/// @file
/// Test creation, evaluation, and destruction for QFunction
/// \test Test creation, evaluation, and destruction for QFunction
#include <ceed.h>
#include <math.h>

#include "t409-qfunction.h"

int main(int argc, char **argv) {
  Ceed ceed;
  CeedVector in[16], out[16];
  CeedVector U, V;
  CeedQFunction qf;
  CeedQFunctionContext ctx;
  CeedInt Q = 8;
  const CeedScalar *v;
  bool is_writable = true;
  CeedScalar ctx_data[5] = {1, 2, 3, 4, 5};

  CeedInit(argv[1], &ceed);

  CeedQFunctionCreateInterior(ceed, 1, scale, scale_loc, &qf);
  CeedQFunctionAddInput(qf, "u", 1, CEED_EVAL_INTERP);
  CeedQFunctionAddOutput(qf, "v", 1, CEED_EVAL_INTERP);

  CeedQFunctionContextCreate(ceed, &ctx);
  CeedQFunctionContextSetData(ctx, CEED_MEM_HOST, CEED_COPY_VALUES,
                              sizeof(ctx_data), &ctx_data);
  CeedQFunctionSetContext(qf, ctx);
  CeedQFunctionSetContextWritable(qf, is_writable);

  CeedVectorCreate(ceed, Q, &U);
  CeedVectorSetValue(U, 1.0);
  CeedVectorCreate(ceed, Q, &V);
  CeedVectorSetValue(V, 0.0);

  {
    in[0] = U;
    out[0] = V;
    CeedQFunctionApply(qf, Q, in, out);
  }

  CeedVectorGetArrayRead(V, CEED_MEM_HOST, &v);
  for (CeedInt i=0; i<Q; i++)
    if (fabs(v[i] - ctx_data[1]) > 100.*CEED_EPSILON)
      // LCOV_EXCL_START
      printf("v[%" CeedInt_FMT "] %f != 2.0\n", i, v[i]);
  // LCOV_EXCL_STOP
  CeedVectorRestoreArrayRead(V, &v);

  // Check for written context data
  CeedScalar *ctx_data_new;
  CeedQFunctionContextGetDataRead(ctx, CEED_MEM_HOST, &ctx_data_new);
  if (ctx_data_new[0] != 42)
    // LCOV_EXCL_START
    printf("Context data not written: %f != 42\n", ctx_data_new[0]);
  // LCOV_EXCL_STOP
  CeedQFunctionContextRestoreDataRead(ctx, &ctx_data_new);

  // Assert that context will not be written
  // Note: The interface cannot enforce this in user code
  //   so setting is_writable == false and then calling
  //   CeedQFunctionApply to mutate the context would lead
  //   to inconsistent data on the GPU.
  //   Only the `/cpu/self/memcheck/*` backends verify that
  //   read-only access resulted in no changes to the context data
  CeedQFunctionContextGetData(ctx, CEED_MEM_HOST, &ctx_data_new);
  ctx_data_new[0] = 5;
  CeedQFunctionContextRestoreData(ctx, &ctx_data_new);
  is_writable = false;
  CeedQFunctionSetContextWritable(qf, is_writable);
  {
    in[0] = U;
    out[0] = V;
    // Will only error in `/cpu/self/memcheck/*` backends
    CeedQFunctionApply(qf, Q, in, out);
  }

  CeedVectorDestroy(&U);
  CeedVectorDestroy(&V);
  CeedQFunctionDestroy(&qf);
  CeedQFunctionContextDestroy(&ctx);
  CeedDestroy(&ceed);
  return 0;
}