// Copyright (c) 2016-2018 Ember - Nomango
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

#pragma once
#include <random>

namespace ember
{
    namespace math
    {
        //
        // 随机数
        //
        // 获取指定范围内的一个随机数, 如:
        // int n = math::Random(1, 5);  // 获取 1~5 内的随机整数, 包含 1 和 5
        // 产生的随机数类型取决于参数的类型, 如获取随机浮点数:
        // float d = math::Random(1.2f, 1.5f);
        //

        int Random(int min, int max);

        unsigned int Random(unsigned int min, unsigned int max);

        long Random(long min, long max);

        unsigned long Random(unsigned long min, unsigned long max);

        char Random(char min, char max);

        float Random(float min, float max);

        double Random(double min, double max);

        //
        // Details of math::Rand
        //

        namespace __rand_detail
        {
            inline std::default_random_engine &GetRandomEngine()
            {
                static std::random_device device;
                static std::default_random_engine engine(device());
                return engine;
            }

            template <typename T>
            inline T RandomInt(T min, T max)
            {
                std::uniform_int_distribution<T> dist(min, max);
                return dist(GetRandomEngine());
            }

            template <typename T>
            inline T RandomReal(T min, T max)
            {
                std::uniform_real_distribution<T> dist(min, max);
                return dist(GetRandomEngine());
            }
        } // namespace __rand_detail

        inline int Random(int min, int max)
        {
            return __rand_detail::RandomInt(min, max);
        }

        inline unsigned int Random(unsigned int min, unsigned int max)
        {
            return __rand_detail::RandomInt(min, max);
        }

        inline long Random(long min, long max)
        {
            return __rand_detail::RandomInt(min, max);
        }

        inline unsigned long Random(unsigned long min, unsigned long max)
        {
            return __rand_detail::RandomInt(min, max);
        }

        inline char Random(char min, char max)
        {
            return static_cast<char>(__rand_detail::RandomInt(static_cast<int>(min), static_cast<int>(max)));
        }

        inline float Random(float min, float max)
        {
            return __rand_detail::RandomReal(min, max);
        }

        inline double Random(double min, double max)
        {
            return __rand_detail::RandomReal(min, max);
        }
    } // namespace math
} // namespace ember
