local component=require("component")
local computer=require("computer")
local fs=require("filesystem")
local shell=require("shell")
local term=require("term")

if not component.isAvailable("internet")then
io.stderr:write("ocv_get: нужна интернет-карта\n")
return
end
local internet=require("internet")

local args=shell.parse(...)
local base,dir=args[1],args[2]or"video"
if not base then
print("usage: ocv_get <url> [folder]")
return
end
if base:sub(-1)~="/"then base=base.."/"end
dir=shell.resolve(dir)

local function human(n)
if n>=1048576 then return string.format("%.2f MB",n/1048576)end
if n>=1024 then return string.format("%.1f KB",n/1024)end
return n.." B"
end

local function status(text)
local _,y=term.getCursor()
term.setCursor(1,y)
term.clearLine()
io.write(text)
end

local function download(name,label)
local path=fs.concat(dir,name)
local file=assert(io.open(path,"wb"))
local size,t0,lastDraw=0,computer.uptime(),0

local ok,err=pcall(function()
for chunk in internet.request(base..name)do
file:write(chunk)
size=size+#chunk
local now=computer.uptime()
if now-lastDraw>=0.25 then
lastDraw=now
status(label.."  "..human(size))
end
end
end)
file:close()

if not ok or size==0 then
fs.remove(path)
error(name..": "..tostring(err or"пустой ответ"),0)
end
status(string.format("%s  %s  %.1fs\n",label,human(size),computer.uptime()-t0))
end

local ok,err=pcall(function()
fs.makeDirectory(dir)
download("index.ocv","index.ocv")

local f=assert(io.open(fs.concat(dir,"index.ocv"),"rb"))
local h=f:read(64)
f:close()
if not h or#h<64 or h:sub(1,4)~="OCV5"then error("index.ocv: не OCV5",0)end

local parts=h:byte(15)*256+h:byte(16)
for i=1,parts do
download(string.format("part%04d.ocv",i),string.format("[%d/%d]",i,parts))
end
print("Готово: ocv "..dir)
end)

if not ok then io.stderr:write("\nocv_get: "..tostring(err).."\n")end