#include <bits/modes.h>
#include <dirent.h>
#include <errno.h>
#include <fcntl.h>
#include <luna/String.h>
#include <os/Directory.h>
#include <os/FileSystem.h>
#include <pwd.h>
#include <stdlib.h>
#include <sys/syscall.h>
#include <unistd.h>

namespace os::FileSystem
{
    bool exists(const Path& path)
    {
        struct stat st;

        if (stat(path, st).has_error()) return false;

        return true;
    }

    bool is_directory(const Path& path)
    {
        struct stat st;

        if (stat(path, st).has_error()) return false;

        return S_ISDIR(st.st_mode);
    }

    Result<void> stat(const Path& path, struct stat& st)
    {
        long rc =
            syscall(SYS_fstatat, path.dirfd(), path.name().chars(), &st, path.is_empty_path() ? AT_EMPTY_PATH : 0);

        return Result<void>::from_syscall(rc);
    }

    Result<void> create_directory(StringView path, mode_t mode)
    {
        long rc = syscall(SYS_mkdir, path.chars(), mode);

        return Result<void>::from_syscall(rc);
    }

    Result<void> remove(const Path& path)
    {
        long rc = syscall(SYS_unlinkat, path.dirfd(), path.name().chars(), 0);

        return Result<void>::from_syscall(rc);
    }

    Result<void> remove_tree(const Path& path)
    {
        auto rc = remove(path);
        if (!rc.has_error()) return {};
        if (rc.error() != ENOTEMPTY) return rc.release_error();

        auto dir = TRY(os::Directory::open(path));

        Vector<String> entries = TRY(dir->list(os::Directory::Filter::ParentAndBase));

        for (const auto& entry : entries) { TRY(remove_tree({ dir->fd(), entry.view() })); }

        return remove(path);
    }

    Result<String> working_directory()
    {
        char* ptr = getcwd(NULL, 0);
        if (!ptr) return err(errno);
        return String { ptr };
    }

    Result<String> home_directory()
    {
        char* home = getenv("HOME");
        if (home) return String::from_cstring(home);

        struct passwd* pw = getpwuid(getuid());
        if (!pw) return err(ENOENT);

        return String::from_cstring(pw->pw_dir);
    }

    Result<void> change_directory(StringView path)
    {
        long rc = syscall(SYS_chdir, path.chars());

        return Result<void>::from_syscall(rc);
    }
}