edit

-- Get file to edit
local tArgs = {...}

if #tArgs == 0 then
    print("Usage: edit <path>")
    return
end

-- Error checking
local sPath = shell.resolve(tArgs[1])
local bReadOnly = fs.isReadOnly(sPath)

if fs.exists(sPath) and fs.isDir(sPath) then
    print("Cannot edit a directory.")
    return
end

local x, y = 1, 1
local w, h = term.getSize()
local scrollX, scrollY = 0, 0

local tLines = {}
local bRunning = true

-- Colors
local highlightColor, keywordColor, commentColor, textColor, bgColor, stringColor, functionColor, numberColor, operatorColor

if term.isColor() then
    bgColor = colors.black
    textColor = colors.white
    highlightColor = colors.cyan
    keywordColor = colors.cyan
    commentColor = colors.green
    stringColor = colors.red
    functionColor = colors.purple
    numberColor = colors.orange
    operatorColor = colors.blue
else
    bgColor = colors.black
    textColor = colors.white
    highlightColor = colors.white
    keywordColor = colors.white
    commentColor = colors.white
    stringColor = colors.white
    functionColor = colors.white
    numberColor = colors.white
    operatorColor = colors.white
end

-- Menus
local bMenu = false
local nMenuItem = 1
local tMenuItems

if bReadOnly then
    tMenuItems = {"Exit"}
else
    tMenuItems = {"Save", "Exit"}
end

local sStatus = "Press Ctrl to access menu"

local function load(_sPath)
    tLines = {}

    if fs.exists(_sPath) then
        local file = io.open(_sPath, "r")
        local sLine = file:read()

        while sLine do
            table.insert(tLines, sLine)
            sLine = file:read()
        end

        file:close()
    end

    if #tLines == 0 then
        table.insert(tLines, "")
    end
end

local function save(_sPath)
    -- Create intervening folder
    local sDir = sPath:sub(1, sPath:len() - fs.getName(sPath):len())

    -- Save
    local file = nil

    local function innerSave()
        file = fs.open(_sPath, "w")

        if file then
            for n, sLine in ipairs(tLines) do
                file.write(sLine .. "\n")
            end
        else
            error("Failed to open " .. _sPath)
        end
    end

    local ok = pcall(innerSave)

    if file then
        file:close()
    end

    return ok
end

local tKeywords = {
    --Keywords
    ["and"] = keywordColor,
    ["break"] = keywordColor,
    ["do"] = keywordColor,
    ["else"] = keywordColor,
    ["elseif"] = keywordColor,
    ["end"] = keywordColor,
    ["false"] = keywordColor,
    ["for"] = keywordColor,
    ["function"] = keywordColor,
    ["if"] = keywordColor,
    ["in"] = keywordColor,
    ["local"] = keywordColor,
    ["nil"] = keywordColor,
    ["not"] = keywordColor,
    ["or"] = keywordColor,
    ["repeat"] = keywordColor,
    ["return"] = keywordColor,
    ["then"] = keywordColor,
    ["true"] = keywordColor,
    ["until"]= keywordColor,
    ["while"] = keywordColor,

    --Bit
    ["bit"] = functionColor,
    ["bit.blshift"] = functionColor,
    ["bit.brshift"] = functionColor,
    ["bit.blogic_rshift"] = functionColor,
    ["bit.bxor"] = functionColor,
    ["bit.bor"] = functionColor,
    ["bit.band"] = functionColor,
    ["bit.bnot"] = functionColor,

    --Colors
    ["colors.white"] = colors.white,
    ["colors.orange"] = colors.orange,
    ["colors.magenta"] = colors.magenta,
    ["colors.lightBlue"] = colors.lightBlue,
    ["colors.yellow"] = colors.yellow,
    ["colors.lime"] = colors.lime,
    ["colors.pink"] = colors.pink,
    ["colors.gray"] = colors.gray,
    ["colors.lightGray"] = colors.lightGray,
    ["colors.cyan"] = colors.cyan,
    ["colors.purple"] = colors.purple,
    ["colors.blue"] = colors.blue,
    ["colors.brown"] = colors.brown,
    ["colors.green"] = colors.green,
    ["colors.red"] = colors.red,
    ["colors.black"] = colors.black,
    ["colors"] = functionColor,
    ["colors.combine"] = functionColor,
    ["colors.subtract"] = functionColor,
    ["colors.test"] = functionColor,

    --Commands
    ["commands"] = functionColor,
    ["commands.exec"] = functionColor,
    ["commands.execAsync"] = functionColor,
    ["commands.list"] = functionColor,
    ["commands.getBlockPosition"] = functionColor,
    ["commands.getBlockInfo"] = functionColor,
    ["commands.getBlockInfos"] = functionColor,

    --Coroutine
    ["coroutine"] = functionColor,
    ["coroutine.create"] = functionColor,
    ["coroutine.resume"] = functionColor,
    ["coroutine.running"] = functionColor,
    ["coroutine.status"] = functionColor,
    ["coroutine.wrap"] = functionColor,
    ["coroutine.yield"] = functionColor,

    --disk
    ["disk"] = functionColor,
    ["disk.isPresent"] = functionColor,
    ["disk.hasData"] = functionColor,
    ["disk.getMountPath"] = functionColor,
    ["disk.setLabel"] = functionColor,
    ["disk.getLabel"] = functionColor,
    ["disk.getId"] = functionColor,
    ["disk.hasAudio"] = functionColor,
    ["disk.getAudioTitle"] = functionColor,
    ["disk.playAudio"] = functionColor,
    ["disk.stopAudio"] = functionColor,
    ["disk.eject"] = functionColor,

    --fs
    ["fs"] = functionColor,
    ["fs.list"] = functionColor,
    ["fs.exists"] = functionColor,
    ["fs.isDir"] = functionColor,
    ["fs.isReadOnly"] = functionColor,
    ["fs.getName"] = functionColor,
    ["fs.getDrive"] = functionColor,
    ["fs.getSize"] = functionColor,
    ["fs.getFreeSpace"] = functionColor,
    ["fs.makeDir"] = functionColor,
    ["fs.move"] = functionColor,
    ["fs.copy"] = functionColor,
    ["fs.delete"] = functionColor,
    ["fs.combine"] = functionColor,
    ["fs.open"] = functionColor,
    ["fs.find"] = functionColor,
    ["fs.getDir"] = functionColor,
    ["fs.complete"] = functionColor,

    --gps
    ["gps"] = functionColor,
    ["gps.locate"] = functionColor,

    --help
    ["help"] = functionColor,
    ["help.path"] = functionColor,
    ["help.setPath"] = functionColor,
    ["help.lookup"] = functionColor,
    ["help.topics"] = functionColor,
    ["help.completeTopic"] = functionColor,

    --HTTP
    ["http"] = functionColor,
    ["http.request"] = functionColor,
    ["http.get"] = functionColor,
    ["http.post"] = functionColor,
    ["http.checkURL"] = functionColor,

    --io
    ["io"] = functionColor,
    ["io.open"] = functionColor,
    ["io.write"] = functionColor,
    ["io.read"] = functionColor,

    --Keys
    ["keys"] = functionColor,
    ["keys.getName"] = functionColor,

    --Math
    ["math"] = functionColor,
    ["math.abs"] = functionColor,
    ["math.acos"] = functionColor,
    ["math.asin"] = functionColor,
    ["math.atan"] = functionColor,
    ["math.atan2"] = functionColor,
    ["math.ceil"] = functionColor,
    ["math.cos"] = functionColor,
    ["math.cosh"] = functionColor,
    ["math.deg"] = functionColor,
    ["math.exp"] = functionColor,
    ["math.floor"] = functionColor,
    ["math.fmod"] = functionColor,
    ["math.frexp"] = functionColor,
    ["math.huge"] = functionColor,
    ["math.ldexp"] = functionColor,
    ["math.log"] = functionColor,
    ["math.log10"] = functionColor,
    ["math.max"] = functionColor,
    ["math.min"] = functionColor,
    ["math.modf"] = functionColor,
    ["math.pi"] = functionColor,
    ["math.pow"] = functionColor,
    ["math.rad"] = functionColor,
    ["math.random"] = functionColor,
    ["math.randomseed"] = functionColor,
    ["math.sin"] = functionColor,
    ["math.sinh"] = functionColor,
    ["math.sqrt"] = functionColor,
    ["math.tan"] = functionColor,
    ["math.tanh"] = functionColor,

    --multishell
    ["multishell"] = functionColor,
    ["multishell.getCurrent"] = functionColor,
    ["multishell.getCount"] = functionColor,
    ["multishell.launch"] = functionColor,
    ["multishell.setFocus"] = functionColor,
    ["multishell.setTitle"] = functionColor,
    ["multishell.getTitle"] = functionColor,
    ["multishell.getFocus"] = functionColor,

    --os
    ["os"] = functionColor,
    ["os.version"] = functionColor,
    ["os.getComputerID"] = functionColor,
    ["os.getComputerLabel"] = functionColor,
    ["os.run"] = functionColor,
    ["os.loadAPI"] = functionColor,
    ["os.unloadAPI"] = functionColor,
    ["os.pullEvent"] = functionColor,
    ["os.pullEventRaw"] = functionColor,
    ["os.queueEvent"] = functionColor,
    ["os.clock"] = functionColor,
    ["os.startTimer"] = functionColor,
    ["os.cancelTimer"] = functionColor,
    ["os.time"] = functionColor,
    ["os.sleep"] = functionColor,
    ["sleep"] = functionColor,
    ["os.day"] = functionColor,
    ["os.setAlarm"] = functionColor,
    ["os.cancelAlarm"] = functionColor,
    ["os.shutdown"] = functionColor,
    ["os.reboot"] = functionColor,

    --paintutils
    ["paintutils"] = functionColor,
    ["paintutils.loadImage"] = functionColor,
    ["paintutils.drawImage"] = functionColor,
    ["paintutils.drawPixel"] = functionColor,
    ["paintutils.drawLine"] = functionColor,
    ["paintutils.drawBox"] = functionColor,
    ["paintutils.drawFilledBox"] = functionColor,

    --parallel
    ["parallel"] = functionColor,
    ["parallel.waitForAny"] = functionColor,
    ["parallel.waitForAll"] = functionColor,

    --peripheral
    ["peripheral"] = functionColor,
    ["peripheral.isPresent"] = functionColor,
    ["peripheral.getType"] = functionColor,
    ["peripheral.getMethods"] = functionColor,
    ["peripheral.call"] = functionColor,
    ["peripheral.wrap"] = functionColor,
    ["peripheral.find"] = functionColor,
    ["peripheral.getNames"] = functionColor,

    --rednet
    ["rednet"] = functionColor,
    ["rednet.open"] = functionColor,
    ["rednet.close"] = functionColor,
    ["rednet.send"] = functionColor,
    ["rednet.broadcast"] = functionColor,
    ["rednet.receive"] = functionColor,
    ["rednet.isOpen"] = functionColor,
    ["rednet.host"] = functionColor,
    ["rednet.unhost"] = functionColor,
    ["rednet.lookup"] = functionColor,
    ["rednet.run"] = functionColor,

    --redstone
    ["redstone"] = functionColor,
    ["redstone.getSides"] = functionColor,
    ["redstone.getInput"] = functionColor,
    ["redstone.setOutput"] = functionColor,
    ["redstone.getOutput"] = functionColor,
    ["redstone.getAnalogIutput"] = functionColor,
    ["redstone.setAnalogOutput"] = functionColor,
    ["redstone.getAnalogOutput"] = functionColor,
    ["redstone.getBundledOutput"] = functionColor,
    ["redstone.setBundledOutput"] = functionColor,
    ["redstone.getBundledIutput"] = functionColor,
    ["redstone.testBundledIutput"] = functionColor,

    --settings
    ["settings"] = functionColor,
    ["settings.set"] = functionColor,
    ["settings.get"] = functionColor,
    ["settings.unset"] = functionColor,
    ["settings.clear"] = functionColor,
    ["settings.getNames"] = functionColor,
    ["settings.load"] = functionColor,
    ["settings.save"] = functionColor,

    --shell
    ["shell"] = functionColor,
    ["shell.exit"] = functionColor,
    ["shell.run"] = functionColor,
    ["shell.dir"] = functionColor,
    ["shell.setDir"] = functionColor,
    ["shell.path"] = functionColor,
    ["shell.setPath"] = functionColor,
    ["shell.resolve"] = functionColor,
    ["shell.resolveProgram"] = functionColor,
    ["shell.aliases"] = functionColor,
    ["shell.setAlias"] = functionColor,
    ["shell.clearAlias"] = functionColor,
    ["shell.programs"] = functionColor,
    ["shell.getRunningProgram"] = functionColor,
    ["shell.openTab"] = functionColor,
    ["shell.switchTab"] = functionColor,
    ["shell.complete"] = functionColor,
    ["shell.completeProgram"] = functionColor,
    ["shell.setCompletionFunction"] = functionColor,
    ["shell.getCompletionInfo"] = functionColor,

    --string
    ["string"] = functionColor,
    ["string.byte"] = functionColor,
    ["string.char"] = functionColor,
    ["string.dump"] = functionColor,
    ["string.find"] = functionColor,
    ["string.format"] = functionColor,
    ["string.gmatch"] = functionColor,
    ["string.gsub"] = functionColor,
    ["string.len"] = functionColor,
    ["string.lower"] = functionColor,
    ["string.upper"] = functionColor,
    ["string.match"] = functionColor,
    ["string.rep"] = functionColor,
    ["string.reverse"] = functionColor,
    ["string.sub"] = functionColor,

    --table
    ["table"] = functionColor,
    ["table.concat"] = functionColor,
    ["table.insert"] = functionColor,
    ["table.maxn"] = functionColor,
    ["table.remove"] = functionColor,
    ["table.sort"] = functionColor,

    --term
    ["term"] = functionColor,
    ["term.write"] = functionColor,
    ["term.blit"] = functionColor,
    ["term.clear"] = functionColor,
    ["term.clearLine"] = functionColor,
    ["term.getCursorPos"] = functionColor,
    ["term.setCursorPos"] = functionColor,
    ["term.setCursorBlink"] = functionColor,
    ["term.isColor"] = functionColor,
    ["term.getSize"] = functionColor,
    ["term.scroll"] = functionColor,
    ["term.redirect"] = functionColor,
    ["term.current"] = functionColor,
    ["term.native"] = functionColor,
    ["term.setTextColor"] = functionColor,
    ["term.getTextColor"] = functionColor,
    ["term.setBackgroundColor"] = functionColor,
    ["term.getBackgroundColor"] = functionColor,

    --textutils
    ["textutils"] = functionColor,
    ["textutils.slowWrite"] = functionColor,
    ["textutils.slowPrint"] = functionColor,
    ["textutils.formatTime"] = functionColor,
    ["textutils.tabulate"] = functionColor,
    ["textutils.pagedTabulate"] = functionColor,
    ["textutils.pagedPrint"] = functionColor,
    ["textutils.serialize"] = functionColor,
    ["textutils.unserialize"] = functionColor,
    ["textutils.serializeJSON"] = functionColor,
    ["textutils.urlEncode"] = functionColor,
    ["textutils.complete"] = functionColor,

    --turtle
    ["turtle"] = functionColor,
    ["turtle.craft"] = functionColor,
    ["turtle.forward"] = functionColor,
    ["turtle.back"] = functionColor,
    ["turtle.up"] = functionColor,
    ["turtle.down"] = functionColor,
    ["turtle.turnLeft"] = functionColor,
    ["turtle.turnRight"] = functionColor,
    ["turtle.select"] = functionColor,
    ["turtle.getSelectedSlot"] = functionColor,
    ["turtle.getItemCount"] = functionColor,
    ["turtle.getItemSpace"] = functionColor,
    ["turtle.getItemDetail"] = functionColor,
    ["turtle.equipLeft"] = functionColor,
    ["turtle.equipRight"] = functionColor,
    ["turtle.attack"] = functionColor,
    ["turtle.attackUp"] = functionColor,
    ["turtle.attackDown"] = functionColor,
    ["turtle.dig"] = functionColor,
    ["turtle.digUp"] = functionColor,
    ["turtle.digDown"] = functionColor,
    ["turtle.place"] = functionColor,
    ["turtle.placeUp"] = functionColor,
    ["turtle.placeDown"] = functionColor,
    ["turtle.detect"] = functionColor,
    ["turtle.detectUp"] = functionColor,
    ["turtle.detectDown"] = functionColor,
    ["turtle.inspect"] = functionColor,
    ["turtle.inspectUp"] = functionColor,
    ["turtle.inspectDown"] = functionColor,
    ["turtle.compare"] = functionColor,
    ["turtle.compareUp"] = functionColor,
    ["turtle.compareDown"] = functionColor,
    ["turtle.compareTo"] = functionColor,
    ["turtle.drop"] = functionColor,
    ["turtle.dropUp"] = functionColor,
    ["turtle.dropDown"] = functionColor,
    ["turtle.suck"] = functionColor,
    ["turtle.suckUp"] = functionColor,
    ["turtle.suckDown"] = functionColor,
    ["turtle.refuel"] = functionColor,
    ["turtle.getFuelLevel"] = functionColor,
    ["turtle.getFuelLimit"] = functionColor,
    ["turtle.transferTo"] = functionColor,

    --vector
    ["vector"] = functionColor,
    ["vector.new"] = functionColor,

    --lua
    ["tonumber"] = functionColor,
    ["tostring"] = functionColor,
    ["print"] = functionColor,
    ["pairs"] = functionColor,
    ["ipairs"] = functionColor,
    ["pcall"] = functionColor,
    ["error"] = functionColor,
}

local function tryWrite(sLine, regex, color)
    local match = string.match(sLine, regex)

    if match then
        if type(color) == "number" then
            term.setTextColor(color)
        else
            term.setTextColor(color(match))
        end

        term.write(match)
        term.setTextColor(textColor)
        return string.sub(sLine, string.len(match) + 1)
    end

    return nil
end

local function writeHighlighted(sLine)
    function match(m)
        if tKeywords[m] then
            return tKeywords[m]
        end
        return textColor
    end

    while string.len(sLine) > 0 do
        sLine =
            tryWrite(sLine, "^%-%-%[%[.-%]%]", commentColor) or
            tryWrite(sLine, "^%-%-.*", commentColor) or
            tryWrite(sLine, "^\".-[^\\]\"", stringColor) or
            tryWrite(sLine, "^\'.-[^\\]\'", stringColor) or
            tryWrite(sLine, "^\"\"", stringColor) or
            tryWrite(sLine, "^''", stringColor) or
            tryWrite(sLine, "^%[%[.-%]%]", stringColor) or
            tryWrite(sLine, "^[.]+", operatorColor) or
            tryWrite(sLine, "^[%d%.]+", numberColor) or
            tryWrite(sLine, "^[%d%a%._]+", match) or
            tryWrite(sLine, "^[^%w_.]", operatorColor)
    end
end

local function redrawText()
    for y = 1,h - 1 do
        term.setCursorPos(1 - scrollX, y)
        term.clearLine()

        local sLine = tLines[y + scrollY]

        if sLine ~= nil then
            writeHighlighted(sLine)
        end
    end

    term.setCursorPos(x - scrollX, y - scrollY)
end

local function redrawLine(_nY)
    local sLine = tLines[_nY]
    term.setCursorPos(1 - scrollX, _nY - scrollY)
    term.clearLine()
    writeHighlighted(sLine)
    term.setCursorPos(x - scrollX, _nY - scrollY)
end

local function redrawMenu()
    -- Clear line
    term.setCursorPos(1, h)
    term.clearLine()

    -- Draw line numbers
    term.setCursorPos(w - string.len("Ln " .. y) + 1, h)
    term.setTextColor(highlightColor)
    term.write("Ln ")
    term.setTextColor(textColor)
    term.write(y)

    term.setCursorPos(1, h)

    if bMenu then
        -- Draw menu
        term.setTextColor(textColor)

        for nItem, sItem in pairs(tMenuItems) do
            if nItem == nMenuItem then
                term.setTextColor(highlightColor)
                term.write("[")
                term.setTextColor(textColor)
                term.write(sItem)
                term.setTextColor(highlightColor)
                term.write("]")
                term.setTextColor(textColor)
            else
                term.write(" " .. sItem .. " ")
            end
        end
    else
        -- Draw status
        term.setTextColor(highlightColor)
        term.write(sStatus)
        term.setTextColor(textColor)
    end

    -- Reset cursor
    term.setCursorPos(x - scrollX, y - scrollY)
end

local tMenuFuncs = {
    Save = function ()
        if bReadOnly then
            sStatus = "Access denied"
        else
            local ok, err = save(sPath)

            if ok then
                sStatus="Press Ctrl to access menu"
            else
                sStatus="Press Ctrl to access menu"
            end
        end

        redrawMenu()
    end,
    Print = function ()
        local printer = peripheral.find("printer")

        if not printer then
            sStatus = "No printer attached"
            return
        end

        local nPage = 0
        local sName = fs.getName(sPath)

        if printer.getInkLevel() < 1 then
            sStatus = "Printer out of ink"
            return
        elseif printer.getPaperLevel() < 1 then
            sStatus = "Printer out of paper"
            return
        end

        local screenTerminal = term.current()
        local printerTerminal = {
            getCursorPos = printer.getCursorPos,
            setCursorPos = printer.setCursorPos,
            getSize = printer.getPageSize,
            write = printer.write,
        }
        printerTerminal.scroll = function ()
            if nPage == 1 then
                printer.setPageTitle(sName .. " (page " .. nPage .. ")")
            end

            while not printer.newPage() do
                if printer.getInkLevel() < 1 then
                    sStatus = "Printer out of ink, please refill"
                elseif printer.getPaperLevel() < 1 then
                    sStatus = "Printer out of paper, please refill"
                else
                    sStatus = "Printer output tray full, please empty"
                end

                term.redirect(screenTerminal)
                redrawMenu()
                term.redirect(printerTerminal)

                local timer = os.startTimer(0.5)
                sleep(0.5)
            end

            nPage = nPage + 1
            if nPage == 1 then
                printer.setPageTitle(sName)
            else
                printer.setPageTitle(sName .. " (page " .. nPage .. ")")
            end
        end

        bMenu = false
        term.redirect(printerTerminal)

        local ok, error = pcall(function ()
            term.scroll()
            for n, sLine in ipairs(tLines) do
                print(sLine)
            end
        end)

        term.redirect(screenTerminal)

        if not ok then
            print(error)
        end

        while not printer.endPage() do
            sStatus = "Printer output tray full, please empty"
            redrawMenu()
            sleep(0.5)
        end

        bMenu = true

        if nPage > 1 then
            sStatus = "Printed " .. nPage .. " Pages"
        else
            sStatus = "Printed 1 Page"
        end

        redrawMenu()
    end,
    Exit = function ()
        bRunning = false
    end
}

local function doMenuItem(_n)
    tMenuFuncs[tMenuItems[_n]]()

    if bMenu then
        bMenu = false
        term.setCursorBlink(true)
    end

    redrawMenu()
end

local function setCursor(x, y)
    local screenX = x - scrollX
    local screenY = y - scrollY

    local bRedraw = false

    if screenX < 1 then
        scrollX = x - 1
        screenX = 1
        bRedraw = true
    elseif screenX > w then
        scrollX = x - w
        screenX = w
        bRedraw = true
    end

    if screenY < 1 then
        scrollY = y - 1
        screenY = 1
        bRedraw = true
    elseif screenY > h - 1 then
        scrollY = y - (h - 1)
        screenY = h - 1
        bRedraw = true
    end

    if bRedraw then
        redrawText()
    end
    term.setCursorPos(screenX, screenY)

    -- Statusbar now pertains to menu, it would probably be safe to redraw the menu on every key event.
    redrawMenu()
end

-- Actual program functionality begins
load(sPath)

term.setBackgroundColor(bgColor)
term.clear()
term.setCursorPos(x, y)
term.setCursorBlink(true)

redrawText()
redrawMenu()

-- Handle input
while bRunning do
    local sEvent, param, param2, param3 = os.pullEvent()

    if sEvent == "key" then
        if param == keys.up then
            -- Up
            if not bMenu then
                if y > 1 then
                    -- Move cursor up
                    y = y - 1
                    x = math.min(x, string.len(tLines[y]) + 1)
                    setCursor(x, y)
                end
            end
        elseif param == keys.down then
            -- Down
            if not bMenu then
                -- Move cursor down
                if y < #tLines then
                    y = y + 1
                    x = math.min(x, string.len(tLines[y]) + 1)
                    setCursor(x, y)
                end
            end
        elseif param == keys.tab then
            -- Tab
            if not bMenu and not bReadOnly then
                -- Indent line
                tLines[y] = "  " .. tLines[y]
                x = x + 2
                setCursor(x, y)
                redrawLine(y)
            end
        elseif param == keys.pageUp then
            -- Page Up
            if not bMenu then
                -- Move up a page
                if y - (h - 1) >= 1 then
                    y = y - (h - 1)
                else
                    y = 1
                end
                x = math.min(x, string.len(tLines[y]) + 1)
                setCursor(x, y)
            end
        elseif param == keys.pageDown then
            -- Page Down
            if not bMenu then
                -- Move down a page
                if y + (h - 1) <= #tLines then
                    y = y + (h - 1)
                else
                    y = #tLines
                end
                x = math.min(x, string.len(tLines[y]) + 1)
                setCursor(x, y)
            end
        elseif param == keys.home then
            -- Home
            if not bMenu then
                -- Move cursor to the beginning
                x = 1
                setCursor(x, y)
            end
        elseif param == keys["end"] then
            -- End
            if not bMenu then
                -- Move cursor to the end
                x = string.len(tLines[y]) + 1
                setCursor(x, y)
            end
        elseif param == keys.left then
            -- Left
            if not bMenu then
                if x > 1 then
                    -- Move cursor left
                    x = x - 1
                elseif x == 1 and y > 1 then
                    x = string.len(tLines[y - 1]) + 1
                    y = y - 1
                end
                setCursor(x, y)
            else
                -- Move menu left
                nMenuItem = nMenuItem - 1
                if nMenuItem < 1 then
                    nMenuItem = #tMenuItems
                end
                redrawMenu()
            end
        elseif param == keys.right then
            -- Right
            if not bMenu then
                if x < string.len(tLines[y]) + 1 then
                    -- Move cursor right
                    x = x + 1
                elseif x == string.len(tLines[y]) + 1 and y < #tLines then
                    x = 1
                    y = y + 1
                end
                setCursor(x, y)
            else
                -- Move menu right
                nMenuItem = nMenuItem + 1
                if nMenuItem > #tMenuItems then
                    nMenuItem = 1
                end
                redrawMenu()
            end
        elseif param == keys.delete then
            -- Delete
            if not bMenu and not bReadOnly then
                if  x < string.len(tLines[y]) + 1 then
                    local sLine = tLines[y]
                    tLines[y] = string.sub(sLine, 1, x - 1) .. string.sub(sLine, x + 1)
                    redrawLine(y)
                elseif y < #tLines then
                    tLines[y] = tLines[y] .. tLines[y + 1]
                    table.remove(tLines, y + 1)
                    redrawText()
                    redrawMenu()
                end
            end
        elseif param == keys.backspace then
            -- Backspace
            if not bMenu and not bReadOnly then
                if x > 1 then
                    -- Remove character
                    local sLine = tLines[y]
                    tLines[y] = string.sub(sLine, 1, x - 2) .. string.sub(sLine, x)
                    redrawLine(y)

                    x = x - 1
                    setCursor(x, y)
                elseif y > 1 then
                    -- Remove newline
                    local sPrevLen = string.len(tLines[y - 1])
                    tLines[y - 1] = tLines[y - 1] .. tLines[y]
                    table.remove(tLines, y)
                    redrawText()

                    x = sPrevLen + 1
                    y = y - 1
                    setCursor(x, y)
                end
            end
        elseif param == keys.enter then
            -- Enter
            if not bMenu and not bReadOnly then
                -- Newline
                local sLine = tLines[y]
                local _, spaces = string.find(sLine, "^[ ]+")

                if not spaces then
                    spaces = 0
                end

                tLines[y] = string.sub(sLine, 1, x - 1)
                table.insert(tLines, y + 1, string.rep(' ', spaces) .. string.sub(sLine, x))
                redrawText()

                x = spaces + 1
                y = y + 1
                setCursor(x, y)
            elseif bMenu then
                -- Menu selection
                doMenuItem(nMenuItem)
            end
        elseif param == keys.leftCtrl then
            -- Menu toggle
            bMenu = not bMenu

            if bMenu then
                term.setCursorBlink(false)
            else
                term.setCursorBlink(true)
            end

            redrawMenu()
        end

    elseif sEvent == "char" then
        if not bMenu and not bReadOnly then
            -- Input text
            local sLine = tLines[y]
            tLines[y] = string.sub(sLine, 1, x - 1) .. param .. string.sub(sLine, x)
            redrawLine(y)

            x = x + 1
            setCursor(x, y)
        elseif bMenu then
            -- Select menu items
            for n, sMenuItem in ipairs(tMenuItems) do
                if string.lower(string.sub(sMenuItem, 1, 1)) == string.lower(param) then
                    doMenuItem(n)
                    break
                end
            end
        end
    elseif sEvent == "paste" then
        if not bMenu and not bReadOnly then
            -- Input text
            local sLine = tLines[y]
            tLines[y] = string.sub(sLine, 1, x - 1) .. param .. string.sub(sLine, x)
            redrawLine(y)

            x = x + string.len(param)
            setCursor(x, y)
        end
    elseif sEvent == "mouse_click" then
        if not bMenu then
            if param == 1 then
                -- Left click
                local cx, cy = param2, param3
                if cy < h then
                    y = math.min(math.max(scrollY + cy, 1), #tLines)
                    x = math.min(math.max(scrollX + cx, 1), string.len(tLines[y]) + 1)
                    setCursor(x, y)
                end
            end
        end
    elseif sEvent == "mouse_scroll" then
        if not bMenu then
            if param == -1 then
                -- Scroll up
                if scrollY > 0 then
                    -- Move cursor up
                    scrollY = scrollY - 1
                    redrawText()
                end
            elseif param == 1 then
                -- Scroll down
                local nMaxScroll = #tLines - (h - 1)

                if scrollY < nMaxScroll then
                    -- Move cursor down
                    scrollY = scrollY + 1
                    redrawText()
                end
            end
        end

    elseif sEvent == "window_resize" then
        w, h = term.getSize()
        setCursor(x, y)
        redrawMenu()
        redrawText()
    end
end

-- Cleanup
term.clear()
term.setCursorBlink(false)
term.setCursorPos(1, 1)