// Copyright (c) 2017-2022, Lawrence Livermore National Security, LLC and other CEED contributors.
// All Rights Reserved. See the top-level LICENSE and NOTICE files for details.
//
// SPDX-License-Identifier: BSD-2-Clause
//
// This file is part of CEED:  http://github.com/ceed

#include <ceed/ceed.h>
#include <ceed/backend.h>
#include <stddef.h>
#include <string.h>
#include "ceed-identity.h"

/**
  @brief Set fields identity QFunction that copies inputs directly into outputs
**/
static int CeedQFunctionInit_Identity(Ceed ceed, const char *requested,
                                      CeedQFunction qf) {
  int ierr;

  // Check QFunction name
  const char *name = "Identity";
  if (strcmp(name, requested))
    // LCOV_EXCL_START
    return CeedError(ceed, CEED_ERROR_UNSUPPORTED,
                     "QFunction '%s' does not match requested name: %s",
                     name, requested);
  // LCOV_EXCL_STOP

  // QFunction fields 'input' and 'output' with requested emodes added
  //   by the library rather than being added here

  ierr = CeedQFunctionSetUserFlopsEstimate(qf, 0); CeedChk(ierr);

  // Context data
  CeedQFunctionContext ctx;
  IdentityCtx ctx_data = {.size = 1};
  ierr = CeedQFunctionContextCreate(ceed, &ctx); CeedChk(ierr);
  ierr = CeedQFunctionContextSetData(ctx, CEED_MEM_HOST, CEED_COPY_VALUES,
                                     sizeof(ctx_data), (void *)&ctx_data);
  CeedChk(ierr);
  ierr = CeedQFunctionContextRegisterInt32(ctx, "size",
         offsetof(IdentityCtx, size), 1, "field size of identity QFunction");
  CeedChk(ierr);
  ierr = CeedQFunctionSetContext(qf, ctx); CeedChk(ierr);
  ierr = CeedQFunctionContextDestroy(&ctx); CeedChk(ierr);

  return CEED_ERROR_SUCCESS;
}

/**
  @brief Register identity QFunction that copies inputs directly into outputs
**/
CEED_INTERN int CeedQFunctionRegister_Identity(void) {
  return CeedQFunctionRegister("Identity", Identity_loc, 1, Identity,
                               CeedQFunctionInit_Identity);
}