#pragma once

#include <petsc/private/snesimpl.h>
#include <petsc/private/linesearchimpl.h>
#include <petscdm.h>

typedef struct {
  /* flags for knowing the global place of this FAS object */
  PetscInt level;  /* level = 0 coarsest level */
  PetscInt levels; /* if level + 1 = levels; we're the last turtle */

  /* smoothing objects */
  SNES smoothu; /* the SNES for presmoothing */
  SNES smoothd; /* the SNES for postsmoothing */

  /* coarse grid correction objects */
  SNES next;        /* the SNES instance for the next coarser level in the hierarchy */
  SNES fine;        /* the finest SNES instance; used as a reference for prefixes */
  SNES previous;    /* the SNES instance for the next finer level in the hierarchy */
  Mat  interpolate; /* interpolation */
  Mat  inject;      /* injection operator (unscaled) */
  Mat  restrct;     /* restriction operator */
  Vec  rscale;      /* the pointwise scaling of the restriction operator */

  /* method parameters */
  PetscInt    n_cycles;               /* number of cycles on this level */
  SNESFASType fastype;                /* FAS type */
  PetscInt    max_up_it;              /* number of pre-smooths */
  PetscInt    max_down_it;            /* number of post-smooth cycles */
  PetscBool   usedmfornumberoflevels; /* uses a DM to generate a number of the levels */
  PetscBool   full_downsweep;         /* smooth on the initial full downsweep */
  PetscBool   full_total;             /* use total residual restriction and total solution interpolation on the initial downsweep and upsweep */
  PetscBool   continuation;           /* sets the setup to default to continuation */
  PetscInt    full_stage;             /* stage of the full cycle -- 0 is the upswing, 1 is the downsweep and final V-cycle */

  /* Galerkin FAS state */
  PetscBool galerkin; /* use Galerkin formation of the coarse problem */
  Vec       Xg;       /* Galerkin solution projection */
  Vec       Fg;       /* Galerkin function projection */

  /* if logging times for each level */
  PetscLogEvent eventsmoothsetup;    /* level setup */
  PetscLogEvent eventsmoothsolve;    /* level smoother solves */
  PetscLogEvent eventresidual;       /* level residual evaluation */
  PetscLogEvent eventinterprestrict; /* level interpolation and restriction */
} SNES_FAS;

PETSC_INTERN PetscErrorCode SNESFASCycleCreateSmoother_Private(SNES, SNES *);