#include "dynamic_font.h"
#define STB_TRUETYPE_IMPLEMENTATION
#include "stb_truetype.h"
#include "os/file_access.h"

void DynamicFontData::lock() {

	fr=font_data.read();

	if (fr.ptr()!=last_data_ptr) {

		last_data_ptr=fr.ptr();

		if (!stbtt_InitFont(&info, last_data_ptr, 0)) {
			valid=false;
		} else {
			valid=true;
		}

		last_data_ptr=fr.ptr();
	}
}

void DynamicFontData::unlock() {

	fr = DVector<uint8_t>::Read();
}

void DynamicFontData::set_font_data(const DVector<uint8_t>& p_font) {
	//clear caches and stuff
	ERR_FAIL_COND(font_data.size())	;
	font_data=p_font;

	lock();

	if (valid) {
		stbtt_GetFontVMetrics(&info, &ascent, &descent, &linegap);
		descent=-descent + linegap;

		for(int i=32;i<1024;i++) {
			for(int j=32;j<1024;j++) {

				int kern = stbtt_GetCodepointKernAdvance(&info, i,j);
				if (kern!=0) {
					KerningPairKey kpk;
					kpk.A=i;
					kpk.B=j;
					kerning_map[kpk]=kern;
				}
			}
		}
	}

	unlock();
	//clear existing stuff

	ERR_FAIL_COND(!valid);
}

Ref<DynamicFontAtSize> DynamicFontData::_get_dynamic_font_at_size(int p_size) {

	ERR_FAIL_COND_V(!valid,Ref<DynamicFontAtSize>());

	if (size_cache.has(p_size)) {
		return Ref<DynamicFontAtSize>( size_cache[p_size] );
	}


	Ref<DynamicFontAtSize> dfas;
	dfas.instance();

	dfas->font=Ref<DynamicFontData>( this );

	size_cache[p_size]=dfas.ptr();

	dfas->size=p_size;

	lock();

	dfas->scale = stbtt_ScaleForPixelHeight(&info, p_size);

	unlock();

	return dfas;

}

DynamicFontData::DynamicFontData()
{
	last_data_ptr=NULL;
	valid=false;
}

DynamicFontData::~DynamicFontData()
{

}



////////////////////

float DynamicFontAtSize::get_height() const {

	return (font->ascent+font->descent)*scale;
}

float DynamicFontAtSize::get_ascent() const {

	return font->ascent*scale;
}
float DynamicFontAtSize::get_descent() const {

	return font->descent*scale;
}

Size2 DynamicFontAtSize::get_char_size(CharType p_char,CharType p_next) const {

	const_cast<DynamicFontAtSize*>(this)->_update_char(p_char);

	const Character *c = char_map.getptr(p_char);
	ERR_FAIL_COND_V(!c,Size2());

	Size2 ret( c->advance, get_height());

	if (p_next) {
		DynamicFontData::KerningPairKey kpk;
		kpk.A=p_char;
		kpk.B=p_next;

		const Map<DynamicFontData::KerningPairKey,int>::Element *K=font->kerning_map.find(kpk);
		if (K) {
			ret.x+=K->get()*scale;
		}

	}

	return ret;
}


float DynamicFontAtSize::draw_char(RID p_canvas_item, const Point2& p_pos, const CharType& p_char,const CharType& p_next,const Color& p_modulate) const {

	const_cast<DynamicFontAtSize*>(this)->_update_char(p_char);

	const Character * c = char_map.getptr(p_char);

	if (!c) {
		return 0;
	}

	Point2 cpos=p_pos;
	cpos.x+=c->h_align;
	cpos.y-=get_ascent();
	cpos.y+=c->v_align;
	ERR_FAIL_COND_V( c->texture_idx<-1 || c->texture_idx>=textures.size(),0);
	if (c->texture_idx!=-1)
		VisualServer::get_singleton()->canvas_item_add_texture_rect_region( p_canvas_item, Rect2( cpos, c->rect.size ), textures[c->texture_idx].texture->get_rid(),c->rect, p_modulate );

	//textures[c->texture_idx].texture->draw(p_canvas_item,Vector2());

	float ret = c->advance;
	if (p_next) {
		DynamicFontData::KerningPairKey kpk;
		kpk.A=p_char;
		kpk.B=p_next;

		const Map<DynamicFontData::KerningPairKey,int>::Element *K=font->kerning_map.find(kpk);
		if (K) {
			ret+=K->get()*scale;
		}

	}

	return ret;
}


void DynamicFontAtSize::_update_char(CharType p_char) {

	if (char_map.has(p_char))
		return;

	font->lock();


	int w,h,xofs,yofs;
	unsigned char * cpbitmap = stbtt_GetCodepointBitmap(&font->info, scale, scale, p_char, &w, &h, &xofs, &yofs );

	if (!cpbitmap) {
		//no glyph

		int advance;
		stbtt_GetCodepointHMetrics(&font->info, p_char, &advance, 0);
		//print_line("char has no bitmap: "+itos(p_char)+" but advance is "+itos(advance*scale));
		Character ch;
		ch.texture_idx=-1;
		ch.advance=advance*scale;
		ch.h_align=0;
		ch.v_align=0;

		char_map[p_char]=ch;

		font->unlock();

		return;
	}

	int mw=w+rect_margin*2;
	int mh=h+rect_margin*2;

	if (mw>4096 || mh>4096) {

		stbtt_FreeBitmap(cpbitmap,NULL);
		font->unlock();
		ERR_FAIL_COND(mw>4096);
		ERR_FAIL_COND(mh>4096);
	}

	//find a texture to fit this...

	int tex_index=-1;
	int tex_x=0;
	int tex_y=0;

	for(int i=0;i<textures.size();i++) {

		CharTexture &ct=textures[i];

		if (mw > ct.texture_size || mh > ct.texture_size) //too big for this texture
			continue;

		tex_y=0x7FFFFFFF;
		tex_x=0;

		for(int j=0;j<ct.texture_size-mw;j++) {

			int max_y=0;

			for(int k=j;k<j+mw;k++) {

				int y = ct.offsets[k];
				if (y>max_y)
					max_y=y;
			}

			if (max_y<tex_y) {
				tex_y=max_y;
				tex_x=j;
			}
		}

		if (tex_y==0x7FFFFFFF || tex_y+mh > ct.texture_size)
			continue; //fail, could not fit it here

		tex_index=i;
		break;
	}

//	print_line("CHAR: "+String::chr(p_char)+" TEX INDEX: "+itos(tex_index)+" X: "+itos(tex_x)+" Y: "+itos(tex_y));

	if (tex_index==-1) {
		//could not find texture to fit, create one

		int texsize = MAX(size*8,256);
		if (mw>texsize)
			texsize=mw; //special case, adapt to it?
		if (mh>texsize)
			texsize=mh; //special case, adapt to it?

		texsize=nearest_power_of_2(texsize);

		texsize=MIN(texsize,4096);


		CharTexture tex;
		tex.texture_size=texsize;
		tex.imgdata.resize(texsize*texsize*2); //grayscale alpha

		{
			//zero texture
			DVector<uint8_t>::Write w = tex.imgdata.write();
			for(int i=0;i<texsize*texsize*2;i++) {
				w[i]=0;
			}
		}
		tex.offsets.resize(texsize);
		for(int i=0;i<texsize;i++) //zero offsets
			tex.offsets[i]=0;

		textures.push_back(tex);
		tex_index=textures.size()-1;

	}


	//fit character in char texture

	CharTexture &tex=textures[tex_index];

	{
		DVector<uint8_t>::Write wr = tex.imgdata.write();

		for(int i=0;i<h;i++) {
			for(int j=0;j<w;j++) {

				int ofs = ( (i+tex_y+rect_margin)*tex.texture_size+j+tex_x+rect_margin)*2;
				wr[ofs+0]=255; //grayscale as 1
				wr[ofs+1]=cpbitmap[i*w+j]; //alpha as 0
			}
		}
	}

	//blit to image and texture
	{

		Image img(tex.texture_size,tex.texture_size,0,Image::FORMAT_GRAYSCALE_ALPHA,tex.imgdata);

		if (tex.texture.is_null()) {
			tex.texture.instance();
			tex.texture->create_from_image(img,Texture::FLAG_FILTER);
		} else {
			tex.texture->set_data(img); //update
		}

	}


	// update height array

	for(int k=tex_x;k<tex_x+mw;k++) {

		tex.offsets[k]=tex_y+mh;
	}

	int advance;
	stbtt_GetCodepointHMetrics(&font->info, p_char, &advance, 0);

	Character chr;
	chr.h_align=xofs;
	chr.v_align=yofs + get_ascent();
	chr.advance=advance*scale;
	chr.texture_idx=tex_index;


	chr.rect=Rect2(tex_x+rect_margin,tex_y+rect_margin,w,h);

	//print_line("CHAR: "+String::chr(p_char)+" TEX INDEX: "+itos(tex_index)+" RECT: "+chr.rect+" X OFS: "+itos(xofs)+" Y OFS: "+itos(yofs));

	char_map[p_char]=chr;

	stbtt_FreeBitmap(cpbitmap,NULL);

	font->unlock();

}

DynamicFontAtSize::DynamicFontAtSize() {

	rect_margin=1;
}

DynamicFontAtSize::~DynamicFontAtSize(){

	ERR_FAIL_COND(!font.ptr());
	font->size_cache.erase(size);
}

/////////////////////////


void DynamicFont::_bind_methods() {

	ObjectTypeDB::bind_method(_MD("set_font_data","data:DynamicFontData"),&DynamicFont::set_font_data);
	ObjectTypeDB::bind_method(_MD("get_font_data:DynamicFontData"),&DynamicFont::get_font_data);

	ObjectTypeDB::bind_method(_MD("set_size","data"),&DynamicFont::set_size);
	ObjectTypeDB::bind_method(_MD("get_size"),&DynamicFont::get_size);

	ADD_PROPERTY(PropertyInfo(Variant::INT,"size"),_SCS("set_size"),_SCS("get_size"));
	ADD_PROPERTY(PropertyInfo(Variant::OBJECT,"font",PROPERTY_HINT_RESOURCE_TYPE,"DynamicFontData"),_SCS("set_font_data"),_SCS("get_font_data"));
}


void DynamicFont::set_font_data(const Ref<DynamicFontData>& p_data) {

	data=p_data;
	data_at_size=data->_get_dynamic_font_at_size(size);
}

Ref<DynamicFontData> DynamicFont::get_font_data() const{

	return data;
}

void DynamicFont::set_size(int p_size){

	if (size==p_size)
		return;
	size=p_size;
	ERR_FAIL_COND(p_size<1);
	if (!data.is_valid())
		return;
	data_at_size=data->_get_dynamic_font_at_size(size);

}
int DynamicFont::get_size() const{

	return size;
}

float DynamicFont::get_height() const{

	if (!data_at_size.is_valid())
		return 1;

	return data_at_size->get_height();
}

float DynamicFont::get_ascent() const{

	if (!data_at_size.is_valid())
		return 1;

	return data_at_size->get_ascent();
}

float DynamicFont::get_descent() const{

	if (!data_at_size.is_valid())
		return 1;

	return data_at_size->get_descent();

}

Size2 DynamicFont::get_char_size(CharType p_char,CharType p_next) const{

	if (!data_at_size.is_valid())
		return Size2(1,1);

	return data_at_size->get_char_size(p_char,p_next);

}

bool DynamicFont::is_distance_field_hint() const{

	return false;
}

float DynamicFont::draw_char(RID p_canvas_item, const Point2& p_pos, const CharType& p_char,const CharType& p_next,const Color& p_modulate) const {

	if (!data_at_size.is_valid())
		return 0;

	return data_at_size->draw_char(p_canvas_item,p_pos,p_char,p_next,p_modulate);

}

DynamicFont::DynamicFont() {

	size=16;
}

DynamicFont::~DynamicFont() {

}

/////////////////////////


RES ResourceFormatLoaderDynamicFont::load(const String &p_path, const String& p_original_path, Error *r_error) {

	if (r_error)
		*r_error=ERR_FILE_CANT_OPEN;


	FileAccess *f = FileAccess::open(p_path,FileAccess::READ);
	ERR_FAIL_COND_V(!f,RES());

	DVector<uint8_t> data;

	data.resize(f->get_len());

	ERR_FAIL_COND_V(data.size()==0,RES());

	{
		DVector<uint8_t>::Write w = data.write();
		f->get_buffer(w.ptr(),data.size());
	}

	Ref<DynamicFontData> dfd;
	dfd.instance();
	dfd->set_font_data(data);

	if (r_error)
		*r_error=OK;

	return dfd;
}

void ResourceFormatLoaderDynamicFont::get_recognized_extensions(List<String> *p_extensions) const {

	p_extensions->push_back("ttf");
}

bool ResourceFormatLoaderDynamicFont::handles_type(const String& p_type) const {

	return (p_type=="DynamicFontData");
}

String ResourceFormatLoaderDynamicFont::get_resource_type(const String &p_path) const {

	String el = p_path.extension().to_lower();
	if (el=="ttf")
		return "DynamicFontData";
	return "";
}