local unicode=require("unicode")
local event=require("event")
local component=require("component")
local computer=require("computer")

local tty={}
tty.window=
{
fullscreen=true,
blink=true,
dx=0,
dy=0,
x=1,
y=1,
output_buffer="",
}

tty.stream={}

local screen_cache={}
local function screen_reset(gpu,addr)
screen_cache[addr or gpu.getScreen()or false]=nil
end

event.listen("screen_resized",screen_reset)

function tty.getViewport()
local window=tty.window
local screen=tty.screen()
if window.fullscreen and screen and not screen_cache[screen]then
screen_cache[screen]=true
window.width,window.height=window.gpu.getViewport()
end

return window.width,window.height,window.dx,window.dy,window.x,window.y
end

function tty.setViewport(width,height,dx,dy,x,y)
checkArg(1,width,"number")
checkArg(2,height,"number")
local window=tty.window
dx,dy,x,y=dx or 0,dy or 0,x or 1,y or 1
window.width,window.height,window.dx,window.dy,window.x,window.y=width,height,dx,dy,x,y
end

function tty.gpu()
return tty.window.gpu
end

function tty.clear()
tty.stream.scroll(math.huge)
tty.setCursor(1,1)
end

function tty.isAvailable()
local gpu=tty.gpu()
return not not(gpu and gpu.getScreen())
end


function tty.stream.read()
local core=require("core/cursor")
local cursor=core.new(tty.window.cursor)


tty.window.cursor=cursor

local ok,result,reason=xpcall(core.read,debug.traceback,cursor)

if not ok or not result then
pcall(cursor.update,cursor)
end

return select(2,assert(ok,result,reason))
end


function tty.stream:write(value)
local gpu=tty.gpu()
if not gpu then
return
end
local window=tty.window
local cursor=window.cursor or{}
cursor.sy=cursor.sy or 0
cursor.tails=cursor.tails or{}
local beeped
local uptime=computer.uptime
local last_sleep=uptime()
window.output_buffer=window.output_buffer..value
while true do
if uptime()-last_sleep>3 then
os.sleep(0)
last_sleep=uptime()
end

local ansi_print=require("vt100").parse(window)



cursor.sy=cursor.sy+self.scroll()


if#window.output_buffer==0 or not ansi_print then
break
end

local x,y=tty.getCursor()

local _,ei,delim=unicode.sub(window.output_buffer,1,window.width):find("([\27\t\r\n\a\b\v\15])")
local segment=ansi_print..(ei and window.output_buffer:sub(1,ei-1)or window.output_buffer)

if segment~=""then
local gpu_x,gpu_y=x+window.dx,y+window.dy
local tail=""
local wlen_needed=unicode.wlen(segment)
local wlen_remaining=window.width-x+1
if wlen_remaining<wlen_needed then
segment=unicode.wtrunc(segment,wlen_remaining+1)
wlen_needed=unicode.wlen(segment)
tail=wlen_needed<wlen_remaining and" "or""
cursor.tails[gpu_y-cursor.sy]=tail
if not window.nowrap then

ei=#segment

delim="\n"
end
end
gpu.set(gpu_x,gpu_y,segment..tail)
x=x+wlen_needed
end

window.output_buffer=ei and window.output_buffer:sub(ei+1)or
unicode.sub(window.output_buffer,window.width+1)

if delim=="\t"then
x=((x-1)-((x-1)%8))+9
elseif delim=="\r"then
x=1
elseif delim=="\n"then
x=1
y=y+1
elseif delim=="\b"then
x=x-1
elseif delim=="\v"then
y=y+1
elseif delim=="\a"and not beeped then
computer.beep()
beeped=true
elseif delim=="\27"then
window.output_buffer=delim..window.output_buffer
end

tty.setCursor(x,y)
end
return cursor.sy
end

function tty.getCursor()
local window=tty.window
return window.x,window.y
end

function tty.setCursor(x,y)
checkArg(1,x,"number")
checkArg(2,y,"number")
local window=tty.window
window.x,window.y=x,y
end

local gpu_intercept=setmetatable({},{__mode="k"})
function tty.bind(gpu)
checkArg(1,gpu,"table")
if not gpu_intercept[gpu]then
gpu_intercept[gpu]=true


local setr,setv=gpu.setResolution,gpu.setViewport
gpu.setResolution=function(...)
screen_reset(gpu)
return setr(...)
end
gpu.setViewport=function(...)
screen_reset(gpu)
return setv(...)
end
end
local window=tty.window
if window.gpu~=gpu then
window.gpu=gpu
window.keyboard=nil
tty.getViewport()
end
screen_reset(gpu)
end

function tty.keyboard()

local window=tty.window

if window.keyboard then
return window.keyboard
end

local system_keyboard=component.isAvailable("keyboard")and component.keyboard
system_keyboard=system_keyboard and system_keyboard.address or"no_system_keyboard"

local screen=tty.screen()

if not screen then

return system_keyboard
end


if component.isAvailable("screen")and component.screen.address==screen then
window.keyboard=system_keyboard
else




window.keyboard=component.invoke(screen,"getKeyboards")[1]or system_keyboard
end

return window.keyboard
end

function tty.screen()
local gpu=tty.gpu()
if not gpu then
return nil
end
return gpu.getScreen()
end

function tty.stream.scroll(lines)
local gpu=tty.gpu()
if not gpu then
return 0
end
local width,height,dx,dy,x,y=tty.getViewport()









if not lines then
if y<1 then
lines=y-1
elseif y>height then
lines=y-height
else
return 0
end
end

lines=math.min(lines,height)
lines=math.max(lines,-height)


local abs_lines=math.abs(lines)
local box_height=height-abs_lines
local fill_top=dy+1+(lines<0 and 0 or box_height)

gpu.copy(dx+1,dy+1+math.max(0,lines),width,box_height,0,-lines)
gpu.fill(dx+1,fill_top,width,abs_lines,' ')

tty.setCursor(x,math.max(1,math.min(y,height)))
return lines
end


local function bfd()return nil,"tty: invalid operation"end
tty.stream.close=bfd
tty.stream.seek=bfd
tty.stream.handle="tty"

return tty