#pragma once

#include <filesystem>

class ScopedFileLock
{
public:
    ScopedFileLock(ScopedFileLock const&)            = delete;
    ScopedFileLock(ScopedFileLock&&)                 = delete;
    ScopedFileLock& operator=(ScopedFileLock const&) = delete;
    ScopedFileLock& operator=(ScopedFileLock&&)      = delete;

protected:
    ScopedFileLock(std::filesystem::path path) : path_(path)
    {
        if (!std::filesystem::exists(path)) {
            throw GenericError { fmt::format("Could not resolve path '{}'",
                                             path.generic_string()) };
        }

        handle_ = ::CreateFile(path.generic_string().c_str(),
                               GENERIC_READ,
                               FILE_SHARE_READ,
                               NULL,
                               OPEN_EXISTING,
                               FILE_ATTRIBUTE_NORMAL,
                               NULL);

        if (handle_ == INVALID_HANDLE_VALUE) {
            throw GenericError { fmt::format("Failed to open the file at path '{}'",
                                             path.generic_string()) };
        }

        if (!::LockFile(handle_, 0, 0, MAXDWORD, MAXDWORD)) {
            ::CloseHandle(handle_);

            throw GenericError { fmt::format("Failed to lock the file at path '{}'",
                                             path.generic_string()) };
        }
    }

    ~ScopedFileLock()
    {
        ::UnlockFile(handle_, 0, 0, MAXDWORD, MAXDWORD);
        ::CloseHandle(handle_);
    }

    std::filesystem::path path_;

    HANDLE handle_;
};

template<typename ios, typename = std::enable_if_t<std::is_base_of_v<std::ios_base, ios>>>
class ScopedFileIOBase : private ScopedFileLock
{
public:
    std::uintmax_t get_file_size() { return file_size_; }

protected:
    ScopedFileIOBase(std::filesystem::path path)
        : ScopedFileLock { path }, stream_ { path, std::ios::binary | std::ios::ate }
    {
        if (!stream_) {
            throw GenericError { fmt::format("Failed to open the file at path '{}'",
                                             path.generic_string()) };
        }

        file_size_ = std::filesystem::file_size(path);
    }

    ios stream_;

    std::uintmax_t file_size_;
};

class ScopedFileReader : public ScopedFileIOBase<std::ifstream>
{
public:
    ScopedFileReader(auto path) : ScopedFileIOBase { path } {}

    template<typename T>
    void ReadTo(T* dest)
    {
        stream_.read(reinterpret_cast<char*>(dest), file_size_);
    }

    ComPtr<ID3DBlob> ReadToBlob()
    {
        ComPtr<ID3DBlob> blob;

        D3DCreateBlob(file_size_, blob.GetAddressOf());

        stream_.read(reinterpret_cast<char*>(blob->GetBufferPointer()), blob->GetBufferSize());

        return blob;
    }
};

class ScopedFileWriter : public ScopedFileIOBase<std::ofstream>
{
public:
    ScopedFileWriter(auto path) : ScopedFileIOBase { path, std::ios::binary } {}

    void Write(std::string const& src) { stream_.write(src.c_str(), src.size()); }
};