Kassenbeleg.lua

-- Author: InDieTasten on server.lycodon.com
-- Date created: 2018-02-24
-- Lua script for use in ComputerCraft

-- settings
local printerSide = "left"
local catalogFilename = "./catalog"

-- program-wide variables
local selectionScreenPage = 1
local catalog = {}
local catalogPagesTotal = 1
local receiptPositions = {}

-- function declarations

local function getProductCatalogFromFile(page)
    local _,height = term.getSize()

    local pageSize = height - 6

    local catalog = {}
    local fileHandle = fs.open(catalogFilename, "r")

    if (fileHandle == nil) then
        error("Catalog file '"..tostring(catalogFilename).."' not found")
    end

    while (true) do
        local product = fileHandle.readLine()
        if (product == nil or product == "") then
            break
        end
        table.insert(catalog, product)
    end

    fileHandle.close()

    return catalog
end

local function enterSelectionScreen()

    term.clear()
    term.setCursorPos(1,1)

    catalogPagesTotal = math.ceil(#catalog/12)

    print("Kassenbeleg Printer v2")
    print("")
    
    -- print available products
    for p = (selectionScreenPage-1)*12+1, math.min(#catalog, selectionScreenPage*12), 1 do
        print(p, ". ", string.sub(catalog[p], 1, 21))
    end

    -- print current receipt positions
    for i, v in ipairs(receiptPositions) do
        term.setCursorPos(28, 2+i)
        if (i > 11) then
            term.write("...")
            break
        else
            term.write("- "..string.sub(receiptPositions[i], 1, 21))
        end
    end

    -- print instructions
    term.setCursorPos(1, 16)
    pageControls = ""
    if (selectionScreenPage > 1) then
        pageControls = " [prev]"
    end
    if (selectionScreenPage < catalogPagesTotal) then
        pageControls = pageControls.." [next]"
    end
    print("Seite "..tostring(selectionScreenPage).." von "..tostring(catalogPagesTotal)..pageControls)
    print("Wähle Produkt, oder Aktion:\n[print] [clear] [add] [exit]")
    return read()
end

local function printReceipt(positions)

    local pagesTotal = math.ceil(#positions/15)
    local printer = peripheral.wrap(printerSide)

    if (printer == nil) then
        error("Printer not found on side '"..tostring(printerSide).."'")
    end

    while (printer.getInkLevel() < pagesTotal) do
        printError("Nicht genügend Tinte. Fülle Tinte nach und drücker anschliessend Enter/Return")
        read()
    end

    while (printer.getPaperLevel() < pagesTotal) do
        printError("Nicht genügend Papier. Fülle Papier nach und drücke anschliessend Enter/Return")
        read()
    end

    if (not printer.newPage()) then
        print("Vorheriger Druckvorgang wird abgebrochen")
        printer.setPageTitle("Abgebrochener Druckvorgang")
        printer.endPage()
        printReceipt(positions)
        return
    end

    for page = 1, pagesTotal, 1 do

        if (page == 1) then
            -- header
            printer.setCursorPos(1,1)
            printer.write("       -- I-EP --")
        else
            while (not printer.newPage()) do
                if (printer.getInkLevel() == 0) then
                    printError("Nicht genügend Tinte. Fülle Tinte nach und drücke anschliessend Enter/Return")
                    read()
                elseif (printer.getPaperLevel() == 0) then
                    printError("Nicht genügend Papier. Fülle Papier nach und drücke anschliessend Enter/Return")
                    read()
                end
            end
        end

        -- set page title
        if (page == 1) then
            printer.setPageTitle("I-EP Kassenbeleg")
        else
            printer.setPageTitle("I-EP Kassenbeleg ["..tostring(page).."]")
        end

        -- print positions
        printer.setCursorPos(1, 3)
        for pos = (page-1)*15+1, math.min(#positions, page*15) do
            printer.write(string.sub(positions[pos], 0, 24))
            printer.setCursorPos(1, ({printer.getCursorPos()})[2] + 1)
        end

        if (page == pagesTotal) then 
            -- footer
            printer.setCursorPos(1, 19)
            printer.write("  Vielen Dank für Ihren")
            printer.setCursorPos(1, 20)
            printer.write("      Einkauf bei")
            printer.setCursorPos(1, 21)
            printer.write(" Ice-Electronic Programs")
        end

        while (not printer.endPage()) do
            printError("Kein Platz mehr im Ausgabefach. Entnehme Seiten und drücke Enter/Return")
            read()
        end
    end

    print("Beleg erfolgreich gedruckt")
end

-- main

local function main()
    catalog = getProductCatalogFromFile()

    while (true) do
        local newReceiptPosition = enterSelectionScreen()
        if (newReceiptPosition == "print") then
            if (#receiptPositions == 0) then
                printError("Ein Beleg muss mindestens ein Produkt enthalten")
                sleep(2)
            else
                printReceipt(receiptPositions)
                break
            end
        elseif (newReceiptPosition == "add") then
            write("Direkteingabe eines Produkts: ")
            local prodName = read()
            if (prodName ~= "") then
                table.insert(receiptPositions, prodName)
            end
        elseif (newReceiptPosition == "clear") then
            receiptPositions = {}
        elseif (newReceiptPosition == "exit") then
            break
        elseif (newReceiptPosition == "next") then
            if (selectionScreenPage < catalogPagesTotal) then
                selectionScreenPage = selectionScreenPage + 1
            end
        elseif (newReceiptPosition == "prev") then
            if (selectionScreenPage > 1) then
                selectionScreenPage = selectionScreenPage - 1
            end
        else
            -- Add product to shopping cart
            local prodName = catalog[tonumber(newReceiptPosition)]
            if (prodName == nil) then
                printError("Not found")
                sleep(1)
            else
                table.insert(receiptPositions, prodName)
            end
        end
    end
end

main()