/*
 * Copyright (C) 2025 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package android.os;

import static android.system.OsConstants.EACCES;
import static android.system.OsConstants.ENOENT;

import android.util.Log;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.nio.file.attribute.PosixFilePermission;
import java.util.EnumSet;
import java.util.Set;

public class FileUtils_ravenwood {
    private static final String TAG = "FileUtils_ravenwood";

    private FileUtils_ravenwood() {
    }

    private static Set<PosixFilePermission> fromIntMode(int mode) {
        Set<PosixFilePermission> perms = EnumSet.noneOf(PosixFilePermission.class);

        // Owner permissions
        if ((mode & 0400) != 0) perms.add(PosixFilePermission.OWNER_READ);
        if ((mode & 0200) != 0) perms.add(PosixFilePermission.OWNER_WRITE);
        if ((mode & 0100) != 0) perms.add(PosixFilePermission.OWNER_EXECUTE);

        // Group permissions
        if ((mode & 0040) != 0) perms.add(PosixFilePermission.GROUP_READ);
        if ((mode & 0020) != 0) perms.add(PosixFilePermission.GROUP_WRITE);
        if ((mode & 0010) != 0) perms.add(PosixFilePermission.GROUP_EXECUTE);

        // Others permissions
        if ((mode & 0004) != 0) perms.add(PosixFilePermission.OTHERS_READ);
        if ((mode & 0002) != 0) perms.add(PosixFilePermission.OTHERS_WRITE);
        if ((mode & 0001) != 0) perms.add(PosixFilePermission.OTHERS_EXECUTE);

        return perms;
    }

    /**
     * Simulates {@link FileUtils#setPermissions}. We ignore uid and gid.
     */
    static int setPermissions(String path, int mode, int uid, int gid) {
        var filePath = Paths.get(path);
        if (!Files.exists(filePath)) {
            return ENOENT;
        }

        try {
            Files.setPosixFilePermissions(filePath, fromIntMode(mode));
        } catch (IOException e) {
            Log.w(TAG, "Failed to set file permissions", e);
            return EACCES;
        }

        return 0;
    }
}