/*
 * Rich text with images.
 * Should there be an offset field, to do subscripts & kerning?
 */
#include <u.h>
#include <libc.h>
#include <draw.h>
#include <event.h>
#include <panel.h>
#include "pldefs.h"
#include "rtext.h"
#define	LEAD	4		/* extra space between lines */
Rtext *pl_rtnew(Rtext **t, int space, int indent, Image *b, Panel *p, Font *f, char *s, int hot, void *user){
	Rtext *new;
	new=malloc(sizeof(Rtext));
	if(new==0) return 0;
	new->hot=hot;
	new->user=user;
	new->space=space;
	new->indent=indent;
	new->b=b;
	new->p=p;
	new->font=f;
	new->text=s;
	new->next=0;
	new->r=Rect(0,0,0,0);
	if(*t)
		(*t)->last->next=new;
	else
		*t=new;
	(*t)->last=new;
	return new;
}
Rtext *plrtpanel(Rtext **t, int space, int indent, Panel *p, void *user){
	return pl_rtnew(t, space, indent, 0, p, 0, 0, 1, user);
}
Rtext *plrtstr(Rtext **t, int space, int indent, Font *f, char *s, int hot, void *user){
	return pl_rtnew(t, space, indent, 0, 0, f, s, hot, user);
}
Rtext *plrtbitmap(Rtext **t, int space, int indent, Image *b, int hot, void *user){
	return pl_rtnew(t, space, indent, b, 0, 0, 0, hot, user);
}
void plrtfree(Rtext *t){
	Rtext *next;
	while(t){
		next=t->next;
		free(t);
		t=next;
	}
}
int pl_tabmin, pl_tabsize;
void pltabsize(int min, int size){
	pl_tabmin=min;
	pl_tabsize=size;
}
int pl_space(int space, int pos, int indent){
	if(space>=0) return space;
	switch(PL_OP(space)){
	default:
		return 0;
	case PL_TAB:
		return ((pos-indent+pl_tabmin)/pl_tabsize+PL_ARG(space))*pl_tabsize+indent-pos;
	}
}
/*
 * initialize rectangles & nextlines of text starting at t,
 * galley width is wid.  Returns the total length of the text
 */
int pl_rtfmt(Rtext *t, int wid){
	Rtext *tp, *eline;
	int ascent, descent, x, space, a, d, w, topy, indent;
	Point p;
	p=Pt(0,0);
	eline=t;
	while(t){
		ascent=0;
		descent=0;
		indent=space=pl_space(t->indent, 0, 0);
		x=0;
		tp=t;
		for(;;){
			if(tp->b){
				a=tp->b->r.max.y-tp->b->r.min.y+2;
				d=0;
				w=tp->b->r.max.x-tp->b->r.min.x+4;
			}
			else if(tp->p){
				/* what if plpack fails? */
				plpack(tp->p, Rect(0,0,wid,wid));
				plmove(tp->p, subpt(Pt(0,0), tp->p->r.min));
				a=tp->p->r.max.y-tp->p->r.min.y;
				d=0;
				w=tp->p->r.max.x-tp->p->r.min.x;
			}
			else{
				a=tp->font->ascent;
				d=tp->font->height-a;
				w=tp->wid=stringwidth(tp->font, tp->text);
			}
			if(x+w+space>wid) break;
			if(a>ascent) ascent=a;
			if(d>descent) descent=d;
			x+=w+space;
			tp=tp->next;
			if(tp==0){
				eline=0;
				break;
			}
			space=pl_space(tp->space, x, indent);
			if(space) eline=tp;
		}
		if(eline==t){	/* No progress!  Force fit the first block! */
			if(a>ascent) ascent=a;
			if(d>descent) descent=d;
			if(tp==t)
				eline=tp->next;
			else
				eline=tp;
		}
		topy=p.y;
		p.y+=ascent;
		p.x=indent=pl_space(t->indent, 0, 0);
		for(;;){
			t->topy=topy;
			t->r.min.x=p.x;
			if(t->b){
				t->r.max.y=p.y;
				t->r.min.y=p.y-(t->b->r.max.y-t->b->r.min.y);
				p.x+=t->b->r.max.x-t->b->r.min.x+2;
				t->r=rectaddpt(t->r, Pt(2, 2));
			}
			else if(t->p){
				t->r.max.y=p.y;
				t->r.min.y=p.y-t->p->r.max.y;
				p.x+=t->p->r.max.x;
			}
			else{
				t->r.min.y=p.y-t->font->ascent;
				t->r.max.y=t->r.min.y+t->font->height;
				p.x+=t->wid;
			}
			t->r.max.x=p.x;
			t->nextline=eline;
			t=t->next;
			if(t==eline) break;
			p.x+=pl_space(t->space, p.x, indent);
		}
		p.y+=descent+LEAD;
	}
	return p.y;
}
void pl_rtdraw(Image *b, Rectangle r, Rtext *t, int yoffs){
	Point offs;
	Rectangle dr;
	Rectangle cr;
	cr=b->clipr;
	replclipr(b, b->repl, r);
	pl_clr(b, r);
	offs=subpt(r.min, Pt(0, yoffs));
	for(;t;t=t->next) if(!eqrect(t->r, Rect(0,0,0,0))){
		dr=rectaddpt(t->r, offs);
		if(dr.max.y>r.min.y
		&& dr.min.y<r.max.y){
			if(t->b){
//				bitblt(b, dr.min, t->b, t->b->r, S|D);
				draw(b, Rpt(dr.min, addpt(dr.min, subpt(t->b->r.max, t->b->r.min))), t->b, 0, t->b->r.min);
				if(t->hot) border(b, insetrect(dr, -2), 1, display->black, ZP);
			}
			else if(t->p){
				plmove(t->p, subpt(dr.min, t->p->r.min));
				pldraw(t->p, b);
			}
			else{
				string(b, dr.min, display->black, ZP, t->font, t->text);
				if(t->hot)
					line(b, Pt(dr.min.x, dr.max.y-1),
						Pt(dr.max.x, dr.max.y-1),
						Endsquare, Endsquare, 0,
						display->black, ZP);
			}
		}
	}
	replclipr(b, b->repl, cr);
}
/*
 * Reposition text already drawn in the window.
 * We just move the pixels and update the positions of any
 * enclosed panels
 */
void pl_reposition(Rtext *t, Image *b, Point p, Rectangle r){
	Point offs;
	pl_cpy(b, p, r);
	offs=subpt(p, r.min);
	for(;t;t=t->next)
		if(!eqrect(t->r, Rect(0,0,0,0)) && !t->b && t->p)
			plmove(t->p, offs);
}
/*
 * Rectangle r of Image b contains an image of Rtext t, offset by oldoffs.
 * Redraw the text to have offset yoffs.
 */
void pl_rtredraw(Image *b, Rectangle r, Rtext *t, int yoffs, int oldoffs){
	int dy, size;
	dy=oldoffs-yoffs;
	size=r.max.y-r.min.y;
	if(dy>=size || -dy>=size)
		pl_rtdraw(b, r, t, yoffs);
	else if(dy<0){
		pl_reposition(t, b, r.min,
			Rect(r.min.x, r.min.y-dy, r.max.x, r.max.y));
		pl_rtdraw(b, Rect(r.min.x, r.max.y+dy, r.max.x, r.max.y),
			t, yoffs+size+dy);
	}
	else if(dy>0){
		pl_reposition(t, b, Pt(r.min.x, r.min.y+dy),
			Rect(r.min.x, r.min.y, r.max.x, r.max.y-dy));
		pl_rtdraw(b, Rect(r.min.x, r.min.y, r.max.x, r.min.y+dy), t, yoffs);
	}
}
Rtext *pl_rthit(Rtext *t, int yoffs, Point p, Point ul){
	if(t==0) return 0;
	p.x-=ul.x;
	p.y+=yoffs-ul.y;
	while(t->nextline && t->nextline->topy<=p.y) t=t->nextline;
	for(;t!=0;t=t->next){
		if(t->topy>p.y) return 0;
		if(ptinrect(p, t->r)) return t;
	}
	return 0;
}