/*

 * Copyright (c) 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

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

 * questions.

 */

package jdk.internal.jshell.tool;

import java.io.InputStream;

import java.io.PrintStream;

import java.util.Locale;

import java.util.Map;

import java.util.Objects;

import java.util.Set;

import java.util.prefs.BackingStoreException;

import java.util.prefs.Preferences;

import jdk.jshell.tool.JavaShellToolBuilder;

/**

 * Builder for programmatically building the jshell tool.

 */

public class JShellToolBuilder implements JavaShellToolBuilder {

    private static final String PREFERENCES_NODE = "tool/JShell";

    private InputStream cmdIn = System.in;

    private InputStream userIn = null;

    private PrintStream cmdOut = System.out;

    private PrintStream console = System.out;

    private PrintStream userOut = System.out;

    private PrintStream cmdErr = System.err;

    private PrintStream userErr = System.err;

    private PersistentStorage prefs = null;

    private Map<String, String> vars = null;

    private Locale locale = Locale.getDefault();

    private boolean capturePrompt = false;

    /**

     * Set the input channels.

     * Default, if not set, {@code in(System.in, null)}.

     *

     * @param cmdIn source of command input

     * @param userIn source of input for running user code, or {@code null} to

     * be extracted from cmdIn

     * @return the {@code JavaShellToolBuilder} instance

     */

    @Override

    public JavaShellToolBuilder in(InputStream cmdIn, InputStream userIn) {

        this.cmdIn = cmdIn;

        this.userIn = userIn;

        return this;

    }

    /**

     * Set the output channels. Same as {@code out(output, output, output)}.

     * Default, if not set, {@code out(System.out)}.

     *

     * @param output destination of command feedback, console interaction, and

     * user code output

     * @return the {@code JavaShellToolBuilder} instance

     */

    @Override

    public JavaShellToolBuilder out(PrintStream output) {

        this.cmdOut = output;

        this.console = output;

        this.userOut = output;

        return this;

    }

    /**

     * Set the output channels.

     * Default, if not set, {@code out(System.out, System.out, System.out)}.

     *

     * @param cmdOut destination of command feedback including error messages

     * for users

     * @param console destination of console interaction

     * @param userOut destination of user code output.  For example, user snippet

     * {@code System.out.println("Hello")} when executed {@code Hello} goes to

     * userOut.

     * @return the {@code JavaShellToolBuilder} instance

     */

    @Override

    public JavaShellToolBuilder out(PrintStream cmdOut, PrintStream console, PrintStream userOut) {

        this.cmdOut = cmdOut;

        this.console = console;

        this.userOut = userOut;

        return this;

    }

    /**

     * Set the error channels. Same as {@code err(error, error)}.

     * Default, if not set, {@code err(System.err)}.

     *

     * @param error destination of tool errors, and

     * user code errors

     * @return the {@code JavaShellToolBuilder} instance

     */

    @Override

    public JavaShellToolBuilder err(PrintStream error) {

        this.cmdErr = error;

        this.userErr = error;

        return this;

    }

    /**

     * Set the error channels.

     * Default, if not set, {@code err(System.err, System.err, System.err)}.

     *

     * @param cmdErr destination of tool start-up and fatal errors

     * @param userErr destination of user code error output.

     * For example, user snippet  {@code System.err.println("Oops")}

     * when executed {@code Oops} goes to userErr.

     * @return the {@code JavaShellToolBuilder} instance

     */

    @Override

    public JavaShellToolBuilder err(PrintStream cmdErr, PrintStream userErr) {

        this.cmdErr = cmdErr;

        this.userErr = userErr;

        return this;

    }

    /**

     * Set the storage mechanism for persistent information which includes

     * input history and retained settings. Default if not set is the

     * tool's standard persistence mechanism.

     *

     * @param prefs an instance of {@link java.util.prefs.Preferences} that

     * is used to retrieve and store persistent information

     * @return the {@code JavaShellToolBuilder} instance

     */

    @Override

    public JavaShellToolBuilder persistence(Preferences prefs) {

        this.prefs = new PreferencesStorage(prefs);

        return this;

    }

    /**

     * Set the storage mechanism for persistent information which includes

     * input history and retained settings.   Default if not set is the

     * tool's standard persistence mechanism.

     *

     * @param prefsMap  an instance of {@link java.util.Map} that

     * is used to retrieve and store persistent information

     * @return the {@code JavaShellToolBuilder} instance

     */

    @Override

    public JavaShellToolBuilder persistence(Map<String, String> prefsMap) {

        this.prefs = new MapStorage(prefsMap);

        return this;

    }

    /**

     * Set the source for environment variables.

     * Default, if not set, {@code env(System.getenv())}.

     *

     * @param vars the Map of environment variable names to values

     * @return the {@code JavaShellToolBuilder} instance

     */

    @Override

    public JavaShellToolBuilder env(Map<String, String> vars) {

        this.vars = vars;

        return this;

    }

    /**

     * Set the locale.

     * Default, if not set, {@code locale(Locale.getDefault())}.

     *

     * @param locale the locale

     * @return the {@code JavaShellToolBuilder} instance

     */

    @Override

    public JavaShellToolBuilder locale(Locale locale) {

        this.locale = locale;

        return this;

    }

    /**

     * Set if the special command capturing prompt override should be used.

     * Default, if not set, {@code promptCapture(false)}.

     *

     * @param capture if {@code true}, basic prompt is the {@code ENQ}

     * character and continuation prompt is the {@code ACK} character.

     * If false, prompts are as set with set-up or user {@code /set} commands.

     * @return the {@code JavaShellToolBuilder} instance

     */

    @Override

    public JavaShellToolBuilder promptCapture(boolean capture) {

        this.capturePrompt = capture;

        return this;

    }

    /**

     * Create a tool instance for testing. Not in JavaShellToolBuilder.

     *

     * @return the tool instance

     */

    public JShellTool rawTool() {

        if (prefs == null) {

            prefs = new PreferencesStorage(Preferences.userRoot().node(PREFERENCES_NODE));

        }

        if (vars == null) {

            vars = System.getenv();

        }

        JShellTool sh = new JShellTool(cmdIn, cmdOut, cmdErr, console, userIn,

                userOut, userErr, prefs, vars, locale);

        sh.testPrompt = capturePrompt;

        return sh;

    }

    /**

     * Run an instance of the Java shell tool as configured by the other methods

     * in this interface.  This call is not destructive, more than one call of

     * this method may be made from a configured builder.

     *

     * @param arguments the command-line arguments (including options), if any

     * @throws Exception an unexpected fatal exception

     */

    @Override

    public void run(String... arguments) throws Exception {

        rawTool().start(arguments);

    }

    /**

     * Persistence stored in Preferences.

     */

    private static class PreferencesStorage implements PersistentStorage {

        final Preferences p;

        PreferencesStorage(Preferences p) {

            this.p = p;

        }

        @Override

        public void clear() {

            try {

                p.clear();

            } catch (BackingStoreException ex) {

                throw new IllegalStateException(ex);

            }

        }

        @Override

        public String[] keys() {

            try {

                return p.keys();

            } catch (BackingStoreException ex) {

                throw new IllegalStateException(ex);

            }

        }

        @Override

        public String get(String key) {

            return p.get(key, null);

        }

        @Override

        public void put(String key, String value) {

            p.put(key, value);

        }

        @Override

        public void remove(String key) {

            p.remove(key);

        }

        @Override

        public void flush() {

            try {

                p.flush();

            } catch (BackingStoreException ex) {

                throw new IllegalStateException(ex);

            }

        }

    }

    /**

     * Persistence stored in a Map.

     */

    private static class MapStorage implements PersistentStorage {

        final Map<String, String> map;

        MapStorage(Map<String, String> map) {

            this.map = map;

        }

        @Override

        public void clear() {

            try {

                map.clear();

            } catch (UnsupportedOperationException ex) {

                throw new IllegalStateException(ex);

            }

        }

        @Override

        public String[] keys() {

            Set<String> ks = map.keySet();

            return ks.toArray(new String[ks.size()]);

        }

        @Override

        public String get(String key) {

            Objects.requireNonNull(key);

            return map.get(key);

        }

        @Override

        public void put(String key, String value) {

            Objects.requireNonNull(key);

            Objects.requireNonNull(value);

            map.put(key, value);

        }

        @Override

        public void remove(String key) {

            Objects.requireNonNull(key);

            map.remove(key);

        }

        @Override

        public void flush() {

            // no-op always up-to-date

        }

    }

}