/*! \file PHY/CODING/nrLDPC_decoder_LYC/nrLDPC_decoder_LYC.cu
 * \brief LDPC cuda support BG1 all length
 * \author NCTU OpinConnect Terng-Yin Hsu,WEI-YING,LIN
 * \email tyhsu@cs.nctu.edu.tw
 * \date 13-05-2020
 * \version
 * \note
 * \warning
 */
#include <iostream>
#include <stdio.h>
#include <unistd.h>
#include <cuda_runtime.h>
#include <cuda.h>
#include "PHY/CODING/nrLDPC_decoder/nrLDPC_types.h"
#include "PHY/CODING/nrLDPC_decoder/nrLDPCdecoder_defs.h"
#include "assertions.h"
#include "bgs/BG1_I0"
#include "bgs/BG1_I1"
#include "bgs/BG1_I2"
#include "bgs/BG1_I3"
#include "bgs/BG1_I4"
#include "bgs/BG1_I5"
#include "bgs/BG1_I6"
#include "bgs/BG1_I7"
#include "bgs/BG2_I0"
#include "bgs/BG2_I1"
#include "bgs/BG2_I2"
#include "bgs/BG2_I3"
#include "bgs/BG2_I4"
#include "bgs/BG2_I5"
#include "bgs/BG2_I6"
#include "bgs/BG2_I7"
#define MAX_ITERATION 2
#define MC	1

typedef void decode_abort_t;
#define cudaCheck(ans) { cudaAssert((ans), __FILE__, __LINE__); }
inline void cudaAssert(cudaError_t code, const char *file, int line)
{
  if (code != cudaSuccess) {
    fprintf(stderr, "GPUassert: %s %s %d\n", cudaGetErrorString(code), file, line);
    exit(code);
  }
}

typedef struct{
  char x;
  char y;
  short value;
} h_element;
#include "bgs/BG1_compact_in_C.h"

__device__ char dev_const_llr[68*384];
__device__ char dev_dt [46*68*384];
__device__ char dev_llr[68*384];
__device__ unsigned char dev_tmp[68*384];

h_element h_compact1 [46*23] = {};
h_element h_compact2 [68*30] = {};

__device__  h_element dev_h_compact1[46*23];  // used in kernel 1
__device__  h_element dev_h_compact2[68*30];  // used in kernel 2

// __device__ __constant__ h_element dev_h_compact1[46*23];  // used in kernel 1
// __device__ __constant__ h_element dev_h_compact2[68*30];  // used in kernel 2

// row and col element count
__device__ __constant__ char h_ele_row_bg1_count[46] = {19, 19, 19, 19, 3, 8, 9, 7, 10, 9, 7, 8, 7, 6, 7, 7, 6, 6, 6, 6, 6, 6, 5,
                                                        5,  6,  5,  5,  4, 5, 5, 5, 5,  5, 5, 5, 5, 5, 4, 5, 5, 4, 5, 4, 5, 5, 4};
__device__ __constant__ char h_ele_col_bg1_count[68] = {
    30, 28, 7, 11, 9, 4, 8, 12, 8, 7, 12, 10, 12, 11, 10, 7, 10, 10, 13, 7, 8, 11, 12, 5, 6, 6, 1, 1, 1, 1, 1, 1, 1, 1,
    1,  1,  1, 1,  1, 1, 1, 1,  1, 1, 1,  1,  1,  1,  1,  1, 1,  1,  1,  1, 1, 1,  1,  1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1};
__device__ __constant__ char h_ele_row_bg2_count[42] = {8, 10, 8, 10, 4, 6, 6, 6, 4, 5, 5, 5, 4, 5, 5, 4, 5, 5, 4, 4, 4,
                                                        4, 3,  4, 4,  3, 5, 3, 4, 3, 5, 3, 4, 4, 4, 4, 4, 3, 4, 4, 4, 4};
__device__ __constant__ char h_ele_col_bg2_count[52] = {22, 23, 10, 5, 5, 14, 7, 13, 6, 8, 9, 16, 9, 12, 1, 1, 1, 1,
                                                        1,  1,  1,  1, 1, 1,  1, 1,  1, 1, 1, 1,  1, 1,  1, 1, 1, 1,
                                                        1,  1,  1,  1, 1, 1,  1, 1,  1, 1, 1, 1,  1, 1,  1, 1};

__global__ void warmup()
{
  // warm up gpu for time measurement
}

extern "C"
void warmup_for_GPU(){
  warmup<<<20, 1024>>>();
}

extern "C"
void set_compact_BG(int Zc,short BG){
  int row, col;
  if (BG == 1) {
    row = 46;
    col = 68;
  } else {
    row = 42;
    col = 52;
  }
  int compact_row = 30;
  int compact_col = 19;
  if (BG == 2) {
    compact_row = 10, compact_col = 23;
  }
  int memorySize_h_compact1 = row * compact_col * sizeof(h_element);
  int memorySize_h_compact2 = compact_row * col * sizeof(h_element);
  int lift_index = 0;
  short lift_set[][9] = {{2, 4, 8, 16, 32, 64, 128, 256},
                         {3, 6, 12, 24, 48, 96, 192, 384},
                         {5, 10, 20, 40, 80, 160, 320},
                         {7, 14, 28, 56, 112, 224},
                         {9, 18, 36, 72, 144, 288},
                         {11, 22, 44, 88, 176, 352},
                         {13, 26, 52, 104, 208},
                         {15, 30, 60, 120, 240},
                         {0}};

  for (int i = 0; lift_set[i][0] != 0; i++) {
    for (int j = 0; lift_set[i][j] != 0; j++) {
      if (Zc == lift_set[i][j]) {
        lift_index = i;
        break;
      }
    }
  }
  printf("\nZc = %d BG = %d\n", Zc, BG);
  switch (lift_index) {
    case 0:
      cudaCheck(cudaMemcpyToSymbol(dev_h_compact1, host_h_compact1_I0, memorySize_h_compact1));
      cudaCheck(cudaMemcpyToSymbol(dev_h_compact2, host_h_compact2_I0, memorySize_h_compact2));
      break;
    case 1:
      cudaCheck(cudaMemcpyToSymbol(dev_h_compact1, host_h_compact1_I1, memorySize_h_compact1));
      cudaCheck(cudaMemcpyToSymbol(dev_h_compact2, host_h_compact2_I1, memorySize_h_compact2));
      break;
    case 2:
      cudaCheck(cudaMemcpyToSymbol(dev_h_compact1, host_h_compact1_I2, memorySize_h_compact1));
      cudaCheck(cudaMemcpyToSymbol(dev_h_compact2, host_h_compact2_I2, memorySize_h_compact2));
      break;
    case 3:
      cudaCheck(cudaMemcpyToSymbol(dev_h_compact1, host_h_compact1_I3, memorySize_h_compact1));
      cudaCheck(cudaMemcpyToSymbol(dev_h_compact2, host_h_compact2_I3, memorySize_h_compact2));
      break;
    case 4:
      cudaCheck(cudaMemcpyToSymbol(dev_h_compact1, host_h_compact1_I4, memorySize_h_compact1));
      cudaCheck(cudaMemcpyToSymbol(dev_h_compact2, host_h_compact2_I4, memorySize_h_compact2));
      break;
    case 5:
      cudaCheck(cudaMemcpyToSymbol(dev_h_compact1, host_h_compact1_I5, memorySize_h_compact1));
      cudaCheck(cudaMemcpyToSymbol(dev_h_compact2, host_h_compact2_I5, memorySize_h_compact2));
      break;
    case 6:
      cudaCheck(cudaMemcpyToSymbol(dev_h_compact1, host_h_compact1_I6, memorySize_h_compact1));
      cudaCheck(cudaMemcpyToSymbol(dev_h_compact2, host_h_compact2_I6, memorySize_h_compact2));
      break;
    case 7:
      cudaCheck(cudaMemcpyToSymbol(dev_h_compact1, host_h_compact1_I7, memorySize_h_compact1));
      cudaCheck(cudaMemcpyToSymbol(dev_h_compact2, host_h_compact2_I7, memorySize_h_compact2));
      break;
  }

  // return 0;
}


// Kernel 1
__global__ void ldpc_cnp_kernel_1st_iter(/*char * dev_llr,*/ int BG, int row, int col, int Zc)
{
  //	if(blockIdx.x == 0 && threadIdx.x == 1) printf("cnp %d\n", threadIdx.x);
  int iMCW = blockIdx.y; // codeword id
  int iBlkRow = blockIdx.x; // block row in h_base
  int iBlkCol; // block col in h_base
  int iSubRow = threadIdx.x; // row index in sub_block of h_base
  int iCol; // overall col index in h_base
  int offsetR;
  int shift_t;

  //	For 2-min algorithm.
  int Q_sign = 0;
  int sq;
  int Q, Q_abs;
  int R_temp;

  int sign = 1;
  int rmin1 = INT32_MAX;
  int rmin2 = INT32_MAX;
  char idx_min = 0;

  h_element h_element_t;
  int s = (BG == 1) ? h_ele_row_bg1_count[iBlkRow] : h_ele_row_bg2_count[iBlkRow];
  offsetR = (iMCW * row * col * Zc) + iBlkRow * Zc + iSubRow; // row*col*Zc = size of dev_dt
  //	if(blockIdx.x == 0 && threadIdx.x == 1) printf("s: %d, offset %d\n", s, offsetR);
  //	The 1st recursion
  for (int i = 0; i < s; i++) // loop through all the ZxZ sub-blocks in a row
  {
    h_element_t = dev_h_compact1[i * row + iBlkRow]; // compact_col == row

    iBlkCol = h_element_t.y;
    shift_t = h_element_t.value;

    shift_t = (iSubRow + shift_t) % Zc;
    iCol = (iMCW * col * Zc) + iBlkCol * Zc + shift_t; // col*Zc = size of llr
    Q = dev_llr[iCol];
    Q_abs = (Q > 0) ? Q : -Q;
    sq = Q < 0;
    //		if(blockIdx.x == 0 && threadIdx.x == 1) printf("i %d, icol %d, Q: %d\n", i, iCol, Q);
    // quick version
    sign = sign * (1 - sq * 2);
    Q_sign |= sq << i;

    if (Q_abs < rmin1) {
      rmin2 = rmin1;
      rmin1 = Q_abs;
      idx_min = i;
    } else if (Q_abs < rmin2) {
      rmin2 = Q_abs;
    }
  }

  //	if(blockIdx.x == 0 && threadIdx.x == 1)printf("min1 %d, min2 %d, min1_idx %d\n", rmin1, rmin2, idx_min);

  //	The 2nd recursion
  for (int i = 0; i < s; i++) {
    // v0: Best performance so far. 0.75f is the value of alpha.
    sq = 1 - 2 * ((Q_sign >> i) & 0x01);
    R_temp = 0.75f * sign * sq * (i != idx_min ? rmin1 : rmin2);
    // write results to global memory
    h_element_t = dev_h_compact1[i * row + iBlkRow];
    int addr_temp = offsetR + h_element_t.y * row * Zc;
    dev_dt[addr_temp] = R_temp;
    //		if(blockIdx.x == 0 && threadIdx.x == 1)printf("R_temp %d, temp_addr %d\n", R_temp, addr_temp);
  }
}

// Kernel_1
__global__ void ldpc_cnp_kernel(/*char * dev_llr, char * dev_dt,*/ int BG, int row, int col, int Zc)
{
  //	if(blockIdx.x == 0 && threadIdx.x == 1) printf("cnp\n");
  int iMCW = blockIdx.y;
  int iBlkRow = blockIdx.x; // block row in h_base
  int iBlkCol; // block col in h_base
  int iSubRow = threadIdx.x; // row index in sub_block of h_base
  int iCol; // overall col index in h_base
  int offsetR;
  int shift_t;

  //	For 2-min algorithm.
  int Q_sign = 0;
  int sq;
  int Q, Q_abs;
  int R_temp;

  int sign = 1;
  int rmin1 = INT32_MAX;
  int rmin2 = INT32_MAX;
  char idx_min = 0;

  h_element h_element_t;
  int s = (BG == 1) ? h_ele_row_bg1_count[iBlkRow] : h_ele_row_bg2_count[iBlkRow];
  offsetR = (iMCW * row * col * Zc) + iBlkRow * Zc + iSubRow; // row * col * Zc = size of dev_dt
  //	if(blockIdx.x == 0 && threadIdx.x == 1) printf("s: %d, offset %d\n", s, offsetR);
  //	The 1st recursion
  for (int i = 0; i < s; i++) // loop through all the ZxZ sub-blocks in a row
  {
    h_element_t = dev_h_compact1[i * row + iBlkRow];

    iBlkCol = h_element_t.y;
    shift_t = h_element_t.value;
    shift_t = (iSubRow + shift_t) % Zc;
    iCol = iBlkCol * Zc + shift_t;

    R_temp = dev_dt[offsetR + iBlkCol * row * Zc];

    Q = dev_llr[iMCW * (col * Zc) + iCol] - R_temp;
    Q_abs = (Q > 0) ? Q : -Q;
    //		if(blockIdx.x == 0 && threadIdx.x == 1) printf("i %d, icol %d, Q: %d\n", i, iCol, Q);
    sq = Q < 0;
    sign = sign * (1 - sq * 2);
    Q_sign |= sq << i;

    if (Q_abs < rmin1) {
      rmin2 = rmin1;
      rmin1 = Q_abs;
      idx_min = i;
    } else if (Q_abs < rmin2) {
      rmin2 = Q_abs;
    }
  }

  //	if(blockIdx.x == 0 && threadIdx.x == 1)printf("min1 %d, min2 %d, min1_idx %d\n", rmin1, rmin2, idx_min);

  //	The 2nd recursion
  for (int i = 0; i < s; i++) {
    sq = 1 - 2 * ((Q_sign >> i) & 0x01);
    R_temp = 0.75f * sign * sq * (i != idx_min ? rmin1 : rmin2);

    // write results to global memory
    h_element_t = dev_h_compact1[i * row + iBlkRow];
    int addr_temp = h_element_t.y * row * Zc + offsetR;
    dev_dt[addr_temp] = R_temp;
    //		if(blockIdx.x == 0 && threadIdx.x == 1)printf("R_temp %d, temp_addr %d\n", R_temp, addr_temp);
  }
}

// Kernel 2: VNP processing
__global__ void
ldpc_vnp_kernel_normal(/*char * dev_llr, char * dev_dt, char * dev_const_llr,*/ int BG, int row, int col, int Zc)
{
  int iMCW = blockIdx.y;
  int iBlkCol = blockIdx.x;
  int iBlkRow;
  int iSubCol = threadIdx.x;
  int iRow;
  int iCol;

  int shift_t, sf;
  int APP;

  h_element h_element_t;

  // update all the llr values
  iCol = iBlkCol * Zc + iSubCol;
  APP = dev_const_llr[iMCW * col * Zc + iCol];
  int offsetDt = iMCW * row * col * Zc + iBlkCol * row * Zc;
  int s = (BG == 1) ? h_ele_col_bg1_count[iBlkCol] : h_ele_col_bg2_count[iBlkCol];

  for (int i = 0; i < s; i++) {
    h_element_t = dev_h_compact2[i * col + iBlkCol];

    shift_t = h_element_t.value % Zc;
    iBlkRow = h_element_t.x;

    sf = iSubCol - shift_t;
    sf = (sf + Zc) % Zc;

    iRow = iBlkRow * Zc + sf;
    APP = APP + dev_dt[offsetDt + iRow];
  }
  if (APP > SCHAR_MAX)
    APP = SCHAR_MAX;
  if (APP < SCHAR_MIN)
    APP = SCHAR_MIN;
  // write back to device global memory
  dev_llr[iMCW * col * Zc + iCol] = APP;
}


__global__ void pack_decoded_bit(/*char *dev, unsigned char *host,*/ int col, int Zc)
{
  __shared__ unsigned char tmp[128];
  int iMCW = blockIdx.y;
  int tid = iMCW * col * Zc + blockIdx.x * 128 + threadIdx.x;
  int btid = threadIdx.x;
  tmp[btid] = 0;

  if (dev_llr[tid] < 0) {
    tmp[btid] = 1 << (7 - (btid & 7));
  }
  __syncthreads();

  if (threadIdx.x < 16) {
    dev_tmp[iMCW * col * Zc + blockIdx.x * 16 + threadIdx.x] = 0;
    for (int i = 0; i < 8; i++) {
      dev_tmp[iMCW * col * Zc + blockIdx.x * 16 + threadIdx.x] += tmp[threadIdx.x * 8 + i];
    }
  }
}

void read_BG(int BG, int *h, int row, int col)
{
  int compact_row = 30, compact_col = 19;
  if (BG == 2) {
    compact_row = 10, compact_col = 23;
  }

  h_element h_element_temp;

  // init the compact matrix
  for (int i = 0; i < compact_col; i++) {
    for (int j = 0; j < row; j++) {
      h_element_temp.x = 0;
      h_element_temp.y = 0;
      h_element_temp.value = -1;
      h_compact1[i * row + j] = h_element_temp; // h[i][0-11], the same column
    }
  }
  // scan the h matrix, and gengerate compact mode of h
  for (int i = 0; i < row; i++) {
    int k = 0;
    for (int j = 0; j < col; j++) {
      if (h[i * col + j] != -1) {
        h_element_temp.x = i;
        h_element_temp.y = j;
        h_element_temp.value = h[i * col + j];
        h_compact1[k * row + i] = h_element_temp;
        k++;
      }
    }
  }

  // h_compact2
  // init the compact matrix
  for (int i = 0; i < compact_row; i++) {
    for (int j = 0; j < col; j++) {
      h_element_temp.x = 0;
      h_element_temp.y = 0;
      h_element_temp.value = -1;
      h_compact2[i * col + j] = h_element_temp;
    }
  }

  for (int j = 0; j < col; j++) {
    int k = 0;
    for (int i = 0; i < row; i++) {
      if (h[i * col + j] != -1) {
        // although h is transposed, the (x,y) is still (iBlkRow, iBlkCol)
        h_element_temp.x = i;
        h_element_temp.y = j;
        h_element_temp.value = h[i * col + j];
        h_compact2[k * col + j] = h_element_temp;
        k++;
      }
    }
  }

  /*
    for(int i = 0; i < compact_col; i++){
    for(int j = 0; j < row; j++){
    printf("%3d, ", h_compact1[i*row+j].value);
    }
    printf("\n");
    }

    for(int i = 0; i < compact_row; i++){
    for(int j = 0; j < col; j++){
    printf("%3d,", h_compact2[i*col+j].value);
    }
    printf("\n");
    }
  */
}

extern "C"
void init_LLR_DMA(t_nrLDPC_dec_params* p_decParams, int8_t* p_llr, int8_t* p_out){
  uint16_t Zc = p_decParams->Z;
  uint8_t BG = p_decParams->BG;
  uint8_t col;
  if (BG == 1) {
    col = 68;
  } else {
    col = 52;
  }
  int memorySize_llr_cuda = col * Zc * sizeof(char) * MC;
  cudaCheck(cudaMemcpyToSymbol(dev_const_llr, p_llr, memorySize_llr_cuda));
  cudaCheck(cudaMemcpyToSymbol(dev_llr, p_llr, memorySize_llr_cuda));
  cudaDeviceSynchronize();
}

using namespace std ;

/* from here: entry points in decoder shared lib */
extern "C"
int ldpc_autoinit(void) {   // called by the library loader
  /*int devices = 0;

    cudaError_t err = cudaGetDeviceCount(&devices);
    AssertFatal(devices>0,"\nNo cuda GPU found\n\n");

    const int kb = 1024;
    const int mb = kb * kb;
    wcout << "NBody.GPU" << endl << "=========" << endl << endl;

    wcout << "CUDA version:   v" << CUDART_VERSION << endl;


    wcout << "CUDA Devices: " << endl << endl;

    for(int i = 0; i < devices; ++i)
    {
    cudaDeviceProp props;
    cudaGetDeviceProperties(&props, i);
    wcout << i << ": " << props.name << ": " << props.major << "." << props.minor << endl;
    wcout << "  Global memory:   " << props.totalGlobalMem / mb << "mb" << endl;
    wcout << "  Shared memory:   " << props.sharedMemPerBlock / kb << "kb" << endl;
    wcout << "  Constant memory: " << props.totalConstMem / kb << "kb" << endl;
    wcout << "  Block registers: " << props.regsPerBlock << endl << endl;

    wcout << "  Warp size:         " << props.warpSize << endl;
    wcout << "  Threads per block: " << props.maxThreadsPerBlock << endl;
    wcout << "  Max block dimensions: [ " << props.maxThreadsDim[0] << ", " << props.maxThreadsDim[1]  << ", " <<
    props.maxThreadsDim[2] << " ]" << endl; wcout << "  Max grid dimensions:  [ " << props.maxGridSize[0] << ", " <<
    props.maxGridSize[1]  << ", " << props.maxGridSize[2] << " ]" << endl; wcout << endl;
    }
  */
  warmup_for_GPU();
  return 0;  
}

extern "C" int32_t LDPCinit()
{
  return 0;
}

extern "C" void LDPCshutdown()
{
}

extern "C"  int32_t LDPCdecoder(t_nrLDPC_dec_params *p_decParams,
                                    uint8_t harq_pid,
                                    uint8_t ulsch_id,
                                    uint8_t C,
                                    int8_t *p_llr,
                                    int8_t *p_out,
                                    t_nrLDPC_time_stats *,
                                    decode_abort_t *ab)
{
  set_compact_BG(p_decParams->Z, p_decParams->BG);
  init_LLR_DMA(p_decParams, p_llr, p_out);
  uint16_t Zc = p_decParams->Z;
  uint8_t BG = p_decParams->BG;
  int block_length = p_decParams->Kprime;
  uint8_t row, col;
  if (BG == 1) {
    row = 46;
    col = 68;
  } else {
    row = 42;
    col = 52;
  }

  //	alloc memory
  unsigned char* hard_decision = (unsigned char*)p_out;
  //	gpu
  int memorySize_llr_cuda = col * Zc * sizeof(char) * MC;
  cudaCheck(cudaMemcpyToSymbol(dev_const_llr, p_llr, memorySize_llr_cuda));
  cudaCheck(cudaMemcpyToSymbol(dev_llr, p_llr, memorySize_llr_cuda));

  // Define CUDA kernel dimension
  int blockSizeX = Zc;
  dim3 dimGridKernel1(row, MC, 1); // dim of the thread blocks
  dim3 dimBlockKernel1(blockSizeX, 1, 1);

  dim3 dimGridKernel2(col, MC, 1);
  dim3 dimBlockKernel2(blockSizeX, 1, 1);
  cudaDeviceSynchronize();

  // lauch kernel

  for (int ii = 0; ii < MAX_ITERATION; ii++) {
    // first kernel
    if (ii == 0) {
      ldpc_cnp_kernel_1st_iter<<<dimGridKernel1, dimBlockKernel1>>>(/*dev_llr,*/ BG, row, col, Zc);
    } else {
      ldpc_cnp_kernel<<<dimGridKernel1, dimBlockKernel1>>>(/*dev_llr,*/ BG, row, col, Zc);
    }
    // second kernel
    ldpc_vnp_kernel_normal<<<dimGridKernel2, dimBlockKernel2>>>
        // (dev_llr, dev_const_llr,BG, row, col, Zc);
        (BG, row, col, Zc);
  }

  int pack = (block_length / 128) + 1;
  dim3 pack_block(pack, MC, 1);
  pack_decoded_bit<<<pack_block, 128>>>(/*dev_llr,*/ /*dev_tmp,*/ col, Zc);

  cudaCheck(cudaMemcpyFromSymbol((void*)hard_decision, (const void*)dev_tmp, (block_length / 8) * sizeof(unsigned char)));
  cudaDeviceSynchronize();

  return MAX_ITERATION;
}
