#include "devices/storage/RAMDisk/RAMDiskDevice.hpp"

#include "kapi/boot_module/boot_module.hpp"
#include "kapi/system.hpp"

#include "devices/BlockDevice.hpp"

#include <kstd/cstring>

#include <cstddef>

namespace devices::storage::ram_disk
{
  ram_disk_device::ram_disk_device()  // TODO BA-FS26 remove when kstd::vector is available
      : block_device(0, 0)
  {}

  ram_disk_device::ram_disk_device(kapi::boot_modules::boot_module const & module, size_t major, size_t minor)
      : block_device(major, minor)
      , m_boot_module(module)
  {}

  auto ram_disk_device::read_block(size_t block_index, void * buffer) const -> void
  {
    if (buffer == nullptr)
    {
      kapi::system::panic("[RAM DISK DEVICE] read_block called with null buffer.");
    }

    size_t const offset = block_index * block_size;
    size_t const limit = m_boot_module.size;

    size_t const available = (offset < limit) ? (limit - offset) : 0;
    size_t const to_copy = (available < block_size) ? available : block_size;

    if (to_copy > 0)
    {
      auto const source = static_cast<std::byte const *>(m_boot_module.start_address) + offset;
      kstd::libc::memcpy(buffer, source, to_copy);
    }

    if (to_copy < block_size)
    {
      kstd::libc::memset(static_cast<std::byte *>(buffer) + to_copy, std::byte{0}, block_size - to_copy);
    }
  }

  auto ram_disk_device::write_block(size_t block_index, void const * buffer) -> void
  {
    if (buffer == nullptr)
    {
      kapi::system::panic("[RAM DISK DEVICE] write_block called with null buffer.");
    }

    size_t const offset = block_index * block_size;
    size_t const limit = m_boot_module.size;

    if (offset >= limit)
      return;

    size_t const available = limit - offset;
    size_t const to_write = (available < block_size) ? available : block_size;

    auto const destination = static_cast<std::byte *>(m_boot_module.start_address) + offset;
    kstd::libc::memcpy(destination, buffer, to_write);
  }
}  // namespace devices::storage::ram_disk