantics.db.layer0.request.VariableURI;
import org.simantics.db.layer0.variable.RVI.RVIPart;
import org.simantics.db.layer0.variable.RVI.ResourceRVIPart;
import org.simantics.db.layer0.variable.RVI.StringRVIPart;
import org.simantics.db.layer0.variable.Variables.Role;
import org.simantics.layer0.Layer0;
import org.simantics.simulator.variable.exceptions.NodeManagerException;

public class StandardGraphChildVariable extends AbstractChildVariable implements ProxyVariableSupport {

	/*
	 * Extension points
	 * 
	 */
	public Variable getPossibleSpecialChild(ReadGraph graph, String name) throws DatabaseException {
		return null;
	}

	public Map<String, Variable> collectSpecialChildren(ReadGraph graph, Map<String, Variable> children) throws DatabaseException {
		return children;
	}

	/*
	 * Standard implementation
	 * 
	 */
	
	final protected Variable parent;
	final public Resource resource;
	
	transient private int hash;
	
	public StandardGraphChildVariable(Variable parent, VariableNode node, Resource resource) {
		super(node);
		this.parent = parent;
		this.resource = resource;
	}

	@Override
	public void validate(ReadGraph graph) throws DatabaseException {
		if(!graph.hasStatement(resource)) throw new InvalidVariableException("The resource has been removed: " + resource);
	}
	
	@Override
	protected Variable getPossibleDomainProperty(ReadGraph graph, String name) throws DatabaseException {
		VariableMap map = getPossiblePropertyVariableMap(graph);
		if(map == null) return null;
		try {
			return map.getVariable(graph, this, name);
		} catch (DatabaseException e) {
			return null;
		}
	}

	@Override
	public Variable getPossibleChild(ReadGraph graph, String name) throws DatabaseException {
		VariableMap map = getPossibleChildVariableMap(graph);
		if(map == null) return getPossibleSpecialChild(graph, name);
		try {
			Variable result = map.getVariable(graph, this, name);
			if(result != null) return result;
			else return getPossibleSpecialChild(graph, name);
		} catch (DatabaseException e) {
			return null;
		}
	}

	@Override
	public Map<String, Variable> collectDomainProperties(ReadGraph graph, Map<String, Variable> properties) throws DatabaseException {
		VariableMap map = getPossiblePropertyVariableMap(graph);
		if(map == null) return properties;
		return map.getVariables(graph, this, properties);
	}

	@Override
	public Collection<Variable> getChildren(ReadGraph graph) throws DatabaseException {
		Map<String, Variable> result = null;
		VariableMap map = getPossibleChildVariableMap(graph);
		if(map != null) result = map.getVariables(graph, this, result);
		result = collectSpecialChildren(graph, result);
		if(result == null) return Collections.emptyList();
		else return result.values();
	}

	@SuppressWarnings("unchecked")
	@Override
	public String getName(ReadGraph graph) throws DatabaseException {
	    if(node != null) {
	        return node.support.manager.getName(node.node);
	    }
		String unescapedName = graph.getPossibleRelatedValue(resource, graph.getService(Layer0.class).HasName, Bindings.STRING);
		if(unescapedName == null) return VariableUtils.unnamedResourceName(resource);
		return unescapedName;
	}

	@Override
	public Variable getNameVariable(ReadGraph graph) throws DatabaseException {
		Resource resource = (Resource) getPossibleRepresents(graph);
		if (resource != null) {
			return new StandardGraphPropertyVariable(graph, this, null, resource, Layer0.getInstance(graph).HasName);
		}
		return super.getNameVariable(graph);
	}
	
	
	@Override
	public String getLabel(ReadGraph graph) throws DatabaseException {
	    if(resource == null) return getName(graph);
		String label = graph.getPossibleRelatedValue2(resource, graph.getService(Layer0.class).HasLabel);
		return label != null ? label : getName(graph);
	}

	@Override
	final protected Variable getLabelVariable(ReadGraph graph) throws DatabaseException {
		Layer0 L0 = Layer0.getInstance(graph);
		if(resource == null) return null;
		return new StandardGraphPropertyVariable(graph, this, L0.HasLabel);
	}
	
//	@Override
//	final public Object getSerialized(ReadGraph graph) throws DatabaseException {
//		Resource represents = getRepresents(graph);
//		if(represents != null) return represents;
//		else return getName(graph);
//	}

	@Override
	public Variable getParent(ReadGraph graph) throws DatabaseException {
		return parent;
	}
	
	@Override
	final public Resource getRepresents(ReadGraph graph) throws DatabaseException {
	    if(resource == null)
	        throw new InvalidVariableException("Variable is not represented by any resource (URI=" + getPossibleURI(graph) + ").");
	    return resource;
//		Layer0X L0X = Layer0X.getInstance(graph);
//		Resource represents = graph.getPossibleObject(resource, L0X.Represents);
//		if(represents != null) return represents;
//		else return resource;
	}

	@Override
	public Resource getPossibleRepresents(ReadGraph graph)
	        throws DatabaseException {
	    return resource;
	}
	
	@Override
	final public String getURI(ReadGraph graph) throws DatabaseException {
		
		try {
			if(parent == null) return "http:/";
			String parentURI = graph.syncRequest(new VariableURI(parent), TransientCacheAsyncListener.<String>instance());
			return parentURI + Role.CHILD.getIdentifier() + encodeString(getName(graph));
		} catch (AssumptionException e) {
			throw new InvalidVariableException(e);
		}
	}

	/**
	 * All variables must have proper URIs, this is only for debugging purposes.
	 * 
	 * @see org.simantics.db.layer0.variable.AbstractVariable#getPossibleURI(org.simantics.db.ReadGraph)
	 */
	@Override
	public String getPossibleURI(ReadGraph graph) throws DatabaseException {
        try {
            return getURI(graph);
        } catch (DatabaseException e) {
            return "<no uri>";
        }
	}

	@Override
	public int hashCode() {
		if(hash == 0) {
			final int prime = 31;
			int result = 1;
			result = prime * result + (parent != null ? parent.hashCode() : 0);
			result = prime * result + (node != null ? node.hashCode() : 0);
			result = prime * result + (resource != null ? resource.hashCode() : 0);
			hash =result;
		}
		return hash;
	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		
		StandardGraphChildVariable other = (StandardGraphChildVariable) obj;
		
		if(node != null) { 
			if(!node.equals(other.node)) return false;
		} else if (other.node != null) return false;

        if(resource != null) {
        	if(!resource.equals(other.resource)) return false;
        } else if (other.resource != null) return false;
		
        if(parent != null) {
        	if(!parent.equals(other.parent)) return false;
        } else if (other.parent != null) return false;
        
        return true;
		
	}
	
	@Override
	public <T> T adapt(ReadGraph graph, Class<T> clazz) throws DatabaseException {
		return graph.adapt(resource, clazz);
	}

    @Override
    public <T> T adaptPossible(ReadGraph graph, Class<T> clazz) throws DatabaseException {
        return graph.getPossibleAdapter(resource, clazz);
    }

	@Override
	public RVIPart getRVIPart(ReadGraph graph) throws DatabaseException {
	    if(resource == null) return new StringRVIPart(Role.CHILD, getName(graph));
        Layer0 L0 = Layer0.getInstance(graph);
        GUID id = graph.getPossibleRelatedValue(resource, L0.identifier, GUID.BINDING);
        if(id != null)
        	return new RVI.GuidRVIPart(Role.CHILD, resource, id.mostSignificant, id.leastSignificant);
        else
        	return new ResourceRVIPart(Role.CHILD, resource);
	}
	
    public String getIdentifier() {
    	return getClass().getSimpleName() + "[" + resource + "]";
    }
	
    protected VariableMap getPossiblePropertyVariableMap(ReadGraph graph) throws DatabaseException {
        if(resource == null) return All.standardChildDomainProperties;
        Resource domainProperties = Layer0.getInstance(graph).domainProperties; 
        return graph.getPossibleRelatedValue2(resource, domainProperties, 
            new StandardGraphPropertyVariable(graph, this, domainProperties));
    }

	protected VariableMap getPossibleChildVariableMap(ReadGraph graph) throws DatabaseException {
	    if(resource == null) return All.standardChildDomainChildren;
	    Resource domainChildren = Layer0.getInstance(graph).domainChildren;
		return graph.getPossibleRelatedValue2(resource, domainChildren, 
				new StandardGraphPropertyVariable(graph, this, domainChildren));
	}
	
	@Override
    public Map<String, Variable> collectDomainProperties(ReadGraph graph, String classification, Map<String, Variable> properties) throws DatabaseException {
    	VariableMap valueMap = getPossiblePropertyVariableMap(graph);
		if(valueMap == null) return properties;
		return valueMap.getVariables(graph, this, classification, properties);
    }
	
    @Override
    public Variable resolve(ReadGraph graph, RVIPart part) throws DatabaseException {
        Resource represents = getPossibleRepresents(graph);
        if (represents == null)
            return StandardRVIResolver.INSTANCE.getVariable(graph, this, part);
        RVIResolver resolver = graph.adapt(represents, RVIResolver.class);
        return resolver.getVariable(graph, this, part);
    }    

    @Override
    public Variable resolvePossible(ReadGraph graph, RVIPart part) throws DatabaseException {
        try {
            return resolve(graph, part);
        } catch (DatabaseException e) {
            return null;
        }
    }

    @SuppressWarnings("unchecked")
    public Set<String> getClassifications(ReadGraph graph) throws DatabaseException {
        Resource represents = getPossibleRepresents(graph);
        Set<String> result = (represents != null) ? graph.syncRequest(new ClassificationsRequest(graph.getPrincipalTypes(represents))) : Collections.<String>emptySet();
        if (result.isEmpty()) {
        	Resource type = getPossibleType(graph);
        	if(type != null) result = graph.syncRequest(new ClassificationsRequest(Collections.singleton(type)));
        }
        if (result.isEmpty() && node != null) {
            try {
                result = node.support.manager.getClassifications(node.node);
            } catch(NodeManagerException e) {
                throw new DatabaseException(e);
            }
        }
        return result;
    }

    @Override
    public RVI getRVI(ReadGraph graph) throws DatabaseException {
        Resource represents = getPossibleRepresents(graph);
        if (represents == null)
            return StandardRVIResolver.INSTANCE.getRVI(graph, this);
        RVIResolver resolver = graph.adapt(represents, RVIResolver.class);
        return resolver.getRVI(graph, this);
    }    
    
    @Override
    public RVI getPossibleRVI(ReadGraph graph) throws DatabaseException {
        Resource represents = getPossibleRepresents(graph);
        if (represents == null)
            return StandardRVIResolver.INSTANCE.getPossibleRVI(graph, this);
        RVIResolver resolver = graph.getPossibleAdapter(represents, RVIResolver.class);
        if(resolver == null) return null;
        return resolver.getPossibleRVI(graph, this);
    }

    @Override
    public Resource getPossiblePredicateResource(ReadGraph graph) throws DatabaseException {
    	return null;
    }

    @Override
    public Variable attachTo(ReadGraph graph, Variable parent) {
        return new StandardGraphChildVariable(parent, node, resource);
    }

    @Override
    public Variable attachToRenamed(ReadGraph graph, Variable parent, String name) {
        return new StandardGraphChildVariable(parent, node, resource) {
            @Override
            public String getName(ReadGraph graph) throws DatabaseException {
                return name;
            }
        };
    }

}