-- mkdir only
-- A portable filesystem API using LuaJIT's FFI
-- Retrieved 2024-07-13 from https://gist.githubusercontent.com/Techcable/503f35ceea9554fb81cf3a5c1aa550da/raw/33a29f59207335b743824fbb657e4721a12ce280/fs.lua
local ffi = require("ffi")
local table = require("table")
require("string")
-- Cache needed functions and locals
local C, errno, string = ffi.C, ffi.errno, ffi.string
local concat, insert = table.concat, table.insert

-- "Standard" C99 functions
ffi.cdef[[
char *strerror(int errnum);
]]

local exists, mkdir, PATH_SEPARATOR
if ffi.os == "Windows" then
    ffi.cdef[[
    bool CreateDirectoryA(const char *path, void *lpSecurityAttributes);
    int _access(const char *path, int mode);
    ]]
    function exists(path)
        assert(type(path) == "string", "path isn't a string")
        local result = C._access(path, 0) -- Check existence
        return result == 0
    end
   
    function mkdir(path, _)
        assert(type(path) == "string", "path isn't a string")
        if not C.CreateDirectoryA(path, nil) then
            local message = string(C.strerror(errno()))
            error("Unable to create directory " .. path .. ": " .. message)
        end
    end
    PATH_SEPARATOR = "\\"
elseif ffi.os == "Linux" or ffi.os == "OSX" then
    ffi.cdef[[
    int mkdir(const char *path, int mode);
    int access(const char *path, int amode);
    ]]
    function exists(path)
        assert(type(path) == "string", "path isn't a string")
        local result = C.access(path, 0) -- Check existence
        return result == 0
    end
    function mkdir(path, mode)
        assert(type(path) == "string", "path isn't a string")
        local mode = tonumber(mode or "755", 8)
        if C.mkdir(path, mode) ~= 0 then
            local message = string(C.strerror(errno()))
            error("Unable to create directory " .. path .. ": " .. message)
        end
    end
    PATH_SEPARATOR = "/"
else
    error("Unsupported operating system: " .. ffi.os)
end

local function join(...)
    local parts = {}
    for i = 1, select("#", ...) do
        local part = select(i, ...)
        insert(parts, part)
    end
    return concat(parts, PATH_SEPARATOR)
end

local function splitPath(path)
    assert(type(path) == "string", "path isn't a string!")
    local parts = {}
    local lastIndex = 0
    for i = 1, path:len() do
        if path:sub(i, i) == PATH_SEPARATOR then
            insert(parts, path:sub(lastIndex, i - 1))
            lastIndex = i + 1
        end
    end
    insert(parts, path:sub(lastIndex))
    return parts
end

local function mkdirs(path)
    local parts = splitPath(path)
    local currentPath = parts[1]
    for i=2, #parts do
        if not exists(currentPath) then
            mkdir(currentPath)
        end
        -- Note: This isn't suboptimal, since we really do need the intermediate results
        currentPath = currentPath .. PATH_SEPARATOR .. parts[i]
    end
    if not exists(path) then
        mkdir(path)
    end
end

return {
    exists = exists,
    join = join,
    mkdir = mkdir,
    mkdirs = mkdirs,
    splitPath = splitPath,
    PATH_SEPERATOR = PATH_SEPARATOR
}