/*

 * Copyright (c) 2015, 2016, 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

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 */

package jdk.internal.jshell.tool;

import jdk.jshell.SourceCodeAnalysis.QualifiedNames;

import jdk.jshell.SourceCodeAnalysis.Suggestion;

import java.awt.event.ActionListener;

import java.io.IOException;

import java.io.InputStream;

import java.io.PrintStream;

import java.io.UncheckedIOException;

import java.lang.reflect.Method;

import java.util.ArrayList;

import java.util.Collection;

import java.util.Collections;

import java.util.HashMap;

import java.util.List;

import java.util.Locale;

import java.util.Map;

import java.util.Objects;

import java.util.Optional;

import java.util.function.Supplier;

import java.util.prefs.BackingStoreException;

import java.util.stream.Collectors;

import java.util.stream.Stream;

import jdk.internal.jline.NoInterruptUnixTerminal;

import jdk.internal.jline.Terminal;

import jdk.internal.jline.TerminalFactory;

import jdk.internal.jline.TerminalSupport;

import jdk.internal.jline.WindowsTerminal;

import jdk.internal.jline.console.ConsoleReader;

import jdk.internal.jline.console.KeyMap;

import jdk.internal.jline.console.UserInterruptException;

import jdk.internal.jline.console.completer.Completer;

import jdk.internal.jline.extra.EditingHistory;

import jdk.internal.jshell.tool.StopDetectingInputStream.State;

class ConsoleIOContext extends IOContext {

    private static final String HISTORY_LINE_PREFIX = "HISTORY_LINE_";

    final JShellTool repl;

    final StopDetectingInputStream input;

    final ConsoleReader in;

    final EditingHistory history;

    String prefix = "";

    ConsoleIOContext(JShellTool repl, InputStream cmdin, PrintStream cmdout) throws Exception {

        this.repl = repl;

        this.input = new StopDetectingInputStream(() -> repl.state.stop(), ex -> repl.hard("Error on input: %s", ex));

        Terminal term;

        if (System.getProperty("test.jdk") != null) {

            term = new TestTerminal(input);

        } else if (System.getProperty("os.name").toLowerCase(Locale.US).contains(TerminalFactory.WINDOWS)) {

            term = new JShellWindowsTerminal(input);

        } else {

            term = new JShellUnixTerminal(input);

        }

        term.init();

        in = new ConsoleReader(cmdin, cmdout, term);

        in.setExpandEvents(false);

        in.setHandleUserInterrupt(true);

        List<String> persistenHistory = Stream.of(repl.prefs.keys())

                                              .filter(key -> key.startsWith(HISTORY_LINE_PREFIX))

                                              .sorted()

                                              .map(key -> repl.prefs.get(key, null))

                                              .collect(Collectors.toList());

        in.setHistory(history = new EditingHistory(in, persistenHistory) {

            @Override protected boolean isComplete(CharSequence input) {

                return repl.analysis.analyzeCompletion(input.toString()).completeness().isComplete();

            }

        });

        in.setBellEnabled(true);

        in.setCopyPasteDetection(true);

        in.addCompleter(new Completer() {

            private String lastTest;

            private int lastCursor;

            private boolean allowSmart = false;

            @Override public int complete(String test, int cursor, List<CharSequence> result) {

                int[] anchor = new int[] {-1};

                List<Suggestion> suggestions;

                if (prefix.isEmpty() && test.trim().startsWith("/")) {

                    suggestions = repl.commandCompletionSuggestions(test, cursor, anchor);

                } else {

                    int prefixLength = prefix.length();

                    suggestions = repl.analysis.completionSuggestions(prefix + test, cursor + prefixLength, anchor);

                    anchor[0] -= prefixLength;

                }

                if (!Objects.equals(lastTest, test) || lastCursor != cursor)

                    allowSmart = true;

                boolean smart = allowSmart &&

                                suggestions.stream()

                                           .anyMatch(s -> s.matchesType());

                lastTest = test;

                lastCursor = cursor;

                allowSmart = !allowSmart;

                suggestions.stream()

                           .filter(s -> !smart || s.matchesType())

                           .map(s -> s.continuation())

                           .forEach(result::add);

                boolean onlySmart = suggestions.stream()

                                               .allMatch(s -> s.matchesType());

                if (smart && !onlySmart) {

                    Optional<String> prefix =

                            suggestions.stream()

                                       .map(s -> s.continuation())

                                       .reduce(ConsoleIOContext::commonPrefix);

                    String prefixStr = prefix.orElse("").substring(cursor - anchor[0]);

                    try {

                        in.putString(prefixStr);

                        cursor += prefixStr.length();

                    } catch (IOException ex) {

                        throw new IllegalStateException(ex);

                    }

                    result.add(repl.messageFormat("jshell.console.see.more"));

                    return cursor; //anchor should not be used.

                }

                if (result.isEmpty()) {

                    try {

                        //provide "empty completion" feedback

                        //XXX: this only works correctly when there is only one Completer:

                        in.beep();

                    } catch (IOException ex) {

                        throw new UncheckedIOException(ex);

                    }

                }

                return anchor[0];

            }

        });

        bind(DOCUMENTATION_SHORTCUT, (ActionListener) evt -> documentation(repl));

        for (FixComputer computer : FIX_COMPUTERS) {

            for (String shortcuts : SHORTCUT_FIXES) {

                bind(shortcuts + computer.shortcut, (ActionListener) evt -> fixes(computer));

            }

        }

    }

    @Override

    public String readLine(String prompt, String prefix) throws IOException, InputInterruptedException {

        this.prefix = prefix;

        try {

            return in.readLine(prompt);

        } catch (UserInterruptException ex) {

            throw (InputInterruptedException) new InputInterruptedException().initCause(ex);

        }

    }

    @Override

    public boolean interactiveOutput() {

        return true;

    }

    @Override

    public Iterable<String> currentSessionHistory() {

        return history.currentSessionEntries();

    }

    @Override

    public void close() throws IOException {

        //save history:

        try {

            for (String key : repl.prefs.keys()) {

                if (key.startsWith(HISTORY_LINE_PREFIX))

                    repl.prefs.remove(key);

            }

            Collection<? extends String> savedHistory = history.save();

            if (!savedHistory.isEmpty()) {

                int len = (int) Math.ceil(Math.log10(savedHistory.size()+1));

                String format = HISTORY_LINE_PREFIX + "%0" + len + "d";

                int index = 0;

                for (String historyLine : savedHistory) {

                    repl.prefs.put(String.format(format, index++), historyLine);

                }

            }

        } catch (BackingStoreException ex) {

            throw new IllegalStateException(ex);

        }

        in.shutdown();

        try {

            in.getTerminal().restore();

        } catch (Exception ex) {

            throw new IOException(ex);

        }

        input.shutdown();

    }

    private void bind(String shortcut, Object action) {

        KeyMap km = in.getKeys();

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

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

            if (value instanceof KeyMap) {

                km = (KeyMap) value;

            } else {

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

            }

        }

    }

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

    private static final String[] SHORTCUT_FIXES = {

        "\033\015", //Alt-Enter (Linux)

        "\033\133\061\067\176", //F6/Alt-F1 (Mac)

        "\u001BO3P" //Alt-F1 (Linux)

    };

    private void documentation(JShellTool repl) {

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

        int cursor = in.getCursorBuffer().cursor;

        String doc;

        if (prefix.isEmpty() && buffer.trim().startsWith("/")) {

            doc = repl.commandDocumentation(buffer, cursor);

        } else {

            doc = repl.analysis.documentation(prefix + buffer, cursor + prefix.length());

        }

        try {

            if (doc != null) {

                in.println();

                in.println(doc);

                in.redrawLine();

                in.flush();

            } else {

                in.beep();

            }

        } catch (IOException ex) {

            throw new IllegalStateException(ex);

        }

    }

    private static String commonPrefix(String str1, String str2) {

        for (int i = 0; i < str2.length(); i++) {

            if (!str1.startsWith(str2.substring(0, i + 1))) {

                return str2.substring(0, i);

            }

        }

        return str2;

    }

    @Override

    public boolean terminalEditorRunning() {

        Terminal terminal = in.getTerminal();

        if (terminal instanceof JShellUnixTerminal)

            return ((JShellUnixTerminal) terminal).isRaw();

        return false;

    }

    @Override

    public void suspend() {

        try {

            in.getTerminal().restore();

        } catch (Exception ex) {

            throw new IllegalStateException(ex);

        }

    }

    @Override

    public void resume() {

        try {

            in.getTerminal().init();

        } catch (Exception ex) {

            throw new IllegalStateException(ex);

        }

    }

    public void beforeUserCode() {

        input.setState(State.BUFFER);

    }

    public void afterUserCode() {

        input.setState(State.WAIT);

    }

    @Override

    public void replaceLastHistoryEntry(String source) {

        history.fullHistoryReplace(source);

    }

    //compute possible options/Fixes based on the selected FixComputer, present them to the user,

    //and perform the selected one:

    private void fixes(FixComputer computer) {

        String input = prefix + in.getCursorBuffer().toString();

        int cursor = prefix.length() + in.getCursorBuffer().cursor;

        FixResult candidates = computer.compute(repl, input, cursor);

        try {

            final boolean printError = candidates.error != null && !candidates.error.isEmpty();

            if (printError) {

                in.println(candidates.error);

            }

            if (candidates.fixes.isEmpty()) {

                in.beep();

                if (printError) {

                    in.redrawLine();

                    in.flush();

                }

            } else if (candidates.fixes.size() == 1 && !computer.showMenu) {

                if (printError) {

                    in.redrawLine();

                    in.flush();

                }

                candidates.fixes.get(0).perform(in);

            } else {

                List<Fix> fixes = new ArrayList<>(candidates.fixes);

                fixes.add(0, new Fix() {

                    @Override

                    public String displayName() {

                        return repl.messageFormat("jshell.console.do.nothing");

                    }

                    @Override

                    public void perform(ConsoleReader in) throws IOException {

                        in.redrawLine();

                    }

                });

                Map<Character, Fix> char2Fix = new HashMap<>();

                in.println();

                for (int i = 0; i < fixes.size(); i++) {

                    Fix fix = fixes.get(i);

                    char2Fix.put((char) ('0' + i), fix);

                    in.println("" + i + ": " + fixes.get(i).displayName());

                }

                in.print(repl.messageFormat("jshell.console.choice"));

                in.flush();

                int read;

                read = in.readCharacter();

                Fix fix = char2Fix.get((char) read);

                if (fix == null) {

                    in.beep();

                    fix = fixes.get(0);

                }

                in.println();

                fix.perform(in);

                in.flush();

            }

        } catch (IOException ex) {

            ex.printStackTrace();

        }

    }

    /**

     * A possible action which the user can choose to perform.

     */

    public interface Fix {

        /**

         * A name that should be shown to the user.

         */

        public String displayName();

        /**

         * Perform the given action.

         */

        public void perform(ConsoleReader in) throws IOException;

    }

    /**

     * A factory for {@link Fix}es.

     */

    public abstract static class FixComputer {

        private final char shortcut;

        private final boolean showMenu;

        /**

         * Construct a new FixComputer. {@code shortcut} defines the key which should trigger this FixComputer.

         * If {@code showMenu} is {@code false}, and this computer returns exactly one {@code Fix},

         * no options will be show to the user, and the given {@code Fix} will be performed.

         */

        public FixComputer(char shortcut, boolean showMenu) {

            this.shortcut = shortcut;

            this.showMenu = showMenu;

        }

        /**

         * Compute possible actions for the given code.

         */

        public abstract FixResult compute(JShellTool repl, String code, int cursor);

    }

    /**

     * A list of {@code Fix}es with a possible error that should be shown to the user.

     */

    public static class FixResult {

        public final List<Fix> fixes;

        public final String error;

        public FixResult(List<Fix> fixes, String error) {

            this.fixes = fixes;

            this.error = error;

        }

    }

    private static final FixComputer[] FIX_COMPUTERS = new FixComputer[] {

        new FixComputer('v', false) { //compute "Introduce variable" Fix:

            @Override

            public FixResult compute(JShellTool repl, String code, int cursor) {

                String type = repl.analysis.analyzeType(code, cursor);

                if (type == null) {

                    return new FixResult(Collections.emptyList(), null);

                }

                return new FixResult(Collections.singletonList(new Fix() {

                    @Override

                    public String displayName() {

                        return repl.messageFormat("jshell.console.create.variable");

                    }

                    @Override

                    public void perform(ConsoleReader in) throws IOException {

                        in.redrawLine();

                        in.setCursorPosition(0);

                        in.putString(type + "  = ");

                        in.setCursorPosition(in.getCursorBuffer().cursor - 3);

                        in.flush();

                    }

                }), null);

            }

        },

        new FixComputer('i', true) { //compute "Add import" Fixes:

            @Override

            public FixResult compute(JShellTool repl, String code, int cursor) {

                QualifiedNames res = repl.analysis.listQualifiedNames(code, cursor);

                List<Fix> fixes = new ArrayList<>();

                for (String fqn : res.getNames()) {

                    fixes.add(new Fix() {

                        @Override

                        public String displayName() {

                            return "import: " + fqn;

                        }

                        @Override

                        public void perform(ConsoleReader in) throws IOException {

                            repl.state.eval("import " + fqn + ";");

                            in.println("Imported: " + fqn);

                            in.redrawLine();

                        }

                    });

                }

                if (res.isResolvable()) {

                    return new FixResult(Collections.emptyList(),

                            repl.messageFormat("jshell.console.resolvable"));

                } else {

                    String error = "";

                    if (fixes.isEmpty()) {

                        error = repl.messageFormat("jshell.console.no.candidate");

                    }

                    if (!res.isUpToDate()) {

                        error += repl.messageFormat("jshell.console.incomplete");

                    }

                    return new FixResult(fixes, error);

                }

            }

        }

    };

    private static final class JShellUnixTerminal extends NoInterruptUnixTerminal {

        private final StopDetectingInputStream input;

        public JShellUnixTerminal(StopDetectingInputStream input) throws Exception {

            this.input = input;

        }

        public boolean isRaw() {

            try {

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

            } catch (IOException | InterruptedException ex) {

                return false;

            }

        }