#include "dmem.hpp"
#include "io-device.hpp"
#include "orbis/KernelAllocator.hpp"
#include "orbis/file.hpp"
#include "orbis/thread/Thread.hpp"
#include "orbis/utils/Logs.hpp"
#include "vm.hpp"
#include <mutex>

struct DmemFile : public orbis::File {};

struct AllocateDirectMemoryArgs {
  std::uint64_t searchStart;
  std::uint64_t searchEnd;
  std::uint64_t len;
  std::uint64_t alignment;
  std::uint32_t memoryType;
};

static constexpr auto dmemSize = 8ull * 1024 * 1024 * 1024;
// static const std::uint64_t nextOffset = 0;
//  static const std::uint64_t memBeginAddress = 0xfe0000000;

orbis::ErrorCode DmemDevice::mmap(void **address, std::uint64_t len,
                                  std::int32_t prot, std::int32_t flags,
                                  std::int64_t directMemoryStart) {
  auto result =
      rx::vm::map(*address, len, prot, flags, 0, this, directMemoryStart);

  ORBIS_LOG_WARNING("dmem mmap", index, directMemoryStart, prot, flags, result);
  if (result == (void *)-1) {
    return orbis::ErrorCode::NOMEM; // TODO
  }

  *address = result;
  return {};
}

static orbis::ErrorCode dmem_ioctl(orbis::File *file, std::uint64_t request,
                                   void *argp, orbis::Thread *thread) {
  auto device = static_cast<DmemDevice *>(file->device.get());

  std::lock_guard lock(device->mtx);
  switch (request) {
  case 0x4008800a: // get size
    ORBIS_LOG_WARNING("dmem getTotalSize", device->index, argp);
    *(std::uint64_t *)argp = device->dmemTotalSize;
    return {};

  case 0xc0208016: { // get available size
    struct Args {
      std::uint64_t searchStart;
      std::uint64_t searchEnd;
      std::uint64_t alignment;
      std::uint64_t size;
    };

    auto args = reinterpret_cast<Args *>(argp);

    return device->queryMaxFreeChunkSize(&args->searchStart, args->searchEnd, args->alignment, &args->size);

    ORBIS_LOG_WARNING("dmem getAvailableSize", device->index, argp, dmemSize);
    // args->searchStart = device->nextOffset;
    // args->size = dmemSize - device->nextOffset;

    return {};
  }

  case 0xc0288011:
  case 0xc0288001: { // sceKernelAllocateDirectMemory
    auto args = reinterpret_cast<AllocateDirectMemoryArgs *>(argp);

    return device->allocate(&args->searchStart, args->searchEnd, args->len,
                            args->alignment, args->memoryType);
  }

  case 0x80108002: { // sceKernelReleaseDirectMemory
    struct Args {
      std::uint64_t address;
      std::uint64_t size;
    };

    auto args = reinterpret_cast<Args *>(argp);

    ORBIS_LOG_WARNING("dmem releaseDirectMemory", device->index, args->address,
                      args->size);

    device->allocations.map(args->address, args->address + args->size,
                            {.memoryType = 0});
    return {};
  }
  }

  thread->where();
  ORBIS_LOG_FATAL("Unhandled dmem ioctl", device->index, request);
  return {};
}

static orbis::ErrorCode dmem_mmap(orbis::File *file, void **address,
                                  std::uint64_t size, std::int32_t prot,
                                  std::int32_t flags, std::int64_t offset,
                                  orbis::Thread *thread) {
  auto device = static_cast<DmemDevice *>(file->device.get());
  return device->mmap(address, size, prot, flags, offset);
}

static const orbis::FileOps ops = {
    .ioctl = dmem_ioctl,
    .mmap = dmem_mmap,
};

orbis::ErrorCode DmemDevice::allocate(std::uint64_t *start,
                                      std::uint64_t searchEnd,
                                      std::uint64_t len,
                                      std::uint64_t alignment,
                                      std::uint32_t memoryType) {
  std::size_t offset = *start;
  while (offset < searchEnd) {
    offset += alignment - 1;
    offset &= ~(alignment - 1);

    if (offset + len > dmemTotalSize) {
      ORBIS_LOG_ERROR("dmem: failed to allocate direct memory: out of memory",
                      *start, searchEnd, len, alignment, memoryType, offset);
      return orbis::ErrorCode::AGAIN;
    }

    auto it = allocations.lowerBound(offset);

    if (it != allocations.end()) {
      auto allocation = *it;
      if (allocation.payload.memoryType == 0) {
        if (offset < allocation.beginAddress) {
          offset = allocation.beginAddress + alignment - 1;
          offset &= ~(alignment - 1);
        }

        if (offset + len >= allocation.endAddress) {
          offset = allocation.endAddress;
          continue;
        }
      } else {
        if (offset + len > allocation.beginAddress) {
          offset = allocation.endAddress;
          continue;
        }
      }
    }

    allocations.map(offset, offset + len,
                    {
                        .memoryType = memoryType,
                    });
    ORBIS_LOG_WARNING("dmem: allocated direct memory", *start, searchEnd, len,
                      alignment, memoryType, offset);
    *start = offset;
    return {};
  }

  ORBIS_LOG_ERROR("dmem: failed to allocate direct memory", *start, searchEnd,
                  len, alignment, memoryType, offset);
  return orbis::ErrorCode::AGAIN;
}

orbis::ErrorCode DmemDevice::queryMaxFreeChunkSize(std::uint64_t *start,
                                                   std::uint64_t searchEnd,
                                                   std::uint64_t alignment,
                                                   std::uint64_t *size) {
  std::size_t offset = *start;
  std::size_t resultSize = 0;
  std::size_t resultOffset = 0;
  while (offset < searchEnd) {
    offset += alignment - 1;
    offset &= ~(alignment - 1);

    if (offset >= dmemTotalSize) {
      break;
    }

    auto it = allocations.lowerBound(offset);

    if (it == allocations.end()) {
      if (resultSize < dmemTotalSize - offset) {
        resultSize = dmemTotalSize - offset;
        resultOffset = offset;
      }

      break;
    }

    auto allocation = *it;
    if (allocation.payload.memoryType == 0) {
      if (offset < allocation.beginAddress) {
        offset = allocation.beginAddress + alignment - 1;
        offset &= ~(alignment - 1);
      }

      if (allocation.endAddress > offset &&
          resultSize < allocation.endAddress - offset) {
        resultSize = allocation.endAddress - offset;
        resultOffset = offset;
      }
    } else if (offset > allocation.beginAddress &&
               resultSize < offset - allocation.beginAddress) {
      resultSize = offset - allocation.beginAddress;
      resultOffset = offset;
    }

    offset = allocation.endAddress;
  }

  *start = resultOffset;
  *size = resultSize;

  ORBIS_LOG_WARNING("dmem queryMaxFreeChunkSize", resultOffset, resultSize);
  return{};
}

orbis::ErrorCode DmemDevice::open(orbis::Ref<orbis::File> *file,
                                  const char *path, std::uint32_t flags,
                                  std::uint32_t mode, orbis::Thread *thread) {
  auto newFile = orbis::knew<DmemFile>();
  newFile->device = this;
  newFile->ops = &ops;
  *file = newFile;
  return {};
}

IoDevice *createDmemCharacterDevice(int index) {
  auto *newDevice = orbis::knew<DmemDevice>();
  newDevice->index = index;
  newDevice->dmemTotalSize = dmemSize;
  return newDevice;
}