/*
 * Copyright 2016, Blender Foundation.
 *
 * 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.
 *
 * Contributor(s): Blender Institute
 *
 */

/** \file workbench_forward.c
 *  \ingroup draw_engine
 */

#include "workbench_private.h"

#include "BIF_gl.h"

#include "BLI_alloca.h"
#include "BLI_dynstr.h"
#include "BLI_utildefines.h"

#include "BKE_node.h"
#include "BKE_particle.h"

#include "DNA_image_types.h"
#include "DNA_mesh_types.h"
#include "DNA_modifier_types.h"
#include "DNA_node_types.h"

#include "ED_uvedit.h"

#include "GPU_shader.h"
#include "GPU_texture.h"

#include "UI_resources.h"

/* *********** STATIC *********** */
static struct {
	struct GPUShader *composite_sh_cache[MAX_SHADERS];
	struct GPUShader *transparent_accum_sh_cache[MAX_SHADERS];
	struct GPUShader *depth_sh;

	struct GPUTexture *object_id_tx; /* ref only, not alloced */
	struct GPUTexture *transparent_accum_tx; /* ref only, not alloced */
	struct GPUTexture *composite_buffer_tx; /* ref only, not alloced */
	int next_object_id;
	float normal_world_matrix[3][3];
} e_data = {NULL};

/* Shaders */
extern char datatoc_workbench_forward_composite_frag_glsl[];
extern char datatoc_workbench_forward_depth_frag_glsl[];
extern char datatoc_workbench_forward_transparent_accum_frag_glsl[];
extern char datatoc_workbench_data_lib_glsl[];
extern char datatoc_workbench_background_lib_glsl[];
extern char datatoc_workbench_object_outline_lib_glsl[];
extern char datatoc_workbench_prepass_vert_glsl[];
extern char datatoc_workbench_common_lib_glsl[];
extern char datatoc_workbench_world_light_lib_glsl[];

/* static functions */
static char *workbench_build_forward_depth_frag(void)
{
	char *str = NULL;

	DynStr *ds = BLI_dynstr_new();

	BLI_dynstr_append(ds, datatoc_workbench_common_lib_glsl);
	BLI_dynstr_append(ds, datatoc_workbench_forward_depth_frag_glsl);

	str = BLI_dynstr_get_cstring(ds);
	BLI_dynstr_free(ds);
	return str;
}

static char *workbench_build_forward_transparent_accum_frag(void)
{
	char *str = NULL;

	DynStr *ds = BLI_dynstr_new();

	BLI_dynstr_append(ds, datatoc_workbench_data_lib_glsl);
	BLI_dynstr_append(ds, datatoc_workbench_common_lib_glsl);
	BLI_dynstr_append(ds, datatoc_workbench_world_light_lib_glsl);
	BLI_dynstr_append(ds, datatoc_workbench_forward_transparent_accum_frag_glsl);

	str = BLI_dynstr_get_cstring(ds);
	BLI_dynstr_free(ds);
	return str;
}

static char *workbench_build_forward_composite_frag(void)
{
	char *str = NULL;

	DynStr *ds = BLI_dynstr_new();

	BLI_dynstr_append(ds, datatoc_workbench_data_lib_glsl);
	BLI_dynstr_append(ds, datatoc_workbench_common_lib_glsl);
	BLI_dynstr_append(ds, datatoc_workbench_background_lib_glsl);
	BLI_dynstr_append(ds, datatoc_workbench_object_outline_lib_glsl);
	BLI_dynstr_append(ds, datatoc_workbench_forward_composite_frag_glsl);

	str = BLI_dynstr_get_cstring(ds);
	BLI_dynstr_free(ds);
	return str;
}

static void workbench_init_object_data(ObjectEngineData *engine_data)
{
	WORKBENCH_ObjectData *data = (WORKBENCH_ObjectData *)engine_data;
	data->object_id = e_data.next_object_id++;
}

static WORKBENCH_MaterialData *get_or_create_material_data(WORKBENCH_Data *vedata, Object *ob, Material *mat, Image *ima, int drawtype)
{
	WORKBENCH_StorageList *stl = vedata->stl;
	WORKBENCH_PassList *psl = vedata->psl;
	WORKBENCH_PrivateData *wpd = stl->g_data;
	WORKBENCH_MaterialData *material;
	WORKBENCH_ObjectData *engine_object_data = (WORKBENCH_ObjectData *)DRW_object_engine_data_ensure(
	        ob, &draw_engine_workbench_solid, sizeof(WORKBENCH_ObjectData), &workbench_init_object_data, NULL);
	WORKBENCH_MaterialData material_template;
	DRWShadingGroup *grp;

	/* Solid */
	workbench_material_get_solid_color(wpd, ob, mat, material_template.color);
	material_template.object_id = engine_object_data->object_id;
	material_template.drawtype = drawtype;
	material_template.ima = ima;
	uint hash = workbench_material_get_hash(&material_template);

	material = BLI_ghash_lookup(wpd->material_hash, SET_UINT_IN_POINTER(hash));
	if (material == NULL) {
		material = MEM_mallocN(sizeof(WORKBENCH_MaterialData), __func__);

		/* transparent accum */
		grp = DRW_shgroup_create(drawtype == OB_SOLID ? wpd->transparent_accum_sh : wpd->transparent_accum_texture_sh, psl->transparent_accum_pass);
		DRW_shgroup_uniform_block(grp, "world_block", wpd->world_ubo);
		workbench_material_set_normal_world_matrix(grp, wpd, e_data.normal_world_matrix);
		copy_v4_v4(material->color, material_template.color);
		switch (drawtype) {
			case OB_SOLID:
				DRW_shgroup_uniform_vec4(grp, "color", material->color, 1);
				break;

			case OB_TEXTURE:
			{
				GPUTexture *tex = GPU_texture_from_blender(ima, NULL, GL_TEXTURE_2D, false, false, false);
				DRW_shgroup_uniform_texture(grp, "image", tex);
				break;
			}
		}
		material->shgrp = grp;

		/* Depth */
		material->shgrp_depth = DRW_shgroup_create(e_data.depth_sh, psl->depth_pass);
		material->object_id = engine_object_data->object_id;
		DRW_shgroup_uniform_int(material->shgrp_depth, "object_id", &material->object_id, 1);
		BLI_ghash_insert(wpd->material_hash, SET_UINT_IN_POINTER(hash), material);
	}
	return material;
}

static void ensure_forward_shaders(WORKBENCH_PrivateData *wpd, int index, int drawtype)
{
	if (e_data.composite_sh_cache[index] == NULL && drawtype == OB_SOLID) {
		char *defines = workbench_material_build_defines(wpd, drawtype);
		char *composite_frag = workbench_build_forward_composite_frag();
		e_data.composite_sh_cache[index] = DRW_shader_create_fullscreen(composite_frag, defines);
		MEM_freeN(composite_frag);
		MEM_freeN(defines);
	}

	if (e_data.transparent_accum_sh_cache[index] == NULL) {
		char *defines = workbench_material_build_defines(wpd, drawtype);
		char *transparent_accum_frag = workbench_build_forward_transparent_accum_frag();
		e_data.transparent_accum_sh_cache[index] = DRW_shader_create(datatoc_workbench_prepass_vert_glsl, NULL, transparent_accum_frag, defines);
		MEM_freeN(transparent_accum_frag);

		MEM_freeN(defines);
	}
}

static void select_forward_shaders(WORKBENCH_PrivateData *wpd)
{
	int index_solid = workbench_material_get_shader_index(wpd, OB_SOLID);
	int index_texture = workbench_material_get_shader_index(wpd, OB_TEXTURE);

	ensure_forward_shaders(wpd, index_solid, OB_SOLID);
	ensure_forward_shaders(wpd, index_texture, OB_TEXTURE);

	wpd->composite_sh = e_data.composite_sh_cache[index_solid];
	wpd->transparent_accum_sh = e_data.transparent_accum_sh_cache[index_solid];
	wpd->transparent_accum_texture_sh = e_data.transparent_accum_sh_cache[index_texture];
}

/* public functions */
void workbench_forward_engine_init(WORKBENCH_Data *vedata)
{
	WORKBENCH_FramebufferList *fbl = vedata->fbl;
	WORKBENCH_PassList *psl = vedata->psl;
	WORKBENCH_StorageList *stl = vedata->stl;
	DefaultTextureList *dtxl = DRW_viewport_texture_list_get();
	DRWShadingGroup *grp;

	if (!stl->g_data) {
		/* Alloc transient pointers */
		stl->g_data = MEM_mallocN(sizeof(*stl->g_data), __func__);
	}
	WORKBENCH_PrivateData *wpd = stl->g_data;
	workbench_private_data_init(wpd);

	if (!e_data.next_object_id) {
		e_data.next_object_id = 1;
		memset(e_data.composite_sh_cache, 0x00, sizeof(struct GPUShader *) * MAX_SHADERS);
		memset(e_data.transparent_accum_sh_cache, 0x00, sizeof(struct GPUShader *) * MAX_SHADERS);

		/* XXX: forward depth does not use any defines ATM. */
		char *defines = workbench_material_build_defines(wpd, OB_SOLID);
		char *forward_depth_frag = workbench_build_forward_depth_frag();
		e_data.depth_sh = DRW_shader_create(datatoc_workbench_prepass_vert_glsl, NULL, forward_depth_frag, defines);
		MEM_freeN(forward_depth_frag);
		MEM_freeN(defines);
	}
	select_forward_shaders(wpd);

	const float *viewport_size = DRW_viewport_size_get();
	const int size[2] = {(int)viewport_size[0], (int)viewport_size[1]};

	e_data.object_id_tx = DRW_texture_pool_query_2D(size[0], size[1], GPU_R32UI, &draw_engine_workbench_transparent);
	e_data.transparent_accum_tx = DRW_texture_pool_query_2D(size[0], size[1], GPU_RGBA16F, &draw_engine_workbench_transparent);
	e_data.composite_buffer_tx = DRW_texture_pool_query_2D(size[0], size[1], GPU_RGBA16F, &draw_engine_workbench_transparent);
	GPU_framebuffer_ensure_config(&fbl->depth_fb, {
		GPU_ATTACHMENT_TEXTURE(dtxl->depth),
		GPU_ATTACHMENT_TEXTURE(e_data.object_id_tx),
	});
	GPU_framebuffer_ensure_config(&fbl->transparent_accum_fb, {
		GPU_ATTACHMENT_NONE,
		GPU_ATTACHMENT_TEXTURE(e_data.transparent_accum_tx),
	});
	GPU_framebuffer_ensure_config(&fbl->composite_fb, {
		GPU_ATTACHMENT_NONE,
		GPU_ATTACHMENT_TEXTURE(e_data.composite_buffer_tx),
	});
	const float clear_color[4] = {0.0f, 0.0f, 0.0f, 0.0f};
	DRW_stats_group_start("Clear Buffers");
	GPU_framebuffer_bind(fbl->transparent_accum_fb);
	GPU_framebuffer_clear_color(fbl->transparent_accum_fb, clear_color);
	GPU_framebuffer_bind(fbl->depth_fb);
	GPU_framebuffer_clear_color(fbl->depth_fb, clear_color);
	DRW_stats_group_end();


	/* Treansparecy Accum */
	{
		int state = DRW_STATE_WRITE_COLOR | DRW_STATE_ADDITIVE;// | DRW_STATE_CULL_BACK;
		psl->transparent_accum_pass = DRW_pass_create("Transparent Accum", state);
	}
	/* Depth */
	{
		int state = DRW_STATE_WRITE_COLOR | DRW_STATE_WRITE_DEPTH | DRW_STATE_DEPTH_LESS;
		psl->depth_pass = DRW_pass_create("Depth", state);
	}
	/* Composite */
	{
		int state = DRW_STATE_WRITE_COLOR;
		psl->composite_pass = DRW_pass_create("Composite", state);

		grp = DRW_shgroup_create(wpd->composite_sh, psl->composite_pass);
		DRW_shgroup_uniform_texture_ref(grp, "objectId", &e_data.object_id_tx);
		DRW_shgroup_uniform_texture_ref(grp, "transparentAccum", &e_data.transparent_accum_tx);
		DRW_shgroup_uniform_block(grp, "world_block", wpd->world_ubo);
		DRW_shgroup_uniform_vec2(grp, "invertedViewportSize", DRW_viewport_invert_size_get(), 1);
		DRW_shgroup_call_add(grp, DRW_cache_fullscreen_quad_get(), NULL);
	}
}

void workbench_forward_engine_free()
{
	for (int index = 0; index < MAX_SHADERS; index++) {
		DRW_SHADER_FREE_SAFE(e_data.composite_sh_cache[index]);
		DRW_SHADER_FREE_SAFE(e_data.transparent_accum_sh_cache[index]);
	}
	DRW_SHADER_FREE_SAFE(e_data.depth_sh);
}

void workbench_forward_cache_init(WORKBENCH_Data *UNUSED(vedata))
{
}

static void workbench_forward_cache_populate_particles(WORKBENCH_Data *vedata, Object *ob)
{
	const DRWContextState *draw_ctx = DRW_context_state_get();
	if (ob == draw_ctx->object_edit) {
		return;
	}
	for (ParticleSystem *psys = ob->particlesystem.first; psys != NULL; psys = psys->next) {
		if (!psys_check_enabled(ob, psys, false)) {
			continue;
		}
		if (!DRW_check_psys_visible_within_active_context(ob, psys)) {
			return;
		}
		ParticleSettings *part = psys->part;
		const int draw_as = (part->draw_as == PART_DRAW_REND) ? part->ren_as : part->draw_as;

		static float mat[4][4];
		unit_m4(mat);

		if (draw_as == PART_DRAW_PATH) {
			struct Gwn_Batch *geom = DRW_cache_particles_get_hair(ob, psys, NULL);
			WORKBENCH_MaterialData *material = get_or_create_material_data(vedata, ob, NULL, NULL, OB_SOLID);
			DRW_shgroup_call_add(material->shgrp, geom, mat);
		}
	}
}

void workbench_forward_cache_populate(WORKBENCH_Data *vedata, Object *ob)
{
	WORKBENCH_StorageList *stl = vedata->stl;
	WORKBENCH_PrivateData *wpd = stl->g_data;

	if (!DRW_object_is_renderable(ob))
		return;

	if (ob->type == OB_MESH) {
		workbench_forward_cache_populate_particles(vedata, ob);
	}
	if (ELEM(ob->type, OB_MESH, OB_CURVE, OB_SURF, OB_FONT)) {
		const DRWContextState *draw_ctx = DRW_context_state_get();
		const bool is_active = (ob == draw_ctx->obact);
		const bool is_sculpt_mode = is_active && (draw_ctx->object_mode & OB_MODE_SCULPT) != 0;
		bool is_drawn = false;

		WORKBENCH_MaterialData *material = get_or_create_material_data(vedata, ob, NULL, NULL, OB_SOLID);
		if (!is_sculpt_mode && wpd->drawtype == OB_TEXTURE && ob->type == OB_MESH) {
			const Mesh *me = ob->data;
			if (me->mloopuv) {
				const int materials_len = MAX2(1, (is_sculpt_mode ? 1 : ob->totcol));
				struct GPUMaterial **gpumat_array = BLI_array_alloca(gpumat_array, materials_len);
				struct Gwn_Batch **geom_array = me->totcol ? DRW_cache_mesh_surface_texpaint_get(ob) : NULL;
				if (materials_len > 0 && geom_array) {
					for (int i = 0; i < materials_len; i++) {
						Material *mat = give_current_material(ob, i + 1);
						Image *image;
						ED_object_get_active_image(ob, i + 1, &image, NULL, NULL, NULL);
						/* use OB_SOLID when no texture could be determined */
						int mat_drawtype = OB_SOLID;
						if (image) {
							mat_drawtype = OB_TEXTURE;
						}
						material = get_or_create_material_data(vedata, ob, mat, image, mat_drawtype);
						DRW_shgroup_call_object_add(material->shgrp_depth, geom_array[i], ob);
						DRW_shgroup_call_object_add(material->shgrp, geom_array[i], ob);
					}
					is_drawn = true;
				}
			}
		}

		/* Fallback from not drawn OB_TEXTURE mode or just OB_SOLID mode */
		if (!is_drawn) {
			if ((wpd->shading.color_type != V3D_SHADING_MATERIAL_COLOR) || is_sculpt_mode) {
				/* No material split needed */
				struct Gwn_Batch *geom = DRW_cache_object_surface_get(ob);
				if (geom) {
					if (is_sculpt_mode) {
						DRW_shgroup_call_sculpt_add(material->shgrp_depth, ob, ob->obmat);
						DRW_shgroup_call_sculpt_add(material->shgrp, ob, ob->obmat);
					}
					else {
						DRW_shgroup_call_object_add(material->shgrp_depth, geom, ob);
						DRW_shgroup_call_object_add(material->shgrp, geom, ob);
					}
				}
			}
			else {
				const int materials_len = MAX2(1, (is_sculpt_mode ? 1 : ob->totcol));
				struct GPUMaterial **gpumat_array = BLI_array_alloca(gpumat_array, materials_len);
				for (int i = 0; i < materials_len; i++) {
					gpumat_array[i] = NULL;
				}

				struct Gwn_Batch **mat_geom = DRW_cache_object_surface_material_get(ob, gpumat_array, materials_len, NULL, NULL, NULL);
				if (mat_geom) {
					for (int i = 0; i < materials_len; ++i) {
						Material *mat = give_current_material(ob, i + 1);
						material = get_or_create_material_data(vedata, ob, mat, NULL, OB_SOLID);
						DRW_shgroup_call_object_add(material->shgrp_depth, mat_geom[i], ob);
						DRW_shgroup_call_object_add(material->shgrp, mat_geom[i], ob);
					}
				}
			}
		}
	}
}

void workbench_forward_cache_finish(WORKBENCH_Data *UNUSED(vedata))
{
}

void workbench_forward_draw_background(WORKBENCH_Data *UNUSED(vedata))
{
	const float clear_depth = 1.0f;
	uint clear_stencil = 0xFF;

	const float clear_color[4] = {0.0f, 0.0f, 0.0f, 0.0f};
	DefaultFramebufferList *dfbl = DRW_viewport_framebuffer_list_get();
	DRW_stats_group_start("Clear Background");
	GPU_framebuffer_bind(dfbl->default_fb);
	int clear_bits = GPU_DEPTH_BIT | GPU_COLOR_BIT;
	GPU_framebuffer_clear(dfbl->default_fb, clear_bits, clear_color, clear_depth, clear_stencil);
	DRW_stats_group_end();
}

void workbench_forward_draw_scene(WORKBENCH_Data *vedata)
{
	WORKBENCH_PassList *psl = vedata->psl;
	WORKBENCH_StorageList *stl = vedata->stl;
	WORKBENCH_FramebufferList *fbl = vedata->fbl;
	WORKBENCH_PrivateData *wpd = stl->g_data;
	DefaultFramebufferList *dfbl = DRW_viewport_framebuffer_list_get();

	/* Write Depth + Object ID */
	GPU_framebuffer_bind(fbl->depth_fb);
	DRW_draw_pass(psl->depth_pass);

	/* Shade */
	GPU_framebuffer_bind(fbl->transparent_accum_fb);
	DRW_draw_pass(psl->transparent_accum_pass);

	/* Composite */
	GPU_framebuffer_bind(fbl->composite_fb);
	DRW_draw_pass(psl->composite_pass);

	/* Color correct */
	GPU_framebuffer_bind(dfbl->color_only_fb);
	DRW_transform_to_display(e_data.composite_buffer_tx);

	workbench_private_data_free(wpd);
}