Lithium OS Installer

--[[
    Lithium OS Launcher by LegoStax
]]--
function download(url, fn)
    -- Download Function --
    -- check for http api
    if not http then
        print("The HTTP API is not enabled.")
        print("Please enable the API in ComputerCraft settings.")
        return
    else
        -- if it's enabled then we download the file into the variable response and then write response to the file specified when the function is called
        local response = http.get(url)
        if response then
            local data = response.readAll()
            response.close()
            local file = fs.open(fn, "w")
            file.write(data)
            file.close()
        else
            -- if there's no response or response is nil
            print("No Response.  Are you connected to the internet?")
            print("If you are, then Pastebin is down.")
            return
        end
    end
end

-- OS installation.  I'm going to replace this with a gui sooner or later
if not fs.exists(".programs") then
    shell.run("delete", "lithos")
    print("Installing Lithium OS")
    download("http://pastebin.com/raw.php?i=m5vPnePf", "lithos")
    print("Installing Programs")
    shell.run("mkdir", ".programs")
    download("http://pastebin.com/raw.php?i=JSFdbuSJ", ".programs/lith")
    download("http://pastebin.com/raw.php?i=aH3S7VhP", ".programs/login")
    download("http://pastebin.com/raw.php?i=Mipa0pFt", ".programs/settings")
    download("http://pastebin.com/raw.php?i=XcSsVkiN", ".programs/sha")
    download("http://pastebin.com/raw.php?i=pnzdr8FB", ".programs/explorer")
    print("Installing Images")
    download("http://pastebin.com/raw.php?i=VjMZQdCX", ".programs/set-bg")
    download("http://pastebin.com/raw.php?i=Uy34X768", ".programs/login_img")
    download("http://pastebin.com/raw.php?i=WPUztxL0", ".programs/update_img")
    download("http://pastebin.com/raw.php?i=Hdwh8X1C", ".programs/desktop")
    print("Finished.")
    print("NOTE: Anything seen in red is an unfinished feature")
    print("Setup:")
    write "Username: "
    user = read()
    x,y = term.getCursorPos()
    term.setCursorPos(x,y+1)
    write "Password: "
    cpass = read("*")
    os.loadAPI(".programs/sha")
    cpass = sha.sha256(cpass)
    info = {
        user = nil;
        cpass = nil;
    }
    info.user = user
    info.cpass = cpass
    local file = fs.open(".programs/user", "w")
    file.write(info)
    file.close()
    print("Rebooting...")
    sleep(2)
    os.reboot()
else
    if not fs.exists(".programs/config") then
        config = {
            autoupdate = nil,
            desktop_img = ".programs/desktop",
            bgcolor = colors.white,
            taskside = "top"
        }
        running = true
        while running do
            term.clear()
            term.setCursorPos(1,1)
            term.write("Autoupdate? (y/n)")
            e = {os.pullEvent("key")}
            if e[2] == keys.y then
                config.autoupdate = true
                running = false
            elseif e[2] == keys.n then
                config.autoupdate = false
                running = false
            end
        end
        local file = fs.open(".programs/config", "w")
        file.write(textutils.serialize(config))
        file.close()
    end
    if not fs.exists(".programs/user") then
        write "Username: "
        user = read()
        x,y = term.getCursorPos()
        term.setCursorPos(x,y+1)
        write "Password: "
        cpass = read("*")
        os.loadAPI(".programs/sha")
        cpass = sha.sha256(cpass)
        info = {
            user = nil;
            cpass = nil;
        }
        info.user = user
        info.cpass = cpass
        local file = fs.open(".programs/user", "w")
        file.write(textutils.serialize(info))
        file.close()
    end
    config = {}
    local file = fs.open(".programs/config", "r")
    config = textutils.unserialize(file.readAll())
    file.close()
    if config.autoupdate == true then
        bg = paintutils.loadImage(".programs/update_img")
        paintutils.drawImage(bg, 1, 1)
        term.setBackgroundColor(colors.lightGray)
        term.setCursorPos(3,1)
        term.write("Lithium OS - Update")
        term.setCursorPos(26,14)
        term.write(" Checking for updates...")
        if not http then
            -- tell user to turn on http api
            term.setCursorPos(26,14)
            term.write(" LithOS Updater cannot  ")
            term.setCursorPos(26,15)
            term.write(" work without the HTTP API")
            sleep(3)
        else
            -- download file
            local response = http.get("http://pastebin.com/raw.php?i=8Kvh0Sze")
            if response then
                local data = response.readAll()
                response.close()
                local file = fs.open(".programs/update", "w")
                file.write(data)
                file.close()
                shell.run(".programs/update")
                if ver > 2.03 then
                    term.setCursorPos(26,15)
                    term.write(" New Version Available ")
                    term.setCursorPos(26,16)
                    term.write(" ")
                    term.setBackgroundColor(colors.gray)
                    term.setCursorPos(27,16)
                    term.write("Update")
                    term.setCursorPos(34,16)
                    term.write("Later")
                    choice = false
                    while not choice do
                        local event, button, x, y = os.pullEvent("mouse_click")
                        if button == 1 then
                            if x >= 27 and x <= 32 and y == 16 then
                                choice = true
                                -- Download new installer
                                local response = http.get("http://pastebin.com/raw.php?i=XYLELffE")
                                if response then
                                    local data = response.readAll()
                                    response.close()
                                    local file = fs.open(".programs/startup", "w")
                                    file.write(data)
                                    file.close()
                                    shell.run("delete", ".programs")
                                    sleep(1)
                                    os.reboot()
                                end
                            elseif x >= 34 and x <= 38 and y == 16 then
                                choice = true
                                -- Begin OS
                            end
                        end
                    end
                else
                    term.setCursorPos(26,14)
                    term.write(" No Updates Found       ")
                    sleep(3)
                end
            else
                -- if no response, we assume this
                term.setCursorPos(26,14)
                term.write(" Unable to connect     ")
                term.setCursorPos(26,15)
                term.write(" to the internet.")
                sleep(3)
            end
        end
    end
    shell.run(".programs/login")
end