package no.uio.ifi.refaktor.analyze.collectors;

import no.uio.ifi.refaktor.prefix.Prefix;
import no.uio.ifi.refaktor.utils.CompilationUnitTextSelection;

import org.eclipse.jdt.core.dom.IVariableBinding;
import org.eclipse.jdt.core.dom.QualifiedName;
import org.eclipse.jdt.core.dom.SimpleName;

/**
 * An abstract property collector responsible for finding
 * prefixes within a selection.
 * 
 * Subclasses are responsible for implementing the 
 * {@link #registerPrefix(Prefix)} method. I.e. they
 * decide how to handle the encountered prefixes.
 */
public abstract class AbstractPrefixCollector extends PropertyCollector {

	public AbstractPrefixCollector(CompilationUnitTextSelection selection) {
		super(selection);
	}

	/**
	 * Register a prefix encountered by the collector.
	 * @param prefix The prefix to register.
	 */
	protected abstract void registerPrefix(Prefix prefix);

	@Override
	public boolean visit(QualifiedName node) {
		if (!nodeInSelection(node))
			return false;

		Prefix prefix = new Prefix(node);
		if (prefix.firstExpressionIsBoundToVariable())
			registerPrefix(prefix);

		// Must be false. Important to prevent double count for simple names.
		return false;
	}

	@Override
	public boolean visit(SimpleName node) {
		if (!nodeInSelection(node))
			return false;

		if (nodeIsUsageOfVariable(node))
			registerPrefix(new Prefix(node));

		return false;
	}

	private boolean nodeIsUsageOfVariable(SimpleName node) {
		return !node.isDeclaration() && node.resolveBinding() instanceof IVariableBinding;
	}
}