/*

 * Copyright (c) 2015, 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 jdk.nashorn.tools.jjs;

import java.io.File;

import java.io.IOException;

import java.io.InputStream;

import java.io.PrintStream;

import java.io.Writer;

import java.nio.file.Files;

import java.util.function.Function;

import java.util.stream.Collectors;

import jdk.internal.jline.NoInterruptUnixTerminal;

import jdk.internal.jline.Terminal;

import jdk.internal.jline.TerminalFactory;

import jdk.internal.jline.TerminalFactory.Flavor;

import jdk.internal.jline.WindowsTerminal;

import jdk.internal.jline.console.ConsoleReader;

import jdk.internal.jline.console.KeyMap;

import jdk.internal.jline.extra.EditingHistory;

import jdk.internal.misc.Signal;

import jdk.internal.misc.Signal.Handler;

class Console implements AutoCloseable {

    private static final String DOCUMENTATION_SHORTCUT = "\033\133\132"; //Shift-TAB

    private final ConsoleReader in;

    private final File historyFile;

    Console(final InputStream cmdin, final PrintStream cmdout, final File historyFile,

            final NashornCompleter completer, final Function<String, String> docHelper) throws IOException {

        this.historyFile = historyFile;

        TerminalFactory.registerFlavor(Flavor.WINDOWS, isCygwin()? JJSUnixTerminal::new : JJSWindowsTerminal::new);

        TerminalFactory.registerFlavor(Flavor.UNIX, JJSUnixTerminal::new);

        in = new ConsoleReader(cmdin, cmdout);

        in.setExpandEvents(false);

        in.setHandleUserInterrupt(true);

        in.setBellEnabled(true);

        in.setCopyPasteDetection(true);

        final Iterable<String> existingHistory = historyFile.exists() ? Files.readAllLines(historyFile.toPath()) : null;

        in.setHistory(new EditingHistory(in, existingHistory) {

            @Override protected boolean isComplete(CharSequence input) {

                return completer.isComplete(input.toString());

            }

        });

        in.addCompleter(completer);

        Runtime.getRuntime().addShutdownHook(new Thread((Runnable)this::saveHistory));

        bind(DOCUMENTATION_SHORTCUT, (Runnable) ()->showDocumentation(docHelper));

        try {

            Signal.handle(new Signal("CONT"), new Handler() {

                @Override public void handle(Signal sig) {

                    try {

                        in.getTerminal().reset();

                        in.redrawLine();

                        in.flush();

                    } catch (Exception ex) {

                        ex.printStackTrace();

                    }

                }

            });

        } catch (IllegalArgumentException ignored) {

            //the CONT signal does not exist on this platform

        }

    }

    String readLine(final String prompt) throws IOException {

        return in.readLine(prompt);

    }

    @Override

    public void close() {

        saveHistory();

    }

    private void saveHistory() {

        try (Writer out = Files.newBufferedWriter(historyFile.toPath())) {

            String lineSeparator = System.getProperty("line.separator");

            out.write(getHistory().save()

                                  .stream()

                                  .collect(Collectors.joining(lineSeparator)));

        } catch (final IOException exp) {}

    }

    EditingHistory getHistory() {

        return (EditingHistory) in.getHistory();

    }

    boolean terminalEditorRunning() {

        Terminal terminal = in.getTerminal();

        if (terminal instanceof JJSUnixTerminal) {

            return ((JJSUnixTerminal) terminal).isRaw();

        }

        return false;

    }

    void suspend() {

        try {

            in.getTerminal().restore();

        } catch (Exception ex) {

            throw new IllegalStateException(ex);

        }

    }

    void resume() {

        try {

            in.getTerminal().init();

        } catch (Exception ex) {

            throw new IllegalStateException(ex);

        }

    }

    static final class JJSUnixTerminal extends NoInterruptUnixTerminal {

        JJSUnixTerminal() throws Exception {

        }

        boolean isRaw() {

            try {

                return getSettings().get("-a").contains("-icanon");

            } catch (IOException | InterruptedException ex) {

                return false;

            }

        }

        @Override

        public void disableInterruptCharacter() {

        }

        @Override

        public void enableInterruptCharacter() {

        }

    }

    static final class JJSWindowsTerminal extends WindowsTerminal {

        public JJSWindowsTerminal() throws Exception {

        }

        @Override

        public void init() throws Exception {

            super.init();

            setAnsiSupported(false);

        }

    }

    private static boolean isCygwin() {

        return System.getenv("SHELL") != null;

    }

    private void bind(String shortcut, Object action) {

        KeyMap km = in.getKeys();

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

            final Object value = km.getBound(Character.toString(shortcut.charAt(i)));

            if (value instanceof KeyMap) {

                km = (KeyMap) value;

            } else {

                km.bind(shortcut.substring(i), action);

            }

        }

    }

    private void showDocumentation(final Function<String, String> docHelper) {

        final String buffer = in.getCursorBuffer().buffer.toString();

        final int cursor = in.getCursorBuffer().cursor;

        final String doc = docHelper.apply(buffer.substring(0, cursor));

        try {

            if (doc != null) {

                in.println();

                in.println(doc);

                in.redrawLine();

                in.flush();

            } else {

                in.beep();

            }

        } catch (IOException ex) {

            throw new IllegalStateException(ex);

        }

    }

}