#include <cstring>
#include <cstdio>
#include "triton/jit.h"
#include "triton/driver/backend.h"
#include "triton/driver/stream.h"

const char* src =
R"(
const tunable int32 TM = {16, 32, 64};
const tunable int32 TN = {16, 32, 64};
const tunable int32 TK = {8, 16};

void matmul(restrict read_only fp32 *a, restrict read_only fp32 *b, fp32 *c,
           int32 M, int32 N, int32 K, int32 bound){
  int32 rxa[TM] = get_global_range[TM](0);
  int32 ryb[TN] = get_global_range[TN](1);
  int32 rka[TK] = 0 ... TK;
  int32 rkb[TK] = 0 ... TK;
  fp32 C[TM, TN] = 0;
  fp32* pa[TM, TK] = a + rka[newaxis, :]*M + rxa[:, newaxis];
  fp32* pb[TN, TK] = b + rkb[newaxis, :]*K + ryb[:, newaxis];
  for(int32 k = K; k > 0;){
    fp32 a[TM, TK] = *pa;
    fp32 b[TN, TK] = *pb;
    C = dot(a, b, C);
    pa = pa + TK*M;
    pb = pb + TK*K;
    k = k - TK;
  }
  int32 rxc[TM] = get_global_range[TM](0);
  int32 ryc[TN] = get_global_range[TN](1);
  fp32* pc[TM, TN] = c + ryc[newaxis, :]*M + rxc[:, newaxis];
  *pc = C;
}
)";


template<class T>
void simple_gemm(std::vector<T> &c, const std::vector<T> &a, const std::vector<T> &b, size_t M, size_t N, size_t K){
  for(size_t m = 0; m < M; m++)
  for(size_t n = 0; n < N; n++){
    T acc = 0;
    for(size_t k = 0; k < K; k++)
      acc += a[m + k*M] * b[n + k*N];
    c[m + n*M] = acc;
  }
}

class timer{
    typedef std::chrono::high_resolution_clock high_resolution_clock;
    typedef std::chrono::nanoseconds nanoseconds;

public:
    explicit timer(bool run = false)
    { if (run) start(); }

    void start()
    { _start = high_resolution_clock::now(); }

    nanoseconds get() const
    { return std::chrono::duration_cast<nanoseconds>(high_resolution_clock::now() - _start); }

private:
    high_resolution_clock::time_point _start;
};

template<class T>
T min(std::vector<T> x)
{ return *std::min_element(x.begin(), x.end()); }


template<class OP, class SYNC>
double bench(OP const & op, SYNC const & sync, unsigned repeat = 20)
{
  timer tmr;
  op();
  sync();
  tmr.start();
  for(unsigned i = 0; i < repeat; i++)
    op();
  sync();
  double time = tmr.get().count();
  return time / repeat;
}

int main() {
  // initialize default compute device
  auto context = triton::driver::backend::contexts::get_default();
  triton::jit jit(context);

  // matrix multiplication parameters
  int32_t M = 256, N = 256, K = 256;
  std::vector<float> hc(M*N);
  std::vector<float> rc(M*N);
  std::vector<float> ha(M*K);
  std::vector<float> hb(K*N);
  srand(0);
  for(size_t i = 0; i < ha.size(); i++)
    ha[i] = (float)rand()/RAND_MAX;
  for(size_t i = 0; i < hb.size(); i++)
    hb[i] = (float)rand()/RAND_MAX;
  for(size_t i = 0; i < hc.size(); i++)
    hc[i] = 0;
  triton::driver::buffer* dc = triton::driver::buffer::create(context, hc.size()*4);
  triton::driver::buffer* da = triton::driver::buffer::create(context, ha.size()*4);
  triton::driver::buffer* db = triton::driver::buffer::create(context, hb.size()*4);
  triton::driver::stream* stream = triton::driver::stream::create(context);
  stream->write(da, true, 0, ha);
  stream->write(db, true, 0, hb);
  stream->write(dc, true, 0, hc);
  stream->synchronize();


  // benchmark a given matrix multiplication kernel
  auto benchmark = [&](triton::driver::kernel* kernel,
                       triton::jit::launch_information info) {
    // launch info
    unsigned TM = info.global_range_size[0];
    unsigned TN = info.global_range_size[1];
    unsigned nthreads = info.num_threads;
    std::array<size_t, 3> grid = {(M + TM - 1)/TM, (N + TN - 1)/TN, 1};
    // fast bounds-checking
    unsigned TK = jit.get_int("TK");
    unsigned lasti = (grid[0]*TM - 1)*TM + TM - 1;
    unsigned lastj = (grid[1]*TN - 1)*TN + TN - 1;
    unsigned lastk = TK - 1;
    bool AT = false;
    bool BT = true;
    unsigned last_safe_a = (AT==false)?(M*K - 1 - lasti)/M - lastk : M*K - 1 - lasti*K - lastk;
    unsigned last_safe_b =  (BT==true)?(N*K - 1 - lastj)/N - lastk : N*K - 1 - lastj*K - lastk;
    int32_t bound = std::max<unsigned>(1, std::max(K - last_safe_a, K - last_safe_b));
    // set argument
    kernel->setArg(0, da);
    kernel->setArg(1, db);
    kernel->setArg(2, dc);
    kernel->setArg(3, M);
    kernel->setArg(4, N);
    kernel->setArg(5, K);
    kernel->setArg(6, bound);
    // dry run
    stream->enqueue(kernel, grid, {nthreads, 1, 1});
    stream->synchronize();
    // benchmark
    double ts = bench([&](){stream->enqueue(kernel, grid, {nthreads, 1, 1});},
                      [&](){ stream->synchronize(); });
    ts = ts * 1e-9;
    double tflops = 2.*M*N*K / ts * 1e-12;
    return tflops;
  };


  // just-in-time compile source-code
  std::vector<unsigned> params = {
    1, 4, 8,
    1, 4, 8,
    1, 1, 4, 4,
    1, 8,
    1,
  };
  params = {8, 2, 64, 16, 2, 64, 4, 16, 2, 2, 8, 8, 4};

//  jit.autotune(src, benchmark);
  jit.add_module(src, params);
  triton::driver::kernel* kernel = jit.get_function("matmul");
  triton::jit::launch_information info = jit.get_launch_info("matmul");
  std::cout << benchmark(kernel, info) << std::endl;
  stream->read(dc, true, 0, hc);
  simple_gemm(rc, ha, hb, M, N, K);
  for(size_t i = 0; i < M*N; i++)
    if(std::abs(hc[i] - rc[i])/std::max(hc[i], rc[i]) > 1e-4){
      std::cout << i << " " << hc[i] << " " << rc[i] << std::endl;
      exit(EXIT_FAILURE);
    }
  std::cout << "Pass!" << std::endl;
}