Lua Script System Installer

-- Lua Script System --
-- set local variables
local advanced = term.isColor()
local scrwidth, scrheight = term.getSize()
local oldsetTextColor = term.setTextColor
local oldsetBackgroundColor = term.setBackgroundColor
local splabg = colors.cyan
local LuaSSdir = "LuaSS/"
local loadingimage = paintutils.loadImage( LuaSSdir.."splash.txt")
local folderStructureS
_G.shell = shell

-- set the new global os.pullEvent function
function os.pullEvent(...)
    local eventType, p1, p2, p3, p4, p5, p6, p7, p8, p9, p10 = os.pullEventRaw(...)
    if eventType == "terminate" then
        error("Terminated installation", 0)
        return
    end
    return eventType, p1, p2, p3, p4, p5, p6, p7, p8, p9, p10
end

-- change color functions to fallback when not advanced computer
if not advanced then
    function term.setTextColor( color )
        if color == colors.black then
            oldsetTextColor(color)
        else
            oldsetTextColor(colors.white)
        end
    end
    function term.setBackgroundColor( color )
        if color == colors.white then
            oldsetBackgroundColor(color)
        else
            oldsetBackgroundColor(colors.black)
        end
    end
end
-- draw a loading screen --
term.setBackgroundColor( splabg )
term.clear()
if loadingimage then
    paintutils.drawImage(loadingimage, math.floor(scrwidth*.5 - 6), math.floor(scrheight*.5 - 2))
end
term.setCursorPos( 1, 1 )

local loadingstring, oldloadingstring = "Starting Lua Script System for the first time...", ""
if loadingimage then loadingstring = "Updating Lua Script System..." end
local loadingframe = -scrwidth*.2
local setCursorPos = term.setCursorPos
local function drawLoadingProgressIndicator()
    while true do -- run a loop to prevent it from stopping the loading function before it returns.
        loadingframe = loadingframe + 1
        if loadingframe > scrwidth*1.2 then
            loadingframe = -scrwidth*.2
        end
        if loadingstring ~= oldloadingstring then
            setCursorPos( scrwidth*.5 - (#loadingstring*.5) + 1, scrheight - 1)
            term.setBackgroundColor( splabg )
            term.clearLine()
            term.write(loadingstring)
        end
        setCursorPos( loadingframe - 1, scrheight )
        term.setBackgroundColor( colors.blue )
        term.clearLine()
        term.setBackgroundColor( colors.lightBlue )
        term.write(string.rep(" ", scrwidth*.2))
        sleep()
    end
end

local function outOfSpaceError()
    term.setBackgroundColor(colors.blue)
    local outofspaceTitle = "Out of space"
    term.clear()
    term.setCursorPos((scrwidth - #outofspaceTitle)*.5, 1)
    term.write(outofspaceTitle)
    term.setCursorPos(1, 8)
    print("You need to free at least "..#folderStructureS - fs.getFreeSpace("").." bytes on your hard disk to install Lua Script System.")
    print("After freeing enough disk space restart the script.")
    error("Cannot continue installing Lua Script System!", 0)
end

local function createFolderForFile(path)
    local curpath = path
    local startHere = 1
    while true do
        local nextSlash = string.find(string.sub(path, startHere, -1), "/")
        if not nextSlash then return end
        nextSlash = nextSlash + startHere
        local folderToCreate = string.sub(curpath, 0, nextSlash - 1)
        if not fs.isDir(folderToCreate) then
            local ok, err = pcall(fs.makeDir, folderToCreate)
            if not ok then
                if string.find(err, "Out of space") then
                    outOfSpaceError()
                end
            end
        end
        startHere = nextSlash
    end
end

local function installLuaScriptSystem()
    local urlToDownload = "https://pastebin.com/raw/c7jJgtgS"
    local handle = http.get(urlToDownload)
    folderStructureS = handle.readAll()
    handle.close()
    local folderStructure = textutils.unserialize(folderStructureS)
    if fs.getFreeSpace("") < #folderStructureS then
        loadingstring = "You are very low on space!!"
    end
    for k, v in pairs(folderStructure) do
        createFolderForFile(k)
        local file = fs.open(k, "w")
        if file then
            file.write(v)
            local ok, err = pcall(file.close)
            if not ok then
                if string.find(err, "Out of space") then
                    outOfSpaceError()
                end
            end
        end
        sleep()
    end
end

parallel.waitForAny(drawLoadingProgressIndicator, installLuaScriptSystem)

shell.run(LuaSSdir.."start")