//Copyright (c) 2018 Emil Dotchevski
//Copyright (c) 2018 Second Spectrum, Inc.

//Distributed under the Boost Software License, Version 1.0. (See accompanying
//file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

#include <boost/leaf/result.hpp>
#include <boost/leaf/expect.hpp>
#include "boost/core/lightweight_test.hpp"
#include <vector>
#include <future>
#include <iterator>
#include <algorithm>

namespace leaf = boost::leaf;

template <int> struct info { int value; };

struct fut_info
{
	int a;
	int b;
	int result;
	std::future<leaf::result<int>> fut;
};

template <class F>
std::vector<fut_info> launch_tasks( int task_count, F f )
{
	assert(task_count>0);
	std::vector<fut_info> fut;
	std::generate_n( std::inserter(fut,fut.end()), task_count, [f]
	{
		int const a = rand();
		int const b = rand();
		int const res = (rand()%10) - 5;
		return fut_info { a, b, res, std::async( std::launch::async, [f,a,b,res]
			{
				leaf::expect<info<1>,info<2>,info<3>> exp;
				return capture(exp,f(a,b,res));
			} ) };
	} );
	return fut;
}

int main()
{
	std::vector<fut_info> fut = launch_tasks( 42, [ ]( int a, int b, int res ) noexcept -> leaf::result<int>
	{
		if( res>=0 )
			return res;
		else
			return leaf::error(info<1>{a},info<2>{b},info<3>{});
	} );
	for( auto & f : fut )
	{
		using namespace leaf::leaf_detail;
		f.fut.wait();
		leaf::expect<info<1>,info<2>,info<4>> exp;
		if( leaf::result<int> r = f.fut.get() )
		{
			BOOST_TEST(*r>=0);
			BOOST_TEST(*r==f.result);
		}
		else
		{
			int c=0;
			bool handled = handle_error( exp, r, [&f,&c]( info<1> const & x1, info<2> const & x2 )
			{
				BOOST_TEST(x1.value==f.a);
				BOOST_TEST(x2.value==f.b);
				++c;
			} );
			BOOST_TEST(handled);
			BOOST_TEST(c==1);
		}
	}
	return boost::report_errors();
}