#include <private/snesimpl.h>   /*I "petscsnes.h" I*/
#include <petscdm.h>            /*I "petscdm.h" I*/

#undef __FUNCT__
#define __FUNCT__ "PetscContainerDestroy_SNESDM"
static PetscErrorCode PetscContainerDestroy_SNESDM(void *ctx)
{
  PetscErrorCode ierr;
  SNESDM sdm = (SNESDM)ctx;

  PetscFunctionBegin;
  if (sdm->dmloopref) {         /* Reconnect old loop before we drop our reference */
    DM dminner;
    ierr = PetscObjectQuery((PetscObject)sdm->vec_sol,"DM",(PetscObject*)&dminner);CHKERRQ(ierr);
    if (dminner) {ierr = PetscObjectReference((PetscObject)dminner);CHKERRQ(ierr);}
  }
  ierr = VecDestroy(&sdm->vec_sol);CHKERRQ(ierr);
  if (sdm->destroy) {ierr = (*sdm->destroy)(sdm);CHKERRQ(ierr);}
  ierr = PetscFree(sdm);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "DMCoarsenHook_SNESDM"
/* Attaches the SNESDM to the coarse level.
 * Under what conditions should we copy versus duplicate?
 */
static PetscErrorCode DMCoarsenHook_SNESDM(DM dm,DM dmc,void *ctx)
{
  PetscErrorCode ierr;

  PetscFunctionBegin;
  ierr = DMSNESCopyContext(dm,dmc);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "DMRestrictHook_SNESDM"
/* Restrict state vector from finest level
 */
static PetscErrorCode DMRestrictHook_SNESDM(DM dm,Mat Restrict,Vec rscale,Mat Inject,DM dmc,void *ctx)
{
  PetscErrorCode ierr;
  SNESDM sdm,sdmc;
  Vec Xcoarse;

  PetscFunctionBegin;
  ierr = DMSNESGetContext(dm,&sdm);CHKERRQ(ierr);
  ierr = DMSNESGetContextWrite(dmc,&sdmc);CHKERRQ(ierr);
  if (sdm->vec_sol) {
    ierr = DMSNESGetSolution(dmc,&Xcoarse);CHKERRQ(ierr);
    ierr = MatRestrict(Restrict,sdm->vec_sol,Xcoarse);CHKERRQ(ierr);
    ierr = VecPointwiseMult(Xcoarse,Xcoarse,rscale);CHKERRQ(ierr);
  }
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "DMSNESGetContext"
/*@C
   DMSNESGetContext - get read-only private SNESDM context from a DM

   Not Collective

   Input Argument:
.  dm - DM to be used with SNES

   Output Argument:
.  snesdm - private SNESDM context

   Level: developer

   Notes:
   Use DMSNESGetContextWrite() if write access is needed. The DMSNESSetXXX API should be used wherever possible.

.seealso: DMSNESGetContextWrite()
@*/
PetscErrorCode DMSNESGetContext(DM dm,SNESDM *snesdm)
{
  PetscErrorCode ierr;
  PetscContainer container;
  SNESDM         sdm;

  PetscFunctionBegin;
  PetscValidHeaderSpecific(dm,DM_CLASSID,1);
  ierr = PetscObjectQuery((PetscObject)dm,"SNESDM",(PetscObject*)&container);CHKERRQ(ierr);
  if (container) {
    ierr = PetscContainerGetPointer(container,(void**)snesdm);CHKERRQ(ierr);
  } else {
    ierr = PetscInfo(dm,"Creating new SNESDM\n");CHKERRQ(ierr);
    ierr = PetscContainerCreate(((PetscObject)dm)->comm,&container);CHKERRQ(ierr);
    ierr = PetscNewLog(dm,struct _n_SNESDM,&sdm);CHKERRQ(ierr);
    ierr = PetscContainerSetPointer(container,sdm);CHKERRQ(ierr);
    ierr = PetscContainerSetUserDestroy(container,PetscContainerDestroy_SNESDM);CHKERRQ(ierr);
    ierr = PetscObjectCompose((PetscObject)dm,"SNESDM",(PetscObject)container);CHKERRQ(ierr);
    ierr = DMCoarsenHookAdd(dm,DMCoarsenHook_SNESDM,DMRestrictHook_SNESDM,PETSC_NULL);CHKERRQ(ierr);
    ierr = PetscContainerGetPointer(container,(void**)snesdm);CHKERRQ(ierr);
    ierr = PetscContainerDestroy(&container);CHKERRQ(ierr);
  }
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "DMSNESGetContextWrite"
/*@C
   DMSNESGetContextWrite - get write access to private SNESDM context from a DM

   Not Collective

   Input Argument:
.  dm - DM to be used with SNES

   Output Argument:
.  snesdm - private SNESDM context

   Level: developer

.seealso: DMSNESGetContext()
@*/
PetscErrorCode DMSNESGetContextWrite(DM dm,SNESDM *snesdm)
{
  PetscErrorCode ierr;
  SNESDM         sdm;

  PetscFunctionBegin;
  PetscValidHeaderSpecific(dm,DM_CLASSID,1);
  ierr = DMSNESGetContext(dm,&sdm);CHKERRQ(ierr);
  if (!sdm->originaldm) sdm->originaldm = dm;
  if (sdm->originaldm != dm) {  /* Copy on write */
    PetscContainer container;
    SNESDM         oldsdm = sdm;
    ierr = PetscInfo(dm,"Copying SNESDM due to write\n");CHKERRQ(ierr);
    ierr = PetscContainerCreate(((PetscObject)dm)->comm,&container);CHKERRQ(ierr);
    ierr = PetscNewLog(dm,struct _n_SNESDM,&sdm);CHKERRQ(ierr);
    ierr = PetscMemcpy(sdm,oldsdm,sizeof *sdm);CHKERRQ(ierr);
    sdm->vec_sol = PETSC_NULL;
    sdm->dmloopref = PETSC_FALSE;
    ierr = PetscContainerSetPointer(container,sdm);CHKERRQ(ierr);
    ierr = PetscContainerSetUserDestroy(container,PetscContainerDestroy_SNESDM);CHKERRQ(ierr);
    ierr = PetscObjectCompose((PetscObject)dm,"SNESDM",(PetscObject)container);CHKERRQ(ierr);
    ierr = PetscContainerDestroy(&container);CHKERRQ(ierr);
  }
  *snesdm = sdm;
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "DMSNESCopyContext"
/*@C
   DMSNESCopyContext - copies a DM context to a new DM

   Logically Collective

   Input Arguments:
+  dmsrc - DM to obtain context from
-  dmdest - DM to add context to

   Level: developer

   Note:
   The context is copied by reference. This function does not ensure that a context exists.

.seealso: DMSNESGetContext(), SNESSetDM()
@*/
PetscErrorCode DMSNESCopyContext(DM dmsrc,DM dmdest)
{
  PetscErrorCode ierr;
  PetscContainer container;

  PetscFunctionBegin;
  PetscValidHeaderSpecific(dmsrc,DM_CLASSID,1);
  PetscValidHeaderSpecific(dmdest,DM_CLASSID,2);
  ierr = PetscObjectQuery((PetscObject)dmsrc,"SNESDM",(PetscObject*)&container);CHKERRQ(ierr);
  if (container) {
    ierr = PetscObjectCompose((PetscObject)dmdest,"SNESDM",(PetscObject)container);CHKERRQ(ierr);
    ierr = DMCoarsenHookAdd(dmdest,DMCoarsenHook_SNESDM,DMRestrictHook_SNESDM,PETSC_NULL);CHKERRQ(ierr);
  }
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "DMSNESSetFunction"
/*@C
   DMSNESSetFunction - set SNES residual evaluation function

   Not Collective

   Input Arguments:
+  dm - DM to be used with SNES
.  func - residual evaluation function, see SNESSetFunction() for calling sequence
-  ctx - context for residual evaluation

   Level: advanced

   Note:
   SNESSetFunction() is normally used, but it calls this function internally because the user context is actually
   associated with the DM.  This makes the interface consistent regardless of whether the user interacts with a DM or
   not. If DM took a more central role at some later date, this could become the primary method of setting the residual.

.seealso: DMSNESSetContext(), SNESSetFunction(), DMSNESSetJacobian()
@*/
PetscErrorCode DMSNESSetFunction(DM dm,PetscErrorCode (*func)(SNES,Vec,Vec,void*),void *ctx)
{
  PetscErrorCode ierr;
  SNESDM sdm;

  PetscFunctionBegin;
  PetscValidHeaderSpecific(dm,DM_CLASSID,1);
  ierr = DMSNESGetContextWrite(dm,&sdm);CHKERRQ(ierr);
  if (func) sdm->computefunction = func;
  if (ctx)  sdm->functionctx = ctx;
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "DMSNESGetFunction"
/*@C
   DMSNESGetFunction - get SNES residual evaluation function

   Not Collective

   Input Argument:
.  dm - DM to be used with SNES

   Output Arguments:
+  func - residual evaluation function, see SNESSetFunction() for calling sequence
-  ctx - context for residual evaluation

   Level: advanced

   Note:
   SNESGetFunction() is normally used, but it calls this function internally because the user context is actually
   associated with the DM.

.seealso: DMSNESSetContext(), DMSNESSetFunction(), SNESSetFunction()
@*/
PetscErrorCode DMSNESGetFunction(DM dm,PetscErrorCode (**func)(SNES,Vec,Vec,void*),void **ctx)
{
  PetscErrorCode ierr;
  SNESDM sdm;

  PetscFunctionBegin;
  PetscValidHeaderSpecific(dm,DM_CLASSID,1);
  ierr = DMSNESGetContext(dm,&sdm);CHKERRQ(ierr);
  if (func) *func = sdm->computefunction;
  if (ctx)  *ctx = sdm->functionctx;
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "DMSNESSetGS"
/*@C
   DMSNESSetGS - set SNES Gauss-Seidel relaxation function

   Not Collective

   Input Argument:
+  dm - DM to be used with SNES
.  func - relaxation function, see SNESSetGS() for calling sequence
-  ctx - context for residual evaluation

   Level: advanced

   Note:
   SNESSetGS() is normally used, but it calls this function internally because the user context is actually
   associated with the DM.  This makes the interface consistent regardless of whether the user interacts with a DM or
   not. If DM took a more central role at some later date, this could become the primary method of setting the residual.

.seealso: DMSNESSetContext(), SNESSetFunction(), DMSNESSetJacobian(), DMSNESSetFunction()
@*/
PetscErrorCode DMSNESSetGS(DM dm,PetscErrorCode (*func)(SNES,Vec,Vec,void*),void *ctx)
{
  PetscErrorCode ierr;
  SNESDM sdm;

  PetscFunctionBegin;
  PetscValidHeaderSpecific(dm,DM_CLASSID,1);
  ierr = DMSNESGetContextWrite(dm,&sdm);CHKERRQ(ierr);
  if (func) sdm->computegs = func;
  if (ctx)  sdm->gsctx = ctx;
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "DMSNESGetGS"
/*@C
   DMSNESGetGS - get SNES Gauss-Seidel relaxation function

   Not Collective

   Input Argument:
.  dm - DM to be used with SNES

   Output Arguments:
+  func - relaxation function, see SNESSetGS() for calling sequence
-  ctx - context for residual evaluation

   Level: advanced

   Note:
   SNESGetGS() is normally used, but it calls this function internally because the user context is actually
   associated with the DM.  This makes the interface consistent regardless of whether the user interacts with a DM or
   not. If DM took a more central role at some later date, this could become the primary method of setting the residual.

.seealso: DMSNESSetContext(), SNESGetGS(), DMSNESGetJacobian(), DMSNESGetFunction()
@*/
PetscErrorCode DMSNESGetGS(DM dm,PetscErrorCode (**func)(SNES,Vec,Vec,void*),void **ctx)
{
  PetscErrorCode ierr;
  SNESDM sdm;

  PetscFunctionBegin;
  PetscValidHeaderSpecific(dm,DM_CLASSID,1);
  ierr = DMSNESGetContext(dm,&sdm);CHKERRQ(ierr);
  if (func) *func = sdm->computegs;
  if (ctx)  *ctx = sdm->gsctx;
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "DMSNESSetJacobian"
/*@C
   DMSNESSetFunction - set SNES Jacobian evaluation function

   Not Collective

   Input Argument:
+  dm - DM to be used with SNES
.  func - Jacobian evaluation function, see SNESSetJacobian() for calling sequence
-  ctx - context for residual evaluation

   Level: advanced

   Note:
   SNESSetJacobian() is normally used, but it calls this function internally because the user context is actually
   associated with the DM.  This makes the interface consistent regardless of whether the user interacts with a DM or
   not. If DM took a more central role at some later date, this could become the primary method of setting the Jacobian.

.seealso: DMSNESSetContext(), SNESSetFunction(), DMSNESGetJacobian(), SNESSetJacobian()
@*/
PetscErrorCode DMSNESSetJacobian(DM dm,PetscErrorCode (*func)(SNES,Vec,Mat*,Mat*,MatStructure*,void*),void *ctx)
{
  PetscErrorCode ierr;
  SNESDM sdm;

  PetscFunctionBegin;
  PetscValidHeaderSpecific(dm,DM_CLASSID,1);
  ierr = DMSNESGetContextWrite(dm,&sdm);CHKERRQ(ierr);
  if (func) sdm->computejacobian = func;
  if (ctx)  sdm->jacobianctx = ctx;
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "DMSNESGetJacobian"
/*@C
   DMSNESGetFunction - get SNES Jacobian evaluation function

   Not Collective

   Input Argument:
.  dm - DM to be used with SNES

   Output Arguments:
+  func - Jacobian evaluation function, see SNESSetJacobian() for calling sequence
-  ctx - context for residual evaluation

   Level: advanced

   Note:
   SNESGetJacobian() is normally used, but it calls this function internally because the user context is actually
   associated with the DM.  This makes the interface consistent regardless of whether the user interacts with a DM or
   not. If DM took a more central role at some later date, this could become the primary method of setting the Jacobian.

.seealso: DMSNESSetContext(), SNESSetFunction(), DMSNESSetJacobian()
@*/
PetscErrorCode DMSNESGetJacobian(DM dm,PetscErrorCode (**func)(SNES,Vec,Mat*,Mat*,MatStructure*,void*),void **ctx)
{
  PetscErrorCode ierr;
  SNESDM sdm;

  PetscFunctionBegin;
  PetscValidHeaderSpecific(dm,DM_CLASSID,1);
  ierr = DMSNESGetContext(dm,&sdm);CHKERRQ(ierr);
  if (func) *func = sdm->computejacobian;
  if (ctx)  *ctx = sdm->jacobianctx;
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "SNESDefaultComputeFunction_DMLegacy"
static PetscErrorCode SNESDefaultComputeFunction_DMLegacy(SNES snes,Vec X,Vec F,void *ctx)
{
  PetscErrorCode ierr;
  DM             dm;

  PetscFunctionBegin;
  ierr = SNESGetDM(snes,&dm);CHKERRQ(ierr);
  ierr = DMComputeFunction(dm,X,F);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "SNESDefaultComputeJacobian_DMLegacy"
static PetscErrorCode SNESDefaultComputeJacobian_DMLegacy(SNES snes,Vec X,Mat *A,Mat *B,MatStructure *mstr,void *ctx)
{
  PetscErrorCode ierr;
  DM             dm;

  PetscFunctionBegin;
  ierr = SNESGetDM(snes,&dm);CHKERRQ(ierr);
  ierr = DMComputeJacobian(dm,X,*A,*B,mstr);CHKERRQ(ierr);
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "DMSNESSetUpLegacy"
/* Sets up calling of legacy DM routines */
PetscErrorCode DMSNESSetUpLegacy(DM dm)
{
  PetscErrorCode ierr;
  SNESDM         sdm;

  PetscFunctionBegin;
  ierr = DMSNESGetContext(dm,&sdm);CHKERRQ(ierr);
  if (!sdm->computefunction) {ierr = DMSNESSetFunction(dm,SNESDefaultComputeFunction_DMLegacy,PETSC_NULL);CHKERRQ(ierr);}
  ierr = DMSNESGetContext(dm,&sdm);CHKERRQ(ierr);
  if (!sdm->computejacobian) {ierr = DMSNESSetJacobian(dm,SNESDefaultComputeJacobian_DMLegacy,PETSC_NULL);CHKERRQ(ierr);}
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "DMSNESGetSolution"
PetscErrorCode DMSNESGetSolution(DM dm,Vec *vec_sol)
{
  PetscErrorCode ierr;
  SNESDM sdm;

  PetscFunctionBegin;
  PetscValidHeaderSpecific(dm,DM_CLASSID,1);
  ierr = DMSNESGetContext(dm,&sdm);CHKERRQ(ierr);
  if (!sdm->vec_sol) {
    ierr = DMCreateGlobalVector(dm,&sdm->vec_sol);CHKERRQ(ierr);
    /* This vector holds an extra reference to the DM, decrement the DM reference count so that it remains constant */
    sdm->dmloopref = PETSC_TRUE;
    ierr = PetscObjectDereference((PetscObject)dm);CHKERRQ(ierr);
  }
  *vec_sol = sdm->vec_sol;
  PetscFunctionReturn(0);
}

#undef __FUNCT__
#define __FUNCT__ "DMSNESSetSolution"
PetscErrorCode DMSNESSetSolution(DM dm,Vec vec_sol)
{
  PetscErrorCode ierr;
  DM dminner;
  SNESDM sdm;

  PetscFunctionBegin;
  PetscValidHeaderSpecific(dm,DM_CLASSID,1);
  ierr = DMSNESGetContext(dm,&sdm);CHKERRQ(ierr);
  if (sdm->vec_sol == vec_sol) PetscFunctionReturn(0);
  if (sdm->dmloopref) {         /* Reconnect old loop before we drop our reference */
    ierr = PetscObjectQuery((PetscObject)sdm->vec_sol,"DM",(PetscObject*)&dminner);CHKERRQ(ierr);
    if (dminner) {ierr = PetscObjectReference((PetscObject)dminner);CHKERRQ(ierr);}
  }
  sdm->dmloopref = PETSC_FALSE;

  if (vec_sol) {ierr = PetscObjectReference((PetscObject)vec_sol);CHKERRQ(ierr);}
  ierr = VecDestroy(&sdm->vec_sol);CHKERRQ(ierr);
  sdm->vec_sol = vec_sol;

  /* Break new loop if we just created one */
  if (sdm->vec_sol) {
    ierr = PetscObjectQuery((PetscObject)sdm->vec_sol,"DM",(PetscObject*)&dminner);CHKERRQ(ierr);
    if (dminner == dm) {
      sdm->dmloopref = PETSC_TRUE;
      if (((PetscObject)dm)->refct <= 1) SETERRQ(((PetscObject)dm)->comm,PETSC_ERR_ARG_WRONG,"The incoming Vec holds the last reference to the DM");
      ierr = PetscObjectDereference((PetscObject)dm);CHKERRQ(ierr);
    }
  }
  PetscFunctionReturn(0);
}