/*
  * Copyright (C) 2018 Philip Langdale <philipl@overt.org>
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 template<typename T>
 __inline__ __device__ T spatial_predictor(T a, T b, T c, T d, T e, T f, T g,
                                           T h, T i, T j, T k, T l, T m, T n)
 {
     int spatial_pred = (d + k)/2;
     int spatial_score = abs(c - j) + abs(d - k) + abs(e - l);
 
     int score = abs(b - k) + abs(c - l) + abs(d - m);
     if (score < spatial_score) {
         spatial_pred = (c + l)/2;
         spatial_score = score;
         score = abs(a - l) + abs(b - m) + abs(c - n);
         if (score < spatial_score) {
           spatial_pred = (b + m)/2;
           spatial_score = score;
         }
     }
     score = abs(d - i) + abs(e - j) + abs(f - k);
     if (score < spatial_score) {
         spatial_pred = (e + j)/2;
         spatial_score = score;
         score = abs(e - h) + abs(f - i) + abs(g - j);
         if (score < spatial_score) {
           spatial_pred = (f + i)/2;
           spatial_score = score;
         }
     }
     return spatial_pred;
 }
 
 __inline__ __device__ int max3(int a, int b, int c)
 {
     int x = max(a, b);
     return max(x, c);
 }
 
 __inline__ __device__ int min3(int a, int b, int c)
 {
     int x = min(a, b);
     return min(x, c);
 }
 
 template<typename T>
 __inline__ __device__ T temporal_predictor(T A, T B, T C, T D, T E, T F,
                                            T G, T H, T I, T J, T K, T L,
                                            T spatial_pred, bool skip_check)
 {
     int p0 = (C + H) / 2;
     int p1 = F;
     int p2 = (D + I) / 2;
     int p3 = G;
     int p4 = (E + J) / 2;
 
     int tdiff0 = abs(D - I);
     int tdiff1 = (abs(A - F) + abs(B - G)) / 2;
     int tdiff2 = (abs(K - F) + abs(G - L)) / 2;
 
     int diff = max3(tdiff0, tdiff1, tdiff2);
 
     if (!skip_check) {
       int maxi = max3(p2 - p3, p2 - p1, min(p0 - p1, p4 - p3));
       int mini = min3(p2 - p3, p2 - p1, max(p0 - p1, p4 - p3));
       diff = max3(diff, mini, -maxi);
     }
 
     if (spatial_pred > p2 + diff) {
       spatial_pred = p2 + diff;
     }
     if (spatial_pred < p2 - diff) {
       spatial_pred = p2 - diff;
     }
 
     return spatial_pred;
 }
 
 template<typename T>
 __inline__ __device__ void yadif_single(T *dst,
                                         cudaTextureObject_t prev,
                                         cudaTextureObject_t cur,
                                         cudaTextureObject_t next,
                                         int dst_width, int dst_height, int dst_pitch,
                                         int src_width, int src_height,
                                         int parity, int tff, bool skip_spatial_check)
 {
     // Identify location
     int xo = blockIdx.x * blockDim.x + threadIdx.x;
     int yo = blockIdx.y * blockDim.y + threadIdx.y;
 
     if (xo >= dst_width || yo >= dst_height) {
         return;
     }
 
     // Don't modify the primary field
     if (yo % 2 == parity) {
       dst[yo*dst_pitch+xo] = tex2D<T>(cur, xo, yo);
       return;
     }
 
     // Calculate spatial prediction
     T a = tex2D<T>(cur, xo - 3, yo - 1);
     T b = tex2D<T>(cur, xo - 2, yo - 1);
     T c = tex2D<T>(cur, xo - 1, yo - 1);
     T d = tex2D<T>(cur, xo - 0, yo - 1);
     T e = tex2D<T>(cur, xo + 1, yo - 1);
     T f = tex2D<T>(cur, xo + 2, yo - 1);
     T g = tex2D<T>(cur, xo + 3, yo - 1);
 
     T h = tex2D<T>(cur, xo - 3, yo + 1);
     T i = tex2D<T>(cur, xo - 2, yo + 1);
     T j = tex2D<T>(cur, xo - 1, yo + 1);
     T k = tex2D<T>(cur, xo - 0, yo + 1);
     T l = tex2D<T>(cur, xo + 1, yo + 1);
     T m = tex2D<T>(cur, xo + 2, yo + 1);
     T n = tex2D<T>(cur, xo + 3, yo + 1);
 
     T spatial_pred =
         spatial_predictor(a, b, c, d, e, f, g, h, i, j, k, l, m, n);
 
     // Calculate temporal prediction
     int is_second_field = !(parity ^ tff);
 
     cudaTextureObject_t prev2 = prev;
     cudaTextureObject_t prev1 = is_second_field ? cur : prev;
     cudaTextureObject_t next1 = is_second_field ? next : cur;
     cudaTextureObject_t next2 = next;
 
     T A = tex2D<T>(prev2, xo,  yo - 1);
     T B = tex2D<T>(prev2, xo,  yo + 1);
     T C = tex2D<T>(prev1, xo,  yo - 2);
     T D = tex2D<T>(prev1, xo,  yo + 0);
     T E = tex2D<T>(prev1, xo,  yo + 2);
     T F = tex2D<T>(cur,   xo,  yo - 1);
     T G = tex2D<T>(cur,   xo,  yo + 1);
     T H = tex2D<T>(next1, xo,  yo - 2);
     T I = tex2D<T>(next1, xo,  yo + 0);
     T J = tex2D<T>(next1, xo,  yo + 2);
     T K = tex2D<T>(next2, xo,  yo - 1);
     T L = tex2D<T>(next2, xo,  yo + 1);
 
     spatial_pred = temporal_predictor(A, B, C, D, E, F, G, H, I, J, K, L,
                                       spatial_pred, skip_spatial_check);
 
     dst[yo*dst_pitch+xo] = spatial_pred;
 }
 
 template <typename T>
 __inline__ __device__ void yadif_double(T *dst,
                                         cudaTextureObject_t prev,
                                         cudaTextureObject_t cur,
                                         cudaTextureObject_t next,
                                         int dst_width, int dst_height, int dst_pitch,
                                         int src_width, int src_height,
                                         int parity, int tff, bool skip_spatial_check)
 {
     int xo = blockIdx.x * blockDim.x + threadIdx.x;
     int yo = blockIdx.y * blockDim.y + threadIdx.y;
 
     if (xo >= dst_width || yo >= dst_height) {
         return;
     }
 
     if (yo % 2 == parity) {
       // Don't modify the primary field
       dst[yo*dst_pitch+xo] = tex2D<T>(cur, xo, yo);
       return;
     }
 
     T a = tex2D<T>(cur, xo - 3, yo - 1);
     T b = tex2D<T>(cur, xo - 2, yo - 1);
     T c = tex2D<T>(cur, xo - 1, yo - 1);
     T d = tex2D<T>(cur, xo - 0, yo - 1);
     T e = tex2D<T>(cur, xo + 1, yo - 1);
     T f = tex2D<T>(cur, xo + 2, yo - 1);
     T g = tex2D<T>(cur, xo + 3, yo - 1);
 
     T h = tex2D<T>(cur, xo - 3, yo + 1);
     T i = tex2D<T>(cur, xo - 2, yo + 1);
     T j = tex2D<T>(cur, xo - 1, yo + 1);
     T k = tex2D<T>(cur, xo - 0, yo + 1);
     T l = tex2D<T>(cur, xo + 1, yo + 1);
     T m = tex2D<T>(cur, xo + 2, yo + 1);
     T n = tex2D<T>(cur, xo + 3, yo + 1);
 

     T spatial_pred;
     spatial_pred.x =
         spatial_predictor(a.x, b.x, c.x, d.x, e.x, f.x, g.x, h.x, i.x, j.x, k.x, l.x, m.x, n.x);
     spatial_pred.y =
         spatial_predictor(a.y, b.y, c.y, d.y, e.y, f.y, g.y, h.y, i.y, j.y, k.y, l.y, m.y, n.y);

 
     // Calculate temporal prediction
     int is_second_field = !(parity ^ tff);
 
     cudaTextureObject_t prev2 = prev;
     cudaTextureObject_t prev1 = is_second_field ? cur : prev;
     cudaTextureObject_t next1 = is_second_field ? next : cur;
     cudaTextureObject_t next2 = next;
 
     T A = tex2D<T>(prev2, xo,  yo - 1);
     T B = tex2D<T>(prev2, xo,  yo + 1);
     T C = tex2D<T>(prev1, xo,  yo - 2);
     T D = tex2D<T>(prev1, xo,  yo + 0);
     T E = tex2D<T>(prev1, xo,  yo + 2);
     T F = tex2D<T>(cur,   xo,  yo - 1);
     T G = tex2D<T>(cur,   xo,  yo + 1);
     T H = tex2D<T>(next1, xo,  yo - 2);
     T I = tex2D<T>(next1, xo,  yo + 0);
     T J = tex2D<T>(next1, xo,  yo + 2);
     T K = tex2D<T>(next2, xo,  yo - 1);
     T L = tex2D<T>(next2, xo,  yo + 1);
 

     spatial_pred.x =

         temporal_predictor(A.x, B.x, C.x, D.x, E.x, F.x, G.x, H.x, I.x, J.x, K.x, L.x,

                            spatial_pred.x, skip_spatial_check);
     spatial_pred.y =

         temporal_predictor(A.y, B.y, C.y, D.y, E.y, F.y, G.y, H.y, I.y, J.y, K.y, L.y,

                            spatial_pred.y, skip_spatial_check);

 
     dst[yo*dst_pitch+xo] = spatial_pred;
 }
 
 extern "C" {
 
 __global__ void yadif_uchar(unsigned char *dst,
                             cudaTextureObject_t prev,
                             cudaTextureObject_t cur,
                             cudaTextureObject_t next,
                             int dst_width, int dst_height, int dst_pitch,
                             int src_width, int src_height,
                             int parity, int tff, bool skip_spatial_check)
 {
     yadif_single(dst, prev, cur, next,
                  dst_width, dst_height, dst_pitch,
                  src_width, src_height,
                  parity, tff, skip_spatial_check);
 }
 
 __global__ void yadif_ushort(unsigned short *dst,
                             cudaTextureObject_t prev,
                             cudaTextureObject_t cur,
                             cudaTextureObject_t next,
                             int dst_width, int dst_height, int dst_pitch,
                             int src_width, int src_height,
                             int parity, int tff, bool skip_spatial_check)
 {
     yadif_single(dst, prev, cur, next,
                  dst_width, dst_height, dst_pitch,
                  src_width, src_height,
                  parity, tff, skip_spatial_check);
 }
 
 __global__ void yadif_uchar2(uchar2 *dst,
                             cudaTextureObject_t prev,
                             cudaTextureObject_t cur,
                             cudaTextureObject_t next,
                             int dst_width, int dst_height, int dst_pitch,
                             int src_width, int src_height,
                             int parity, int tff, bool skip_spatial_check)
 {
     yadif_double(dst, prev, cur, next,
                  dst_width, dst_height, dst_pitch,
                  src_width, src_height,
                  parity, tff, skip_spatial_check);
 }
 
 __global__ void yadif_ushort2(ushort2 *dst,
                             cudaTextureObject_t prev,
                             cudaTextureObject_t cur,
                             cudaTextureObject_t next,
                             int dst_width, int dst_height, int dst_pitch,
                             int src_width, int src_height,
                             int parity, int tff, bool skip_spatial_check)
 {
     yadif_double(dst, prev, cur, next,
                  dst_width, dst_height, dst_pitch,
                  src_width, src_height,
                  parity, tff, skip_spatial_check);
 }
 
 } /* extern "C" */