/*
Minetest
Copyright (C) 2010-2013 celeron55, Perttu Ahola <celeron55@gmail.com>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.

You should have received a copy of the GNU Lesser 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.
*/

#include "client/renderingengine.h"
#include "clouds.h"
#include "noise.h"
#include "constants.h"
#include "debug.h"
#include "profiler.h"
#include "settings.h"
#include <cmath>


// Menu clouds are created later
class Clouds;
Clouds *g_menuclouds = NULL;
irr::scene::ISceneManager *g_menucloudsmgr = NULL;

// Constant for now
static constexpr const float cloud_size = BS * 64.0f;

static void cloud_3d_setting_changed(const std::string &settingname, void *data)
{
	((Clouds *)data)->readSettings();
}

Clouds::Clouds(scene::ISceneManager* mgr,
		s32 id,
		u32 seed
):
	scene::ISceneNode(mgr->getRootSceneNode(), mgr, id),
	m_seed(seed)
{
	m_material.setFlag(video::EMF_LIGHTING, false);
	//m_material.setFlag(video::EMF_BACK_FACE_CULLING, false);
	m_material.setFlag(video::EMF_BACK_FACE_CULLING, true);
	m_material.setFlag(video::EMF_BILINEAR_FILTER, false);
	m_material.setFlag(video::EMF_FOG_ENABLE, true);
	m_material.setFlag(video::EMF_ANTI_ALIASING, true);
	//m_material.MaterialType = video::EMT_TRANSPARENT_VERTEX_ALPHA;
	m_material.MaterialType = video::EMT_TRANSPARENT_ALPHA_CHANNEL;

	m_params.height        = 120;
	m_params.density       = 0.4f;
	m_params.thickness     = 16.0f;
	m_params.color_bright  = video::SColor(229, 240, 240, 255);
	m_params.color_ambient = video::SColor(255, 0, 0, 0);
	m_params.speed         = v2f(0.0f, -2.0f);

	readSettings();
	g_settings->registerChangedCallback("enable_3d_clouds",
		&cloud_3d_setting_changed, this);

	updateBox();
}

Clouds::~Clouds()
{
	g_settings->deregisterChangedCallback("enable_3d_clouds",
		&cloud_3d_setting_changed, this);
}

void Clouds::OnRegisterSceneNode()
{
	if(IsVisible)
	{
		SceneManager->registerNodeForRendering(this, scene::ESNRP_TRANSPARENT);
		//SceneManager->registerNodeForRendering(this, scene::ESNRP_SOLID);
	}

	ISceneNode::OnRegisterSceneNode();
}

void Clouds::render()
{

	if (m_params.density <= 0.0f)
		return; // no need to do anything

	video::IVideoDriver* driver = SceneManager->getVideoDriver();

	if(SceneManager->getSceneNodeRenderPass() != scene::ESNRP_TRANSPARENT)
	//if(SceneManager->getSceneNodeRenderPass() != scene::ESNRP_SOLID)
		return;

	ScopeProfiler sp(g_profiler, "Clouds::render()", SPT_AVG);

	int num_faces_to_draw = m_enable_3d ? 6 : 1;

	m_material.setFlag(video::EMF_BACK_FACE_CULLING, m_enable_3d);

	driver->setTransform(video::ETS_WORLD, AbsoluteTransformation);
	driver->setMaterial(m_material);

	/*
		Clouds move from Z+ towards Z-
	*/

	const float cloud_full_radius = cloud_size * m_cloud_radius_i;

	v2f camera_pos_2d(m_camera_pos.X, m_camera_pos.Z);
	// Position of cloud noise origin from the camera
	v2f cloud_origin_from_camera_f = m_origin - camera_pos_2d;
	// The center point of drawing in the noise
	v2f center_of_drawing_in_noise_f = -cloud_origin_from_camera_f;
	// The integer center point of drawing in the noise
	v2s16 center_of_drawing_in_noise_i(
		std::floor(center_of_drawing_in_noise_f.X / cloud_size),
		std::floor(center_of_drawing_in_noise_f.Y / cloud_size)
	);

	// The world position of the integer center point of drawing in the noise
	v2f world_center_of_drawing_in_noise_f = v2f(
		center_of_drawing_in_noise_i.X * cloud_size,
		center_of_drawing_in_noise_i.Y * cloud_size
	) + m_origin;

	/*video::SColor c_top(128,b*240,b*240,b*255);
	video::SColor c_side_1(128,b*230,b*230,b*255);
	video::SColor c_side_2(128,b*220,b*220,b*245);
	video::SColor c_bottom(128,b*205,b*205,b*230);*/
	video::SColorf c_top_f(m_color);
	video::SColorf c_side_1_f(m_color);
	video::SColorf c_side_2_f(m_color);
	video::SColorf c_bottom_f(m_color);
	c_side_1_f.r *= 0.95;
	c_side_1_f.g *= 0.95;
	c_side_1_f.b *= 0.95;
	c_side_2_f.r *= 0.90;
	c_side_2_f.g *= 0.90;
	c_side_2_f.b *= 0.90;
	c_bottom_f.r *= 0.80;
	c_bottom_f.g *= 0.80;
	c_bottom_f.b *= 0.80;
	video::SColor c_top = c_top_f.toSColor();
	video::SColor c_side_1 = c_side_1_f.toSColor();
	video::SColor c_side_2 = c_side_2_f.toSColor();
	video::SColor c_bottom = c_bottom_f.toSColor();

	// Get fog parameters for setting them back later
	video::SColor fog_color(0,0,0,0);
	video::E_FOG_TYPE fog_type = video::EFT_FOG_LINEAR;
	f32 fog_start = 0;
	f32 fog_end = 0;
	f32 fog_density = 0;
	bool fog_pixelfog = false;
	bool fog_rangefog = false;
	driver->getFog(fog_color, fog_type, fog_start, fog_end, fog_density,
			fog_pixelfog, fog_rangefog);

	// Set our own fog
	driver->setFog(fog_color, fog_type, cloud_full_radius * 0.5,
			cloud_full_radius*1.2, fog_density, fog_pixelfog, fog_rangefog);

	// Read noise

	std::vector<char> grid(m_cloud_radius_i * 2 * m_cloud_radius_i * 2); // vector<bool> is broken
	std::vector<video::S3DVertex> vertices;
	vertices.reserve(16 * m_cloud_radius_i * m_cloud_radius_i);

	for(s16 zi = -m_cloud_radius_i; zi < m_cloud_radius_i; zi++) {
		u32 si = (zi + m_cloud_radius_i) * m_cloud_radius_i * 2 + m_cloud_radius_i;

		for (s16 xi = -m_cloud_radius_i; xi < m_cloud_radius_i; xi++) {
			u32 i = si + xi;

			grid[i] = gridFilled(
				xi + center_of_drawing_in_noise_i.X,
				zi + center_of_drawing_in_noise_i.Y
			);
		}
	}

#define GETINDEX(x, z, radius) (((z)+(radius))*(radius)*2 + (x)+(radius))
#define INAREA(x, z, radius) \
	((x) >= -(radius) && (x) < (radius) && (z) >= -(radius) && (z) < (radius))

	for (s16 zi0= -m_cloud_radius_i; zi0 < m_cloud_radius_i; zi0++)
	for (s16 xi0= -m_cloud_radius_i; xi0 < m_cloud_radius_i; xi0++)
	{
		s16 zi = zi0;
		s16 xi = xi0;
		// Draw from back to front for proper transparency
		if(zi >= 0)
			zi = m_cloud_radius_i - zi - 1;
		if(xi >= 0)
			xi = m_cloud_radius_i - xi - 1;

		u32 i = GETINDEX(xi, zi, m_cloud_radius_i);

		if (!grid[i])
			continue;

		v2f p0 = v2f(xi,zi)*cloud_size + world_center_of_drawing_in_noise_f;

		video::S3DVertex v[4] = {
			video::S3DVertex(0,0,0, 0,0,0, c_top, 0, 1),
			video::S3DVertex(0,0,0, 0,0,0, c_top, 1, 1),
			video::S3DVertex(0,0,0, 0,0,0, c_top, 1, 0),
			video::S3DVertex(0,0,0, 0,0,0, c_top, 0, 0)
		};

		const f32 rx = cloud_size / 2.0f;
		// if clouds are flat, the top layer should be at the given height
		const f32 ry = m_enable_3d ? m_params.thickness * BS : 0.0f;
		const f32 rz = cloud_size / 2;

		for(int i=0; i<num_faces_to_draw; i++)
		{
			switch(i)
			{
			case 0:	// top
				for (video::S3DVertex &vertex : v) {
					vertex.Normal.set(0,1,0);
				}
				v[0].Pos.set(-rx, ry,-rz);
				v[1].Pos.set(-rx, ry, rz);
				v[2].Pos.set( rx, ry, rz);
				v[3].Pos.set( rx, ry,-rz);
				break;
			case 1: // back
				if (INAREA(xi, zi - 1, m_cloud_radius_i)) {
					u32 j = GETINDEX(xi, zi - 1, m_cloud_radius_i);
					if(grid[j])
						continue;
				}
				for (video::S3DVertex &vertex : v) {
					vertex.Color = c_side_1;
					vertex.Normal.set(0,0,-1);
				}
				v[0].Pos.set(-rx, ry,-rz);
				v[1].Pos.set( rx, ry,-rz);
				v[2].Pos.set( rx,  0,-rz);
				v[3].Pos.set(-rx,  0,-rz);
				break;
			case 2: //right
				if (INAREA(xi + 1, zi, m_cloud_radius_i)) {
					u32 j = GETINDEX(xi+1, zi, m_cloud_radius_i);
					if(grid[j])
						continue;
				}
				for (video::S3DVertex &vertex : v) {
					vertex.Color = c_side_2;
					vertex.Normal.set(1,0,0);
				}
				v[0].Pos.set( rx, ry,-rz);
				v[1].Pos.set( rx, ry, rz);
				v[2].Pos.set( rx,  0, rz);
				v[3].Pos.set( rx,  0,-rz);
				break;
			case 3: // front
				if (INAREA(xi, zi + 1, m_cloud_radius_i)) {
					u32 j = GETINDEX(xi, zi + 1, m_cloud_radius_i);
					if(grid[j])
						continue;
				}
				for (video::S3DVertex &vertex : v) {
					vertex.Color = c_side_1;
					vertex.Normal.set(0,0,-1);
				}
				v[0].Pos.set( rx, ry, rz);
				v[1].Pos.set(-rx, ry, rz);
				v[2].Pos.set(-rx,  0, rz);
				v[3].Pos.set( rx,  0, rz);
				break;
			case 4: // left
				if (INAREA(xi-1, zi, m_cloud_radius_i)) {
					u32 j = GETINDEX(xi-1, zi, m_cloud_radius_i);
					if(grid[j])
						continue;
				}
				for (video::S3DVertex &vertex : v) {
					vertex.Color = c_side_2;
					vertex.Normal.set(-1,0,0);
				}
				v[0].Pos.set(-rx, ry, rz);
				v[1].Pos.set(-rx, ry,-rz);
				v[2].Pos.set(-rx,  0,-rz);
				v[3].Pos.set(-rx,  0, rz);
				break;
			case 5: // bottom
				for (video::S3DVertex &vertex : v) {
					vertex.Color = c_bottom;
					vertex.Normal.set(0,-1,0);
				}
				v[0].Pos.set( rx,  0, rz);
				v[1].Pos.set(-rx,  0, rz);
				v[2].Pos.set(-rx,  0,-rz);
				v[3].Pos.set( rx,  0,-rz);
				break;
			}

			v3f pos(p0.X, m_params.height * BS, p0.Y);
			pos -= intToFloat(m_camera_offset, BS);

			for (video::S3DVertex &vertex : v) {
				vertex.Pos += pos;
				vertices.push_back(vertex);
			}
		}
	}
	int quad_count = vertices.size() / 4;
	std::vector<u16> indices;
	indices.reserve(quad_count * 6);
	for (int k = 0; k < quad_count; k++) {
		indices.push_back(4 * k + 0);
		indices.push_back(4 * k + 1);
		indices.push_back(4 * k + 2);
		indices.push_back(4 * k + 2);
		indices.push_back(4 * k + 3);
		indices.push_back(4 * k + 0);
	}
	driver->drawVertexPrimitiveList(vertices.data(), vertices.size(), indices.data(), 2 * quad_count,
			video::EVT_STANDARD, scene::EPT_TRIANGLES, video::EIT_16BIT);

	// Restore fog settings
	driver->setFog(fog_color, fog_type, fog_start, fog_end, fog_density,
			fog_pixelfog, fog_rangefog);
}

void Clouds::step(float dtime)
{
	m_origin = m_origin + dtime * BS * m_params.speed;
}

void Clouds::update(const v3f &camera_p, const video::SColorf &color_diffuse)
{
	video::SColorf ambient(m_params.color_ambient);
	video::SColorf bright(m_params.color_bright);
	m_camera_pos = camera_p;
	m_color.r = core::clamp(color_diffuse.r * bright.r, ambient.r, 1.0f);
	m_color.g = core::clamp(color_diffuse.g * bright.g, ambient.g, 1.0f);
	m_color.b = core::clamp(color_diffuse.b * bright.b, ambient.b, 1.0f);
	m_color.a = bright.a;

	// is the camera inside the cloud mesh?
	m_camera_inside_cloud = false; // default
	if (m_enable_3d) {
		float camera_height = camera_p.Y;
		if (camera_height >= m_box.MinEdge.Y &&
				camera_height <= m_box.MaxEdge.Y) {
			v2f camera_in_noise;
			camera_in_noise.X = floor((camera_p.X - m_origin.X) / cloud_size + 0.5);
			camera_in_noise.Y = floor((camera_p.Z - m_origin.Y) / cloud_size + 0.5);
			bool filled = gridFilled(camera_in_noise.X, camera_in_noise.Y);
			m_camera_inside_cloud = filled;
		}
	}
}

void Clouds::readSettings()
{
	m_cloud_radius_i = g_settings->getU16("cloud_radius");
	m_enable_3d = g_settings->getBool("enable_3d_clouds");
}

bool Clouds::gridFilled(int x, int y) const
{
	float cloud_size_noise = cloud_size / (BS * 200.f);
	float noise = noise2d_perlin(
			(float)x * cloud_size_noise,
			(float)y * cloud_size_noise,
			m_seed, 3, 0.5);
	// normalize to 0..1 (given 3 octaves)
	static constexpr const float noise_bound = 1.0f + 0.5f + 0.25f;
	float density = noise / noise_bound * 0.5f + 0.5f;
	return (density < m_params.density);
}