/*

 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package sun.security.util;

import javax.security.auth.callback.Callback;

import javax.security.auth.callback.CallbackHandler;

import javax.security.auth.callback.ConfirmationCallback;

import javax.security.auth.callback.NameCallback;

import javax.security.auth.callback.PasswordCallback;

import javax.security.auth.callback.TextOutputCallback;

import javax.security.auth.callback.UnsupportedCallbackException;

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStream;

import java.io.InputStreamReader;

/**

 * A {@code CallbackHandler} that prompts and reads from the command line

 * for answers to authentication questions.

 */

public class ConsoleCallbackHandler implements CallbackHandler {

    /**

     * Creates a callback handler that prompts and reads from the

     * command line for answers to authentication questions.

     */

    public ConsoleCallbackHandler() { }

    /**

     * Handles the specified set of callbacks.

     *

     * @param callbacks the callbacks to handle

     * @throws IOException if an input or output error occurs.

     * @throws UnsupportedCallbackException if the callback is not an

     * instance of NameCallback or PasswordCallback

     */

    public void handle(Callback[] callbacks)

        throws IOException, UnsupportedCallbackException

    {

        ConfirmationCallback confirmation = null;

        for (int i = 0; i < callbacks.length; i++) {

            if (callbacks[i] instanceof TextOutputCallback) {

                TextOutputCallback tc = (TextOutputCallback) callbacks[i];

                String text;

                switch (tc.getMessageType()) {

                case TextOutputCallback.INFORMATION:

                    text = "";

                    break;

                case TextOutputCallback.WARNING:

                    text = "Warning: ";

                    break;

                case TextOutputCallback.ERROR:

                    text = "Error: ";

                    break;

                default:

                    throw new UnsupportedCallbackException(

                        callbacks[i], "Unrecognized message type");

                }

                String message = tc.getMessage();

                if (message != null) {

                    text += message;

                }

                if (text != null) {

                    System.err.println(text);

                }

            } else if (callbacks[i] instanceof NameCallback) {

                NameCallback nc = (NameCallback) callbacks[i];

                if (nc.getDefaultName() == null) {

                    System.err.print(nc.getPrompt());

                } else {

                    System.err.print(nc.getPrompt() +

                                " [" + nc.getDefaultName() + "] ");

                }

                System.err.flush();

                String result = readLine();

                    result = nc.getDefaultName();

                }

                nc.setName(result);

            } else if (callbacks[i] instanceof PasswordCallback) {

                PasswordCallback pc = (PasswordCallback) callbacks[i];

                System.err.print(pc.getPrompt());

                System.err.flush();

                pc.setPassword(Password.readPassword(System.in, pc.isEchoOn()));

            } else if (callbacks[i] instanceof ConfirmationCallback) {

                confirmation = (ConfirmationCallback) callbacks[i];

            } else {

                throw new UnsupportedCallbackException(

                    callbacks[i], "Unrecognized Callback");

            }

        }

        /* Do the confirmation callback last. */

        if (confirmation != null) {

            doConfirmation(confirmation);

        }

    }

    /* Reads a line of input */

    private String readLine() throws IOException {

        String result = new BufferedReader

            (new InputStreamReader(System.in)).readLine();

        if (result == null) {

            throw new IOException("Cannot read from System.in");

        }

        return result;

    }

    private void doConfirmation(ConfirmationCallback confirmation)

        throws IOException, UnsupportedCallbackException

    {

        String prefix;

        int messageType = confirmation.getMessageType();

        switch (messageType) {

        case ConfirmationCallback.WARNING:

            prefix =  "Warning: ";

            break;

        case ConfirmationCallback.ERROR:

            prefix = "Error: ";

            break;

        case ConfirmationCallback.INFORMATION:

            prefix = "";

            break;

        default:

            throw new UnsupportedCallbackException(

                confirmation, "Unrecognized message type: " + messageType);

        }

        class OptionInfo {

            String name;

            int value;

            OptionInfo(String name, int value) {

                this.name = name;

                this.value = value;

            }

        }

        OptionInfo[] options;

        int optionType = confirmation.getOptionType();

        switch (optionType) {

        case ConfirmationCallback.YES_NO_OPTION:

            options = new OptionInfo[] {

                new OptionInfo("Yes", ConfirmationCallback.YES),

                new OptionInfo("No", ConfirmationCallback.NO)

            };

            break;

        case ConfirmationCallback.YES_NO_CANCEL_OPTION:

            options = new OptionInfo[] {

                new OptionInfo("Yes", ConfirmationCallback.YES),

                new OptionInfo("No", ConfirmationCallback.NO),

                new OptionInfo("Cancel", ConfirmationCallback.CANCEL)

            };

            break;

        case ConfirmationCallback.OK_CANCEL_OPTION:

            options = new OptionInfo[] {

                new OptionInfo("OK", ConfirmationCallback.OK),

                new OptionInfo("Cancel", ConfirmationCallback.CANCEL)

            };

            break;

        case ConfirmationCallback.UNSPECIFIED_OPTION:

            String[] optionStrings = confirmation.getOptions();

            options = new OptionInfo[optionStrings.length];

            for (int i = 0; i < options.length; i++) {

                options[i] = new OptionInfo(optionStrings[i], i);

            }

            break;

        default:

            throw new UnsupportedCallbackException(

                confirmation, "Unrecognized option type: " + optionType);

        }

        int defaultOption = confirmation.getDefaultOption();

        String prompt = confirmation.getPrompt();

        if (prompt == null) {

            prompt = "";

        }

        prompt = prefix + prompt;

            System.err.println(prompt);

        }

        for (int i = 0; i < options.length; i++) {

            if (optionType == ConfirmationCallback.UNSPECIFIED_OPTION) {

                // defaultOption is an index into the options array

                System.err.println(

                    i + ". " + options[i].name +

                    (i == defaultOption ? " [default]" : ""));

            } else {

                // defaultOption is an option value

                System.err.println(

                    i + ". " + options[i].name +

                    (options[i].value == defaultOption ? " [default]" : ""));

            }

        }

        System.err.print("Enter a number: ");

        System.err.flush();

        int result;

        try {

            result = Integer.parseInt(readLine());

            if (result < 0 || result > (options.length - 1)) {

                result = defaultOption;

            }

            result = options[result].value;

        } catch (NumberFormatException e) {

            result = defaultOption;

        }

        confirmation.setSelectedIndex(result);

    }

}