#include "content/providers/disk_provider.hpp"

#include <hex/api/localization.hpp>

#include <hex/helpers/fmt.hpp>
#include <hex/helpers/utils.hpp>
#include <hex/ui/imgui_imhex_extensions.h>

#include <bitset>
#include <filesystem>

#include <imgui.h>

#if defined(OS_LINUX)

    #include <fcntl.h>
    #include <unistd.h>
    #include <sys/stat.h>
    #include <sys/types.h>

    #define lseek lseek64

#elif defined(OS_MACOS)

    #include <fcntl.h>
    #include <unistd.h>
    #include <sys/stat.h>
    #include <sys/types.h>

#endif

namespace hex::plugin::builtin::prv {

    DiskProvider::DiskProvider() : Provider() {
        this->reloadDrives();
    }

    bool DiskProvider::isAvailable() const {
        #if defined(OS_WINDOWS)

            return this->m_diskHandle != INVALID_HANDLE_VALUE;

        #else

            return this->m_diskHandle != -1;

        #endif
    }

    bool DiskProvider::isReadable() const {
        return this->m_readable;
    }

    bool DiskProvider::isWritable() const {
        return this->m_writable;
    }

    bool DiskProvider::isResizable() const {
        return false;
    }

    bool DiskProvider::isSavable() const {
        return false;
    }


    void DiskProvider::setPath(const std::fs::path &path) {
        this->m_path = path;
    }

    bool DiskProvider::open() {
        this->m_readable = true;
        this->m_writable = true;

        #if defined(OS_WINDOWS)

            const auto &path = this->m_path.native();

            this->m_diskHandle = reinterpret_cast<HANDLE>(CreateFileW(path.c_str(), GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ, nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, nullptr));
            if (this->m_diskHandle == INVALID_HANDLE_VALUE) {
                this->m_diskHandle = reinterpret_cast<HANDLE>(CreateFileW(path.c_str(), GENERIC_READ, FILE_SHARE_READ, nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, nullptr));
                this->m_writable   = false;

                if (this->m_diskHandle == INVALID_HANDLE_VALUE)
                    return false;
            }

            {
                DISK_GEOMETRY_EX diskGeometry = { };
                DWORD bytesRead               = 0;
                if (DeviceIoControl(
                        this->m_diskHandle,
                        IOCTL_DISK_GET_DRIVE_GEOMETRY_EX,
                        nullptr,
                        0,
                        &diskGeometry,
                        sizeof(DISK_GEOMETRY_EX),
                        &bytesRead,
                        nullptr)) {
                    this->m_diskSize   = diskGeometry.DiskSize.QuadPart;
                    this->m_sectorSize = diskGeometry.Geometry.BytesPerSector;
                    this->m_sectorBuffer.resize(this->m_sectorSize);
                }
            }

            if (this->m_diskHandle == nullptr || this->m_diskHandle == INVALID_HANDLE_VALUE) {
                this->m_readable   = false;
                this->m_diskHandle = nullptr;
                CloseHandle(this->m_diskHandle);

                return false;
            }

        #else

            const auto &path = this->m_path.native();

            struct stat driveStat;

            if (::stat(path.c_str(), &driveStat) == 0)
                this->m_diskSize   = driveStat.st_size;
            else
                this->m_diskSize = 0;

            this->m_sectorSize = 0;

            this->m_diskHandle = ::open(path.c_str(), O_RDWR);
            if (this->m_diskHandle == -1) {
                this->m_diskHandle = ::open(path.c_str(), O_RDONLY);
                this->m_writable   = false;
            }

            if (this->m_diskHandle == -1) {
                this->m_readable = false;
                return false;
            }

        #endif

        return Provider::open();
    }

    void DiskProvider::close() {
        #if defined(OS_WINDOWS)

            if (this->m_diskHandle != INVALID_HANDLE_VALUE)
                ::CloseHandle(this->m_diskHandle);

            this->m_diskHandle = INVALID_HANDLE_VALUE;

        #else

            if (this->m_diskHandle != -1)
                ::close(this->m_diskHandle);

            this->m_diskHandle = -1;

        #endif

        Provider::close();
    }

    void DiskProvider::readRaw(u64 offset, void *buffer, size_t size) {
        #if defined(OS_WINDOWS)

            DWORD bytesRead = 0;

            u64 startOffset = offset;

            while (size > 0) {
                LARGE_INTEGER seekPosition;
                seekPosition.LowPart  = (offset & 0xFFFF'FFFF) - (offset % this->m_sectorSize);
                seekPosition.HighPart = offset >> 32;

                if (this->m_sectorBufferAddress != static_cast<u64>(seekPosition.QuadPart)) {
                    ::SetFilePointer(this->m_diskHandle, seekPosition.LowPart, &seekPosition.HighPart, FILE_BEGIN);
                    ::ReadFile(this->m_diskHandle, this->m_sectorBuffer.data(), this->m_sectorBuffer.size(), &bytesRead, nullptr);
                    this->m_sectorBufferAddress = seekPosition.QuadPart;
                }

                std::memcpy(reinterpret_cast<u8 *>(buffer) + (offset - startOffset), this->m_sectorBuffer.data() + (offset & (this->m_sectorSize - 1)), std::min(this->m_sectorSize, size));

                size = std::max<ssize_t>(static_cast<ssize_t>(size) - this->m_sectorSize, 0);
                offset += this->m_sectorSize;
            }

        #else

        u64 startOffset    = offset;

        while (size > 0) {
            u64 seekPosition = offset - (offset % this->m_sectorSize);

            if (this->m_sectorBufferAddress != seekPosition) {
                ::lseek(this->m_diskHandle, seekPosition, SEEK_SET);
                if (::read(this->m_diskHandle, buffer, size) < 0)
                    break;

                this->m_sectorBufferAddress = seekPosition;
            }

            std::memcpy(reinterpret_cast<u8 *>(buffer) + (offset - startOffset), this->m_sectorBuffer.data() + (offset & (this->m_sectorSize - 1)), std::min(this->m_sectorSize, size));

            size = std::max<ssize_t>(static_cast<ssize_t>(size) - this->m_sectorSize, 0);
            offset += this->m_sectorSize;
        }

        #endif
    }

    void DiskProvider::writeRaw(u64 offset, const void *buffer, size_t size) {
        #if defined(OS_WINDOWS)

            DWORD bytesWritten = 0;

            u64 startOffset = offset;

            std::vector<u8> modifiedSectorBuffer;
            modifiedSectorBuffer.resize(this->m_sectorSize);

            while (size > 0) {
                u64 sectorBase  = offset - (offset % this->m_sectorSize);
                size_t currSize = std::min(size, this->m_sectorSize);

                this->readRaw(sectorBase, modifiedSectorBuffer.data(), modifiedSectorBuffer.size());
                std::memcpy(modifiedSectorBuffer.data() + ((offset - sectorBase) % this->m_sectorSize), reinterpret_cast<const u8 *>(buffer) + (startOffset - offset), currSize);

                LARGE_INTEGER seekPosition;
                seekPosition.LowPart  = (offset & 0xFFFF'FFFF) - (offset % this->m_sectorSize);
                seekPosition.HighPart = offset >> 32;

                ::SetFilePointer(this->m_diskHandle, seekPosition.LowPart, &seekPosition.HighPart, FILE_BEGIN);
                ::WriteFile(this->m_diskHandle, modifiedSectorBuffer.data(), modifiedSectorBuffer.size(), &bytesWritten, nullptr);

                offset += currSize;
                size -= currSize;
            }

        #else

            u64 startOffset = offset;

            std::vector<u8> modifiedSectorBuffer;
            modifiedSectorBuffer.resize(this->m_sectorSize);

            while (size > 0) {
                u64 sectorBase  = offset - (offset % this->m_sectorSize);
                size_t currSize = std::min(size, this->m_sectorSize);

                this->readRaw(sectorBase, modifiedSectorBuffer.data(), modifiedSectorBuffer.size());
                std::memcpy(modifiedSectorBuffer.data() + ((offset - sectorBase) % this->m_sectorSize), reinterpret_cast<const u8 *>(buffer) + (startOffset - offset), currSize);

                ::lseek(this->m_diskHandle, sectorBase, SEEK_SET);
                if (::write(this->m_diskHandle, modifiedSectorBuffer.data(), modifiedSectorBuffer.size()) < 0)
                    break;

                offset += currSize;
                size -= currSize;
            }

        #endif
    }

    size_t DiskProvider::getActualSize() const {
        return this->m_diskSize;
    }

    std::string DiskProvider::getName() const {
        return this->m_path.string();
    }

    std::vector<std::pair<std::string, std::string>> DiskProvider::getDataInformation() const {
        return {
            {"hex.builtin.provider.disk.selected_disk"_lang, this->m_path.string()                },
            { "hex.builtin.provider.disk.disk_size"_lang,    hex::toByteString(this->m_diskSize)  },
            { "hex.builtin.provider.disk.sector_size"_lang,  hex::toByteString(this->m_sectorSize)}
        };
    }


    void DiskProvider::reloadDrives() {
        #if defined(OS_WINDOWS)

            this->m_availableDrives.clear();
            std::bitset<32> drives = ::GetLogicalDrives();
            for (char i = 0; i < 26; i++) {
                if (drives[i])
                    this->m_availableDrives.insert(hex::format(R"(\\.\{:c}:)", 'A' + i));
            }

            auto logicalDrives = this->m_availableDrives;
            for (const auto &drive : logicalDrives) {
                auto handle = reinterpret_cast<HANDLE>(::CreateFile(drive.data(), GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE, nullptr, OPEN_EXISTING, 0, nullptr));

                if (handle == INVALID_HANDLE_VALUE) continue;

                VOLUME_DISK_EXTENTS diskExtents = { };
                DWORD bytesRead                 = 0;
                auto result                     = ::DeviceIoControl(
                    handle,
                    IOCTL_VOLUME_GET_VOLUME_DISK_EXTENTS,
                    nullptr,
                    0,
                    &diskExtents,
                    sizeof(VOLUME_DISK_EXTENTS),
                    &bytesRead,
                    nullptr);

                if (result) {
                    auto diskPath = hex::format(R"(\\.\PhysicalDrive{})", diskExtents.Extents[0].DiskNumber);
                    this->m_availableDrives.insert(diskPath);
                }

                ::CloseHandle(handle);
            }

        #endif
    }

    void DiskProvider::drawLoadInterface() {
        #if defined(OS_WINDOWS)

            if (ImGui::BeginListBox("hex.builtin.provider.disk.selected_disk"_lang)) {

                for (const auto &drive : this->m_availableDrives) {
                    if (ImGui::Selectable(drive.c_str(), this->m_path == drive))
                        this->m_path = drive;
                }

                ImGui::EndListBox();
            }

            ImGui::SameLine();

            if (ImGui::Button("hex.builtin.provider.disk.reload"_lang)) {
                this->reloadDrives();
        }

        #else

            if (ImGui::InputText("hex.builtin.provider.disk.selected_disk"_lang, this->m_pathBuffer.data(), this->m_pathBuffer.size(), ImGuiInputTextFlags_CallbackResize, ImGui::UpdateStringSizeCallback, &this->m_pathBuffer))
                this->m_path = this->m_pathBuffer;

        #endif
    }

    nlohmann::json DiskProvider::storeSettings(nlohmann::json settings) const {
        settings["path"] = this->m_path.string();

        return Provider::storeSettings(settings);
    }

    void DiskProvider::loadSettings(const nlohmann::json &settings) {
        Provider::loadSettings(settings);

        this->setPath(settings["path"].get<std::string>());
        this->reloadDrives();
    }

    std::pair<Region, bool> DiskProvider::getRegionValidity(u64 address) const {
        if (address < this->getActualSize())
            return { Region { address, this->getActualSize() - address }, true };
        else
            return { Region::Invalid(), false };
    }

}