RedBIT Train Network Platform Screen

local function findPeripheral( kind )
    for _,v in pairs( rs.getSides() ) do
        if peripheral.getType( v ) == kind then
            return v
        end
    end

    return nil
end

local monitor  -- empty variable waiting for peripheral.wrap
local monitorSide = findPeripheral( "monitor" )
local sizeX, sizeY = term.getSize() -- get the pixel size of the screen ( currently the computers screen )

if not monitorSide then
    print( "No monitor found! :(")
    error() -- exit the program here
else
    monitor = peripheral.wrap(monitorSide)
end

local function cwrite( msg, y )
    local w, h = term.getSize() -- get the pixel size of the current screen
    term.setCursorPos( w/2-#msg/2+1, y or h/2 ) -- set the cursor position so the supplied text will be in the middle of the screen
    write( msg ) -- draw the message
end

local function cline( y, col )
    term.setCursorPos(1,y)
    term.setBackgroundColor( col )
    term.clearLine()
    term.setBackgroundColor( colors.black )
end

local activeLines = {
    approch = "Train Approching",
    leaving = "Train Leaving",
    here = "Train Arrived",
}

local function drawScreen()
    term.clear()
    term.setCursorPos(1,1)
    term.setTextColor( colors.white )
    local w, h = term.getSize()

    cline( 1, colors.gray )
    cwrite("\[Pitsea Station\]",1)

    local rsInput = rs.getBundledInput("bottom")

    term.setTextColor( colors.white )
    cline( 3, colors.red )
    cwrite("Platform 1",3)
    cwrite("No Trains",5)
    if colors.test( rsInput, colors.blue ) then
        term.setTextColor( colors.lime )
        cwrite( activeLines.here, 5)
    end
    if colors.test( rsInput, colors.lime ) then
        term.setTextColor( colors.blue )
        cwrite( activeLines.approch, 5)
    end
    if colors.test( rsInput, colors.orange ) then
        term.setTextColor( colors.red )
        cwrite( activeLines.leaving, 5)
    end

    term.setTextColor( colors.white )
    cline( h/2+2, colors.blue )
    cwrite("Platform 2",h/2+2)
    cwrite("No Trains", h/2+4)
    if colors.test( rsInput, colors.red ) then
        term.setTextColor( colors.lime )
        cwrite( activeLines.here, h/2+4)
    end
    if colors.test( rsInput, colors.black ) then
        term.setTextColor( colors.blue )
        cwrite( activeLines.approch, h/2+4)
    end
    if colors.test( rsInput, colors.white ) then
        term.setTextColor( colors.red )
        cwrite( activeLines.leaving, h/2+4)
    end
end

term.clear() -- clear the terminal screen
cwrite( "Monitor has focus" ) -- print in the middle of the screen that the monitor has control

term.redirect( monitor ) -- give control of term functions to the monitor object meaning term. print and write will all show on the monitor

local refresh = os.startTimer( 1 ) -- this starts a timer that takes 1 second to complete, used for refreshing ( its better than sleep but requires event loops )

while true do
    drawScreen() -- call the function that will draw the screen

    os.pullEvent( "timer" ) -- the program will wait here until the timer finishes

    refresh = os.startTimer( 1 ) -- restart the refresh timer
end

term.restore() -- give term control back to the computer screen