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

function M.open(dir)
local o=Y.overlay
if o and o.kind=="switcher"then return o.step(dir)end
local list={}
for i=#Y.windows,1,-1 do
local w=Y.windows[i]
if w.ws==Y.ws then list[#list+1]=w end
end
if#list==0 then return end
o={kind="switcher",sel=#list>1 and(dir<0 and#list or 2)or 1}
local W,H=Y.size()
local cw=16
local n=math.min(#list,(W-8)//cw)
local bw=n*cw+2
local x0,y0=(W-bw)//2,H//2-3

local function activate()
local w=list[o.sel]
Y.closeOverlay()
if w then Y.focusWin(w)end
end
function o.step(d)
o.sel=(o.sel-1+d)%#list+1
gfx.damage(x0,y0-1,bw+1,12)
end
function o.draw()
local t=Y.theme
ui.card(x0,y0,bw,9,t.menu)
local first=math.max(1,math.min(o.sel-n+1,#list-n+1))
for i=first,math.min(#list,first+n-1)do
local w=list[i]
local x=x0+1+(i-first)*cw
local sel=i==o.sel
local bg=sel and t.menuHi or t.menu
if sel then ui.round(x,y0+1,cw-1,6,bg)end
local a=Y.apps[w.app]
Y.drawIcon(x+(cw-9)//2,y0+1,a and a.icon or"generic")
local name=ui.trunc(a and a.name or(w.title or""),cw-2)
gfx.text(x+(cw-1-unicode.len(name))//2,y0+5,name,t.menuFg,bg)
local idx=i
o.hits[#o.hits+1]={x,y0+1,cw-1,6,function()o.sel=idx;activate()end}
end
local title=ui.trunc(list[o.sel].title or"",bw-4)

gfx.text(x0+(bw-unicode.len(title))//2,y0+7,title,t.dim,t.menu)
end
function o.keyUp(_,char,code)
local K=Y.K
if code==K.lalt or code==K.ralt or code==K.lsuper or code==K.rsuper or code==K.lctrl or code==K.rctrl then
if not(Y.mods.alt()or Y.mods.super()or Y.mods.ctrl())then activate()end
end
end
function o.key(_,char,code)
local K=Y.K
if code==K.esc then Y.closeOverlay()
elseif code==K.enter then activate()
elseif code==K.left then o.step(-1)
elseif code==K.right or code==K.tab then o.step(1)end
end
function o.touch()Y.closeOverlay()return true end
Y.openOverlay(o)
return o
end

return M