#include "kernel/filesystem/device_inode.hpp"

#include "kernel/test_support/cpu.hpp"
#include "kernel/test_support/devices/block_device.hpp"
#include "kernel/test_support/devices/character_device.hpp"

#include <kstd/memory>
#include <kstd/print>
#include <kstd/vector>

#include <catch2/catch_test_macros.hpp>

#include <cstddef>
#include <cstdint>

SCENARIO("Device inode construction", "[filesystem][device_inode]")
{
  GIVEN("a block device")
  {
    auto device = kstd::make_shared<kernel::tests::devices::block_device>(0, 0, "test_block_device", 512, 3 * 512);

    WHEN("constructing a device inode with the block device")
    {
      auto inode = kernel::filesystem::device_inode{device};

      THEN("the device inode has the correct device")
      {
        REQUIRE(inode.device() == device);
      }

      THEN("the device inode has the correct kind")
      {
        REQUIRE(inode.is_device());
        REQUIRE_FALSE(inode.is_directory());
        REQUIRE_FALSE(inode.is_regular());
      }
    }

    WHEN("constructing a device inode with a null device")
    {
      THEN("the constructor panics")
      {
        REQUIRE_THROWS_AS((kernel::filesystem::device_inode{nullptr}), kernel::tests::cpu::halt);
      }
    }
  }
}

SCENARIO("Device inode read/write", "[filesystem][device_inode]")
{
  GIVEN("a block device and a device inode for that device")
  {
    auto device = kstd::make_shared<kernel::tests::devices::block_device>(0, 0, "test_block_device", 512, 3 * 512);
    auto inode = kernel::filesystem::device_inode{device};

    WHEN("writing to the device inode")
    {
      kstd::vector<uint8_t> write_buffer(1024);
      for (size_t i = 0; i < write_buffer.size(); ++i)
      {
        write_buffer[i] = static_cast<uint8_t>(i % 256);
      }

      auto bytes_written = inode.write(write_buffer.data(), 256, write_buffer.size());

      THEN("the correct number of bytes is written")
      {
        REQUIRE(bytes_written == 1024);
      }

      THEN("the data written matches the data read back from the device inode")
      {
        kstd::vector<uint8_t> read_buffer(1024);
        auto bytes_read = inode.read(read_buffer.data(), 256, read_buffer.size());

        REQUIRE(bytes_read == write_buffer.size());
        REQUIRE(read_buffer == write_buffer);
      }
    }
  }
}

SCENARIO("Device inode read/write with a non-block device", "[filesystem][device_inode]")
{
  GIVEN("a non-block device and a device inode for that device")
  {
    auto device = kstd::make_shared<kernel::tests::devices::character_device>(0, 0, "test_character_device");
    auto inode = kernel::filesystem::device_inode{device};

    WHEN("reading from the device inode")
    {
      kstd::vector<uint8_t> read_buffer(512);
      THEN("the system panics")
      {
        REQUIRE_THROWS_AS(inode.read(read_buffer.data(), 0, read_buffer.size()), kernel::tests::cpu::halt);
      }
    }

    WHEN("writing to the device inode")
    {
      kstd::vector<uint8_t> write_buffer(512);
      THEN("the system panics")
      {
        REQUIRE_THROWS_AS(inode.write(write_buffer.data(), 0, write_buffer.size()), kernel::tests::cpu::halt);
      }
    }
  }
}