package de.tobject.findbugs;

import java.io.File;
import java.io.IOException;
import java.net.URL;

import org.eclipse.core.runtime.FileLocator;
import org.eclipse.core.runtime.Path;
import org.eclipse.core.runtime.Platform;
import org.eclipse.jdt.core.ClasspathVariableInitializer;
import org.eclipse.jdt.core.JavaCore;
import org.eclipse.jdt.core.JavaModelException;
import org.osgi.framework.Bundle;

public class AnnotationClasspathInitializer extends
		ClasspathVariableInitializer {

	private static final String FINDBUGS_ANNOTATIONS = "FINDBUGS_ANNOTATIONS";
	private static final String JSR305_ANNOTATIONS = "JSR305_ANNOTATIONS";

	private static final String FINDBUGS_LIBRARY = "/lib/annotations.jar";
	private static final String JSR305_LIBRARY = "/lib/jsr305.jar";

	@Override
	public void initialize(String variable) {
		Bundle bundle = Platform.getBundle(FindbugsPlugin.PLUGIN_ID);
		if (bundle == null) {
			return;
		}
		String fullPath = getLibraryPath(bundle, FINDBUGS_LIBRARY);
		setVariable(fullPath, FINDBUGS_ANNOTATIONS);
		fullPath = getLibraryPath(bundle, JSR305_LIBRARY);
		setVariable(fullPath, JSR305_ANNOTATIONS);
	}

	private void setVariable(String fullPath, String variableName) {
		if (fullPath == null) {
			FindbugsPlugin.getDefault().logError(
					"unable to find path for variable: " + variableName);
			return;
		}
		try {
			JavaCore.setClasspathVariable(variableName, new Path(fullPath), null);
		} catch (JavaModelException e1) {
			FindbugsPlugin.getDefault().logException(e1,
					"unable to set annotations classpath");
		}
	}

	private String getLibraryPath(Bundle bundle, String libName) {
		URL installLocation = bundle.getEntry(libName);
		if(installLocation == null){
			FindbugsPlugin.getDefault().logError("Library not found in plugin: " + libName);
			return null;
		}
		String fullPath = null;
		try {
			URL local = FileLocator.toFileURL(installLocation);
			fullPath = new File(local.getPath()).getCanonicalPath();
		} catch (IOException e) {
			FindbugsPlugin.getDefault().logException(e,
					"unable to set classpath for " + libName);
		}
		return fullPath;
	}

}