// Copyright (c) Microsoft. All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.

#include "CppUnitTest.h"
#include <krabs.hpp>

using namespace Microsoft::VisualStudio::CppUnitTestFramework;
using namespace std::placeholders;


// The tests in this file are designed to verify that the different types
// of callbacks that providers accept (1) compile appropriately and (2)
// are invoked in the appropriate situations. The nature of these tests
// is super gnarly because of the nature of callbacks. Sorry.

bool was_c_style_callback_invoked = false;

void c_style_callback(const EVENT_RECORD &)
{
    was_c_style_callback_invoked = true;
}


struct functor {
public:
    void operator()(const EVENT_RECORD &)
    {
        called_ = true;
    }

    void my_member_func(const EVENT_RECORD &)
    {
        called_ = true;
    }

public:

    bool has_been_called()
    {
        return called_;
    }

private:
    bool called_ = false;
};


// Designed to be used as a temporary, it takes the location of a bool
// that it will populate when it's called.
struct tmp_functor {
public:
    tmp_functor(bool &b)
        : called_(b)
    {}

    void operator()(const EVENT_RECORD &)
    {
        called_ = true;
    }

private:
    tmp_functor &operator=(const tmp_functor &) = delete;
    bool &called_;
};


namespace krabstests
{
    TEST_CLASS(test_event_callbacks)
    {
        static krabs::provider<> init()
        {
            // Microsoft-Windows-PowerShell provider
            krabs::guid id(L"{A0C1853B-5C40-4B15-8766-3CF1C58F985A}");
            krabs::provider<> provider(id);
            return provider;
        }

        krabs::provider<> provider = init();
    public:

        TEST_METHOD(add_callback_should_allow_c_style_functors_as_callback)
        {
            provider.add_on_event_callback(c_style_callback);
        }

        TEST_METHOD(add_callback_should_allow_cpp_style_functors_as_callback)
        {
            functor func;
            provider.add_on_event_callback(func);
        }

        TEST_METHOD(add_callback_should_allow_lambdas_as_callbacks)
        {
            provider.add_on_event_callback([&](const EVENT_RECORD &) {});
        }

        TEST_METHOD(add_callback_should_allow_temporary_objects_as_callbacks)
        {
            provider.add_on_event_callback(functor());
        }

        TEST_METHOD(add_callback_should_allow_pointer_to_member_functions_as_callbacks)
        {
            functor func;
            provider.add_on_event_callback(std::bind(&functor::my_member_func, &func, _1));
        }

        TEST_METHOD(trace_add_callback)
        {
            // Set up a user_trace and a provider with several types of callback, verify
            // that the callbacks are invoked.
            krabs::user_trace trace;

            bool was_lambda_invoked = false;
            bool was_tmp_invoked = false;

            functor func1, func2;
            krabs::guid id(L"{A0C1853B-5C40-4B15-8766-3CF1C58F985A}");

            provider.add_on_event_callback(c_style_callback);
            provider.add_on_event_callback(func1);
            provider.add_on_event_callback([&](const EVENT_RECORD &) {
                was_lambda_invoked = true;
            });

            provider.add_on_event_callback(tmp_functor(was_tmp_invoked));
            provider.add_on_event_callback(std::bind(&functor::my_member_func, &func2, _1));
            trace.enable(provider);

            // Kick off a fake event.
            krabs::testing::user_trace_proxy proxy(trace);
            proxy.start();

            krabs::testing::record_builder builder(id, krabs::id(7942), krabs::version(1));

            builder.add_properties()
                (L"ClassName", L"FakeETWEventForRealz")
                (L"Message", L"This message is completely faked");

            auto record = builder.pack_incomplete();
            proxy.push_event(record);

            // "should call the C-style callback"
            Assert::IsTrue(was_c_style_callback_invoked);
            
            // "should call the C++-style functor callback"
            Assert::IsTrue(func1.has_been_called());

            // "should call the lambda callback"
            Assert::IsTrue(was_lambda_invoked);

            // "should call the temporary object callback"
            Assert::IsTrue(was_tmp_invoked);

            // "should call the pointer-to-member callback"
            Assert::IsTrue(func2.has_been_called());
        }
    };
}