Venatus Floor Display Sign

-- market display sign
-- files used:
--  monside (top/bottom/left/etc) - side monitor is on. Can also use this to specify modem-connected stuff
--  floorno - the REVERSE INDEXED floor number this computer serves (used for highlighting)
--  floors  - the floor listing (top to bottom), one floor/line

-- ===============================================
-- reads a config for floor names
f = fs.open('floors','r')
floorList = {}

curLine = f.readLine()
while curLine ~= nil do
    table.insert(floorList, curLine)
    curLine = f.readLine()
end
f.close()
f = fs.open('floorno','r')
curFloor = tonumber( f.readAll() )
f.close()
-- end floor config read
-- ===============================================
-- hw init

f = fs.open('monside','r')
curMon = peripheral.wrap(f.readAll())
f.close()
curMon.clear()
curMon.setTextColor(colors.white)
local width, height = curMon.getSize()

-- end hw init
-- ===============================================
local function computeCenteringPos(strlen, padding)
    return (width-strlen)/2 + 1 + padding
end
local function printHorizRule(mon, y)
    mon.setTextColor(colors.white)
    mon.setCursorPos(1,y)
    mon.write(string.rep('-', width))
end
local function renderFloor(floorNum, mon)
    local floorText = floorList[floorNum]
    -- half of this stuff deals with text based on the size of it.
    -- strip and extract the color preprocessors
    preProcStart, preProcEnd = string.find(floorText, '~')
    preProcColor = nil
    if preProcStart == 1 then
        -- found the preproc!
        preProcStart, preProcEnd = string.find(floorText, '~',2)
        preProcColor = string.sub(floorText, 2,preProcEnd-1)
        print("preprocessor: "..preProcColor)
        floorText = floorText.sub(floorText, preProcEnd+1)
    end


    local width, height = mon.getSize()
    local strlen = string.len(floorText)
    local cursorPosX = 0
    local cursorPosY = height-( (#floorList-floorNum) *2)
    -- text rendering :D

    -- set the color appropriately
    if floorNum == curFloor then
        mon.setTextColor(colors.lime)
    elseif preProcColor ~= nil and colors[preProcColor] ~= nil then
        mon.setTextColor(colors[preProcColor])
    else
        mon.setTextColor(colors.white)
    end

    floorCode = nil
    -- attempt to crudely center this
    if floorNum == curFloor then
        floorCode = '==> '
    else
        floorCode = 'L'..(#floorList-floorNum+1)..': '
    end
    if strlen + string.len(floorCode) > width then
        -- wider than screen. Left justify it.
        mon.setCursorPos(1, cursorPosY)
        mon.write(floorCode..floorText)
    else
        -- ( (width-len(txt)) /2)*' ' + txt

        -- "+1" because LUA has 1-based indexes. This piece is designed for 0-based indices -_-
        -- "+2" to make it look centered against the offset that the floor numbers take up
        --cursorPosX = (width-strlen)/2 + 1 + 2
        cursorPosX = computeCenteringPos(strlen,2)
        mon.setCursorPos(1,cursorPosY)
        mon.write(floorCode)

        mon.setCursorPos(cursorPosX, cursorPosY)
        mon.write(floorText)
    end
end

-- print store header
txt = 'Hastwell Industries'
curMon.setCursorPos(computeCenteringPos(string.len(txt),0),1)
curMon.write(txt)

printHorizRule(curMon,2)

for i = 1, #floorList do
    renderFloor(i,curMon)
end