local Y=require("yaru.core")
local gfx=require("yaru.gfx")
local ui=require("yaru.ui")
local image=require("yaru.image")
local fs=require("filesystem")
local unicode=require("unicode")
local M={}

local PALETTE={0x000000,0x3C3C3C,0x787878,0xB4B4B4,0xFFFFFF,0xCC0000,0xFF4940,0xFF9240,
0xFFDB40,0x99FF40,0x33B640,0x006D40,0x33DBBF,0x0092FF,0x0049BF,0x330080,
0x9949FF,0xCC49BF,0xFF92BF,0x996D40,0x663300,0x2C001E,0xE95420,0xFFDBBF}
local TOOLS={{"pen","▪ Pencil"},{"erase","▯ Eraser"},{"fill","◧ Fill"},{"pick","◉ Picker"}}

function M.open(path)


local st={tool="pen",c1=0x000000,c2=0xFFFFFF,undo={},dirty=false,size=1}
local win=Y.newWindow{app="paint",title="Paint",w=100,h=34,minW=50,minH=16,precise=true}
local function new(w,ph)
st.w,st.ph,st.px=w,ph+ph%2,{}
for i=1,st.w*st.ph do st.px[i]=0xFFFFFF end
st.path,st.dirty=nil,false
win.title="Untitled"
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
local function load(p)
local img,err=image.load(p,true)
if not img then return Y.notify("Paint",tostring(err))end
local w,h,d=img[1],img[2],img[3]
st.w,st.ph,st.px=w,h*2,{}
for y=1,h do for x=1,w do
local k=((y-1)*w+x)*3
local top,bot=halves(d[k-2],d[k-1],d[k])
if d[k]<0 then
if d[k-2]==0x2580 then bot=-1 elseif d[k-2]==0x2584 then top=-1 else top,bot=-1,-1 end
end
st.px[(2*y-2)*w+x],st.px[(2*y-1)*w+x]=top,bot
end end
st.path,st.dirty=p,false
win.title=fs.name(p)
end
local function snapshot()
local c={}
for i=1,#st.px do c[i]=st.px[i]end
st.undo[#st.undo+1]=c
if#st.undo>10 then table.remove(st.undo,1)end
end
local function toImage()
local d,h={},st.ph//2
for y=1,h do for x=1,st.w do
local k=((y-1)*st.w+x)*3
local top,bot=st.px[(2*y-2)*st.w+x],st.px[(2*y-1)*st.w+x]
if top<0 and bot<0 then d[k-2],d[k-1],d[k]=32,0,-1
elseif top<0 then d[k-2],d[k-1],d[k]=0x2584,bot,-1
elseif bot<0 then d[k-2],d[k-1],d[k]=0x2580,top,-1
elseif top==bot then d[k-2],d[k-1],d[k]=32,top,top
else d[k-2],d[k-1],d[k]=0x2580,top,bot end
end end
return{st.w,h,d}
end
local function save(p,after)
p=p or st.path
if not p then
Y.dialog{title="Save Picture",text="File name (full path)",entry="/home/Pictures/picture.pic",
buttons={{"Cancel"},{"Save",function(txt)if txt and txt~=""then
if not txt:match("%.pic$")then txt=txt..".pic"end
save(txt,after)end end,"suggested"}}}
return
end
local ok,err=image.save(p,toImage())
if not ok then return Y.notify("Could not save",tostring(err))end
st.path,st.dirty=p,false
win.title=fs.name(p)
for _,w in ipairs(Y.windowsOf("files"))do if w.reload then w.reload()end end
if after then after()end
end
local function setPx(x,y,c)
for dy=0,st.size-1 do for dx=0,st.size-1 do
local xx,yy=x+dx,y+dy
if xx>=1 and yy>=1 and xx<=st.w and yy<=st.ph then st.px[(yy-1)*st.w+xx]=c end
end end
st.dirty=true
end
local function fill(x,y,color)
local target=st.px[(y-1)*st.w+x]
if target==color then return end
local stack={x,y}
while#stack>0 do
local yy,xx=table.remove(stack),table.remove(stack)
local k=(yy-1)*st.w+xx
if xx>=1 and yy>=1 and xx<=st.w and yy<=st.ph and st.px[k]==target then
st.px[k]=color
stack[#stack+1]=xx+1;stack[#stack+1]=yy
stack[#stack+1]=xx-1;stack[#stack+1]=yy
stack[#stack+1]=xx;stack[#stack+1]=yy+1
stack[#stack+1]=xx;stack[#stack+1]=yy-1
end
end
st.dirty=true
end

local SIDE=20
local cx0,cy0
local lastPx
local function apply(px,py,btn,kind)
local color=btn==1 and st.c2 or st.c1
if st.tool=="pen"or st.tool=="erase"then
local c=st.tool=="erase"and-1 or color

if kind=="drag"and lastPx then
local x0,y0=lastPx[1],lastPx[2]
local dx,dy=math.abs(px-x0),-math.abs(py-y0)
local sx,sy=x0<px and 1 or-1,y0<py and 1 or-1
local err=dx+dy
while true do
setPx(x0,y0,c)
if x0==px and y0==py 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
else setPx(px,py,c)end
lastPx={px,py}
elseif st.tool=="fill"then fill(px,py,color)
elseif st.tool=="pick"then
local c=st.px[(py-1)*st.w+px]
if c<0 then c=0xFFFFFF end
if btn==1 then st.c2=c else st.c1=c end
st.tool="pen"
end
end

function win.header(w,hw)
local x=2
x=x+ui.button(w,x,1,"New",function()
Y.dialog{title="New Picture",text="Size in pixels (a cell holds 1x2 pixels), e.g. 32x32",entry=st.w.."x"..st.ph,
buttons={{"Cancel"},{"Create",function(s)
local a,b=(s or""):match("(%d+)%s*[xX×]%s*(%d+)")
a,b=tonumber(a),tonumber(b)
if a and b and a>=1 and b>=1 and a<=160 and b<=100 then snapshot();new(a,b)end
end,"suggested"}}}
end)+1
x=x+ui.button(w,x,1,"Open…",function()
Y.dialog{title="Open Picture",text="Path to a .pic file",entry=st.path or"/home/Pictures/",
buttons={{"Cancel"},{"Open",function(p)if p and p~=""then load(p)end end,"suggested"}}}
end)+1
x=x+ui.button(w,x,1,"Undo",function()local u=table.remove(st.undo)if u then st.px=u end end,"flat")+1
ui.button(w,hw-7,1,"Save",function()save()end,"suggested",7)
end

function win.draw(w,cw,ch)
local t=Y.theme
gfx.fill(1,1,SIDE,ch,t.sidebar)
gfx.text(2,1,"Tools",t.dim)
for i,tl in ipairs(TOOLS)do
local y=1+i
if st.tool==tl[1]then ui.select(2,y,SIDE-2,t.dark and 0x454545 or 0xDEDDDA)end
gfx.text(4,y,tl[2],t.fg)
ui.hit(w,1,y,SIDE,1,function()st.tool=tl[1]end)
end
local py=#TOOLS+3
gfx.text(2,py,"Brush",t.dim)
for i=1,3 do
local bx=9+(i-1)*4
if st.size==i then ui.pill(bx-1,py,3,t.accent)end
gfx.prect(bx,py*2-(i>1 and 1 or 0),i,i,st.size==i and 0xFFFFFF or t.fg)
ui.hit(w,bx-1,py,3,1,function()st.size=i end)
end
py=py+2
gfx.text(2,py,"Colours",t.dim)
for i,c in ipairs(PALETTE)do
local x,y=2+((i-1)%4)*4,py+1+(i-1)//4
ui.pill(x,y,3,c)
ui.hit(w,x,y,3,1,function(_,_,_,btn)if btn==1 then st.c2=c else st.c1=c end end)
end
py=py+2+math.ceil(#PALETTE/4)
gfx.text(2,py,"Left",t.dim);ui.round(8,py,10,1,st.c1)
gfx.text(2,py+1,"Right",t.dim);ui.round(8,py+1,10,1,st.c2)
gfx.text(2,py+3,ui.trunc(st.w.."×"..st.ph.." px",SIDE-2),t.dim)
ui.hit(w,8,py,10,2,function()
Y.dialog{title="Custom Colour",text="Hex RGB, e.g. E95420",entry=string.format("%06X",st.c1),
buttons={{"Cancel"},{"Set",function(s)local v=tonumber((s or""):gsub("#",""),16)if v then st.c1=v&0xFFFFFF end end,"suggested"}}}
end)

local ax,aw=SIDE+1,cw-SIDE
gfx.fill(ax,1,aw,ch,t.dark and 0x1E1E1E or 0xDEDDDA)
local hc=st.ph//2
cx0=ax+math.max(1,(aw-st.w)//2)
cy0=1+math.max(1,(ch-hc)//2)
gfx.pushClip(ax,1,aw,ch)
ui.card(cx0,cy0,st.w,hc,0xFFFFFF)
for y=1,st.ph do
local base=(y-1)*st.w
local py0=(cy0-1)*2+y
for x=1,st.w do
local c=st.px[base+x]
if c<0 then c=((x+y)%2==0)and 0xF0F0F0 or 0xC3C3C3 end
gfx.pset(cx0+x-1,py0,c)
end
end
gfx.popClip()
end



function win.touch(w,lx,ly,btn,kind)
if not cx0 then return end
local px=lx-cx0+1
local cyl=ly-cy0+1
local lower=(Y.touchFrac and Y.touchFrac>=0.5)or(not Y.touchFrac and Y.mods.shift())
local py=cyl*2-(lower and 0 or 1)
if px<1 or py<1 or px>st.w or py>st.ph then lastPx=nil return end
if kind=="touch"then snapshot();lastPx=nil end
if kind=="drop"then lastPx=nil return end
if kind=="drag"and(st.tool~="pen"and st.tool~="erase")then return end
apply(px,py,btn,kind)
end

function win.key(w,char,code)
local K=Y.K
if Y.mods.ctrl()then
if code==K.s then save()elseif code==0x2C then local u=table.remove(st.undo)if u then st.px=u end end
return
end
if char==91 then st.size=math.max(1,st.size-1)elseif char==93 then st.size=math.min(3,st.size+1)end
end

function win.onclose(w)
if not st.dirty then return true end
Y.dialog{title="Save the picture before closing?",text="Unsaved changes will be lost.",
buttons={{"Cancel"},{"Close without Saving",function()Y.closeWin(w,true)end,"destructive"},
{"Save",function()save(nil,function()Y.closeWin(w,true)end)end,"suggested"}}}
return false
end

if path and fs.exists(path)then load(path)else new(32,32);if path then st.path=path;win.title=fs.name(path)end end
return win
end

return M