OpenComputers Gitlab API Library Installer

--Installer for OpenComputers Gitlab API Library
--For More Info See: https://gitlab.com/Corbinhol/opencomputers-gitlab-api-library
if gitlab ~= nil then
    io.write("It seems that the gitlab library is already loaded. Unloading...");
    gitlab = nil;
    if gitlab ~= nil then
        io.write("Failed.\n");
        os.exit();
    end
    io.write("Done.\n")
end

local filesystem = require("filesystem");
local internet = require("internet");
local term = require("term");

function combine(handle)
    local out = "";
    for chunk in handle do out = out .. chunk end
    return out;
end

function download(url, dir)
    local handle = internet.request(url);
    local result, data = pcall(combine, handle);
    if not result then
        error("Failure to connect to " .. url);
    end
    local file = io.open(dir, "w");
    file:write(data);
    file:close();
    return true;
end

if not filesystem.exists("/usr/lib") then
    io.write("User library folder does not seem to exist. Creating now...");
    filesystem.makeDirectory("/usr/lib");
    io.write("done.\n");
end
io.write("Beginning Installation of Gitlab API Library...\n");
io.write("Downloading Gitlab Module...");
download("https://gitlab.com/Corbinhol/opencomputers-gitlab-api-library/-/raw/main/gitlab.lua?ref_type=heads", "/usr/lib/gitlab.lua");
io.write("done.\n");
io.write("Downloading Base64 Dependency...");
download("https://gitlab.com/Corbinhol/opencomputers-gitlab-api-library/-/raw/main/base64.lua?ref_type=heads", "/usr/lib/base64.lua");
io.write("done.\n");
io.write("Downloading JSON Dependency...");
download("https://gitlab.com/Corbinhol/opencomputers-gitlab-api-library/-/raw/main/json.lua?ref_type=heads", "/usr/lib/json.lua");
io.write("done.\n");
if not filesystem.exists("/usr/bin") then
    io.write("User bin folder does not seem to exist. Creating now...");
    filesystem.makeDirectory("/usr/bin");
    io.write("done.\n");
end
io.write("Downloading Gitlab Application...");
download("https://gitlab.com/Corbinhol/opencomputers-gitlab-api-library/-/raw/main/Program/Gitlab.lua?ref_type=heads", "/usr/bin/gitlab.lua");
io.write("done.\n");
io.write("If you have an API Key you'd like to use, please enter it. If not, then just press enter. [Warning Key will be saved on computer.\nDo not use if you share this computer with others you do not trust!!]: ");
local key = term.read({pwchar = "*", dobreak=false});
local key = string.gsub(key, "\n", "");
if key ~= "" then
    io.write("\nSaving key...");
    local gitlab = require("gitlab");
    gitlab.save_key(key);
    io.write("done.\n");
else
    io.write("\nSkipping Key.\n");
end
io.write("Instalation Complete!");