/*
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software  Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * The Original Code is Copyright (C) 2005 by the Blender Foundation.
 * All rights reserved.
 */

/** \file
 * \ingroup modifiers
 */


#include <stddef.h>

#include "DNA_mesh_types.h"
#include "DNA_object_types.h"
#include "DNA_scene_types.h"

#include "BLI_utildefines.h"

#include "BKE_cdderivedmesh.h"
#include "BKE_mesh.h"
#include "BKE_multires.h"
#include "BKE_modifier.h"
#include "BKE_subdiv.h"
#include "BKE_subdiv_ccg.h"
#include "BKE_subdiv_mesh.h"
#include "BKE_subsurf.h"

#include "DEG_depsgraph_query.h"

#include "MOD_modifiertypes.h"

static void initData(ModifierData *md)
{
	MultiresModifierData *mmd = (MultiresModifierData *)md;

	mmd->lvl = 0;
	mmd->sculptlvl = 0;
	mmd->renderlvl = 0;
	mmd->totlvl = 0;
	mmd->uv_smooth = SUBSURF_UV_SMOOTH_PRESERVE_CORNERS;
	mmd->quality = 3;
}

static void copyData(const ModifierData *md_src, ModifierData *md_dst, const int flag)
{
	MultiresModifierData *mmd_dst = (MultiresModifierData *)md_dst;

	modifier_copyData_generic(md_src, md_dst, flag);

	mmd_dst->subdiv = NULL;
}

static void freeData(ModifierData *md)
{
	MultiresModifierData *mmd = (MultiresModifierData *) md;
	if (mmd->subdiv != NULL) {
		BKE_subdiv_free(mmd->subdiv);
	}
}

/* Main goal of this function is to give usable subdivision surface descriptor
 * which matches settings and topology. */
static Subdiv *subdiv_descriptor_ensure(MultiresModifierData *mmd,
                                        const SubdivSettings *subdiv_settings,
                                        const Mesh *mesh)
{
	Subdiv *subdiv = BKE_subdiv_update_from_mesh(
	        mmd->subdiv, subdiv_settings, mesh);
	if (false) {
		mmd->subdiv = subdiv;
	}
	return subdiv;
}

/* Subdivide into fully qualified mesh. */

static Mesh *multires_as_mesh(MultiresModifierData *mmd,
                              const ModifierEvalContext *ctx,
                              Mesh *mesh,
                              Subdiv *subdiv)
{
	Mesh *result = mesh;
	const bool use_render_params = (ctx->flag & MOD_APPLY_RENDER);
	const bool ignore_simplify = (ctx->flag & MOD_APPLY_IGNORE_SIMPLIFY);
	const Scene *scene = DEG_get_evaluated_scene(ctx->depsgraph);
	Object *object = ctx->object;
	SubdivToMeshSettings mesh_settings;
	BKE_multires_subdiv_mesh_settings_init(
        &mesh_settings, scene, object, mmd, use_render_params, ignore_simplify);
	if (mesh_settings.resolution < 3) {
		return result;
	}
	BKE_subdiv_displacement_attach_from_multires(subdiv, mesh, mmd);
	result = BKE_subdiv_to_mesh(subdiv, &mesh_settings, mesh);
	return result;
}

/* Subdivide into CCG. */

static void multires_ccg_settings_init(SubdivToCCGSettings *settings,
                                       const MultiresModifierData *mmd,
                                       const ModifierEvalContext *ctx,
                                       Mesh *mesh)
{
	const bool has_mask =
	        CustomData_has_layer(&mesh->ldata, CD_GRID_PAINT_MASK);
	const bool use_render_params = (ctx->flag & MOD_APPLY_RENDER);
	const bool ignore_simplify = (ctx->flag & MOD_APPLY_IGNORE_SIMPLIFY);
	const Scene *scene = DEG_get_evaluated_scene(ctx->depsgraph);
	Object *object = ctx->object;
	const int level = multires_get_level(
	        scene, object, mmd, use_render_params, ignore_simplify);
	settings->resolution = (1 << level) + 1;
	settings->need_normal = true;
	settings->need_mask = has_mask;
}

static Mesh *multires_as_ccg(MultiresModifierData *mmd,
                             const ModifierEvalContext *ctx,
                             Mesh *mesh,
                             Subdiv *subdiv)
{
	Mesh *result = mesh;
	SubdivToCCGSettings ccg_settings;
	multires_ccg_settings_init(&ccg_settings, mmd, ctx, mesh);
	if (ccg_settings.resolution < 3) {
		return result;
	}
	BKE_subdiv_displacement_attach_from_multires(subdiv, mesh, mmd);
	result = BKE_subdiv_to_ccg_mesh(subdiv, &ccg_settings, mesh);
	return result;
}

static Mesh *applyModifier(ModifierData *md,
                           const ModifierEvalContext *ctx,
                           Mesh *mesh)
{
	Mesh *result = mesh;
	MultiresModifierData *mmd = (MultiresModifierData *)md;
	SubdivSettings subdiv_settings;
	BKE_multires_subdiv_settings_init(&subdiv_settings, mmd);
	if (subdiv_settings.level == 0) {
		return result;
	}
	BKE_subdiv_settings_validate_for_mesh(&subdiv_settings, mesh);
	Subdiv *subdiv = subdiv_descriptor_ensure(mmd, &subdiv_settings, mesh);
	if (subdiv == NULL) {
		/* Happens on bad topology, ut also on empty input mesh. */
		return result;
	}
	/* NOTE: Orco needs final coordinates on CPU side, which are expected to be
	 * accessible via MVert. For this reason we do not evaluate multires to
	 * grids when orco is requested. */
	const bool for_orco = (ctx->flag & MOD_APPLY_ORCO) != 0;
	if ((ctx->object->mode & OB_MODE_SCULPT) && !for_orco) {
		/* NOTE: CCG takes ownership over Subdiv. */
		result = multires_as_ccg(mmd, ctx, mesh, subdiv);
		result->runtime.subdiv_ccg_tot_level = mmd->totlvl;
		// BKE_subdiv_stats_print(&subdiv->stats);
	}
	else {
		result = multires_as_mesh(mmd, ctx, mesh, subdiv);
		// BKE_subdiv_stats_print(&subdiv->stats);
		if (subdiv != mmd->subdiv) {
			BKE_subdiv_free(subdiv);
		}
	}
	return result;
}

ModifierTypeInfo modifierType_Multires = {
	/* name */              "Multires",
	/* structName */        "MultiresModifierData",
	/* structSize */        sizeof(MultiresModifierData),
	/* type */              eModifierTypeType_Constructive,
	/* flags */             eModifierTypeFlag_AcceptsMesh |
	                        eModifierTypeFlag_SupportsMapping |
	                        eModifierTypeFlag_RequiresOriginalData,

	/* copyData */          copyData,

	/* deformVerts_DM */    NULL,
	/* deformMatrices_DM */ NULL,
	/* deformVertsEM_DM */  NULL,
	/* deformMatricesEM_DM*/NULL,
	/* applyModifier_DM */  NULL,

	/* deformVerts */       NULL,
	/* deformMatrices */    NULL,
	/* deformVertsEM */     NULL,
	/* deformMatricesEM */  NULL,
	/* applyModifier */     applyModifier,

	/* initData */          initData,
	/* requiredDataMask */  NULL,
	/* freeData */          freeData,
	/* isDisabled */        NULL,
	/* updateDepsgraph */   NULL,
	/* dependsOnTime */     NULL,
	/* dependsOnNormals */	NULL,
	/* foreachObjectLink */ NULL,
	/* foreachIDLink */     NULL,
	/* foreachTexLink */    NULL,
};