Word processor

-- Word processor written by PaymentOption for ComputerCraft 1.42 --

-- VARIABLES --
bPrinted = false -- Whether or not the document has been printed.
tDocument = {}

bHasPaper = false
nPaperCount = 0
nPaperWidth, nPaperHeight = 0,0

bHasInk = false
nInkCount = 0

bHasPrinter = false
sPrinterSide = nil

bFirstPage = false -- Whether or not the first page has been started.
-- The wrapped printer.
printer = nil

nScreenWidth, nScreenHeight = term.getSize()
nSelection = 1 -- The selection of the print confirmation dialog box.
---------------

-- INITIALIZATION METHODS --
-- Returns true and the side the printer exists on if there a printer is found.
function checkForPrinter()
    local tSides = rs.getSides()
    -- Run through all of the possible sides and check for a printer peripheral.
    for index, side in ipairs( tSides ) do
        -- If a printer is found.
        if peripheral.isPresent( side ) and peripheral.getType( side ) == "printer" then
            return true, side
        end
    end

    -- No printer was found.
    return false, nil
end

-- Returns the wrapped printer object.
function wrapPrinter( side )
    return peripheral.wrap( side )
end

-- Returns true and the amount of paper if there is paper; false and nil if there is none.
function checkForPaper( side, printerWrap )
    if printerWrap.getPaperLevel() > 0 then
        return true, printerWrap.getPaperLevel()
    else
        return false, 0
    end
end

-- Returns true and the amount of ink if there is ink; false and nil if there is none.
function checkForInk( side, printerWrap )
    if printerWrap.getInkLevel() > 0 then
        return true, printerWrap.getInkLevel()
    else
        return false, 0
    end
end

-- Returns the width and height of the paper stored.
function getPaperDimensions( printerWrap )
    return printerWrap.getPageSize()
end

-- Sets up the page to be printed on: clears it and repositions the cursor to (1, 1)
function setCursorToPrint( printerWrap )
    clearPage() -- Clear the page of any previous data.
    printerWrap.setCursorPos( 1, 1 )
end

-- Runs all necessary checks, if they pass then true is returned and all variables are setup.
function initializePrinterAndProgram()
    local bPrinterExists, sSide = checkForPrinter()

    local bPaper, bInk = false
    local nPaper, nInk = 0

    if bPrinterExists then
        -- Assign the global printer wrap to the newly found and wrapped peripheral.
        printer = wrapPrinter( sSide )
        -- Check for paper and ink amounts.
        bPaper, nPaper = checkForPaper( sSide, printer )
        bInk, nInk = checkForInk( sSide, printer )

        if bPaper and bInk then
            -- Assign the global variables to their proper values.
            bHasPaper = bPaper
            bHasInk = bInk

            nPaperCount = nPaper
            nInkCount = nInk

            bFirstPage = printer.newPage() -- Start the first page.
            nPaperWidth, nPaperHeight = getPaperDimensions( printer )
            setCursorToPrint( printer ) -- Setup the page so it is blank and the cursor is in the upper left hand corner (1, 1).
            -- Report a successful printer initialization.
            return true
        -- There was either no paper, or no ink.
        else
            -- There was no paper.
            if not bPaper then
                return false, true -- bHasPaper = false, bHasInk = true
            -- There was no ink, but there was paper.
            else
                return true, false -- bHasPaper = true, bHasInk = false
            end
        end
    -- No printer was found.
    else
        return false
    end
end
----------------------------

-- CUSTOM PRINTER METHODS --
-- Clears the current page of all textual data.
function clearPage()
    for nCurrentHeight=1, nPaperHeight do
        printer.setCursorPos( 1, nCurrentHeight )
        printer.write( string.rep( " ", nPaperWidth ) )
    end
end

-- Prints the page with the specified title and string.
function printPage( sTitle, tPage )
    printer.setPageTitle( sTitle )

    for nHeight=1, #tPage do
        printer.setCursorPos( 1, nHeight )
        printer.write( tPage[nHeight] )
    end

    if printer.endPage() then
        return true
    else
        return false
    end
end
----------------------------

-- TERMINAL ROUTINES (COMPUTER SPECIFIC METHODS) --
function clearScreen()
    term.clear()
    term.setCursorPos( 1, 1 )
end

-- Prints a string to the very center of the screen on the specified line.
function printCentered( nHeight, sString )
    term.setCursorPos( nScreenWidth/2 - string.len( sString )/2, nHeight )
    write( sString )
end

-- Prints a string to the very right of the screen on the specified line.
function printRight( nHeight, sString )
    term.setCursorPos( nScreenWidth - string.len( sString ), nHeight )
    write( sString )
end

-- Draws a box with a width of nBoxWidth.
function drawBox( nBoxWidth )
    printCentered( 4, "+" .. string.rep( "-", nBoxWidth ) .. "+" )
    for nHeight = 5, 12 do
        printCentered( nHeight, "|" .. string.rep( " ", nBoxWidth ) .. "|" )
    end
    printCentered( 13, "+" .. string.rep( "-", nBoxWidth ) .. "+" )
end

-- Handles the key presses thrown when we're getting print confirmation.
function handleKeyPress( nKey )
    -- If the right key is pressed and the current selection is 'YES'.
    if nKey == 205 and nSelection == 1 then
        nSelection = 2
    -- If the left key is pressed and the current selection is 'NO'.
    elseif nKey == 203 and nSelection == 2 then
        nSelection = 1
    -- If the enter key is pressed.
    elseif nKey == 28 then
        -- If the user wants to print then print the prompt the user for a tile to the document.
        if nSelection == 1 then
            local sPageTitle = getPageTitle()
            if printPage( sPageTitle, tDocument ) then
                -- End the program.
                clearScreen()
                print( os.version() )
                bPrinted = true
            else
                clearScreen()
                print( os.version() )
                error( "Printing error!" )
            end
        -- If the user does not want to print the re-edit the document.
        elseif nSelection == 2 then
            tDocument = readLines( tDocument )
            getConfirmation()
        end
    end
end

-- Reads a fixed amount of characters without ruining a GUI that may be printed on the same line.
function limitRead( nLength, cReplaceChar )
    term.setCursorBlink( true )

    nLength = nLength or -1 -- -1 is unlimited
    sReturnString = ""

    xPos, yPos = term.getCursorPos()

    while true do
        event, char = os.pullEvent()

        if nLength ~= -1 and string.len( sReturnString ) >= nLength then term.setCursorBlink( false ); return sReturnString end -- Length check

        if event == "char" then sReturnString = sReturnString .. char
        elseif event == "key" and char == 28 then term.setCursorBlink( false ); return sReturnString -- Enter
        elseif event == "key" and char == 14 then -- Backspace
            term.setCursorPos( xPos, yPos )
            term.write( string.rep( " ", string.len( sReturnString ) ) )
            sReturnString = string.sub( sReturnString, 1, string.len( sReturnString )-1 )
            term.setCursorPos( xPos, yPos )

            if not cReplaceChar then term.write( sReturnString )
            else term.write( string.rep( cReplaceChar, string.len( sReturnString ) ) ) end
        end

        term.setCursorPos( xPos, yPos )
        term.write( string.rep( " ", string.len( sReturnString ) ) )
        term.setCursorPos( xPos, yPos )
        if not cReplaceChar then term.write( sReturnString )
        else term.write( string.rep( cReplaceChar, string.len( sReturnString ) ) ) end
    end
end

-- Takes a line and checks if a word has not finished. If it hasn't
-- then it returns the table of lines with the corrected new line.
--[[function fixTruncation( tLines )
    -- Remove the \n chracter.
    sLine = sLine:sub( 1, string.len( sLine ) - 1 )
    -- Check if the line has not finished.
    if tLines[#tLines]:sub( 1, 2 ) ~= " " then
        for  in string.gfind(  )
        tLines[#tLines - 1] = tLines[#tLines - 1]:sub( 1,  )
    end
end--]]

-- TODO: Remove the truncation effect when jumping lines.
-- Reads multiple lines as one string.
function readLines( tLines )
    term.setCursorBlink( true )

    local bExistingDocument = nil
    if tLines then
        bExistingDocument = true
    else
        bExistingDocument = true
    end

    local tLines = tLines or {}
    local nLineWidthCap = nPaperWidth
    local nLineCap = nScreenHeight

    -- Initialize the lines.
    if #tLines == 0 then
        for nLine = 1, nLineCap do
            tLines[nLine] = ""
        end
    end

    local nReturnKey = 207 -- 'End'

    local nCursorPosX = 1
    local nCurrentLine = 1
    local nCurrentLineLength = 0

    -- Draws the paper border so people know where the page ends.
    local function drawBorder()
        for nHeight = 1, nScreenHeight do
            term.setCursorPos( 12, nHeight )
            term.write( "|" )

            term.setCursorPos( 12 + nPaperWidth + 1, nHeight )
            term.write( "|" )
        end

        term.setCursorPos( 1, nScreenHeight )
        term.write( "'END' menu" )
        printRight( nScreenHeight, "Ln " .. nCurrentLine .. " of ".. nScreenHeight )
    end

    clearScreen()
    drawBorder()
    if bExistingDocument then
        for nHeight=1, #tLines do
            term.setCursorPos( 13, nHeight )
            term.write( tLines[nHeight] )
        end
    end
    while nCurrentLine < nLineCap do
        term.setCursorPos( 13 + nCursorPosX - 1, nCurrentLine )
        local sEvent, cChar = os.pullEvent()

        if sEvent == "char" then
            if tLines[nCurrentLine]:len() + 1 < nLineWidthCap then
                tLines[nCurrentLine] = tLines[nCurrentLine]:sub( 1, nCursorPosX - 1 ) .. cChar .. tLines[nCurrentLine]:sub( nCursorPosX, tLines[nCurrentLine]:len() )
                nCursorPosX = nCursorPosX + 1
            else
                if nCurrentLine + 1 <= nLineCap then
                    tLines[nCurrentLine] = tLines[nCurrentLine] .. cChar
                    nCurrentLine = nCurrentLine+1
                    nCursorPosX = 1
                else
                    term.setCursorBlink( false )
                    return tLines
                end
            end
        elseif sEvent == "key" then
            if cChar == 14 then
                if nCursorPosX - 1 > 0 then
                    tLines[nCurrentLine] = tLines[nCurrentLine]:sub( 1, nCursorPosX - 2 ) .. tLines[nCurrentLine]:sub( nCursorPosX, tLines[nCurrentLine]:len() )
                    nCursorPosX = nCursorPosX - 1
                else
                    if nCurrentLine > 1 then
                        nCurrentLine = nCurrentLine - 1
                        if tLines[nCurrentLine]:len() == nLineWidthCap then
                            tLines[nCurrentLine] = tLines[nCurrentLine]:sub( 1, tLines[nCurrentLine]:len() - 1 )
                        end
                        nCursorPosX = tLines[nCurrentLine]:len() + 1
                    end
                end
            elseif cChar == 28 then
                if nCurrentLine + 1 <= nLineCap then
                    nCurrentLine = nCurrentLine+1
                    nCursorPosX = 1
                else
                    term.setCursorBlink( false )
                    return tLines
                end
            elseif cChar == 203 then
                if nCursorPosX - 1 > 1 then
                    nCursorPosX = nCursorPosX - 1
                end
            elseif cChar == 205 then
                if nCursorPosX + 1 < tLines[nCurrentLine]:len() + 2 then
                    nCursorPosX = nCursorPosX + 1
                end
            elseif cChar == 200 then
                if nCurrentLine - 1 > 0 then
                    nCurrentLine = nCurrentLine - 1
                    if tLines[nCurrentLine]:len() < nCursorPosX then
                        if tLines[nCurrentLine]:len() > 0 then
                            nCursorPosX = tLines[nCurrentLine]:len()
                        else
                            nCursorPosX = 1
                        end
                    end
                end
            elseif cChar == 208 then
                if nCurrentLine + 1 < #tLines then
                    nCurrentLine = nCurrentLine + 1
                    if tLines[nCurrentLine]:len() < nCursorPosX then
                        if tLines[nCurrentLine]:len() > 0 then
                            nCursorPosX = tLines[nCurrentLine]:len()
                        else
                            nCursorPosX = 1
                        end
                    end
                end
            elseif cChar == 15 then
                if tLines[nCurrentLine]:len() + 3 > nLineWidthCap then
                    local nSpaceLeft = nLineWidthCap - tLines[nCurrentLine]:len()
                    if nSpaceLeft > 0 then
                        tLines[nCurrentLine] = tLines[nCurrentLine] .. string.rep( " ", nSpaceLeft )
                    end

                    nCurrentLine = nCurrentLine + 1
                    nCursorPosX = 1
                else
                    tLines[nCurrentLine] = tLines[nCurrentLine] .. "   "
                    nCursorPosX = nCursorPosX + 3
                end
            elseif cChar == nReturnKey then
                term.setCursorBlink( false )
                return tLines
            end
        end

        clearScreen()
        drawBorder()
        for nHeight=1, #tLines do
            term.setCursorPos( 13, nHeight )
            term.write( tLines[nHeight] )
        end
    end

    term.setCursorBlink( false )
    return tLines
end
---------------------------------------------------

-- SCREENS --
-- This method gets whether or not the user wants to print the document typed. (used in drawAndGetPrintConfirmationScreen)
function getConfirmation()
    local function drawSelections()
        if nSelection == 1 then
            printCentered( 9, "[YES] NO " )
        elseif nSelection == 2 then
            printCentered( 9, " YES [NO]" )
        end
    end

    -- Draw the confirmation options.
    drawBox( 20 )
    printCentered( 6, "PRINT?" )

    -- Get a 'YES' or 'NO' from the user with a simple menu.
    while not bPrinted do
        drawSelections()
        local sEvent, nKey = os.pullEvent( "key" )

        if nKey == 28 or nKey == 205 or nKey == 203 then
            handleKeyPress( nKey )
        end
    end

    return true
end

-- Gets the title for the page to be printed.
function getPageTitle()
    drawBox( 20 )
    printCentered( 6, "Page Title:" )
    term.setCursorPos( nScreenWidth/2 - 9, 9 )

    local sPageTitle = tostring( limitRead( 18 ) )
    if not sPageTitle or string.len( sPageTitle ) == 0 then
        sPageTitle = "Default_PageTitle"
    end

    return sPageTitle
end

-- This screen will prompt the user for a yes or no answer.
function drawAndGetPrintConfirmationScreen()
    getConfirmation()
end
------------

initializePrinterAndProgram()
tDocument = readLines()
drawAndGetPrintConfirmationScreen()