// Copyright (C) 2012-2014 ChaosForge Ltd
// http://chaosforge.org/
//
// This file is part of NV Libraries.
// For conditions of distribution and use, see copyright notice in nv.hh

#include "nv/gui/gui_renderer.hh"

#include <glm/gtc/matrix_transform.hpp>

#include "nv/interface/device.hh"
#include "nv/interface/context.hh"
#include "nv/core/logging.hh"

static const char *nv_gui_vertex_shader = R"(
#version 120
attribute vec2 nv_position;
attribute vec2 nv_texcoord;
attribute vec4 nv_color;
varying vec4 v_color;
varying vec2 v_texcoord;
uniform mat4 nv_m_projection;
void main(void)
{
	gl_Position = nv_m_projection * vec4(nv_position.x, nv_position.y, 0.0, 1.0);
	v_texcoord  = nv_texcoord;
	v_color     = nv_color;
}
)";

static const char *nv_gui_fragment_shader = R"(
#version 120
varying vec4 v_color;
varying vec2 v_texcoord;
uniform sampler2D nv_t_diffuse;
void main(void)
{
	vec4 tex_color = texture2D( nv_t_diffuse, v_texcoord );
	gl_FragColor   = v_color * tex_color;
}
)";


using namespace nv;
using namespace nv::gui;

struct vertex
{
	ivec2 position;
	vec2  texcoord;
	vec4  color;
	vertex() {}
	vertex( const nv::ivec2& cr, const nv::vec2& tc, const nv::vec4& c )
		: position( cr ), texcoord( tc ), color( c )
	{
	}
};

const ivec2 atlas_size = ivec2( 1024, 1024 );

struct gui_quad
{
	vertex vtx[6];
	gui_quad( const nv::ivec2& coorda, const nv::ivec2& coordb, const nv::vec4& color )
	{
		set_color( color );
		vtx[0].position = coorda;
		vtx[1].position = nv::ivec2( coorda.x, coordb.y );
		vtx[2].position = coordb;
		vtx[3].position = coordb;
		vtx[4].position = nv::ivec2( coordb.x, coorda.y );
		vtx[5].position = coorda;
	}
	gui_quad( const nv::ivec2& coorda, const nv::ivec2& coordb, const nv::vec4& color, const nv::vec2& tcoorda, const nv::vec2& tcoordb )
	{
		set_color( color );
		vtx[0].position = coorda;
		vtx[1].position = nv::ivec2( coorda.x, coordb.y );
		vtx[2].position = coordb;
		vtx[3].position = coordb;
		vtx[4].position = nv::ivec2( coordb.x, coorda.y );
		vtx[5].position = coorda;
		vtx[0].texcoord = tcoorda;
		vtx[1].texcoord = nv::vec2( tcoorda.x, tcoordb.y );
		vtx[2].texcoord = tcoordb;
		vtx[3].texcoord = tcoordb;
		vtx[4].texcoord = nv::vec2( tcoordb.x, tcoorda.y );
		vtx[5].texcoord = tcoorda;
	}
	gui_quad( const nv::ivec2& coorda, const nv::ivec2& coordb, const nv::ivec2& coordc, const nv::ivec2& coordd, const nv::vec4& color )
	{
		set_color( color );
		vtx[0].position = coorda;
		vtx[1].position = coordb;
		vtx[2].position = coordc;
		vtx[3].position = coordc;
		vtx[4].position = coordd;
		vtx[5].position = coorda;
	}
	inline void set_color( const nv::vec4& color )
	{
		vtx[0].color = color; vtx[1].color = color;	vtx[2].color = color;
		vtx[3].color = color; vtx[4].color = color;	vtx[5].color = color;
	}
};


class screen_render_data : public render_data
{
public:
	screen_render_data( context* actx, size_t initial_size )
		: buffer( actx, VERTEX_BUFFER, DYNAMIC_DRAW, initial_size ), ctx( actx ), varray(), shader()
	{

	}
	~screen_render_data() 
	{ 
		ctx->get_device()->release( shader ); 
		ctx->release( varray ); 
	}

	nv::sliced_buffer<gui_quad> buffer;
	nv::context*      ctx;
	nv::texture       tex;
	nv::vertex_array  varray;
	nv::program       shader;
};

class element_render_data : public render_data
{
public:
	element_render_data( nv::sliced_buffer<gui_quad>* cbuffer )
		: buffer( cbuffer ) {}

	nv::buffer_slice< gui_quad > buffer;
};

renderer::renderer( window* w )
	: m_window(w)
	, m_style()
	, m_atlas( atlas_size, 4 )
	, m_reupload( true )
{
	NV_LOG( LOG_TRACE, "Creating GUI renderer..." );
	m_context = w->get_context();
	m_area.dim( dimension( w->get_width(), w->get_height() ) );
	region white = m_atlas.get_region( ivec2(3,3) );
	size_t wsize = m_atlas.get_depth()*4*4;
	uint8* wfill = new uint8[m_atlas.get_depth()*4*4];
	std::fill( wfill, wfill + wsize, 255 );
	white.pos = ivec2();
	m_atlas.set_region( white, wfill );
	delete[] wfill;

	NV_LOG( LOG_TRACE, "Creating render data..." );
	screen_render_data* sr = new screen_render_data( w->get_context(), 1024 );
	m_render_data = sr;
	sr->shader     = m_window->get_device()->create_program( nv_gui_vertex_shader, nv_gui_fragment_shader );
	m_scene_state.get_camera().set_ortho( 0.0f, float( m_window->get_width() ), float( m_window->get_height() ), 0.0f );

	sr->varray     = m_window->get_context()->create_vertex_array();
	buffer vb      = sr->buffer.get_buffer();
	m_window->get_context()->add_vertex_buffers< vertex >( sr->varray, vb );

	nv::sampler sampler( nv::sampler::LINEAR, nv::sampler::CLAMP_TO_EDGE );
	sr->tex = m_window->get_device()->create_texture( m_atlas.get_size(), image_format( nv::RGBA, nv::UBYTE ), sampler, nullptr );

	m_render_state.depth_test.enabled = false;
	m_render_state.culling.enabled    = false;
	m_render_state.blending.enabled   = true;
	m_render_state.blending.src_rgb_factor   = blending::SRC_ALPHA;
	m_render_state.blending.dst_rgb_factor   = blending::ONE_MINUS_SRC_ALPHA;
	m_render_state.blending.src_alpha_factor = blending::SRC_ALPHA;
	m_render_state.blending.dst_alpha_factor = blending::ONE_MINUS_SRC_ALPHA;
	NV_LOG( LOG_TRACE, "GUI Renderer created" );
}

texture_font* renderer::get_font( size_t name ) const
{
	if ( name >= m_fonts.size() ) return nullptr;
	return m_fonts[ name ];
}

const image_info* renderer::get_image( size_t name ) const
{
	if ( name >= m_images.size() ) return nullptr;
	return &m_images[ name ];
}

size_t renderer::load_font( const std::string& filename, size_t size )
{
	std::string id_name( filename );
	id_name.append( to_string( size ) );
	auto i = m_font_names.find( id_name );
	if ( i != m_font_names.end() )
	{
		return i->second;
	}
	size_t result = (size_t)m_fonts.size();
	texture_font* f = new texture_font( &m_atlas, filename.c_str(), (float)size );
	f->load_glyphs( "!\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~ " );
	m_fonts.push_back( f );
	m_reupload = true;
	m_font_names[ id_name ] = result;
	return result;
}

size_t renderer::load_image( const std::string& filename )
{
	auto i = m_image_names.find( filename );
	if ( i != m_image_names.end() )
	{
		return i->second;
	}
	size_t result = m_images.size();
	image_data* data = m_window->get_device()->create_image_data( filename );
	// TODO: Repitching
	assert( data->get_depth() == 4 );
	region r = m_atlas.get_region( data->get_size() );
	m_atlas.set_region( r, data->get_data() );
	m_images.emplace_back( vec2( r.pos ) / vec2( atlas_size ), vec2( r.size + r.pos ) / vec2( atlas_size ), r.size );
	delete data;
	m_reupload = true;
	m_image_names[ filename ] = result;
	return result;
}

void renderer::load_style( const std::string& filename )
{
	m_style.load_style( filename );
}

void renderer::redraw( element* e, uint32 )
{
	screen_render_data* sr = (screen_render_data*)m_render_data;
	if ( e->m_render_data == nullptr )
	{
		e->m_render_data = new element_render_data( &sr->buffer );
	}
	element_render_data* er = (element_render_data*)(e->m_render_data);
	size_t size_before = er->buffer.data().size();

	std::vector< gui_quad >& qvec = er->buffer.lock();

	qvec.clear();
	rectangle abs = e->m_absolute;
	if ( e->m_absolute != m_area )
	{
		int border = 0;
		vec4 color;
		std::string path;
		std::string text;
		const char* stext[] = { nullptr, "selected", "hover" };
		const char* selector = stext[border];
		if ( e->m_flags[HOVER] )    selector = stext[2];
		if ( e->m_flags[SELECTED] ) selector = stext[1];

		if ( m_style.get( e, "skin", selector, path ) )
		{
			size_t image_id = load_image( path );
			const image_info* image  = get_image( image_id );
			if ( image )
			{
				color = vec4( 2, 2, 2, 1 );
				ivec2 isize3  = image->size / 3;
				ivec2 isize3x = ivec2( isize3.x, 0 );
				ivec2 isize3y = ivec2( 0, isize3.y );
				vec2 tsize    = ( image->t2 - image->t1 );
				vec2 tsize3   = ( image->t2 - image->t1 ) / 3.0f;
				vec2 tsize32  = ( image->t2 - image->t1 ) * ( 2.0f / 3.0f );
				vec2 tsizex   = vec2( tsize.x, 0.0f );
				vec2 tsizey   = vec2( 0.0f, tsize.y );
				vec2 tsize3x  = vec2( tsize3.x, 0.0f );
				vec2 tsize3y  = vec2( 0.0f, tsize3.y );
				vec2 tsize3x2 = vec2( tsize32.x, 0.0f );
				vec2 tsize3y2 = vec2( 0.0f, tsize32.y );

				rectangle inner = abs.shrinked( isize3 );
				qvec.emplace_back( abs.ul, inner.ul, color, image->t1, image->t1+tsize3 );
				qvec.emplace_back( abs.ul+isize3x, inner.ur(), color, image->t1+tsize3x, image->t1+tsize3x2+tsize3y);
				qvec.emplace_back( abs.ur()-isize3x, inner.ur()+isize3x, color, image->t1+tsize3x2, image->t1+tsizex+tsize3y );

				qvec.emplace_back( abs.ul+isize3y, inner.ll(), color, image->t1+tsize3y, image->t1+tsize3y2+tsize3x );
				qvec.emplace_back( inner.ul, inner.lr, color, image->t1+tsize3, image->t1+tsize32 );
				qvec.emplace_back( inner.ur(), inner.lr+isize3x, color, image->t1+tsize3+tsize3x, image->t1+tsize32+tsize3x );


				qvec.emplace_back( abs.ll()-isize3y, inner.ll()+isize3y, color, image->t1+tsize3y2, image->t1+tsize3y2+tsize3 );
				qvec.emplace_back( inner.ll(), abs.lr-isize3x, color, image->t1+tsize3y2+tsize3x, image->t1+tsize32+tsize3y );
				qvec.emplace_back( inner.lr, abs.lr, color, image->t1+tsize32, image->t1+tsize );

	
// 				qvec.emplace_back( abs.ul, abs.ll(), inner.ll(), inner.ul, color );
// 				qvec.emplace_back( inner.ur(), inner.lr, abs.lr, abs.ur(), color );
// 				qvec.emplace_back( inner.ll(), abs.ll(), abs.lr, inner.lr, color );
				abs = inner;

			}

		}
		else
		{

			if ( m_style.get( e, "border", selector, border ) && m_style.get( e, "border_color", selector, color ) )
			{
				rectangle inner = abs.shrinked( border );
				qvec.emplace_back( abs.ul, inner.ul, inner.ur(), abs.ur(), color );
				qvec.emplace_back( abs.ul, abs.ll(), inner.ll(), inner.ul, color );
				qvec.emplace_back( inner.ur(), inner.lr, abs.lr, abs.ur(), color );
				qvec.emplace_back( inner.ll(), abs.ll(), abs.lr, inner.lr, color );
				abs = inner;
			}

			if ( m_style.get( e, "background_color", selector, color ) )
			{
				qvec.emplace_back( abs.ul, abs.lr, color );
			}
		}

		text = e->m_text;
		if ( !text.empty() )
		{
			if ( m_style.get( e, "text_color", selector, color ) && m_style.get( e, "text_font", selector, path ) && m_style.get( e, "text_size", selector, border ) )
			{
				size_t font_id = load_font( path, (uint16)border );
				texture_font* font = get_font( font_id );
				position p = abs.ul + position( 0, border );
				for ( char c : text )
				{
					const texture_glyph* g = font->get_glyph( static_cast<uint16>(c) );
					if (g)
					{
						position gp = position( g->offset.x, -g->offset.y );
						position p2 = p + g->size + gp;
						qvec.emplace_back( p + gp, p2, color, g->tl, g->br );
						p += g->advance;
					}
				}
			}
		}
	}

	if ( size_before != er->buffer.data().size() )
	{
		sr->buffer.reset();
	}
}

void renderer::on_hover_change( element* e, bool hover )
{
	// TODO: FIX
	NV_LOG( nv::LOG_DEBUG, "on_hover_change" );
	e->m_flags[DIRTY] = true;
}

void renderer::on_select_change( element* e, bool select )
{
	// TODO: FIX
	NV_LOG( nv::LOG_DEBUG, "on_select_change" );
	e->m_flags[DIRTY] = true;
}


void renderer::draw( element* e )
{
	element_render_data* er = (element_render_data*)(e->m_render_data);
	er->buffer.commit();
}

void renderer::draw()
{
	screen_render_data* sr = (screen_render_data*)m_render_data;

	if ( m_reupload )
	{
		m_context->update( sr->tex, (void*)m_atlas.get_data() );
		m_reupload = false;
	}

	if ( sr->buffer.commit() )
	{
		buffer vb = sr->buffer.get_buffer();
		m_context->replace_vertex_buffer( sr->varray, vb, false );
	}
	m_context->bind( sr->tex, TEX_DIFFUSE );
	m_context->draw( TRIANGLES, m_render_state, m_scene_state, sr->shader, sr->varray, sr->buffer.get_size() * 6 );
}

renderer::~renderer()
{
	for ( auto p : m_fonts )
	{
		delete p;
	}
	if ( m_render_data )
	{
		m_context->get_device()->release( ((screen_render_data*)m_render_data)->tex );
		delete m_render_data;
	}
}