/*
 * Copyright (C) 2017 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.dx.mockito.inline;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.concurrent.Callable;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;

/**
 * Called by method entry hooks. Dispatches these hooks to the {@code MockMethodAdvice}.
 */
@SuppressWarnings("unused")
public class MockMethodDispatcher {
    // An instance of {@code MockMethodAdvice}
    private Object mAdvice;

    // All dispatchers for various identifiers
    private static final ConcurrentMap<String, MockMethodDispatcher> INSTANCE =
            new ConcurrentHashMap<>();

    /**
     * Get the dispatcher for a identifier.
     *
     * @param identifier identifier of the dispatcher
     * @param instance instance that might be mocked
     *
     * @return dispatcher for the identifier
     */
    public static MockMethodDispatcher get(String identifier, Object instance) {
        if (instance == INSTANCE) {
            // Avoid endless loop if ConcurrentHashMap was redefined to check for being a mock.
            return null;
        } else {
            return INSTANCE.get(identifier);
        }
    }

    /**
     * Create a new dispatcher.
     *
     * @param advice Advice the dispatcher should call
     */
    private MockMethodDispatcher(Object advice) {
        mAdvice = advice;
    }

    /**
     * Set up a new advice to receive calls for an identifier
     *
     * @param identifier a unique identifier
     * @param advice advice the dispatcher should call
     */
    public static void set(String identifier, Object advice) {
        INSTANCE.putIfAbsent(identifier, new MockMethodDispatcher(advice));
    }

    /**
     * Calls {@code MockMethodAdvice#handle}
     */
    public Callable<?> handle(Object instance, Method origin, Object[] arguments) throws Throwable {
        try {
            return (Callable<?>) mAdvice.getClass().getMethod("handle", Object.class, Method.class,
                    Object[].class).invoke(mAdvice, instance, origin, arguments);
        } catch (InvocationTargetException e) {
            throw e.getCause();
        }
    }

    /**
     * Calls {@code MockMethodAdvice#isMock}
     */
    public boolean isMock(Object instance) {
        try {
            return (Boolean) mAdvice.getClass().getMethod("isMock", Object.class).invoke(mAdvice,
                    instance);
        } catch (IllegalAccessException | InvocationTargetException | NoSuchMethodException e) {
            throw new IllegalStateException(e);
        }
    }

    /**
     * Calls {@code MockMethodAdvice#isMocked}
     */
    public boolean isMocked(Object instance) {
        try {
            return (Boolean) mAdvice.getClass().getMethod("isMocked", Object.class).invoke(mAdvice,
                    instance);
        } catch (IllegalAccessException | InvocationTargetException | NoSuchMethodException e) {
            throw new IllegalStateException(e);
        }
    }

    /**
     * Calls {@code MockMethodAdvice#isOverridden}
     */
    public boolean isOverridden(Object instance, Method origin) {
        try {
            return (Boolean) mAdvice.getClass().getMethod("isOverridden", Object.class,
                    Method.class).invoke(mAdvice, instance, origin);
        } catch (IllegalAccessException | InvocationTargetException | NoSuchMethodException e) {
            throw new IllegalStateException(e);
        }
    }

    /**
     * Calls {@code MockMethodAdvice#getOrigin}
     */
    public Method getOrigin(Object mock, String instrumentedMethodWithTypeAndSignature)
            throws Throwable {
        return (Method) mAdvice.getClass().getMethod("getOrigin", Object.class,
                String.class).invoke(mAdvice, mock, instrumentedMethodWithTypeAndSignature);
    }
}