local unicode=require("unicode")
local ubyte,uchar,sort,concat=string.byte,unicode.char,table.sort,table.concat

local gfx={}
local gpu
local W,H=0,0
local back,front={},{}

local pal,palIdx,palN={},{},0
local ox,oy=0,0
local cx1,cy1,cx2,cy2=1,1,0,0
local dmg={x1=1,y1=1,x2=0,y2=0}
local hints={}
local clipStack={}
gfx.stats={frames=0,set=0,fill=0,copy=0,fg=0,bg=0,cells=0}






local function delta(a,b)
local dr,dg,db=(a>>16)-(b>>16),((a>>8)&255)-((b>>8)&255),(a&255)-(b&255)
return 0.2126*dr*dr+0.7152*dg*dg+0.0722*db*db
end
for i=0,15 do pal[i]=(i+1)*0x0F0F0F end
for r=0,5 do for g=0,7 do for b=0,4 do
pal[16+r*40+g*5+b]=(r*51)<<16|((g*255+3)//7)<<8|((b*255+2)//4)
end end end
palN=256

local function color(rgb)
local i=palIdx[rgb]
if i then return i end
local best,bd=0,math.huge
for k=0,15 do local d=delta(pal[k],rgb)if d<bd then best,bd=k,d end end
local r=((rgb>>16)*5+127)//255
local g=(((rgb>>8)&255)*7+127)//255
local b=((rgb&255)*4+127)//255
local ci=16+r*40+g*5+b
if delta(pal[ci],rgb)<bd then best=ci end
palIdx[rgb]=best
return best
end
gfx.color=color
function gfx.rgb(i)return pal[i]end
function gfx.snap(rgb)return pal[color(rgb)]end

local blendCache={}



function gfx.setCustomPalette(list,force)
for i=0,15 do
local c=list[i+1]or(i+1)*0x0F0F0F
if force or pal[i]~=c then pal[i]=c;if gpu then gpu.setPaletteColor(i,c)end end
end
palIdx={}
blendCache={}
if gpu then gfx.invalidate()end
end
function gfx.defaultPalette()
for i=0,15 do
pal[i]=(i+1)*0x0F0F0F
if gpu then gpu.setPaletteColor(i,pal[i])end
end
palIdx={}
blendCache={}
end

function gfx.init(g,w,h)
gpu,W,H=g,w,h
back,front={},{}
local blank=32|(color(0xFFFFFF)<<21)|(color(0)<<29)
for i=1,W*H do back[i]=blank;front[i]=-1 end
gfx.resetClip()
gfx.damageAll()
end
function gfx.size()return W,H end


function gfx.resetClip()ox,oy=0,0;cx1,cy1,cx2,cy2=dmg.x1,dmg.y1,dmg.x2,dmg.y2 end
function gfx.origin(x,y)ox,oy=x,y end
function gfx.getOrigin()return ox,oy end
function gfx.pushClip(x,y,w,h)
clipStack[#clipStack+1]={cx1,cy1,cx2,cy2,ox,oy}
x,y=x+ox,y+oy
if x>cx1 then cx1=x end
if y>cy1 then cy1=y end
if x+w-1<cx2 then cx2=x+w-1 end
if y+h-1<cy2 then cy2=y+h-1 end
return cx1<=cx2 and cy1<=cy2
end
function gfx.popClip()
local c=table.remove(clipStack)
cx1,cy1,cx2,cy2,ox,oy=c[1],c[2],c[3],c[4],c[5],c[6]
end
function gfx.visible(x,y,w,h)
x,y=x+ox,y+oy
return x<=cx2 and y<=cy2 and x+w-1>=cx1 and y+h-1>=cy1
end


function gfx.damage(x,y,w,h)
if w<=0 or h<=0 then return end
local x2,y2=x+w-1,y+h-1
if x<1 then x=1 end
if y<1 then y=1 end
if x2>W then x2=W end
if y2>H then y2=H end
if x>x2 or y>y2 then return end
if dmg.x1>dmg.x2 then
dmg.x1,dmg.y1,dmg.x2,dmg.y2=x,y,x2,y2
else
if x<dmg.x1 then dmg.x1=x end
if y<dmg.y1 then dmg.y1=y end
if x2>dmg.x2 then dmg.x2=x2 end
if y2>dmg.y2 then dmg.y2=y2 end
end
end
function gfx.damageAll()dmg.x1,dmg.y1,dmg.x2,dmg.y2=1,1,W,H end
function gfx.isDamaged()return dmg.x1<=dmg.x2 end
function gfx.damaged(x,y,w,h)
return x<=dmg.x2 and y<=dmg.y2 and x+w-1>=dmg.x1 and y+h-1>=dmg.y1
end
function gfx.invalidate()
for i=1,W*H do front[i]=-1 end
gfx.damageAll()
end


function gfx.fill(x,y,w,h,bg,fg,ch)
x,y=x+ox,y+oy
local x2,y2=x+w-1,y+h-1
if x<cx1 then x=cx1 end
if y<cy1 then y=cy1 end
if x2>cx2 then x2=cx2 end
if y2>cy2 then y2=cy2 end
if x>x2 or y>y2 then return end
local v=(ch and utf8.codepoint(ch)or 32)|(color(fg or 0xFFFFFF)<<21)|(color(bg)<<29)
for yy=y,y2 do
local base=(yy-1)*W
for i=base+x,base+x2 do back[i]=v end
end
end


function gfx.text(x,y,s,fg,bg)
y=y+oy
if y<cy1 or y>cy2 then return end
x=x+ox
if x>cx2 then return end
local fgk=color(fg)<<21
local bgk=bg and(color(bg)<<29)
local base=(y-1)*W
local ascii=not s:find("[\128-\255]")
local n=ascii and#s or unicode.len(s)
if x+n-1<cx1 then return end
local i0=1
if x<cx1 then i0=cx1-x+1 end
local last=n
if x+n-1>cx2 then last=cx2-x+1 end
if ascii then
for i=i0,last do
local idx=base+x+i-1
back[idx]=ubyte(s,i)|fgk|(bgk or(back[idx]&(255<<29)))
end
else
local i=0
for _,cp in utf8.codes(s)do
i=i+1
if i>last then break end
if i>=i0 then
local idx=base+x+i-1
back[idx]=cp|fgk|(bgk or(back[idx]&(255<<29)))
end
end
end
end


function gfx.cell(x,y,ch,fg,bg)
x,y=x+ox,y+oy
if x<cx1 or x>cx2 or y<cy1 or y>cy2 then return end
local idx=(y-1)*W+x
back[idx]=utf8.codepoint(ch)|(color(fg)<<21)|(bg and(color(bg)<<29)or(back[idx]&(255<<29)))
end



local function mix(c,rgb,a)
local ia=1-a
return((c>>16)*ia+(rgb>>16)*a+.5)//1<<16|(((c>>8)&255)*ia+((rgb>>8)&255)*a+.5)//1<<8
|((c&255)*ia+(rgb&255)*a+.5)//1
end
function gfx.blend(x,y,w,h,rgb,a,bgOnly)
x,y=x+ox,y+oy
local x2,y2=x+w-1,y+h-1
if x<cx1 then x=cx1 end
if y<cy1 then y=cy1 end
if x2>cx2 then x2=cx2 end
if y2>cy2 then y2=cy2 end
if x>x2 or y>y2 then return end
local key=rgb*1000+(a*999)//1
local map=blendCache[key]
if not map then map={};blendCache[key]=map end
for yy=y,y2 do
local base=(yy-1)*W
for i=base+x,base+x2 do
local v=back[i]
local fi,bi=(v>>21)&255,(v>>29)&255
local nf,nb=map[fi],map[bi]
if bgOnly then nf=fi elseif not nf then nf=color(mix(pal[fi],rgb,a));map[fi]=nf end
if not nb then nb=color(mix(pal[bi],rgb,a));map[bi]=nb end
back[i]=(v&0x1FFFFF)|(nf<<21)|(nb<<29)
end
end
end


function gfx.half(x,y,w,rgb,top,a)
x,y=x+ox,y+oy
if y<cy1 or y>cy2 then return end
local x2=x+w-1
if x<cx1 then x=cx1 end
if x2>cx2 then x2=cx2 end
local ch=top and 0x2580 or 0x2584
local base=(y-1)*W
local fi=rgb and color(rgb)
for i=base+x,base+x2 do
local v=back[i]
local bi=(v>>29)&255
local f=fi
if a then
local key=rgb*1000+(a*999)//1
local map=blendCache[key]
if not map then map={};blendCache[key]=map end
f=map[bi]
if not f then f=color(mix(pal[bi],rgb,a));map[bi]=f end
end
back[i]=ch|(f<<21)|(bi<<29)
end
end





local UPPER,LOWER,FULL=0x2580,0x2584,0x2588
local function halvesOf(v)
local cp,f,b=v&0x1FFFFF,(v>>21)&255,(v>>29)&255
if cp==UPPER then return f,b elseif cp==LOWER then return b,f elseif cp==FULL then return f,f end
return b,b
end
local function setHalf(i,isTop,ci)
local t,b=halvesOf(back[i])
if isTop then t=ci else b=ci end
if t==b then back[i]=32|(t<<21)|(t<<29)else back[i]=UPPER|(t<<21)|(b<<29)end
end
function gfx.pset(px,py,rgb)
local x,y=px+ox,(py+1)//2+oy
if x<cx1 or x>cx2 or y<cy1 or y>cy2 then return end
setHalf((y-1)*W+x,py%2==1,color(rgb))
end

function gfx.prect(px,py,pw,ph,rgb)
if pw<=0 or ph<=0 then return end
local ci=color(rgb)
local py2=py+ph-1
local y=py
if y%2==0 then
for x=px,px+pw-1 do gfx.pset(x,y,rgb)end
y=y+1
end
local full=(py2-y+1)//2
if full>0 then gfx.fill(px,(y+1)//2,pw,full,rgb)end
y=y+full*2
if y<=py2 then for x=px,px+pw-1 do gfx.pset(x,y,rgb)end end
end

function gfx.prrect(px,py,pw,ph,rgb)
gfx.prect(px+1,py,pw-2,ph,rgb)
gfx.prect(px,py+1,1,ph-2,rgb)
gfx.prect(px+pw-1,py+1,1,ph-2,rgb)
end
function gfx.pline(x0,y0,x1,y1,rgb)
local dx,dy=math.abs(x1-x0),-math.abs(y1-y0)
local sx,sy=x0<x1 and 1 or-1,y0<y1 and 1 or-1
local err=dx+dy
while true do
gfx.pset(x0,y0,rgb)
if x0==x1 and y0==y1 then break end
local e2=2*err
if e2>=dy then err=err+dy;x0=x0+sx end
if e2<=dx then err=err+dx;y0=y0+sy end
end
end
function gfx.pcircle(cx,cy,r,rgb)
for y=-r,r do
local w=math.floor(math.sqrt(r*r-y*y)+0.5)
gfx.prect(cx-w,cy+y,2*w+1,1,rgb)
end
end


function gfx.bgAt(x,y)
x,y=x+ox,y+oy
if x<1 or y<1 or x>W or y>H then return 0 end
return pal[(back[(y-1)*W+x]>>29)&255]
end

function gfx.shade(x,y,w,h,a)gfx.blend(x,y,w,h,0,a or 0.45)end





local wall,wallW,wallChars


function gfx.setWallpaper(str,w,chars)wall,wallW,wallChars=str,w,chars end
function gfx.drawWallpaper()
if not wall then return gfx.fill(1-ox,1-oy,W,H,0)end
local sb=ubyte
for y=cy1,cy2 do
local base,wb=(y-1)*W,(y-1)*wallW*3
for x=cx1,cx2 do
local p=wb+x*3-2
local pat,f,b=sb(wall,p,p+2)
if not pat then back[base+x]=32 else
back[base+x]=(wallChars and wallChars[pat]or(pat==0 and 32 or 0x2800+pat))|(f<<21)|(b<<29)
end
end
end
end


function gfx.drawWallpaperScaled(x,y,w,h)
if not wall then return end
local sb=ubyte
local wh=#wall//(wallW*3)
for yy=0,h-1 do
local sy=yy*wh//h
for xx=0,w-1 do
local sx=xx*wallW//w
local p=(sy*wallW+sx)*3+1
local pat,f,b=sb(wall,p,p+2)
local X,Yy=x+xx+ox,y+yy+oy
if pat and X>=cx1 and X<=cx2 and Yy>=cy1 and Yy<=cy2 then
back[(Yy-1)*W+X]=(wallChars and wallChars[pat]or(pat==0 and 32 or 0x2800+pat))|(f<<21)|(b<<29)
end
end
end
end


function gfx.image(x,y,img)
x,y=x+ox,y+oy
local iw,ih,d=img[1],img[2],img[3]
for yy=math.max(y,cy1),math.min(y+ih-1,cy2)do
local base,ib=(yy-1)*W,(yy-y)*iw-x+1
for xx=math.max(x,cx1),math.min(x+iw-1,cx2)do
local k=(ib+xx)*3
local idx=base+xx
local bg=d[k]
back[idx]=d[k-2]|(color(d[k-1])<<21)|(bg>=0 and(color(bg)<<29)or(back[idx]&(255<<29)))
end
end
end




local function halves(cp,fg,bg)
if cp==0x2580 then return fg,bg elseif cp==0x2584 then return bg,fg
elseif cp==0x2588 then return fg,fg end
return bg,bg
end
function gfx.imageScaled(x,y,w,h,img)
local iw,ih,d=img[1],img[2],img[3]
local ph,sh=h*2,ih*2
for yy=0,h-1 do
for xx=0,w-1 do
local X,Yy=x+xx+ox,y+yy+oy
if X>=cx1 and X<=cx2 and Yy>=cy1 and Yy<=cy2 then
local sx=xx*iw//w
local c={}
for half=0,1 do
local spy=(yy*2+half)*sh//ph
local k=((spy//2)*iw+sx+1)*3
local bg=d[k]>=0 and d[k]or 0
local top,bot=halves(d[k-2],d[k-1],bg)
c[half+1]=spy%2==0 and top or bot
end
back[(Yy-1)*W+X]=0x2580|(color(c[1])<<21)|(color(c[2])<<29)
end
end
end
end


function gfx.blit(grid,gw,gh,x,y)
x,y=x+ox,y+oy
local sx1,sy1=math.max(x,cx1),math.max(y,cy1)
local sx2,sy2=math.min(x+gw-1,cx2),math.min(y+gh-1,cy2)
if sx1>sx2 or sy1>sy2 then return end
for yy=sy1,sy2 do
local base,gbase=(yy-1)*W,(yy-y)*gw-x+1
for xx=sx1,sx2 do back[base+xx]=grid[gbase+xx]end
end
end




function gfx.blitScaled(grid,gw,gh,x,y,dw,dh)
local ph,sh=dh*2,gh*2
local rowSrc={}
for py=0,ph-1 do rowSrc[py]=py*sh//ph end
for yy=0,dh-1 do
local Yy=y+yy+oy
if Yy>=cy1 and Yy<=cy2 then
local spT,spB=rowSrc[yy*2],rowSrc[yy*2+1]
local cT,cB=(spT//2)*gw,(spB//2)*gw
local loT,loB=spT%2==1,spB%2==1
local base=(Yy-1)*W
for xx=0,dw-1 do
local X=x+xx+ox
if X>=cx1 and X<=cx2 then
local sx=xx*gw//dw+1
local vt,vb=grid[cT+sx],grid[cB+sx]
local t,b
do
local cp,f,bg=vt&0x1FFFFF,(vt>>21)&255,(vt>>29)&255
local up,lo=bg,bg
if cp==0x2580 then up=f elseif cp==0x2584 then lo=f elseif cp==0x2588 then up,lo=f,f end
t=loT and lo or up
end
do
local cp,f,bg=vb&0x1FFFFF,(vb>>21)&255,(vb>>29)&255
local up,lo=bg,bg
if cp==0x2580 then up=f elseif cp==0x2584 then lo=f elseif cp==0x2588 then up,lo=f,f end
b=loB and lo or up
end
back[base+X]=(t==b and 32 or 0x2580)|(t<<21)|(b<<29)
end
end
end
end
end


function gfx.scrollHint(x,y,w,h,dy)
local last=hints[#hints]
if last and not last.move and last[1]==x and last[2]==y and last[3]==w and last[4]==h then
last[5]=last[5]+dy
else
hints[#hints+1]={x,y,w,h,dy}
end
end



function gfx.moveHint(x,y,w,h,dx,dy)
if dx==0 and dy==0 then return end
if x<1 or y<1 or x+w-1>W or y+h-1>H then return end
if x+dx<1 or y+dy<1 or x+dx+w-1>W or y+dy+h-1>H then return end
hints[#hints+1]={x,y,w,h,dx,dy,move=true}
end

local function applyMove(h)
local x,y,w,hh,dx,dy=h[1],h[2],h[3],h[4],h[5],h[6]
gpu.copy(x,y,w,hh,dx,dy)
gfx.stats.copy=gfx.stats.copy+1
local tmp,n={},0
for r=y,y+hh-1 do
local b=(r-1)*W
for c=x,x+w-1 do n=n+1;tmp[n]=front[b+c]end
end
n=0
for r=y+dy,y+dy+hh-1 do
local b=(r-1)*W
for c=x+dx,x+dx+w-1 do n=n+1;front[b+c]=tmp[n]end
end
end


local rY,rX,rS,rK,rH,rSp,order={},{},{},{},{},{},{}
local cps={}

local function applyHint(h)
local x,y,w,hh,dy=h[1],h[2],h[3],h[4],h[5]
if dy==0 or math.abs(dy)>=hh then return end
if x<1 or y<1 or x+w-1>W or y+hh-1>H then return end

local srcY=dy>0 and y+dy or y
local n=hh-math.abs(dy)
gpu.copy(x,srcY,w,n,0,-dy)
gfx.stats.copy=gfx.stats.copy+1

if dy>0 then
for r=0,n-1 do
local d,s=(y+r-1)*W,(y+r+dy-1)*W
for c=x,x+w-1 do front[d+c]=front[s+c]end
end
else
for r=n-1,0,-1 do
local d,s=(y+r-dy-1)*W,(y+r-1)*W
for c=x,x+w-1 do front[d+c]=front[s+c]end
end
end
end

function gfx.flush()
if not gpu then return 0 end
local st=gfx.stats
for i=1,#hints do local h=hints[i];if h.move then applyMove(h)else applyHint(h)end;hints[i]=nil end
local n=0
local fx1,fx2=dmg.x1,dmg.x2
local y1,y2=dmg.y1,dmg.y2
for y=y1,y2 do
do
local base=(y-1)*W
local x=fx1
while x<=fx2 do
local i=base+x
local v=back[i]
if v~=front[i]then
local key=v>>21
local start,lastDiff=x,x
local space=(v&0x1FFFFF)==32
x=x+1
while x<=fx2 do
local v2=back[base+x]
if(v2>>21)~=key then break end
if v2~=front[base+x]then lastDiff=x
elseif x-lastDiff>4 then break end
x=x+1
end
local nc=0
for j=base+start,base+lastDiff do
local c=back[j]&0x1FFFFF
if c~=32 then space=false end
nc=nc+1
cps[nc]=c
front[j]=back[j]
end
n=n+1
rY[n],rX[n],rK[n],rH[n],rSp[n]=y,start,key,1,space
if space then
rS[n]=nc
else
rS[n]=nc<200 and uchar(table.unpack(cps,1,nc))or nil
if not rS[n]then
local parts={}
for k=1,nc,200 do parts[#parts+1]=uchar(table.unpack(cps,k,math.min(nc,k+199)))end
rS[n]=concat(parts)
end
end
st.cells=st.cells+nc
x=lastDiff+1
else
x=x+1
end
end
end
end

local stack,alive={},{}
for k=1,n do
alive[k]=true
if rSp[k]then
local id=rX[k]*4096+rS[k]*8+0
local sk=id..":"..(rK[k]>>8)
local prev=stack[sk]
if prev and rY[prev]+rH[prev]==rY[k]then
rH[prev]=rH[prev]+1
alive[k]=false
else
stack[sk]=k
end
end
end

local m=0
for k=1,n do
if alive[k]then
m=m+1
order[m]=k
local bgi,fgi=rK[k]>>8,rK[k]&255
rK[k]=bgi*512+(rSp[k]and 0 or fgi+1)
end
end
for k=m+1,#order do order[k]=nil end
sort(order,function(a,b)return rK[a]<rK[b]end)
local curBg,curFg=-1,-1
for j=1,m do
local k=order[j]
local key=rK[k]
local bgi,fgp=key//512,key%512
if bgi~=curBg then gpu.setBackground(bgi<16 and bgi or pal[bgi],bgi<16);curBg=bgi;st.bg=st.bg+1 end
if fgp>0 and fgp-1~=curFg then gpu.setForeground(fgp<=16 and fgp-1 or pal[fgp-1],fgp<=16);curFg=fgp-1;st.fg=st.fg+1 end
if rSp[k]then
if rH[k]>1 then
gpu.fill(rX[k],rY[k],rS[k],rH[k]," ");st.fill=st.fill+1
else
gpu.set(rX[k],rY[k],string.rep(" ",rS[k]));st.set=st.set+1
end
else
gpu.set(rX[k],rY[k],rS[k]);st.set=st.set+1
end
end
for k=1,n do rS[k]=nil end
st.frames=st.frames+1
dmg.x1,dmg.y1,dmg.x2,dmg.y2=1,1,0,0
return m
end


function gfx.peek(x,y)
local v=back[(y-1)*W+x]
return v&0x1FFFFF,pal[(v>>21)&255],pal[(v>>29)&255]
end


function gfx.dump()
local rows={}
for y=1,H do
local t={}
for x=1,W do t[x]=uchar(back[(y-1)*W+x]&0x1FFFFF)end
rows[y]=concat(t)
end
return rows
end

return gfx