/*

 * Copyright (c) 2015, 2018, 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.ArrayList;

import java.util.List;

import java.util.function.Function;

import java.util.stream.Collectors;

import java.util.stream.StreamSupport;

import jdk.internal.org.jline.reader.Candidate;

import jdk.internal.org.jline.reader.CompletingParsedLine;

import jdk.internal.org.jline.reader.EOFError;

import jdk.internal.org.jline.reader.History;

import jdk.internal.org.jline.reader.LineReader;

import jdk.internal.org.jline.reader.LineReader.Option;

import jdk.internal.org.jline.reader.LineReaderBuilder;

import jdk.internal.org.jline.reader.Parser;

import jdk.internal.org.jline.reader.Parser.ParseContext;

import jdk.internal.org.jline.reader.Widget;

import jdk.internal.org.jline.reader.impl.LineReaderImpl;

import jdk.internal.org.jline.reader.impl.completer.ArgumentCompleter.ArgumentLine;

import jdk.internal.org.jline.terminal.Attributes.LocalFlag;

import jdk.internal.org.jline.terminal.Terminal;

class Console implements AutoCloseable {

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

    private final LineReader 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;

        Parser parser = (line, cursor, context) -> {

            if (context == ParseContext.COMPLETE) {

                List<Candidate> candidates = new ArrayList<>();

                int anchor = completer.complete(line, cursor, candidates);

                anchor = Math.min(anchor, line.length());

                return new CompletionLine(line.substring(anchor), cursor, candidates);

            } else if (!completer.isComplete(line)) {

                throw new EOFError(cursor, cursor, line);

            }

            return new ArgumentLine(line, cursor);

        };

        in = LineReaderBuilder.builder()

                              .option(Option.DISABLE_EVENT_EXPANSION, true)

                              .completer((in, line, candidates) -> candidates.addAll(((CompletionLine) line).candidates))

                              .parser(parser)

                              .build();

        if (historyFile.exists()) {

            StringBuilder line = new StringBuilder();

            for (String h : Files.readAllLines(historyFile.toPath())) {

                if (line.length() > 0) {

                    line.append("\n");

                }

                line.append(h);

                try {

                    parser.parse(line.toString(), line.length());

                    in.getHistory().add(line.toString());

                    line.delete(0, line.length());

                } catch (EOFError e) {

                    //continue;

                }

            }

            if (line.length() > 0) {

                in.getHistory().add(line.toString());

            }

        }

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

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

    }

    String readLine(final String prompt, final String continuationPrompt) throws IOException {

        in.setVariable(LineReader.SECONDARY_PROMPT_PATTERN, continuationPrompt);

        return in.readLine(prompt);

    }

    String readUserLine(final String prompt) throws IOException {

        Parser prevParser = in.getParser();

        try {

            ((LineReaderImpl) in).setParser((line, cursor, context) -> new ArgumentLine(line, cursor));

            return in.readLine(prompt);

        } finally {

            ((LineReaderImpl) in).setParser(prevParser);

        }

    }

    @Override

    public void close() {

        saveHistory();

    }

    private void saveHistory() {

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

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

            out.write(StreamSupport.stream(getHistory().spliterator(), false)

                                   .map(e -> e.line())

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

        } catch (final IOException exp) {}

    }

    History getHistory() {

        return in.getHistory();

    }

    boolean terminalEditorRunning() {

        Terminal terminal = in.getTerminal();

        return !terminal.getAttributes().getLocalFlag(LocalFlag.ICANON);

    }

    void suspend() {

    }

    void resume() {

    }

    private void bind(String shortcut, Widget action) {

        in.getKeyMaps().get(LineReader.MAIN).bind(action, shortcut);

    }

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

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

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

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

        if (doc != null) {

            in.getTerminal().writer().println();

            in.printAbove(doc);

            return true;

        } else {

            return false;

        }

    }

    private static final class CompletionLine extends ArgumentLine implements CompletingParsedLine {

        public final List<Candidate> candidates;

        public CompletionLine(String word, int cursor, List<Candidate> candidates) {

            super(word, cursor);

            this.candidates = candidates;

        }

        public CharSequence escape(CharSequence candidate, boolean complete) {

            return candidate;

        }

        public int rawWordCursor() {

            return word().length();

        }

        public int rawWordLength() {

            return word().length();

        }

    }

}