#ifndef UTILS_HPP
#define UTILS_HPP

#include <cstdint>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <exception>
#include <ios>
#include <memory>
#include <new>
#include <sstream>
#include <stdexcept>
#include <string>
#include <type_traits>
#include <utility>
#include <vector>

#include "common.hpp"
#include "error.hpp"
#include "utils.hpp"

#if IS_WINDOWS
 #include <windows.h>
#else
 #include <sys/stat.h>
#endif


namespace cpptrace {
namespace detail {
    inline std::vector<std::string> split(const std::string& str, const std::string& delims) {
        std::vector<std::string> vec;
        size_t old_pos = 0;
        size_t pos = 0;
        while((pos = str.find_first_of(delims, old_pos)) != std::string::npos) {
            vec.emplace_back(str.substr(old_pos, pos - old_pos));
            old_pos = pos + 1;
        }
        vec.emplace_back(str.substr(old_pos));
        return vec;
    }

    template<typename C>
    inline std::string join(const C& container, const std::string& delim) {
        auto iter = std::begin(container);
        auto end = std::end(container);
        std::string str;
        if(std::distance(iter, end) > 0) {
            str += *iter;
            while(++iter != end) {
                str += delim;
                str += *iter;
            }
        }
        return str;
    }

    constexpr const char* const whitespace = " \t\n\r\f\v";

    inline std::string trim(const std::string& str) {
        if(str.empty()) {
            return "";
        }
        const size_t left = str.find_first_not_of(whitespace);
        const size_t right = str.find_last_not_of(whitespace) + 1;
        return str.substr(left, right - left);
    }

    inline std::string to_hex(uintptr_t addr) {
        std::stringstream sstream;
        sstream<<std::hex<<addr;
        return std::move(sstream).str();
    }

    inline bool is_little_endian() {
        uint16_t num = 0x1;
        auto* ptr = (uint8_t*)&num;
        return ptr[0] == 1;
    }

    // Modified from
    // https://stackoverflow.com/questions/105252/how-do-i-convert-between-big-endian-and-little-endian-values-in-c
    template<typename T, size_t N>
    struct byte_swapper;

    template<typename T>
    struct byte_swapper<T, 1> {
        T operator()(T val) {
            return val;
        }
    };

    template<typename T>
    struct byte_swapper<T, 2> {
        T operator()(T val) {
            return ((((val) >> 8) & 0xff) | (((val) & 0xff) << 8));
        }
    };

    template<typename T>
    struct byte_swapper<T, 4> {
        T operator()(T val) {
            return ((((val) & 0xff000000) >> 24) |
                    (((val) & 0x00ff0000) >>  8) |
                    (((val) & 0x0000ff00) <<  8) |
                    (((val) & 0x000000ff) << 24));
        }
    };

    template<typename T>
    struct byte_swapper<T, 8> {
        T operator()(T val) {
            return ((((val) & 0xff00000000000000ull) >> 56) |
                    (((val) & 0x00ff000000000000ull) >> 40) |
                    (((val) & 0x0000ff0000000000ull) >> 24) |
                    (((val) & 0x000000ff00000000ull) >> 8 ) |
                    (((val) & 0x00000000ff000000ull) << 8 ) |
                    (((val) & 0x0000000000ff0000ull) << 24) |
                    (((val) & 0x000000000000ff00ull) << 40) |
                    (((val) & 0x00000000000000ffull) << 56));
        }
    };

    template<typename T, typename std::enable_if<std::is_integral<T>::value, int>::type = 0>
    T byteswap(T value) {
        return byte_swapper<T, sizeof(T)>{}(value);
    }

    inline void enable_virtual_terminal_processing_if_needed() {
        // enable colors / ansi processing if necessary
        #if IS_WINDOWS
         // https://docs.microsoft.com/en-us/windows/console/console-virtual-terminal-sequences#example-of-enabling-virtual-terminal-processing
         #ifndef ENABLE_VIRTUAL_TERMINAL_PROCESSING
          constexpr DWORD ENABLE_VIRTUAL_TERMINAL_PROCESSING = 0x4;
         #endif
         HANDLE hOut = GetStdHandle(STD_OUTPUT_HANDLE);
         DWORD dwMode = 0;
         if(hOut == INVALID_HANDLE_VALUE) return;
         if(!GetConsoleMode(hOut, &dwMode)) return;
         if(dwMode != (dwMode | ENABLE_VIRTUAL_TERMINAL_PROCESSING))
         if(!SetConsoleMode(hOut, dwMode | ENABLE_VIRTUAL_TERMINAL_PROCESSING)) return;
        #endif
    }

    // NOLINTNEXTLINE(misc-no-recursion)
    inline constexpr unsigned n_digits(unsigned value) {
        return value < 10 ? 1 : 1 + n_digits(value / 10);
    }
    static_assert(n_digits(1) == 1, "n_digits utility producing the wrong result");
    static_assert(n_digits(9) == 1, "n_digits utility producing the wrong result");
    static_assert(n_digits(10) == 2, "n_digits utility producing the wrong result");
    static_assert(n_digits(11) == 2, "n_digits utility producing the wrong result");
    static_assert(n_digits(1024) == 4, "n_digits utility producing the wrong result");

    // TODO: Re-evaluate use of off_t
    template<typename T, typename std::enable_if<std::is_pod<T>::value, int>::type = 0>
    T load_bytes(FILE* obj_file, off_t offset) {
        T object;
        CPPTRACE_VERIFY(fseek(obj_file, offset, SEEK_SET) == 0, "fseek error");
        CPPTRACE_VERIFY(fread(&object, sizeof(T), 1, obj_file) == 1, "fread error");
        return object;
    }

    struct nullopt_t {};

    static constexpr nullopt_t nullopt;

    template<
        typename T,
        typename std::enable_if<!std::is_same<typename std::decay<T>::type, void>::value, int>::type = 0
    >
    class optional {
        bool holds_value = false;

        union {
            T uvalue;
        };

    public:
        // clang-tidy false positive
        // NOLINTNEXTLINE(modernize-use-equals-default)
        optional() noexcept {}

        optional(nullopt_t) noexcept {}

        ~optional() {
            reset();
        }

        optional(const optional& other) : holds_value(other.holds_value) {
            if(holds_value) {
                new (static_cast<void*>(std::addressof(uvalue))) T(other.uvalue);
            }
        }

        optional(optional&& other)
            noexcept(std::is_nothrow_move_constructible<T>::value)
            : holds_value(other.holds_value)
        {
            if(holds_value) {
                new (static_cast<void*>(std::addressof(uvalue))) T(std::move(other.uvalue));
            }
        }

        optional& operator=(const optional& other) {
            optional copy(other);
            swap(*this, copy);
            return *this;
        }

        optional& operator=(optional&& other)
            noexcept(std::is_nothrow_move_assignable<T>::value && std::is_nothrow_move_constructible<T>::value)
        {
            reset();
            if(other.holds_value) {
                new (static_cast<void*>(std::addressof(uvalue))) T(std::move(other.uvalue));
                holds_value = true;
            }
            return *this;
        }

        template<
            typename U = T,
            typename std::enable_if<!std::is_same<typename std::decay<U>::type, optional<T>>::value, int>::type = 0
        >
        // clang-tidy false positive
        // NOLINTNEXTLINE(bugprone-forwarding-reference-overload)
        optional(U&& value) : holds_value(true) {
            new (static_cast<void*>(std::addressof(uvalue))) T(std::forward<U>(value));
        }

        template<
            typename U = T,
            typename std::enable_if<!std::is_same<typename std::decay<U>::type, optional<T>>::value, int>::type = 0
        >
        optional& operator=(U&& value) {
            if(holds_value) {
                uvalue = std::forward<U>(value);
            } else {
                new (static_cast<void*>(std::addressof(uvalue))) T(std::forward<U>(value));
                holds_value = true;
            }
            return *this;
        }

        optional& operator=(nullopt_t) noexcept {
            reset();
            return *this;
        }

        void swap(optional& other) {
            if(holds_value && other.holds_value) {
                std::swap(uvalue, other.uvalue);
            } else if(holds_value && !other.holds_value) {
                new (&other.uvalue) T(std::move(uvalue));
                uvalue.~T();
            } else if(!holds_value && other.holds_value) {
                new (static_cast<void*>(std::addressof(uvalue))) T(std::move(other.uvalue));
                other.uvalue.~T();
            }
            std::swap(holds_value, other.holds_value);
        }

        bool has_value() const {
            return holds_value;
        }

        operator bool() const {
            return holds_value;
        }

        void reset() {
            if(holds_value) {
                uvalue.~T();
            }
            holds_value = false;
        }

        T& unwrap() & {
            if(!holds_value) {
                throw std::runtime_error{"Optional does not contain a value"};
            }
            return uvalue;
        }

        const T& unwrap() const & {
            if(!holds_value) {
                throw std::runtime_error{"Optional does not contain a value"};
            }
            return uvalue;
        }

        T&& unwrap() && {
            if(!holds_value) {
                throw std::runtime_error{"Optional does not contain a value"};
            }
            return std::move(uvalue);
        }

        const T&& unwrap() const && {
            if(!holds_value) {
                throw std::runtime_error{"Optional does not contain a value"};
            }
            return std::move(uvalue);
        }

        template<typename U>
        T value_or(U&& default_value) const & {
            return holds_value ? uvalue : static_cast<T>(std::forward<U>(default_value));
        }

        template<typename U>
        T value_or(U&& default_value) && {
            return holds_value ? std::move(uvalue) : static_cast<T>(std::forward<U>(default_value));
        }
    };

    // shamelessly stolen from stackoverflow
    inline bool directory_exists(const std::string& path) {
        #if IS_WINDOWS
         DWORD dwAttrib = GetFileAttributesA(path.c_str());
         return dwAttrib != INVALID_FILE_ATTRIBUTES && (dwAttrib & FILE_ATTRIBUTE_DIRECTORY);
        #else
         struct stat sb;
         return stat(path.c_str(), &sb) == 0 && S_ISDIR(sb.st_mode);
        #endif
    }

    inline std::string basename(const std::string& path) {
        // Assumes no trailing /'s
        auto pos = path.rfind('/');
        if(pos == std::string::npos) {
            return path;
        } else {
            return path.substr(pos + 1);
        }
    }
}
}

#endif