/*
 * Copyright (C) 2024 The Android Open Source Project
 *
 * Licensed 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 com.android.tools.test;

import java.io.IOException;
import java.lang.Class;
import java.lang.String;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.util.Arrays;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;
import org.junit.runners.Suite;
import org.junit.runner.notification.RunNotifier;
import org.junit.runners.model.InitializationError;
import org.junit.runners.model.RunnerBuilder;

public class ModuleTestSuiteRunner extends Suite {

    private static boolean assertIsEmpty = System.getenv("ASSERT_TEST_IS_EMPTY") != null;

    public ModuleTestSuiteRunner(Class<?> suiteClass, RunnerBuilder builder)
            throws InitializationError, ClassNotFoundException, IOException {
        super(new ModuleRunnerBuilder(builder), getTestClasses(suiteClass));
    }

    private static Class<?>[] getTestClasses(Class<?> suiteClass) throws IOException {
        String toolsIdea = System.getProperty("idea.root");
        String module = System.getenv("TEST_MODULE");
        Path dir = Paths.get(toolsIdea + "/out/studio/classes/test/" + module);
        List<Path> classes = Files.walk(dir)
            .filter(Files::isRegularFile)
            .filter(p -> p.toString().endsWith(".class"))
            .collect(Collectors.toList());
        ArrayList<Class<?>> suites = new ArrayList<>();
        if (assertIsEmpty)
            suites.add(AllowNoTests.class);
        for (Path cl : classes) {
            String name = dir.relativize(cl).toString();
            name = name.replaceAll("/", ".");
            name = name.replaceFirst("\\.class$", "");
            try {
                Class<?> aClass = Class.forName(name);
                if (aClass.getAnnotation(RunWith.class) != null) {
                    suites.add(aClass);
                }
            } catch (ClassNotFoundException e) {
                // Ignore
            }
        }
        return suites.toArray(new Class[]{});
    }

    public void run(RunNotifier notifier) {
        // This runner supports checking for splits to ensure no tests are left outside the splits.
        // When checking the "left overs" split, we assert that the AllowNoTests is the only one in.
        if (assertIsEmpty && testCount() > 1) {
            throw new IllegalStateException("This test suite should be empty");
        }
        super.run(notifier);
    }

    @RunWith(JUnit4.class)
    public static class AllowNoTests {
        @Test
        public void allowNoTests() {

        }
    }
}