package org.simantics.modeling;

import gnu.trove.map.hash.THashMap;

import java.util.Collections;
import java.util.Map;

import org.simantics.db.ReadGraph;
import org.simantics.db.RequestProcessor;
import org.simantics.db.Resource;
import org.simantics.db.common.request.ResourceRead;
import org.simantics.db.common.uri.UnescapedChildMapOfResource;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.layer0.request.PropertyInfo;
import org.simantics.db.layer0.request.PropertyInfoRequest;
import org.simantics.layer0.Layer0;
import org.simantics.scl.compiler.types.Type;
import org.simantics.structural.stubs.StructuralResource2;
import org.simantics.utils.datastructures.Pair;

/**
 * Contains necessary information about a component type to represent its
 * variable space.
 * 
 * @author Hannu Niemistö
 */
public class ComponentTypeSubstructure {
    
    public final THashMap<String, Type> properties;
    public final Map<String, ComponentTypeSubstructure> children;
    
    private ComponentTypeSubstructure(THashMap<String, Type> properties,
            Map<String, ComponentTypeSubstructure> children) {
        this.properties = properties;
        this.children = children;
    }
    
    public Pair<String,Type> possibleTypedRVI(String name) {
        StringBuilder b = new StringBuilder();
        int namePos = 0;
        ComponentTypeSubstructure substructure = this;
        
        // Find the children
        int p;
        while( (p = name.indexOf('.', namePos)) >= 0 ) {
            String childName = name.substring(namePos, p);
            ComponentTypeSubstructure childSubstructure = substructure.children.get(childName);
            if(childSubstructure == null)
                return null;
            b.append('/').append(childName);
            namePos = p+1;
            substructure = childSubstructure;
        }
        
        // Find the property
        String propertyName = name.substring(namePos);
        Type type = substructure.properties.get(propertyName);
        if(type == null)
            return null;
        b.append('#').append(propertyName);
        return Pair.make(b.toString(), type);
    }

    public static ComponentTypeSubstructure forType(RequestProcessor processor, Resource componentType) throws DatabaseException {
        return processor.syncRequest(new ResourceRead<ComponentTypeSubstructure>(componentType) {
            @Override
            public ComponentTypeSubstructure perform(ReadGraph graph)
                    throws DatabaseException {
                // Properties
                THashMap<String, Type> properties = new THashMap<String, Type>();
                collect(graph, resource, properties);
                for(Resource t : graph.getSupertypes(resource)) collect(graph, t, properties);
                
                // Children
                Map<String, ComponentTypeSubstructure> children;
                
                StructuralResource2 STR = StructuralResource2.getInstance(graph);
                Resource composite = graph.getPossibleObject(resource, STR.IsDefinedBy);
                if(composite == null)
                    children = Collections.<String, ComponentTypeSubstructure>emptyMap();
                else {
                    Map<String, Resource> childMap = graph.syncRequest(new UnescapedChildMapOfResource(composite));
                    children = new THashMap<String, ComponentTypeSubstructure>(childMap.size());
                    for(Map.Entry<String,Resource> entry : childMap.entrySet()) {
                        Resource component = entry.getValue();
                        Resource type = graph.getPossibleType(component, STR.Component);
                        if(type != null)
                            children.put(entry.getKey(), forType(graph, type));
                    }
                }
                    
                // Return the result
                return new ComponentTypeSubstructure(properties, children);
            }
        });
    }
    
    private static void collect(ReadGraph graph, Resource t, THashMap<String, Type> result) throws DatabaseException {
        Layer0 L0 = Layer0.getInstance(graph);
        for(Resource relation : graph.getObjects(t, L0.DomainOf)) {
            if(graph.isSubrelationOf(relation, L0.HasProperty)) {
                PropertyInfo propertyInfo = graph.syncRequest(new PropertyInfoRequest(relation));
                result.put(propertyInfo.name, SCLTypeUtils.getType(propertyInfo));
            }
        }
    }
}