#ifndef ARBUTILS_RANDOM_HPP
#define ARBUTILS_RANDOM_HPP

// PCG uses unsigned shifts, and overflows a lot. Disable the sanitizer for that.
#if defined(__clang__)
// If we don't ignore this diagnostic, and the sanitizer is not known yet in the clang version, this spams tens of
// thousands of warnings. Hence we disable it for a bit.
#pragma GCC diagnostic push
#pragma clang diagnostic ignored "-Wunknown-sanitizers"
#pragma clang attribute push(__attribute__((no_sanitize("unsigned-shift-base", "unsigned-integer-overflow"))),         \
                             apply_to = function)
#endif

#include <pcg_random.hpp>

#if defined(__clang__)
#pragma clang attribute pop
#pragma clang diagnostic pop
#endif

#include <chrono>
#include <cstdint>
#include <random>
#include "Ensure.hpp"

namespace ArbUt {
    /// @brief A helper class for getting random numbers.
    /// @tparam RandomT A type for the desired random number generator.
    template <class RandomT> class BaseRandom {
    private:
        uint_fast32_t _seed;
        RandomT _rng;
        std::uniform_real_distribution<double> _distribution;

    public:
        inline constexpr BaseRandom() noexcept
            : _seed(std::chrono::duration_cast<std::chrono::milliseconds>(
                        std::chrono::system_clock::now().time_since_epoch())
                        .count()),
              _rng(_seed), _distribution(0.0, 1.0) {}

        /// @brief Instantiate random class with a specific seed.
        /// @param seed The seed the random number generator should be instantiated with.
        explicit inline constexpr BaseRandom(uint_fast32_t seed) noexcept
            : _seed(seed), _rng(seed), _distribution(0.0, 1.0){};

        /// @brief The random number generator that is backing the random class.
        inline RandomT& GetRandomEngine() noexcept { return _rng; }

        /// @brief Gets a random float between 0.0 and 1.0.
        [[nodiscard]] inline constexpr f32 GetFloat() noexcept { return static_cast<float>(GetDouble()); }

        /// @brief Gets a random double between 0.0 and 1.0.
        [[nodiscard]] inline constexpr f64 GetDouble() noexcept { return _distribution(_rng); }

        /// @brief Gets a random 32 bit integer
        inline constexpr i32 Get() noexcept { return static_cast<i32>(_rng()); }

        /// @brief Gets a random 32 bit integer between 0, and given max parameter.
        /// @param max The exclusive max value the random value should be.
        [[nodiscard]] inline i32 Get(i32 max) {
            Ensure(max > 0);
            std::uniform_int_distribution<i32> distribution(0, max - 1);
            return distribution(_rng);
        }

        /// @brief Gets a random 32 bit integer between given min and max parameters.
        /// @param min The inclusive min value the random value should be.
        /// @param max The exclusive max value the random value should be.
        [[nodiscard]] inline i32 Get(i32 min, i32 max) {
            Ensure(max > min);
            std::uniform_int_distribution<i32> distribution(min, max - 1);
            return distribution(_rng);
        }

        /// @brief Gets a random 32 bit unsigned integer between 0 and max unsigned int.
        [[nodiscard]] inline constexpr u32 GetUnsigned() noexcept { return _rng(); }

        /// @brief Gets a random 32 bit unsigned integer between 0, and given max parameter.
        /// @param max The exclusive max value the random value should be.
        [[nodiscard]] inline u32 GetUnsigned(u32 max) noexcept {
            std::uniform_int_distribution<u32> distribution(0, max - 1);
            return distribution(_rng);
        }

        /// @brief Gets a random 32 bit unsigned integer between given min and max parameters.
        /// @param min The inclusive min value the random value should be.
        /// @param max The exclusive max value the random value should be.
        [[nodiscard]] inline u32 GetUnsigned(u32 min, u32 max) {
            Ensure(max > min);
            std::uniform_int_distribution<u32> distribution(min, max - 1);
            return distribution(_rng);
        }

        /// @brief The seed the random class is generating from.
        [[nodiscard]] inline constexpr uint_fast32_t GetSeed() const noexcept { return _seed; }
    };

    /// @brief Implementation of the BaseRandom class with pcg32 as random number generator.
    class Random : public BaseRandom<pcg32> {
    public:
        constexpr Random() noexcept : BaseRandom() {}
        /// @brief Instantiate random class with a specific seed.
        /// @param seed The seed the random number generator should be instantiated with.
        explicit constexpr Random(uint_fast32_t seed) noexcept : BaseRandom(seed) {}
    };
}

#endif // ARBUTILS_RANDOM_HPP