package org.simantics.selectionview;

import org.simantics.Simantics;
import org.simantics.db.ReadGraph;
import org.simantics.db.Resource;
import org.simantics.db.exception.DatabaseException;
import org.simantics.db.layer0.variable.Variable;
import org.simantics.db.layer0.variable.Variables;
import org.simantics.scl.runtime.function.Function;
import org.simantics.ui.selection.WorkbenchSelectionUtils;

abstract public class AbstractVariableTabContribution extends AbstractTabContribution<SelectionInput> {

	public AbstractVariableTabContribution(ReadGraph graph, Resource configuration) throws DatabaseException {
	    super(graph, configuration);
	}

    @Override
    public boolean accept(ReadGraph graph, Object input) throws DatabaseException {
        if (!super.accept(graph, input))
            return false;
        Variable variable = getPossibleVariable(graph, input);
        if (variable == null)
            return false;

		if(input instanceof SelectionInput) {
		
			SelectionViewResources SEL = SelectionViewResources.getInstance(graph);
		
			Variable configurationVariable = Variables.getVariable(graph, configuration);
			Function f = configurationVariable.getPossiblePropertyValue(graph, SEL.AbstractVariableTabContribution_testFunction);
			if(f != null) {
				Boolean pass = Simantics.<Boolean>applySCLRead(graph, f, variable);
				if(!pass) return false;
			}
			
		} else {
			return false;
		}
		return true;
	}
	
	final private Variable getPossibleVariable(ReadGraph graph, Object selection) throws DatabaseException {
		if(selection instanceof SelectionInput) {
			SelectionInput si = (SelectionInput)selection;
			if(si.getElements().size() == 1) {
				return WorkbenchSelectionUtils.getPossibleVariable(graph, si.getElements().iterator().next());
			}
		}
		return null;
	} 
}