#include <vector>
#include <sstream>
#include <torch/torch.h>
#include <torch/script.h>
#include "ATen/cuda/CUDAContext.h"
#include "triton/runtime/jit.h"
#include "triton/driver/stream.h"
#include "triton/dnn/conv.h"
#include "triton/tools/bench.hpp"

#define CHECK_CUDA(x) AT_CHECK(x.type().is_cuda(), #x " must be a CUDA tensor")
#define CHECK_CONTIGUOUS(x) AT_CHECK(x.is_contiguous(), #x " must be contiguous")
#define CHECK_INPUT(x) CHECK_CUDA(x); CHECK_CONTIGUOUS(x)

typedef std::tuple<int32_t, int32_t, int32_t, int32_t, int32_t,
                   int32_t, int32_t, int32_t, int32_t,
                   int32_t, int32_t, int32_t,
                   int32_t, int32_t, int32_t,
                   triton::dnn::conv::type, bool> conv_key_t;

static std::map<CUstream, std::unique_ptr<triton::driver::stream>> m_stream;
static std::map<conv_key_t,  std::unique_ptr<triton::jit>>         m_jit;
static std::map<conv_key_t, std::unique_ptr<triton::dnn::conv>>    m_config;

torch::Tensor conv_common(
    int32_t B, int32_t C, int32_t D, int32_t H, int32_t W,
    int32_t T, int32_t R, int32_t S, int32_t NF,
    int32_t stride_d, int32_t stride_h, int32_t stride_w,
    int32_t pad_d, int32_t pad_h, int32_t pad_w,
    triton::dnn::conv::type ty,
    torch::Tensor torcha, torch::Tensor torchb, torch::Tensor torchbias,
    bool autotune = false
    ) {

  // Wrap CUDA handles
  c10::DeviceIndex device = torcha.storage().device().index();

  // Get stream
  CUstream custream = (CUstream)at::cuda::getCurrentCUDAStream(device).stream();
  triton::driver::stream* stream;
  if(m_stream.find(custream) == m_stream.end())
    stream = m_stream.emplace(custream, new triton::driver::cu_stream(custream, false)).first->second.get();
  else
    stream = m_stream.at(custream).get();

  // Get context
  triton::driver::context* ctx = stream->context();

  // Get configuration
  bool has_bias = torchbias.storage().size() > 0;
  conv_key_t key = {B, C, D, H, W, T, R, S, NF, stride_d, stride_h, stride_w, pad_d, pad_h, pad_w, ty, has_bias};
  triton::dnn::conv* configuration;
  if(m_config.find(key) == m_config.end())
    configuration = m_config.emplace(key, new triton::dnn::conv(
                                                B, C, D, H, W, T, R, S, NF,
                                                stride_d, stride_h, stride_w,
                                                pad_d, pad_h, pad_w,
                                                1, 1, 1,
                                                ty, has_bias)).first->second.get();
  else
    configuration = m_config.at(key).get();

  // Bind memory
  triton::driver::cu_buffer a(ctx, (CUdeviceptr)torcha.storage().data(), false);
  triton::driver::cu_buffer b(ctx, (CUdeviceptr)torchb.storage().data(), false);
  triton::driver::cu_buffer cubias(ctx, (CUdeviceptr)torchbias.storage().data(), false);
  triton::driver::buffer* bias = has_bias ? &cubias : nullptr;

  // Allocate output
  std::vector<int32_t> c_shapes = configuration->c_shapes();
  torch::Tensor torchc;
  if(ty == triton::dnn::conv::WGRAD)
    torchc = torch::empty({c_shapes[0], c_shapes[2], c_shapes[3], c_shapes[4]}, torch::kFloat).cuda();
  else
    torchc = torch::empty({c_shapes[0], c_shapes[1], c_shapes[3], c_shapes[4]}, torch::kFloat).cuda();
  triton::driver::cu_buffer c(ctx, (CUdeviceptr)torchc.storage().data(), false);

  // Get JIT
  triton::jit* jit;
  if(m_jit.find(key) == m_jit.end()){
    jit = m_jit.emplace(key, new triton::jit(ctx)).first->second.get();
    std::ostringstream oss;
    configuration->src(oss);
    std::string src = oss.str();
    // benchmark a given convolution kernel
    auto benchmark = [&](triton::driver::kernel* kernel,
                         triton::jit::launch_information info) {
      configuration->init(stream, (triton::driver::cu_module*)kernel->module());
      unsigned TM = info.global_range_size[0];
      unsigned TN = info.global_range_size[1];
      unsigned nthreads = info.num_threads;
      unsigned GZ = jit->get_int("GZ");
      configuration->enqueue(stream, kernel, &a, &b, &c, bias, TM, TN, GZ, nthreads);
      stream->synchronize();
      double ts = triton::tools::bench([&](){ configuration->enqueue(stream, kernel, &a, &b, &c, bias, TM, TN, GZ, nthreads); },
                        [&](){ stream->synchronize(); }, stream->context()->device());
      return configuration->get_nflops() / ts * 1e-3;
    };
    // auto-tune and save result
    if(autotune) {
      triton::jit::tune_res_t best = jit->autotune("conv", src.c_str(), benchmark);
      jit->add_module("conv", src.c_str(), best.params);
    }
    else {
      jit->add_module("conv", src.c_str(), configuration->default_params());
    }
    triton::driver::kernel* kernel = jit->get_function("conv");
    configuration->init(stream, (triton::driver::cu_module*)kernel->module());
  }
  else
    jit = m_jit.at(key).get();

  // Run
  triton::driver::kernel* kernel = jit->get_function("conv");
  triton::jit::launch_information info = jit->get_launch_info("conv");
  unsigned GZ = jit->get_int("GZ");
  // launch info
  unsigned TM = info.global_range_size[0];
  unsigned TN = info.global_range_size[1];
  unsigned nthreads = info.num_threads;
  // enqueue
  configuration->enqueue(stream, kernel, &a, &b, &c, bias, TM, TN, GZ, nthreads);
  return torchc;
}

torch::Tensor conv_fprop(
    const torch::Tensor data,
    const torch::Tensor weight,
    const torch::Tensor bias,
    int64_t stride_h, int64_t stride_w,
    int64_t pad_h, int64_t pad_w) {
  // Check
  CHECK_INPUT(data);
  CHECK_INPUT(weight);
  // Unpack data shapes
  const int32_t B  = data.size(0);
  const int32_t Ci = data.size(1);
  const int32_t D = 1;
  const int32_t H  = data.size(2);
  const int32_t W  = data.size(3);
  // Unpack weight shapes
  const int32_t Cf = weight.size(0);
  const int32_t T  = 1;
  const int32_t R  = weight.size(1);
  const int32_t S  = weight.size(2);
  const int32_t NF  = weight.size(3);
  // Configuration
  const int32_t stride_d = 1;
  const int32_t pad_d = 0;
  // Check
  AT_CHECK(Ci == Cf, "Number of channels in data and weights must match");
  return conv_common(B, Ci, D, H, W, T, R, S, NF, stride_d, stride_h, stride_w, pad_d, pad_h, pad_w, triton::dnn::conv::FPROP, data, weight, bias);
}

torch::Tensor conv_bprop(
    const torch::Tensor derror,
    const torch::Tensor weight,
    const torch::Tensor bias,
    int64_t H, int64_t W,
    int64_t stride_h, int64_t stride_w,
    int64_t pad_h, int64_t pad_w){
  // Check
  CHECK_INPUT(derror);
  CHECK_INPUT(weight);
  // Unpack data shapes
  const int32_t B  = derror.size(0);
  const int32_t Ki = derror.size(1);
  const int32_t M = 1;
  const int32_t P  = derror.size(2);
  const int32_t Q  = derror.size(3);
  // Unpack weight shapes
  const int32_t C = weight.size(0);
  const int32_t T  = 1;
  const int32_t R  = weight.size(1);
  const int32_t S  = weight.size(2);
  const int32_t Kw  = weight.size(3);
  // Compute M, P, Q
  const int32_t stride_d = 1;
  int32_t pad_d = 0;
  int32_t D = 1;
  // Check
  AT_CHECK(Ki == Kw, "Number of channels in error and weights must match");
  return conv_common(B, C, D, H, W, T, R, S, Kw, stride_d, stride_h, stride_w, pad_d, pad_h, pad_w, triton::dnn::conv::BPROP, derror, weight, bias);
}

torch::Tensor conv_wgrad(
    const torch::Tensor data,
    const torch::Tensor derror,
    const torch::Tensor bias,
    int64_t R, int64_t S,
    int64_t stride_h, int64_t stride_w,
    int64_t pad_h, int64_t pad_w
    ){
  // Check
  CHECK_INPUT(data);
  CHECK_INPUT(derror);
  // Unpack data shapes
  const int32_t Ba  = data.size(0);
  const int32_t C = data.size(1);
  const int32_t D = 1;
  const int32_t H  = data.size(2);
  const int32_t W  = data.size(3);
  // Unpack error shapes
  const int32_t Bb = derror.size(0);
  const int32_t K  = derror.size(1);
  const int32_t M  = 1;
  const int32_t P  = derror.size(2);
  const int32_t Q  = derror.size(3);
  // Compute M, P, Q
  const int32_t upsample_d = 1, upsample_h = 1, upsample_w = 1;
  const int32_t stride_d = 1;
  const int32_t pad_d = 0;
  const int32_t T = 1;
  // Check
  AT_CHECK(Ba == Bb, "Number of channels in error and weights must match");
  return conv_common(Ba, C, D, H, W, T, R, S, K, stride_d, stride_h, stride_w, pad_d, pad_h, pad_w, triton::dnn::conv::WGRAD, data, derror, bias);
}

static auto registry =
  torch::jit::RegisterOperators("triton::conv_fprop", &conv_fprop)
                            .op("triton::conv_bprop", &conv_bprop)
                            .op("triton::conv_wgrad", &conv_wgrad);