Revise paste CC typer

-- typist.lua
-- Realistic terminal typing for ComputerCraft 1.7

-- ===== CONFIG =====
local BASE_DELAY  = 0.05
local VARIANCE    = 0.04
local PUNCT_DELAY = 0.12
local LINE_DELAY  = 0.25

-- ===== SETUP =====
local args = { ... }
if not args[1] then
    print("Usage: typist <file>")
    return
end

local filename = args[1]
if not fs.exists(filename) then
    print("File not found.")
    return
end

local file = fs.open(filename, "r")
if not file then
    print("Could not open file.")
    return
end

math.randomseed(os.time())

local function humanSleep(base)
    local d = base + (math.random() * VARIANCE * 2 - VARIANCE)
    if d < 0 then d = 0 end
    sleep(d)
end

-- ===== TERMINAL HELPERS =====
local function advanceCursor()
    local x, y = term.getCursorPos()
    local w, h = term.getSize()

if x > w then
        x = 1
        y = y + 1
    end

if y > h then
        term.scroll(1)
        y = h
    end

term.setCursorPos(x, y)
end

local function typeChar(c)
    term.write(c)
    advanceCursor()

if c:match("[%.%,%!%?]") then
        humanSleep(PUNCT_DELAY)
    else
        humanSleep(BASE_DELAY)
    end
end

local function newLine()
    local _, y = term.getCursorPos()
    local _, h = term.getSize()

if y >= h then
        term.scroll(1)
        term.setCursorPos(1, h)
    else
        term.setCursorPos(1, y + 1)
    end

sleep(LINE_DELAY)
end

-- ===== MAIN LOOP =====
while true do
    local line = file.readLine()
    if not line then break end

for i = 1, #line do
        typeChar(line:sub(i, i))
    end

newLine()
end

file.close()