/*******************************************************************************
 *
 * Copyright (c) 2004-2010, Oracle Corporation.
 *
 * 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:
 *
 *
 *
 *
 *******************************************************************************/ 

package org.jvnet.hudson.test;

import hudson.Extension;
import hudson.ExtensionComponent;
import hudson.ExtensionFinder;
import hudson.model.Hudson;
import net.java.sezpoz.Index;
import net.java.sezpoz.IndexItem;

import java.lang.reflect.AnnotatedElement;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * Loads {@link TestExtension}s.
 *
 * @author Kohsuke Kawaguchi
 */
@Extension
public class TestExtensionLoader extends ExtensionFinder {

    @Override
    public <T> Collection<ExtensionComponent<T>> find(Class<T> type, Hudson hudson) {
        TestEnvironment env = TestEnvironment.get();

        List<ExtensionComponent<T>> result = new ArrayList<ExtensionComponent<T>>();

        ClassLoader cl = hudson.getPluginManager().uberClassLoader;
        for (IndexItem<TestExtension, Object> item : Index.load(TestExtension.class, Object.class, cl)) {
            try {
                AnnotatedElement e = item.element();
                Class<?> extType;
                if (e instanceof Class) {
                    extType = (Class) e;
                    if (!isActive(env, extType)) {
                        continue;
                    }
                } else if (e instanceof Field) {
                    Field f = (Field) e;
                    if (!f.getDeclaringClass().isInstance(env.testCase)) {
                        continue;      // not executing the enclosing test
                    }
                    extType = f.getType();
                } else if (e instanceof Method) {
                    Method m = (Method) e;
                    if (!m.getDeclaringClass().isInstance(env.testCase)) {
                        continue;      // not executing the enclosing test
                    }
                    extType = m.getReturnType();
                } else {
                    throw new AssertionError();
                }

                String testName = item.annotation().value();
                if (testName.length() > 0 && !env.testCase.getName().equals(testName)) {
                    continue;   // doesn't apply to this test
                }
                if (type.isAssignableFrom(extType)) {
                    Object instance = item.instance();
                    if (instance != null) {
                        result.add(new ExtensionComponent<T>(type.cast(instance)));
                    }
                }
            } catch (InstantiationException e) {
                LOGGER.log(Level.WARNING, "Failed to load " + item.className(), e);
            }
        }

        return result;
    }

    private boolean isActive(TestEnvironment env, Class<?> extType) {
        for (Class<?> outer = extType; outer != null; outer = outer.getEnclosingClass()) {
            if (outer.isInstance(env.testCase)) {
                return true;      // enclosed
            }
        }
        return false;
    }
    private static final Logger LOGGER = Logger.getLogger(TestExtensionLoader.class.getName());
}