/*

 * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.jpackage.test;

import java.lang.reflect.Constructor;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

import java.util.ArrayList;

import java.util.List;

import java.util.Map;

import java.util.function.Consumer;

import java.util.function.Function;

import java.util.stream.Collectors;

import java.util.stream.Stream;

import jdk.jpackage.test.Annotations.Parameter;

import jdk.jpackage.test.Annotations.Parameters;

import jdk.jpackage.test.Annotations.Test;

import jdk.jpackage.test.Functional.ThrowingConsumer;

import jdk.jpackage.test.Functional.ThrowingFunction;

import jdk.jpackage.test.Functional.ThrowingSupplier;

final class TestBuilder implements AutoCloseable {

    @Override

    public void close() throws Exception {

        flushTestGroup(null);

    }

    TestBuilder(Consumer<TestInstance> testConsumer) {

        argProcessors = Map.of(CMDLINE_ARG_PREFIX + "after-run",

                arg -> getJavaMethodsFromArg(arg).forEach(

                        (method) -> afterActions.add(wrap(method, dryRun))),

                CMDLINE_ARG_PREFIX + "before-run",

                arg -> getJavaMethodsFromArg(arg).forEach(

                        (method) -> beforeActions.add(wrap(method, dryRun))),

                CMDLINE_ARG_PREFIX + "run",

                arg -> flushTestGroup(getJavaMethodsFromArg(arg).map(

                        TestBuilder::toMethodCalls).flatMap(List::stream).collect(

                        Collectors.toList())),

                CMDLINE_ARG_PREFIX + "dry-run",

                arg -> dryRun = true);

        this.testConsumer = testConsumer;

        clear();

    }

    void processCmdLineArg(String arg) throws Throwable {

        int separatorIdx = arg.indexOf('=');

        final String argName;

        final String argValue;

        if (separatorIdx != -1) {

            argName = arg.substring(0, separatorIdx);

            argValue = arg.substring(separatorIdx + 1);

        } else {

            argName = arg;

            argValue = null;

        }

        try {

            ThrowingConsumer<String> argProcessor = argProcessors.get(argName);

            if (argProcessor == null) {

                throw new ParseException("Unrecognized");

            }

            argProcessor.accept(argValue);

        } catch (ParseException ex) {

            ex.setContext(arg);

            throw ex;

        }

    }

    private void flushTestGroup(List<MethodCall> newTestGroup) {

        if (testGroup != null) {

            testGroup.forEach(testBody -> createTestInstance(testBody));

            clear();

        }

        testGroup = newTestGroup;

    }

    private void createTestInstance(MethodCall testBody) {

        ThrowingFunction<MethodCall, Object> testContructor;

        if (dryRun) {

            testContructor = (unused) -> null;

            testBody = DRY_RUN_TEST_BODY;

        } else {

            testContructor = TestBuilder::constructTest;

        }

        TestInstance test = new TestInstance(testContructor, testBody,

                beforeActions, afterActions);

        trace(String.format("[%s] test constructed", test.fullName()));

        testConsumer.accept(test);

    }

    public static void nop () {

    }

    private final static MethodCall DRY_RUN_TEST_BODY = ThrowingSupplier.toSupplier(() -> {

        return new MethodCall(TestBuilder.class.getMethod("nop"));

    }).get();

    private static Object constructTest(MethodCall testBody) throws

            NoSuchMethodException, InstantiationException,

            IllegalAccessException, IllegalArgumentException,

            InvocationTargetException {

        Constructor ctor = testBody.getRequiredConstructor();

        if (ctor == null) {

            return null;

        }

        return ctor.newInstance();

    }

    private void clear() {

        beforeActions = new ArrayList<>();

        afterActions = new ArrayList<>();

        testGroup = null;

    }

    private static Class probeClass(String name) {

        try {

            return Class.forName(name);

        } catch (ClassNotFoundException ex) {

            return null;

        }

    }

    private static Stream<String> cmdLineArgValueToMethodNames(String v) {

        List<String> result = new ArrayList<>();

        String defaultClassName = null;

        for (String token : v.split(",")) {

            Class testSet = probeClass(token);

            if (testSet != null) {

                // Test set class specified. Pull in all public methods

                // from the class with @Test annotation removing name duplicates.

                // Overloads will be handled at the next phase of processing.

                defaultClassName = token;

                Stream.of(testSet.getMethods()).filter(

                        m -> m.isAnnotationPresent(Test.class)).map(

                                Method::getName).distinct().forEach(

                                name -> result.add(String.join(".", token, name)));

                continue;

            }

            final String qualifiedMethodName;

            final int lastDotIdx = token.lastIndexOf('.');

            if (lastDotIdx != -1) {

                qualifiedMethodName = token;

                defaultClassName = token.substring(0, lastDotIdx);

            } else if (defaultClassName == null) {

                throw new ParseException("Default class name not found in");

            } else {

                qualifiedMethodName = String.join(".", defaultClassName, token);

            }

            result.add(qualifiedMethodName);

        }

        return result.stream();

    }

    private static boolean filterMethod(String expectedMethodName, Method method) {

        if (!method.getName().equals(expectedMethodName)) {

            return false;

        }

        switch (method.getParameterCount()) {

            case 0:

                return !isParametrized(method);

            case 1:

                return isParametrized(method);

        }

        return false;

    }

    private static boolean isParametrized(Method method) {

        return method.isAnnotationPresent(Parameters.class) || method.isAnnotationPresent(

                Parameter.class);

    }

    private static List<Method> getJavaMethodFromString(

            String qualifiedMethodName) {

        int lastDotIdx = qualifiedMethodName.lastIndexOf('.');

        if (lastDotIdx == -1) {

            throw new ParseException("Class name not found in");

        }

        String className = qualifiedMethodName.substring(0, lastDotIdx);

        String methodName = qualifiedMethodName.substring(lastDotIdx + 1);

        Class methodClass;

        try {

            methodClass = Class.forName(className);

        } catch (ClassNotFoundException ex) {

            throw new ParseException(String.format("Class [%s] not found;",

                    className));

        }

        // Get the list of all public methods as need to deal with overloads.

        List<Method> methods = Stream.of(methodClass.getMethods()).filter(

                (m) -> filterMethod(methodName, m)).collect(Collectors.toList());

        if (methods.isEmpty()) {

            new ParseException(String.format(

                    "Method [%s] not found in [%s] class;",

                    methodName, className));

        }

        // Make sure default constructor is accessible if the one is needed.

        // Need to probe all methods as some of them might be static and

        // some class members.

        // Onlu class members require default ctor.

        for (Method method : methods) {

            try {

                MethodCall.getRequiredConstructor(method);

            } catch (NoSuchMethodException ex) {

                throw new ParseException(String.format(

                        "Default constructor not found in [%s] class;",

                        className));

            }

        }

        trace(String.format("%s -> %s", qualifiedMethodName, methods));

        return methods;

    }

    private static Stream<Method> getJavaMethodsFromArg(String argValue) {

        return cmdLineArgValueToMethodNames(argValue).map(

                ThrowingFunction.toFunction(

                        TestBuilder::getJavaMethodFromString)).flatMap(

                        List::stream).sequential();

    }

    private static Parameter[] getParameters(Method method) {

        if (method.isAnnotationPresent(Parameters.class)) {

            return ((Parameters) method.getAnnotation(Parameters.class)).value();

        }

        if (method.isAnnotationPresent(Parameter.class)) {

            return new Parameter[]{(Parameter) method.getAnnotation(

                Parameter.class)};

        }

        // Unexpected

        return null;

    }

    private static List<MethodCall> toMethodCalls(Method method) {

        if (!isParametrized(method)) {

            return List.of(new MethodCall(method));

        }

        Parameter[] annotations = getParameters(method);

        if (annotations.length == 0) {

            return List.of(new MethodCall(method));

        }

        return Stream.of(annotations).map((a) -> {

            String annotationValue = a.value();

            Class paramClass = method.getParameterTypes()[0];

            return new MethodCall(method,

                    fromString(annotationValue, paramClass));

        }).collect(Collectors.toList());

    }

    private static Object fromString(String value, Class toType) {

        Function<String, Object> converter = conv.get(toType);

        if (converter == null) {

            throw new RuntimeException(String.format(

                    "Failed to find a conversion of [%s] string to %s type",

                    value, toType));

        }

        return converter.apply(value);

    }

    // Wraps Method.invike() into ThrowingRunnable.run()

    private static ThrowingConsumer wrap(Method method, boolean dryRun) {

        return (test) -> {

            Class methodClass = method.getDeclaringClass();

            String methodName = String.join(".", methodClass.getName(),

                    method.getName());

            TKit.log(String.format("[ CALL     ] %s()", methodName));

            if (!dryRun) {

                if (methodClass.isInstance(test)) {

                    method.invoke(test);

                } else {

                    method.invoke(null);

                }

            }

        };

    }

    private static class ParseException extends IllegalArgumentException {

        ParseException(String msg) {

            super(msg);

        }

        void setContext(String badCmdLineArg) {

            this.badCmdLineArg = badCmdLineArg;

        }

        @Override

        public String getMessage() {

            String msg = super.getMessage();

            if (badCmdLineArg != null) {

                msg = String.format("%s parameter=[%s]", msg, badCmdLineArg);

            }

            return msg;

        }

        private String badCmdLineArg;

    }

    private static void trace(String msg) {

        if (TKit.VERBOSE_TEST_SETUP) {

            TKit.log(msg);

        }

    }

    private final Map<String, ThrowingConsumer<String>> argProcessors;

    private Consumer<TestInstance> testConsumer;

    private List<MethodCall> testGroup;

    private List<ThrowingConsumer> beforeActions;

    private List<ThrowingConsumer> afterActions;

    private boolean dryRun;

    private final static Map<Class, Function<String, Object>> conv = Map.of(

            boolean.class, Boolean::valueOf,

            Boolean.class, Boolean::valueOf,

            int.class, Integer::valueOf,

            Integer.class, Integer::valueOf,

            long.class, Long::valueOf,

            Long.class, Long::valueOf,

            String.class, String::valueOf);

    final static String CMDLINE_ARG_PREFIX = "--jpt-";

}