file_utils.lua

local utils = {}

utils.slash = package.config:sub(1, 1)

local function getOS()
    if utils.slash == "\\" then
        return "windows"
    end
    if utils.slash == "/" then
        return "unix"
    end

    print("Error: unknown type of OS!")
    os.exit(1)
end

utils.osType = getOS()

function utils.fileExists(file)
    local ok, err, code = os.rename(file, file)
    if code == 13 then -- permission denied, file exists
        return true
    end
    return ok, err
end

function utils.directoryExists(dir)
    local slashes = utils.osType == "windows" and "\\" or "/"
    return utils.fileExists(dir .. slashes)
end

function utils.createDirectory(dir)
    os.execute("mkdir " .. dir)
end

function utils.getListOfFiles(dir)
    local files = {}
    local loop = utils.osType == "windows" and 'dir "' .. dir .. '" /b' or "ls -pa " .. dir .. " | grep -v /"

    for file in io.popen(loop):lines() do
        files[#files + 1] = file
    end

    return files
end

function utils.getScriptDir()
    local dir = debug.getinfo(2, "S").source
    if dir:sub(1, 1) == "@" then
        dir = dir:sub(2)
    end

    local path
    if not dir:match("^/") or not dir:match("^%a:") then
        path = (os.getenv("PWD") or io.popen("cd"):read("*l")) .. "/" .. dir
    else
        path = dir
    end

    path = path:gsub(utils.slash, "/")

    return dir:match("(.*/)")
end

function utils.expandPath(path)
    if path:sub(1, 1) == "~" then
        local home = os.getenv("HOME") or "~"
        path = home .. path:sub(2)
    end

    path = path:gsub("%$(%w+)", function(env)
        return os.getenv(env) or ("$" .. env)
    end)

    return path
end

function utils.isModuleAvailable(name)
    if package.loaded[name] then
        return true
    else
        for _, searcher in ipairs(package.searchers or package.loaders) do
            local loader = searcher(name)
            if type(loader) == "function" then
                package.preload[name] = loader
                return true
            end
        end
        return false
    end
end

return utils