local component=require("component")
local computer=require("computer")
local event=require("event")
local keyboard=require("keyboard")
local term=require("term")
local unicode=require("unicode")
local fs=require("filesystem")
local shell=require("shell")
local W=require("ocweb")

local gpu=component.gpu
local inet=component.isAvailable("internet")and component.internet or nil
local args=shell.parse(...)

local SW,SH=gpu.getResolution()
local C={
bar=0x16213e,urlBox=0x0f3460,urlFocus=0x533483,urlText=0xe0e0e0,btnFg=0xffffff,off=0x6c7086,
accent=0x533483,pageBg=0x1e1e2e,status=0xa6adc8,scrollbar=0x313244,scrollFg=0x585b70,sel=0x533483,
find=0x45475a,
}
local PAGE_COLORS={text=0xcdd6f4,heading=0xcba6f7,link=0x89b4fa,dim=0x6c7086,accent=0xf5c2e7,
code=0xa6e3a1,strong=0xffffff,em=0xf9e2af}

local PAGE_Y=4
local PAGE_H=SH-PAGE_Y+1
local PAGE_W=SW-1
local BTN={{" ◄ ","back",2},{" ► ","fwd",6},{" ↺ ","reload",10},{" ⌂ ","home",14},{" ◇ ","mark",18}}
local URL_X,URL_W=23,SW-26
local GO_X=SW-2

local ui={editing=false,addr="",cur=0,find=nil,findLine=nil,dirtyBar=true,dirtyPage=true}
local S=W.session{inet=inet,width=PAGE_W-1,colors=PAGE_COLORS,
onChange=function()ui.dirtyBar,ui.dirtyPage=true,true end,
download=function(u,body)
fs.makeDirectory("/home/Downloads")
local name=(u:match("([^/?#]+)[?#]?[^/]*$")or"download"):gsub("[^%w%._%-]","_")
local f=io.open("/home/Downloads/"..name,"wb")
if f then f:write(body or"");f:close()end
S.status="Saved /home/Downloads/"..name
end}


local function set(x,y,s,fg,bg)if bg then gpu.setBackground(bg)end if fg then gpu.setForeground(fg)end gpu.set(x,y,s)end
local function clamp(s,w)if unicode.len(s)<=w then return s end return unicode.sub(s,1,math.max(0,w-1)).."…"end

local function drawBar()
gpu.setBackground(C.bar)
gpu.fill(1,1,SW,3," ")
set(2,1,clamp(S.title or"OCBrowser",SW-2),C.status,C.bar)
for _,b in ipairs(BTN)do
local on=(b[2]~="back"or#S.back>0)and(b[2]~="fwd"or#S.fwd>0)
local label=b[2]=="reload"and S.job and" × "or b[2]=="mark"and(S.isBookmarked()and" ◆ "or" ◇ ")or b[1]
set(b[3],2,label,on and C.btnFg or C.off,C.urlBox)
end
local bg=ui.editing and C.urlFocus or C.urlBox
gpu.setBackground(bg)
gpu.fill(URL_X,2,URL_W,1," ")
local text=ui.editing and ui.addr or S.url
local off=ui.editing and math.max(0,ui.cur-(URL_W-3))or 0
set(URL_X+1,2,clamp(unicode.sub(text,off+1),URL_W-2),C.urlText,bg)
if ui.editing then
local ch=unicode.sub(ui.addr,ui.cur+1,ui.cur+1)
set(URL_X+1+ui.cur-off,2,ch==""and" "or ch,bg,C.urlText)
end
set(GO_X,2," ▶",C.btnFg,C.accent)

gpu.setBackground(C.bar)
local status=ui.find and("Find: "..ui.find.."_   (Enter next, Esc close)")or(S.status or"")
local sel=S.page and S.page.links[S.sel or 0]
if sel and not ui.find then status="→ "..W.resolve(S.url,sel.href)end
set(2,3,clamp(status,SW-24),C.status,C.bar)
if S.job then
local bw=20
local p=S.job.progress or((computer.uptime()*0.7)%1)
local n=math.floor((bw-2)*p)
set(SW-bw,3,"["..string.rep("■",n)..string.rep(" ",bw-2-n).."]",C.status,C.bar)
end
end

local function drawPage()
gpu.setBackground(C.pageBg)
gpu.fill(1,PAGE_Y,PAGE_W,PAGE_H," ")
local page=S.page
if not page then return end
local lines=page.lines
S.scroll=math.max(0,math.min(S.scroll or 0,math.max(0,#lines-PAGE_H)))
local sel=page.links[S.sel or 0]
for row=1,PAGE_H do
local li=S.scroll+row
local line=lines[li]
if not line then break end
local y=PAGE_Y+row-1
local rowBg=ui.findLine==li and C.find or C.pageBg
if rowBg~=C.pageBg then gpu.setBackground(rowBg);gpu.fill(1,y,PAGE_W,1," ")end
local x=2+(line.indent or 0)
for _,seg in ipairs(line.segs)do
local isSel=sel and seg.href and sel.line==li and sel.href==seg.href
set(x,y,seg.text,isSel and 0xffffff or seg.fg or PAGE_COLORS.text,isSel and C.sel or rowBg)
x=x+unicode.len(seg.text)
end
end

gpu.setBackground(C.scrollbar)
gpu.fill(SW,PAGE_Y,1,PAGE_H," ")
if#lines>PAGE_H then
local h=math.max(1,PAGE_H*PAGE_H//#lines)
local y=(PAGE_H-h)*S.scroll//math.max(1,#lines-PAGE_H)
gpu.setBackground(C.scrollFg)
gpu.fill(SW,PAGE_Y+y,1,h," ")
end
end

local function redraw()
if ui.dirtyBar then drawBar();ui.dirtyBar=false end
if ui.dirtyPage then drawPage();ui.dirtyPage=false end
end
local function dirty(page)ui.dirtyBar=true;if page then ui.dirtyPage=true end end


local function scrollBy(n)if S.page then S.scroll=(S.scroll or 0)+n;dirty(true)end end
local function selectLink(dir)
local links=S.page and S.page.links or{}
if#links==0 then return end
S.sel=((S.sel or 0)-1+dir)%#links+1
local li=links[S.sel].line
if li<=S.scroll then S.scroll=li-1 elseif li>S.scroll+PAGE_H then S.scroll=li-PAGE_H end
dirty(true)
end
local function follow(href)if href then ui.editing=false;S.navigate(W.resolve(S.url,href));dirty(true)end end
local function editAddress()ui.editing,ui.addr=true,S.url;ui.cur=unicode.len(ui.addr);dirty()end
local function findNext()
local i=S.find(ui.find or"",ui.findLine or S.scroll)
ui.findLine=i
if i then S.scroll=math.max(0,i-3)end
dirty(true)
end
local function savePage()
fs.makeDirectory("/home/Downloads")
local p="/home/Downloads/"..((S.title or"page"):gsub("[^%w%-_]","_"):sub(1,24))..".html"
local f=io.open(p,"w")
if f then f:write(S.body or"");f:close();S.status="Saved "..p end
dirty()
end

local function onClick(x,y,btn)
if y==2 then
for _,b in ipairs(BTN)do
if x>=b[3]and x<b[3]+3 then
if b[2]=="back"then S.goBack()elseif b[2]=="fwd"then S.goForward()
elseif b[2]=="reload"then if S.job then S.stop()else S.reload()end
elseif b[2]=="home"then S.navigate("about:home")
else S.toggleBookmark()end
ui.editing=false
return dirty(true)
end
end
if x>=URL_X and x<URL_X+URL_W then return editAddress()end
if x>=GO_X then if ui.editing then ui.editing=false;S.navigate(ui.addr)end return dirty(true)end
end
if y>=PAGE_Y and S.page then
local li=(S.scroll or 0)+y-PAGE_Y+1
for _,l in ipairs(S.page.links)do
if l.line==li and x-2>=l.x1 and x-2<l.x2 then return follow(l.href)end
end
end
if ui.editing then ui.editing=false;dirty()end
end

local function onKey(char,code)
local K=keyboard.keys
local ctrl,alt=keyboard.isControlDown(),keyboard.isAltDown()
if ui.editing then
if code==K.enter then ui.editing=false;S.navigate(ui.addr)
elseif code==K.escape then ui.editing=false
elseif code==K.back then if ui.cur>0 then ui.addr=unicode.sub(ui.addr,1,ui.cur-1)..unicode.sub(ui.addr,ui.cur+1);ui.cur=ui.cur-1 end
elseif code==K.delete then ui.addr=unicode.sub(ui.addr,1,ui.cur)..unicode.sub(ui.addr,ui.cur+2)
elseif code==K.left then ui.cur=math.max(0,ui.cur-1)
elseif code==K.right then ui.cur=math.min(unicode.len(ui.addr),ui.cur+1)
elseif code==K.home then ui.cur=0 elseif code==K["end"]then ui.cur=unicode.len(ui.addr)
elseif char>=32 then ui.addr=unicode.sub(ui.addr,1,ui.cur)..unicode.char(char)..unicode.sub(ui.addr,ui.cur+1);ui.cur=ui.cur+1 end
return dirty(true)
end
if ui.find then
if code==K.enter then return findNext()
elseif code==K.escape then ui.find,ui.findLine=nil,nil;return dirty(true)
elseif code==K.back then ui.find=unicode.sub(ui.find,1,-2);return dirty()
elseif char>=32 and not ctrl then ui.find=ui.find..unicode.char(char);return dirty()end
end
if ctrl then
if code==K.l then editAddress()
elseif code==K.f then ui.find="";dirty()
elseif code==K.d then S.toggleBookmark();dirty()
elseif code==K.u then S.toggleSource();dirty(true)
elseif code==K.s then savePage()
elseif code==K.b then S.navigate("about:bookmarks")
elseif code==K.h then S.navigate("about:history")
elseif code==K.q then return"quit"end
return
end
if alt and code==K.left then S.goBack()elseif alt and code==K.right then S.goForward()
elseif code==K.f5 then S.reload()
elseif code==K.escape then S.stop();dirty()
elseif code==K.up then scrollBy(-1)elseif code==K.down then scrollBy(1)
elseif code==K.pageUp then scrollBy(-PAGE_H+1)elseif code==K.pageDown or char==32 then scrollBy(PAGE_H-1)
elseif code==K.home then S.scroll=0;dirty(true)elseif code==K["end"]then scrollBy(1e9)
elseif code==K.tab then selectLink(keyboard.isShiftDown()and-1 or 1)
elseif code==K.enter then local l=S.page and S.page.links[S.sel or 0]if l then follow(l.href)end
elseif code==K.back then S.goBack()end
dirty(true)
end


local function main()
local fg0,bg0=gpu.getForeground(),gpu.getBackground()
gpu.setBackground(C.pageBg)
gpu.fill(1,1,SW,SH," ")
if not inet then S.status="No Internet Card: only about: pages work"end
S.navigate(args[1]or"about:home",false)
while true do
redraw()
local name,_,a,b,c=event.pull(S.job and 0.05 or 1)
if name=="interrupted"then break
elseif name=="key_down"then if onKey(a,b)=="quit"then break end
elseif name=="touch"then onClick(math.floor(a),math.floor(b),c)
elseif name=="scroll"then scrollBy(c>0 and-3 or 3)
elseif name=="clipboard"then if ui.editing then ui.addr=ui.addr..a;ui.cur=unicode.len(ui.addr);dirty()end
end
if S.job then S.step();dirty(S.job==nil)end
end
S.stop()
gpu.setForeground(fg0);gpu.setBackground(bg0)
gpu.fill(1,1,SW,SH," ")
term.setCursor(1,1)
end

local ok,err=pcall(main)
if not ok then
gpu.setBackground(0);gpu.setForeground(0xffffff)
term.clear()
io.stderr:write("browser: "..tostring(err).."\n")
end