#include <luna/CString.h>
#include <os/Directory.h>

#include <errno.h>
#include <fcntl.h>
#include <sys/syscall.h>
#include <unistd.h>

static bool should_skip_entry(const char* name, os::Directory::Filter filter)
{
    if (filter == os::Directory::Filter::None) return false;

    if (filter == os::Directory::Filter::Hidden) return *name == '.';

    if (filter == os::Directory::Filter::ParentAndBase) return !strcmp(name, ".") || !strcmp(name, "..");

    unreachable();
}

namespace os
{
    Result<SharedPtr<Directory>> Directory::open(StringView path)
    {
        auto dir = TRY(adopt_shared_if_nonnull(new (std::nothrow) Directory({})));

        DIR* dp = opendir(path.chars());
        if (!dp) return err(errno);

        dir->m_dirp = dp;

        return dir;
    }

    Result<SharedPtr<Directory>> Directory::openat(int dirfd, StringView path)
    {
        auto dir = TRY(adopt_shared_if_nonnull(new (std::nothrow) Directory({})));

        long rc = syscall(SYS_openat, dirfd, path.chars(), O_RDONLY | O_DIRECTORY, 0);
        int fd = TRY(Result<int>::from_syscall(rc));

        DIR* dp = fdopendir(fd);
        if (!dp)
        {
            close(fd);
            return err(errno);
        }

        dir->m_dirp = dp;

        return dir;
    }

    Result<String> Directory::next(Filter filter)
    {
        errno = 0;

        struct dirent* ent;
        do {
            ent = readdir(m_dirp);
        } while (ent && should_skip_entry(ent->d_name, filter));

        if (!ent && errno) return err(errno);

        if (!ent) return String {};

        return String::from_cstring(ent->d_name);
    }

    Directory::~Directory()
    {
        if (m_dirp) closedir(m_dirp);
    }

    Directory::Directory(Badge<Directory>)
    {
    }
}