#include <torch/csrc/python_headers.h>
#ifdef _MSC_VER
#include <c10/util/win32-headers.h>
#endif
#include <structmember.h>

#include <ATen/mps/MPSDevice.h>
#include <c10/core/CPUAllocator.h>
#include <libshm.h>
#include <torch/csrc/CudaIPCTypes.h>
#include <torch/csrc/Device.h>
#include <torch/csrc/DynamicTypes.h>
#include <torch/csrc/StorageMethods.h>
#include <torch/csrc/StorageSharing.h>
#include <torch/csrc/THP.h>
#include <torch/csrc/autograd/utils/wrap_outputs.h>
#include <torch/csrc/copy_utils.h>
#include <torch/csrc/utils/python_arg_parser.h>

#include <c10/util/intrusive_ptr.h>
#include <fmt/format.h>

template <>
void THPPointer<c10::StorageImpl>::free() {
  if (ptr) {
    c10::raw::intrusive_ptr::decref(ptr);
  }
}

PyObject* THPStorageClass = nullptr;

PyObject* THPStorage_New(c10::intrusive_ptr<c10::StorageImpl> ptr) {
  AT_ASSERT(ptr);
  PyTypeObject* type = (PyTypeObject*)THPStorageClass;
  PyObject* obj = type->tp_alloc(type, 0);
  if (obj) {
    ((THPStorage*)obj)->cdata = ptr.release();
  }
  return obj;
}

static void THPStorage_dealloc(THPStorage* self) {
  if (self->cdata) {
    c10::raw::intrusive_ptr::decref(self->cdata);
  }
  Py_TYPE(self)->tp_free((PyObject*)self);
}

static PyObject* THPStorage_pynew(
    PyTypeObject* type,
    PyObject* args,
    PyObject* kwargs) {
  HANDLE_TH_ERRORS

  static torch::PythonArgParser parser({
      THPStorageStr "(*, int64_t allocator=None, Device device=None)",
      THPStorageStr
      "(int64_t size, *, int64_t allocator=None, Device device=None)",
      THPStorageStr
      "(PyObject* sequence, *, int64_t allocator=None, Device device=None)",
  });
  torch::ParsedArgs<3> parsed_args;
  auto r = parser.parse(args, kwargs, parsed_args);

  int64_t allocator_arg_idx = 0;
  int64_t device_arg_idx = 1;

  if (r.idx > 0) {
    allocator_arg_idx = 1;
    device_arg_idx = 2;
  }

  c10::optional<int64_t> allocator_opt = r.toInt64Optional(allocator_arg_idx);
  c10::optional<at::Device> device_opt = r.deviceOptional(device_arg_idx);

  TORCH_CHECK(
      !allocator_opt.has_value() || !device_opt.has_value(),
      THPStorageStr,
      "(): only one or neither of 'allocator' or 'device' can ",
      "be given, but not both");

  THPStoragePtr self((THPStorage*)type->tp_alloc(type, 0));
  THPUtils_assert(self, "failed to allocate a " THPStorageStr " object");
  c10::Allocator* allocator = nullptr;
  at::OptionalDeviceGuard device_guard;

  if (allocator_opt.has_value()) {
    allocator = reinterpret_cast<c10::Allocator*>(allocator_opt.value());
  } else if (device_opt.has_value()) {
    at::Device device = device_opt.value();
    if (device.type() == at::kCPU) {
      allocator = c10::GetDefaultCPUAllocator();
#ifdef USE_CUDA
    } else if (device.type() == at::kCUDA) {
      at::globalContext().lazyInitCUDA();
      allocator = c10::cuda::CUDACachingAllocator::get();
#endif
#ifdef USE_MPS
    } else if (device.type() == at::kMPS) {
      allocator = at::mps::GetMPSAllocator();
#endif
    } else if (device.type() == at::DeviceType::XPU) {
      allocator = c10::GetAllocator(device.type());
    } else if (device.type() == at::DeviceType::Meta) {
      allocator = c10::GetAllocator(device.type());
    } else {
      TORCH_CHECK(
          false,
          THPStorageStr,
          "(): Storage device not recognized: ",
          device.type());
    }
    device_guard.reset_device(device);
  } else {
    allocator = c10::GetDefaultCPUAllocator();
  }

  // torch.Storage(*, ...)
  if (r.idx == 0) {
    self->cdata = c10::make_intrusive<at::StorageImpl>(
                      c10::StorageImpl::use_byte_size_t(),
                      0,
                      allocator,
                      /*resizable=*/true)
                      .release();
    return (PyObject*)self.release();

    // torch.Storage(size, *, ...)
  } else if (r.idx == 1) {
    int64_t size = r.toInt64(0);
    self->cdata = c10::make_intrusive<at::StorageImpl>(
                      c10::StorageImpl::use_byte_size_t(),
                      size,
                      allocator,
                      /*resizable=*/true)
                      .release();
    return (PyObject*)self.release();

    // torch.Storage(sequence, *, ...)
  } else if (r.idx == 2) {
    PyObject* sequence = r.pyobject(0);
    Py_ssize_t length = PySequence_Length(sequence);
    TORCH_CHECK(
        PySequence_Check(sequence),
        THPStorageStr,
        "(): Expected a sequence type, but got ",
        THPUtils_typename(sequence));
    TORCH_CHECK(
        length >= 0,
        THPStorageStr,
        "(): Could not obtain the length of sequence of type ",
        THPUtils_typename(sequence));
    self->cdata = c10::make_intrusive<at::StorageImpl>(
                      c10::StorageImpl::use_byte_size_t(),
                      length,
                      allocator,
                      /*resizable=*/true)
                      .release();
    THPObjectPtr item;
    try {
      for (Py_ssize_t i = 0; i < length; i++) {
        item = PySequence_GetItem(sequence, i);
        // NOLINTNEXTLINE(cppcoreguidelines-init-variables)
        uint8_t value = THPByteUtils_unpackReal(item.get());
        if (allocator == c10::GetDefaultCPUAllocator()) {
          self->cdata->unsafe_data<uint8_t>()[i] = value;
        } else {
          // TODO: this might be slow - consider batched updates?
          storage_set(
              at::unsafeStorageFromTH(self->cdata, /*retain=*/true), i, value);
        }
      }
    } catch (const std::exception& e) {
      THPUtils_setError(
          THPStorageStr
          "(): tried to construct a storage from a sequence (%s), "
          "but one of the items was of type %s instead of int",
          THPUtils_typename(sequence),
          THPUtils_typename(item.get()));
      return nullptr;
    }
    return (PyObject*)self.release();
  }
  Py_RETURN_NONE;
  END_HANDLE_TH_ERRORS
}

static Py_ssize_t THPStorage_length(THPStorage* self) {
  HANDLE_TH_ERRORS
  return self->cdata->nbytes() / sizeof(uint8_t);
  END_HANDLE_TH_ERRORS_RET(-1)
}

static PyObject* THPStorage_get(THPStorage* self, PyObject* index) {
  HANDLE_TH_ERRORS
  /* Integer index */
  if (THPUtils_checkLong(index)) {
    int64_t nindex = THPUtils_unpackLong(index);
    if (nindex < 0)
      nindex += (self->cdata->nbytes() / sizeof(uint8_t));
    if (nindex < 0 ||
        nindex >=
            static_cast<int64_t>(self->cdata->nbytes() / sizeof(uint8_t))) {
      PyErr_SetString(
          PyExc_IndexError,
          fmt::format(
              "index {} out of range for storage of size {}",
              nindex,
              self->cdata->nbytes() / sizeof(uint8_t)));
      return nullptr;
    }
    uint8_t value = storage_get(
        at::unsafeStorageFromTH(self->cdata, /*retain=*/true), nindex);
    return THPByteUtils_newReal(value);
    /* Slice index */
  } else if (PySlice_Check(index)) {
    // NOLINTNEXTLINE(cppcoreguidelines-init-variables)
    Py_ssize_t start, stop, slicelength, step;
    int64_t len = self->cdata->nbytes() / sizeof(uint8_t);
    if (!THPUtils_parseSlice(index, len, &start, &stop, &step, &slicelength))
      return nullptr;
    if (step != 1) {
      THPUtils_setError(
          "Trying to slice with a step of %lld, but only a step of "
          "1 is supported",
          (long long)step);
      return nullptr;
    }

    uint8_t* data = self->cdata->data<uint8_t>();

    at::StorageImpl* old_storage = self->cdata;
    c10::raw::intrusive_ptr::incref(old_storage);
    auto new_storage = c10::make_intrusive<at::StorageImpl>(
        c10::StorageImpl::use_byte_size_t(),
#ifdef THQUANTIZED
        slicelength * sizeof(quantized_t),
#else
        slicelength * sizeof(uint8_t),
#endif
        at::DataPtr(
            static_cast<void*>(data + start),
            old_storage,
            [](void* s) {
              c10::raw::intrusive_ptr::decref(static_cast<at::StorageImpl*>(s));
            },
            old_storage->device()),
        old_storage->allocator(),
        /* resizable */ false);

    PyObject* _ret = THPStorage_New(std::move(new_storage));
    return _ret;
  }
  PyErr_Format(
      PyExc_TypeError,
      "can't index a " THPStorageStr " with %s",
      THPUtils_typename(index));
  return nullptr;
  END_HANDLE_TH_ERRORS
}

static int THPStorage_set(THPStorage* self, PyObject* index, PyObject* value) {
  HANDLE_TH_ERRORS
  if (!THPByteUtils_checkReal(value)) {
    THPUtils_setError(
        "can only set storage content with a int types, but got "
        "%s instead",
        THPUtils_typename(value));
    return -1;
  }

  uint8_t rvalue = THPByteUtils_unpackReal(value);
  if (THPUtils_checkLong(index)) {
    int64_t nindex = THPUtils_unpackLong(index);
    storage_set(
        at::unsafeStorageFromTH(self->cdata, /*retain=*/true), nindex, rvalue);
    return 0;
  } else if (PySlice_Check(index)) {
    // NOLINTNEXTLINE(cppcoreguidelines-init-variables)
    Py_ssize_t start, stop, slicelength, step;
    int64_t len = self->cdata->nbytes() / sizeof(uint8_t);
    if (!THPUtils_parseSlice(index, len, &start, &stop, &step, &slicelength))
      return -1;
    if (step != 1) {
      THPUtils_setError(
          "Trying to slice with a step of %lld, but only a step of "
          "1 is supported",
          (long long)step);
      return 0;
    }
    // TODO: check the bounds only once
    // TODO: fill?
    for (; start < stop; start++)
      storage_set(
          at::unsafeStorageFromTH(self->cdata, /*retain=*/true), start, rvalue);
    return 0;
  }
  THPUtils_setError(
      "can't index a " THPStorageStr " with %s", THPUtils_typename(index));
  return -1;
  END_HANDLE_TH_ERRORS_RET(-1)
}

static PyMappingMethods THPStorage_mappingmethods = {
    (lenfunc)THPStorage_length,
    (binaryfunc)THPStorage_get,
    (objobjargproc)THPStorage_set};

// TODO: implement equality
PyTypeObject THPStorageType = {
    PyVarObject_HEAD_INIT(
        nullptr,
        0) "torch._C." THPStorageBaseStr, /* tp_name */
    sizeof(THPStorage), /* tp_basicsize */
    0, /* tp_itemsize */
    (destructor)THPStorage_dealloc, /* tp_dealloc */
    0, /* tp_vectorcall_offset */
    nullptr, /* tp_getattr */
    nullptr, /* tp_setattr */
    nullptr, /* tp_reserved */
    nullptr, /* tp_repr */
    nullptr, /* tp_as_number */
    nullptr, /* tp_as_sequence */
    &THPStorage_mappingmethods, /* tp_as_mapping */
    nullptr, /* tp_hash  */
    nullptr, /* tp_call */
    nullptr, /* tp_str */
    nullptr, /* tp_getattro */
    nullptr, /* tp_setattro */
    nullptr, /* tp_as_buffer */
    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
    nullptr, /* tp_doc */
    nullptr, /* tp_traverse */
    nullptr, /* tp_clear */
    nullptr, /* tp_richcompare */
    0, /* tp_weaklistoffset */
    nullptr, /* tp_iter */
    nullptr, /* tp_iternext */
    nullptr,
    /* will be assigned in init */ /* tp_methods */
    nullptr,
    /* will be assigned in init */ /* tp_members */
    nullptr, /* tp_getset */
    nullptr, /* tp_base */
    nullptr, /* tp_dict */
    nullptr, /* tp_descr_get */
    nullptr, /* tp_descr_set */
    0, /* tp_dictoffset */
    nullptr, /* tp_init */
    nullptr, /* tp_alloc */
    THPStorage_pynew, /* tp_new */
};

// NOLINTNEXTLINE(cppcoreguidelines-avoid-c-arrays,modernize-avoid-c-arrays,cppcoreguidelines-avoid-non-const-global-variables)
static struct PyMemberDef THPStorage_members[] = {
    {(char*)"_cdata",
     T_ULONGLONG,
     offsetof(THPStorage, cdata),
     READONLY,
     nullptr},
    {nullptr}};

static PyObject* THPStorage_device(THPStorage* self, void* unused) {
  HANDLE_TH_ERRORS
  return THPDevice_New(self->cdata->device());
  END_HANDLE_TH_ERRORS
}

typedef PyObject* (*getter)(PyObject*, void*);

// NOLINTNEXTLINE(cppcoreguidelines-avoid-c-arrays,modernize-avoid-c-arrays,cppcoreguidelines-avoid-non-const-global-variables)
static struct PyGetSetDef THPStorage_properties[] = {
    {"device", (getter)THPStorage_device, nullptr, nullptr, nullptr},
    {nullptr}};

bool THPStorage_init(PyObject* module) {
  static std::vector<PyMethodDef> methods;
  THPUtils_addPyMethodDefs(methods, THPStorage_getMethods());
  THPUtils_addPyMethodDefs(methods, THPStorage_getSharingMethods());

  THPStorageType.tp_methods = methods.data();
  THPStorageType.tp_members = THPStorage_members;
  THPStorageType.tp_getset = THPStorage_properties;
  if (PyType_Ready(&THPStorageType) < 0)
    return false;
  Py_INCREF(&THPStorageType);
  PyModule_AddObject(module, THPStorageBaseStr, (PyObject*)&THPStorageType);
  return true;
}

void THPStorage_postInit(PyObject* module) {
  THPStorageClass = PyObject_GetAttrString(module, "UntypedStorage");
  if (!THPStorageClass)
    throw python_error();
}