#include <fcntl.h>
#include <os/ArgumentParser.h>
#include <os/Directory.h>
#include <os/File.h>
#include <os/FileSystem.h>
#include <stdio.h>
#include <sys/stat.h>

Result<int> luna_main(int argc, char** argv)
{
    StringView pathname;
    bool show_all { false };
    bool show_almost_all { false };
    bool long_list { false };

    os::ArgumentParser parser;
    parser.add_description("List files contained in a directory (defaults to '.', the current directory)"_sv);
    parser.add_system_program_info("ls"_sv);
    parser.add_positional_argument(pathname, "directory"_sv, "."_sv);
    parser.add_switch_argument(show_all, 'a', "all"_sv, "also list hidden files (whose filename begins with a dot)"_sv);
    parser.add_switch_argument(show_almost_all, 'A', "almost-all"_sv, "list all files except '.' and '..'"_sv);
    parser.add_switch_argument(long_list, 'l', ""_sv, "use a long listing format"_sv);
    parser.parse(argc, argv);

    Vector<String> files;
    int dirfd = AT_FDCWD;
    SharedPtr<os::Directory> dir;

    if (os::FileSystem::is_directory(pathname))
    {
        dir = TRY(os::Directory::open(pathname));
        dirfd = dir->fd();

        auto filter = os::Directory::Filter::Hidden;
        if (show_almost_all) filter = os::Directory::Filter::ParentAndBase;
        else if (show_all)
            filter = os::Directory::Filter::None;

        files = TRY(dir->list(filter));
    }
    else if (os::FileSystem::exists(pathname))
    {
        auto str = TRY(String::from_string_view(pathname));
        TRY(files.try_append(move(str)));
    }
    else
        return err(ENOENT);

    if (!long_list)
    {
        auto list = TRY(String::join(files, " "_sv));
        if (!list.is_empty()) os::println("%s", list.chars());
    }
    else
    {
        for (const auto& file : files)
        {
            struct stat st;
            if (fstatat(dirfd, file.chars(), &st, 0) < 0)
            {
                perror(file.chars());
                return 1;
            }

            os::println("%6o %u %4u %4u %10lu %s", st.st_mode, st.st_nlink, st.st_uid, st.st_gid, st.st_size,
                        file.chars());
        }
    }

    return 0;
}