/*
* ***** BEGIN GPL LICENSE BLOCK *****
 *
 * 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) 2009 Blender Foundation.
 * All rights reserved.
 * 
 * Contributor(s): Blender Foundation
 *
 * ***** END GPL LICENSE BLOCK *****
 */

/** \file blender/editors/interface/interface_style.c
 *  \ingroup edinterface
 */


#include <limits.h>
#include <math.h>
#include <stdlib.h>
#include <string.h>

#include "MEM_guardedalloc.h"

#include "DNA_screen_types.h"
#include "DNA_userdef_types.h"

#include "BLI_math.h"
#include "BLI_listbase.h"
#include "BLI_rect.h"
#include "BLI_string.h"

#include "BKE_global.h"


#include "BLF_api.h"

#include "UI_interface.h"

#include "ED_datafiles.h"

#include "interface_intern.h"


/* style + theme + layout-engine = UI */

/* 
 This is a complete set of layout rules, the 'state' of the Layout 
 Engine. Multiple styles are possible, defined via C or Python. Styles 
 get a name, and will typically get activated per region type, like 
 "Header", or "Listview" or "Toolbar". Properties of Style definitions 
 are:
 
 - default collumn properties, internal spacing, aligning, min/max width
 - button alignment rules (for groups)
 - label placement rules
 - internal labeling or external labeling default
 - default minimum widths for buttons/labels (in amount of characters)
 - font types, styles and relative sizes for Panel titles, labels, etc.

*/


/* ********************************************** */

static uiStyle *ui_style_new(ListBase *styles, const char *name)
{
	uiStyle *style= MEM_callocN(sizeof(uiStyle), "new style");
	
	BLI_addtail(styles, style);
	BLI_strncpy(style->name, name, MAX_STYLE_NAME);
	
	style->panelzoom= 1.0;

	style->paneltitle.uifont_id= UIFONT_DEFAULT;
	style->paneltitle.points= 12;
	style->paneltitle.kerning= 1;
	style->paneltitle.shadow= 1;
	style->paneltitle.shadx= 0;
	style->paneltitle.shady= -1;
	style->paneltitle.shadowalpha= 0.15f;
	style->paneltitle.shadowcolor= 1.0f;
	
	style->grouplabel.uifont_id= UIFONT_DEFAULT;
	style->grouplabel.points= 12;
	style->grouplabel.kerning= 1;
	style->grouplabel.shadow= 3;
	style->grouplabel.shadx= 0;
	style->grouplabel.shady= -1;
	style->grouplabel.shadowalpha= 0.25f;
	
	style->widgetlabel.uifont_id= UIFONT_DEFAULT;
	style->widgetlabel.points= 11;
	style->widgetlabel.kerning= 1;
	style->widgetlabel.shadow= 3;
	style->widgetlabel.shadx= 0;
	style->widgetlabel.shady= -1;
	style->widgetlabel.shadowalpha= 0.15f;
	style->widgetlabel.shadowcolor= 1.0f;
	
	style->widget.uifont_id= UIFONT_DEFAULT;
	style->widget.points= 11;
	style->widget.kerning= 1;
	style->widget.shadowalpha= 0.25f;

	style->columnspace= 8;
	style->templatespace= 5;
	style->boxspace= 5;
	style->buttonspacex= 8;
	style->buttonspacey= 2;
	style->panelspace= 8;
	style->panelouter= 4;
	
	return style;
}

static uiFont *uifont_to_blfont(int id)
{
	uiFont *font= U.uifonts.first;
	
	for(; font; font= font->next) {
		if(font->uifont_id==id) {
			return font;
		}
	}
	return U.uifonts.first;
}

/* *************** draw ************************ */


void uiStyleFontDrawExt(uiFontStyle *fs, rcti *rect, const char *str,
	float *r_xofs, float *r_yofs)
{
	float height;
	int xofs=0, yofs;
	
	uiStyleFontSet(fs);
	
	height= BLF_height(fs->uifont_id, "2"); /* correct offset is on baseline, the j is below that */
	yofs= floor( 0.5f*(rect->ymax - rect->ymin - height));

	if(fs->align==UI_STYLE_TEXT_CENTER) {
		xofs= floor( 0.5f*(rect->xmax - rect->xmin - BLF_width(fs->uifont_id, str)));
		/* don't center text if it chops off the start of the text, 2 gives some margin */
		if(xofs < 2) {
			xofs= 2;
		}
	}
	else if(fs->align==UI_STYLE_TEXT_RIGHT) {
		xofs= rect->xmax - rect->xmin - BLF_width(fs->uifont_id, str) - 1;
	}
	
	/* clip is very strict, so we give it some space */
	BLF_clipping(fs->uifont_id, rect->xmin-1, rect->ymin-4, rect->xmax+1, rect->ymax+4);
	BLF_enable(fs->uifont_id, BLF_CLIPPING);
	BLF_position(fs->uifont_id, rect->xmin+xofs, rect->ymin+yofs, 0.0f);

	if (fs->shadow) {
		BLF_enable(fs->uifont_id, BLF_SHADOW);
		BLF_shadow(fs->uifont_id, fs->shadow, fs->shadowcolor, fs->shadowcolor, fs->shadowcolor, fs->shadowalpha);
		BLF_shadow_offset(fs->uifont_id, fs->shadx, fs->shady);
	}

	if (fs->kerning == 1)
		BLF_enable(fs->uifont_id, BLF_KERNING_DEFAULT);

	BLF_draw(fs->uifont_id, str, 65535); /* XXX, use real length */
	BLF_disable(fs->uifont_id, BLF_CLIPPING);
	if (fs->shadow)
		BLF_disable(fs->uifont_id, BLF_SHADOW);
	if (fs->kerning == 1)
		BLF_disable(fs->uifont_id, BLF_KERNING_DEFAULT);

	*r_xofs= xofs;
	*r_yofs= yofs;
}

void uiStyleFontDraw(uiFontStyle *fs, rcti *rect, const char *str)
{
	float xofs, yofs;
	uiStyleFontDrawExt(fs, rect, str,
		&xofs, &yofs);
}

/* drawn same as above, but at 90 degree angle */
void uiStyleFontDrawRotated(uiFontStyle *fs, rcti *rect, const char *str)
{
	float height;
	int xofs, yofs;
	float angle;
	rcti txtrect;

	uiStyleFontSet(fs);

	height= BLF_height(fs->uifont_id, "2");	/* correct offset is on baseline, the j is below that */
	/* becomes x-offset when rotated */
	xofs= floor( 0.5f*(rect->ymax - rect->ymin - height)) + 1;

	/* ignore UI_STYLE, always aligned to top */

	/* rotate counter-clockwise for now (assumes left-to-right language)*/
	xofs+= height;
	yofs= BLF_width(fs->uifont_id, str) + 5;
	angle= 90.0f;

	/* translate rect to vertical */
	txtrect.xmin= rect->xmin - (rect->ymax - rect->ymin);
	txtrect.ymin= rect->ymin - (rect->xmax - rect->xmin);
	txtrect.xmax= rect->xmin;
	txtrect.ymax= rect->ymin;

	/* clip is very strict, so we give it some space */
	/* clipping is done without rotation, so make rect big enough to contain both positions */
	BLF_clipping(fs->uifont_id, txtrect.xmin-1, txtrect.ymin-yofs-xofs-4, rect->xmax+1, rect->ymax+4);
	BLF_enable(fs->uifont_id, BLF_CLIPPING);
	BLF_position(fs->uifont_id, txtrect.xmin+xofs, txtrect.ymax-yofs, 0.0f);

	BLF_enable(fs->uifont_id, BLF_ROTATION);
	BLF_rotation(fs->uifont_id, angle);

	if (fs->shadow) {
		BLF_enable(fs->uifont_id, BLF_SHADOW);
		BLF_shadow(fs->uifont_id, fs->shadow, fs->shadowcolor, fs->shadowcolor, fs->shadowcolor, fs->shadowalpha);
		BLF_shadow_offset(fs->uifont_id, fs->shadx, fs->shady);
	}

	if (fs->kerning == 1)
		BLF_enable(fs->uifont_id, BLF_KERNING_DEFAULT);

	BLF_draw(fs->uifont_id, str, 65535); /* XXX, use real length */
	BLF_disable(fs->uifont_id, BLF_ROTATION);
	BLF_disable(fs->uifont_id, BLF_CLIPPING);
	if (fs->shadow)
		BLF_disable(fs->uifont_id, BLF_SHADOW);
	if (fs->kerning == 1)
		BLF_disable(fs->uifont_id, BLF_KERNING_DEFAULT);
}

/* ************** helpers ************************ */

/* temporarily, does widget font */
int UI_GetStringWidth(const char *str)
{
	uiStyle *style= U.uistyles.first;
	uiFontStyle *fstyle= &style->widget;
	int width;
	
	if (fstyle->kerning==1)	/* for BLF_width */
		BLF_enable(fstyle->uifont_id, BLF_KERNING_DEFAULT);
	
	uiStyleFontSet(fstyle);
	width= BLF_width(fstyle->uifont_id, str);	
	
	if (fstyle->kerning==1)
		BLF_disable(fstyle->uifont_id, BLF_KERNING_DEFAULT);
	
	return width;
}

/* temporarily, does widget font */
void UI_DrawString(float x, float y, const char *str)
{
	uiStyle *style= U.uistyles.first;
	
	if (style->widget.kerning == 1)
		BLF_enable(style->widget.uifont_id, BLF_KERNING_DEFAULT);

	uiStyleFontSet(&style->widget);
	BLF_position(style->widget.uifont_id, x, y, 0.0f);
	BLF_draw(style->widget.uifont_id, str, 65535); /* XXX, use real length */

	if (style->widget.kerning == 1)
		BLF_disable(style->widget.uifont_id, BLF_KERNING_DEFAULT);
}

/* ************** init exit ************************ */

/* called on each startup.blend read */
/* reading without uifont will create one */
void uiStyleInit(void)
{
	uiFont *font= U.uifonts.first;
	uiStyle *style= U.uistyles.first;
	
	/* recover from uninitialized dpi */
	if(U.dpi == 0)
		U.dpi= 72;
	CLAMP(U.dpi, 48, 128);
	
	/* default builtin */
	if(font==NULL) {
		font= MEM_callocN(sizeof(uiFont), "ui font");
		BLI_addtail(&U.uifonts, font);
		
		strcpy(font->filename, "default");
		font->uifont_id= UIFONT_DEFAULT;
	}
	
	for(font= U.uifonts.first; font; font= font->next) {
		
		if(font->uifont_id==UIFONT_DEFAULT) {
			font->blf_id= BLF_load_mem("default", (unsigned char*)datatoc_bfont_ttf, datatoc_bfont_ttf_size);
		}		
		else {
			font->blf_id= BLF_load(font->filename);
			if(font->blf_id == -1)
				font->blf_id= BLF_load_mem("default", (unsigned char*)datatoc_bfont_ttf, datatoc_bfont_ttf_size);
		}

		if (font->blf_id == -1) {
			if (G.f & G_DEBUG)
				printf("uiStyleInit error, no fonts available\n");
		}
		else {
			/* ? just for speed to initialize?
			 * Yes, this build the glyph cache and create
			 * the texture.
			 */
			BLF_size(font->blf_id, 11, U.dpi);
			BLF_size(font->blf_id, 12, U.dpi);
			BLF_size(font->blf_id, 14, U.dpi);
		}
	}
	
	if(style==NULL) {
		ui_style_new(&U.uistyles, "Default Style");
	}
	
	// XXX, this should be moved into a style, but for now best only load the monospaced font once.
	if (blf_mono_font == -1)
		blf_mono_font= BLF_load_mem_unique("monospace", (unsigned char *)datatoc_bmonofont_ttf, datatoc_bmonofont_ttf_size);

	BLF_size(blf_mono_font, 12, 72);
	
	/* second for rendering else we get threading problems */
	if (blf_mono_font_render == -1)
		blf_mono_font_render= BLF_load_mem_unique("monospace", (unsigned char *)datatoc_bmonofont_ttf, datatoc_bmonofont_ttf_size);

	BLF_size(blf_mono_font_render, 12, 72);
}

void uiStyleFontSet(uiFontStyle *fs)
{
	uiFont *font= uifont_to_blfont(fs->uifont_id);
	
	BLF_size(font->blf_id, fs->points, U.dpi);
}