/*******************************************************************************
 * Copyright (c) 2010, 2011 Association for Decentralized Information Management in
 * Industry THTH ry.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.browsing.ui.model.children;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;

import org.simantics.browsing.ui.BuiltinKeys;
import org.simantics.browsing.ui.NodeContext;
import org.simantics.browsing.ui.model.InvalidContribution;
import org.simantics.browsing.ui.model.nodetypes.NodeType;
import org.simantics.databoard.Bindings;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.common.utils.NameUtils;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.layer0.exception.PendingVariableException;
import org.simantics.viewpoint.ontology.ViewpointResource;

/**
 * A child contribution adds child nodes to the instances of a specific node type.
 * @author Hannu Niemistö
 */
public class ChildContribution {
	
	double priority;
	String identifier;
    NodeType parentNodeType;
    NodeType childNodeType;
    ChildRule childRule;
        
    public ChildContribution(String identifier, double priority, NodeType parentNodeType, NodeType childNodeType,
            ChildRule childRule) throws InvalidContribution {
        if(!childRule.isCompatible(
                parentNodeType.getContentType()
                ))
            throw new InvalidContribution("Child rule is not compatible with the parent content type.");
        this.parentNodeType = parentNodeType;
        this.childNodeType = childNodeType;
        this.childRule = childRule;
        this.identifier = identifier;
        this.priority = priority;
    }

    public static ChildContribution create(ReadGraph g, Resource childContributionResource) throws DatabaseException, InvalidContribution {
        ViewpointResource vr = ViewpointResource.getInstance(g);
        
        Resource parentNodeTypeResource = g.getSingleObject(childContributionResource, vr.ChildContribution_HasParentNodeType);
        NodeType parentNodeType = g.adapt(parentNodeTypeResource, NodeType.class);
        
        Resource childNodeTypeResource = g.getSingleObject(childContributionResource, vr.ChildContribution_HasChildNodeType);
        NodeType childNodeType = g.adapt(childNodeTypeResource, NodeType.class);
        
        Resource childRuleResource = g.getSingleObject(childContributionResource, vr.ChildContribution_HasRule);
        ChildRule childRule = g.adapt(childRuleResource, ChildRule.class);
        
        String identifier = g.getPossibleRelatedValue(childContributionResource, vr.ChildContribution_identifier, Bindings.STRING);
        if(identifier == null) identifier = "";
        if("".equals(identifier)) {
        	identifier = g.getPossibleURI(childContributionResource);
            if(identifier == null) identifier = NameUtils.getSafeName(g, childContributionResource, true);
        }
        
        Double priority = g.getPossibleRelatedValue(childContributionResource, vr.ChildContribution_priority, Bindings.DOUBLE);
        if(priority == null) priority = 0.0;
        
        return new ChildContribution(identifier, priority, parentNodeType, childNodeType, childRule);
        
    }

    public NodeType getParentNodeType() {
        return parentNodeType;
    }
    
    public NodeType getChildNodeType() {
        return childNodeType;
    }
    
    public String getIdentifier() {
    	return identifier;
    }

    public double getPriority() {
    	return priority;
    }
    
    /**
     * Given a parent node context returns a child node contexts contributed by
     * this contribution.
     */
    public Collection<NodeContext> getChildren(ReadGraph graph, NodeContext parent) {
        try {
            Object parentContent = parent.getConstant(BuiltinKeys.INPUT);
            Collection<?> childContents = childRule.getChildren(graph, parentContent);
            if(childContents.isEmpty())
                return Collections.emptyList();
            ArrayList<NodeContext> children = new ArrayList<NodeContext>(childContents.size());
            for(Object childContent : childContents) {
                NodeContext child = childNodeType.createNodeContext(graph, childContent);
                if(child != null)
                    children.add(child);
            }
            return children;
        } catch(PendingVariableException e) {
            return Collections.emptyList();
        } catch(DatabaseException e) {
            e.printStackTrace();
            // TODO return some kind of error node
            return Collections.emptyList();
        }
    }
    
    /**
     * Given a child node context returns a collection of possible parent node contexts.
     */
    public Collection<NodeContext> getParents(ReadGraph graph, NodeContext child) {
        try {
            Object childContent = child.getConstant(BuiltinKeys.INPUT);
            Collection<?> parentContents = childRule.getParents(graph, childContent);
            if(parentContents.isEmpty())
                return Collections.emptyList();
            ArrayList<NodeContext> parents = new ArrayList<NodeContext>(parentContents.size());
            for(Object parentContent : parentContents) {
                NodeContext parent = parentNodeType.createNodeContext(graph, parentContent);
                if(parent != null)
                    parents.add(parent);
            }
            return parents;
        } catch(DatabaseException e) {
            e.printStackTrace();
            return Collections.emptyList();
        }
    }

    public boolean hasChildren(ReadGraph graph, NodeContext parent) {
        try {
            Object parentContent = parent.getConstant(BuiltinKeys.INPUT);
            Collection<?> childContents = childRule.getChildren(graph, parentContent);
            if(childContents.isEmpty())
                return false;
            for(Object childContent : childContents) {
                NodeContext child = childNodeType.createNodeContext(graph, childContent);
                if(child != null)
                    return true;
            }
        } catch(DatabaseException e) {
            e.printStackTrace();
        }
        return false;
    }
    
    @Override
    public String toString() {
    	return identifier;
    }
    
}