/*
 * Copyright (C) 2017 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 com.android.server.wifi;

import android.app.AppGlobals;
import android.content.pm.IPackageManager;
import android.os.Binder;
import android.os.ShellCommand;

import java.io.PrintWriter;

/**
 * Interprets and executes 'adb shell cmd wifi [args]'.
 *
 * To add new commands:
 * - onCommand: Add a case "<command>" execute. Return a 0
 *   if command executed successfully.
 * - onHelp: add a description string.
 *
 * If additional state objects are necessary add them to the
 * constructor.
 *
 * Permissions: currently root permission is required for all
 * commands. If the requirement needs to be relaxed then modify
 * the onCommand method to check for specific permissions on
 * individual commands.
 */
public class WifiShellCommand extends ShellCommand {
    private final WifiStateMachine mStateMachine;
    private final IPackageManager mPM;

    WifiShellCommand(WifiStateMachine stateMachine) {
        mStateMachine = stateMachine;
        mPM = AppGlobals.getPackageManager();
    }

    @Override
    public int onCommand(String cmd) {
        checkRootPermission();

        final PrintWriter pw = getOutPrintWriter();
        try {
            switch (cmd != null ? cmd : "") {
                case "set-ipreach-disconnect": {
                    boolean enabled;
                    String nextArg = getNextArgRequired();
                    if ("enabled".equals(nextArg)) {
                        enabled = true;
                    } else if ("disabled".equals(nextArg)) {
                        enabled = false;
                    } else {
                        pw.println(
                                "Invalid argument to 'set-ipreach-disconnect' - must be 'enabled'"
                                        + " or 'disabled'");
                        return -1;
                    }
                    mStateMachine.setIpReachabilityDisconnectEnabled(enabled);
                    return 0;
                }
                case "get-ipreach-disconnect":
                    pw.println("IPREACH_DISCONNECT state is "
                            + mStateMachine.getIpReachabilityDisconnectEnabled());
                    return 0;
                case "set-poll-rssi-interval-msecs":
                    int newPollIntervalMsecs;
                    try {
                        newPollIntervalMsecs = Integer.parseInt(getNextArgRequired());
                    } catch (NumberFormatException e) {
                        pw.println(
                                "Invalid argument to 'set-poll-rssi-interval-msecs' "
                                        + "- must be a positive integer");
                        return -1;
                    }

                    if (newPollIntervalMsecs < 1) {
                        pw.println(
                                "Invalid argument to 'set-poll-rssi-interval-msecs' "
                                        + "- must be a positive integer");
                        return -1;
                    }

                    mStateMachine.setPollRssiIntervalMsecs(newPollIntervalMsecs);
                    return 0;
                case "get-poll-rssi-interval-msecs":
                    pw.println("WifiStateMachine.mPollRssiIntervalMsecs = "
                            + mStateMachine.getPollRssiIntervalMsecs());
                    return 0;
                default:
                    return handleDefaultCommands(cmd);
            }
        } catch (Exception e) {
            pw.println("Exception: " + e);
        }
        return -1;
    }

    private void checkRootPermission() {
        final int uid = Binder.getCallingUid();
        if (uid == 0) {
            // Root can do anything.
            return;
        }
        throw new SecurityException("Uid " + uid + " does not have access to wifi commands");
    }

    @Override
    public void onHelp() {
        final PrintWriter pw = getOutPrintWriter();

        pw.println("Wi-Fi (wifi) commands:");
        pw.println("  help");
        pw.println("    Print this help text.");
        pw.println("  set-ipreach-disconnect enabled|disabled");
        pw.println("    Sets whether CMD_IP_REACHABILITY_LOST events should trigger disconnects.");
        pw.println("  get-ipreach-disconnect");
        pw.println("    Gets setting of CMD_IP_REACHABILITY_LOST events triggering disconnects.");
        pw.println("  set-poll-rssi-interval-msecs <int>");
        pw.println("    Sets the interval between RSSI polls to <int> milliseconds.");
        pw.println("  get-poll-rssi-interval-msecs");
        pw.println("    Gets current interval between RSSI polls, in milliseconds.");
        pw.println();
    }
}