/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.sling.performance;

import org.apache.sling.performance.annotation.AfterSuite;
import org.apache.sling.performance.annotation.BeforeSuite;
import org.apache.sling.performance.annotation.PerformanceTest;
import org.apache.sling.performance.annotation.PerformanceTestFactory;
import org.apache.sling.performance.annotation.PerformanceTestSuite;
import org.junit.After;
import org.junit.Before;
import org.junit.runner.notification.Failure;
import org.junit.runner.notification.RunNotifier;
import org.junit.runners.BlockJUnit4ClassRunner;
import org.junit.runners.model.FrameworkMethod;
import org.junit.runners.model.InitializationError;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.lang.annotation.Annotation;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.LinkedList;
import java.util.List;

/**
 * The custom JUnit runner that collects the performance tests
 *
 */


public class PerformanceRunner extends BlockJUnit4ClassRunner {
    private static final Logger logger = LoggerFactory.getLogger(ReportLogger.class);

    protected LinkedList<FrameworkMethod> tests = new LinkedList<FrameworkMethod>();
    private List<PerformanceSuiteState> suitesState = new ArrayList<PerformanceSuiteState>();
    public ReportLevel reportLevel = ReportLevel.ClassLevel;
    public String referenceMethod = null;

    public static enum ReportLevel{
        ClassLevel,
        MethodLevel
    }

    @Retention(RetentionPolicy.RUNTIME)
    @Target(ElementType.TYPE)
    public @interface Parameters {
        public ReportLevel reportLevel() default ReportLevel.ClassLevel;
        /** This is the name of the reference method used to compute statistics */
        public String referenceMethod() default "";
    }

    public PerformanceRunner(Class<?> clazz) throws InitializationError {
        super(clazz);

        // set the report level for the tests that are run with the PerformanceRunner
        // by default set to class level for legacy tests compatibility
        if (clazz.getAnnotation(Parameters.class) != null){
            reportLevel = clazz.getAnnotation(Parameters.class).reportLevel();
            referenceMethod = clazz.getAnnotation(Parameters.class).referenceMethod();
            if ("".equals(referenceMethod)) {
                referenceMethod = null;
            } else {
                boolean found = false;
                for (Method method : clazz.getMethods()) {
                    if (method.getName().equals(referenceMethod) && method.getParameterTypes().length == 0) {
                        found = true;
                        break;
                    }
                }
                if (!found) {
                    referenceMethod = null;
                }
            }
        }

        try {
            computeTests();
        } catch (Exception e) {
            throw new InitializationError(e);
        }
    }

    @Override
    public void run(RunNotifier notifier) {
        super.run(notifier);
        try {
            ReportLogger.writeAllResults();
        } catch (Exception e) {
            logger.error(e.getMessage(), e);
        }
        try {
            for (Failure failure : ReportLogger.checkAllThresholds()) {
                notifier.fireTestFailure(failure);
            }
        } catch (Exception e) {
            logger.error(e.getMessage(), e);
        }
    }

    /**
     * Compute the tests that will be run
     *
     * @throws Exception
     */
    protected void computeTests() throws Exception {
        // add normal JUnit tests
        tests.addAll(super.computeTestMethods());

        // add the performance tests
        tests.addAll(computePerformanceTests());

        // This is called here to ensure the test class constructor is called at
        // least
        // once during testing.
        createTest();
    }

    /**
     * Compute performance tests
     *
     * @return the list containing the performance test methods
     * @throws Exception
     */
    protected Collection<? extends FrameworkMethod> computePerformanceTests()
            throws Exception {
        List<FrameworkMethod> tests = new LinkedList<FrameworkMethod>();

        List<Object> testObjects = new ArrayList<Object>();
        List<Object> testObjectsTmp = new ArrayList<Object>();


        ParameterizedTestList testCenter = new ParameterizedTestList();

        // Retrieve the test objects included in the Performance test suite
        for (FrameworkMethod method : getTestClass().getAnnotatedMethods(
                PerformanceTestSuite.class)) {
            Object targetObject = getTestClass().getJavaClass().newInstance();
            if (method.getMethod().getReturnType()
                    .equals(ParameterizedTestList.class)) {
                testCenter = (ParameterizedTestList) method.getMethod().invoke(
                        targetObject);
                testObjectsTmp = testCenter.getTestObjectList();

                // Iterate through all the test cases and see if they have a factory
                for (Object testObject : testObjectsTmp) {
                    Method[] factoryMethods = getSpecificMethods(
                            testObject.getClass(), PerformanceTestFactory.class);

                    // If we have a factory method, get all the instance objects returned by this factory
                    if (factoryMethods.length > 0) {
                        // Make sure there's only one factory method
                        if (factoryMethods.length > 1) {
                            throw new IllegalStateException(
                                    "There should be at most one PerformanceTestFactory method");
                        }
                        Method factoryMethod = factoryMethods[0];

                        // Execute the method (statically)
                        Object instances = factoryMethod.invoke(testObject);

                        // If the factory returned an array, make a list
                        if (instances.getClass().isArray()) {
                            instances = Arrays.asList((Object[]) instances);
                        }

                        // If the factory returned a single element, put it in a list
                        if (!(instances instanceof Iterable<?>)) {
                            instances = Collections.singletonList(instances);
                        }
                        testObjects.addAll((List) instances);
                    } else {
                        testObjects.add(testObject);
                    }
                }
            } else {
                throw new InitializationError(
                        "Wrong signature for the @PerformanceTestSuite method");
            }
        }

        // Retrieve the methods before running the methods from the test suite
        List<FrameworkMethod> beforeSuiteMethods = getTestClass()
                .getAnnotatedMethods(BeforeSuite.class);
        if (beforeSuiteMethods.size() > 1) {
            throw new InitializationError(
                    "Only one @BeforeSuite method is allowed for a @PerformanceSuite");
        }

        // Retrieve the methods before running the methods from the test suite
        List<FrameworkMethod> afterSuiteMethods = getTestClass()
                .getAnnotatedMethods(AfterSuite.class);
        if (afterSuiteMethods.size() > 1) {
            throw new InitializationError(
                    "Only one @AfterSuite method is allowed for a @PerformanceSuite");
        }

        PerformanceSuiteState current = null;
        boolean suiteAlreadyRegistered = false;

        for (PerformanceSuiteState suiteState : suitesState) {
            if (suiteState.testSuiteName.equals(testCenter.getTestSuiteName())) {
                suiteAlreadyRegistered = true;
                suiteState.incrementNumberOfTestMethodsInSuite();
                current = suiteState;
                break;
            }
        }

        // Create a new PerformanceSuiteState object
        PerformanceSuiteState newSuite = new PerformanceSuiteState(
                testCenter.getTestSuiteName());

        if (!suiteAlreadyRegistered) {
            if (beforeSuiteMethods.size() == 1) {
                newSuite.setBeforeSuiteMethod(beforeSuiteMethods.get(0).getMethod());
            }
            if (afterSuiteMethods.size() == 1) {
                newSuite.setAfterSuiteMethod(afterSuiteMethods.get(0).getMethod());
            }

            current = newSuite;
            newSuite.setTargetObjectSuite(getTestClass().getJavaClass().newInstance());

        }

        // In case there are any objects retrieved from the Performance Suite
        // we should add them to the tests that will be run and increase the
        // number of methods
        // contained in the PerformanceSuite
        if (!testObjects.isEmpty()) {
            for (Object testObject : testObjects) {

                // retrieve the test methods from the test classes
                Method[] testMethods = getSpecificMethods(testObject.getClass(), PerformanceTest.class);

                for (Method method : testMethods) {
                    FrameworkPerformanceMethod performaceTestMethod =
                            new FrameworkPerformanceMethod(method, testObject, current, reportLevel, referenceMethod);
                    tests.add(performaceTestMethod);
                }

                if (!suiteAlreadyRegistered) {
                    newSuite.incrementNumberOfTestMethodsInSuite();
                }
            }

            // add the new suite to the list of suites
            suitesState.add(newSuite);
        }

        // Retrieve the performance tests in the case we don't have a
        // performance test suite
        for (FrameworkMethod method : getTestClass().getAnnotatedMethods(PerformanceTest.class)) {
            Object targetObject = getTestClass().getJavaClass().newInstance();
            FrameworkPerformanceMethod performanceTestMethod = new FrameworkPerformanceMethod(
                    method.getMethod(), targetObject, current, reportLevel, referenceMethod);
            tests.add(performanceTestMethod);
        }

        return tests;
    }


    /**
     * Retrieve specific method from test class
     *
     * @param testClass
     *            the test class that we need to search in
     * @param annotation
     *            the annotation that we should look for
     * @return the list with the methods that have the specified annotation
     */
    @SuppressWarnings({ "rawtypes" })
    private Method[] getSpecificMethods(Class testClass,
            Class<? extends Annotation> annotation) {
        Method[] allMethods = testClass.getDeclaredMethods();

        List<Method> methodListResult = new ArrayList<Method>();

        for (Method testMethod : allMethods) {
            if (testMethod.isAnnotationPresent(annotation)) {
                methodListResult.add(testMethod);
            }
        }
        return methodListResult.toArray(new Method[] {});
    }

    /**
     * {@inheritDoc}
     *
     * @see org.junit.runners.BlockJUnit4ClassRunner#computeTestMethods()
     */
    @Override
    protected List<FrameworkMethod> computeTestMethods() {
        return tests;
    }

    /**
     * Need to override method otherwise the validation will fail because of
     * some hardcoded conditions in JUnit
     */
    @Override
    protected void validateInstanceMethods(List<Throwable> errors) {
        validatePublicVoidNoArgMethods(After.class, false, errors);
        validatePublicVoidNoArgMethods(Before.class, false, errors);
        validateTestMethods(errors);
    }

}