/*
 * 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
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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.
/**
 * 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, in(System.in, null). 
Params:
cmdIn – source of command input
userIn – source of input for running user code, or null to be extracted from cmdIn
Returns:
the JavaShellToolBuilder instance/**
     * 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 out(output, output, output). Default, if not set, out(System.out). 
Params:
output – destination of command feedback, console interaction, and
user code output
Returns:
the JavaShellToolBuilder instance/**
     * 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, out(System.out, System.out, System.out). 
Params:
cmdOut – destination of command feedback including error messages
for users
console – destination of console interaction
userOut – destination of user code output. For example, user snippet System.out.println("Hello") when executed Hello goes to userOut.
Returns:
the JavaShellToolBuilder instance/**
     * 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 err(error, error). Default, if not set, err(System.err). 
Params:
error – destination of tool errors, and
user code errors
Returns:
the JavaShellToolBuilder instance/**
     * 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, err(System.err, System.err, System.err). 
Params:
cmdErr – destination of tool start-up and fatal errors
userErr – destination of user code error output. For example, user snippet System.err.println("Oops") when executed Oops goes to userErr.
Returns:
the JavaShellToolBuilder instance/**
     * 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.
Params:
prefs – an instance of Preferences that is used to retrieve and store persistent information
Returns:
the JavaShellToolBuilder instance/**
     * 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.
Params:
prefsMap –  an instance of Map that is used to retrieve and store persistent information
Returns:
the JavaShellToolBuilder instance/**
     * 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, env(System.getenv()). 
Params:
vars – the Map of environment variable names to values
Returns:
the JavaShellToolBuilder instance/**
     * 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, locale(Locale.getDefault()). 
Params:
locale – the locale
Returns:
the JavaShellToolBuilder instance/**
     * 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, promptCapture(false). 
Params:
capture – if true, basic prompt is the ENQ character and continuation prompt is the ACK character. If false, prompts are as set with set-up or user /set commands.
Returns:
the JavaShellToolBuilder instance/**
     * 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.
Returns:
the tool instance/**
     * 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. The  exit code from
the Java shell tool is ignored.
Params:
arguments – the command-line arguments (including options), if any
Throws:
Exception – an unexpected fatal exception/**
     * 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. The  exit code from
     * the Java shell tool is ignored.
     *
     * @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);
    }

    
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.
Params:
arguments – the command-line arguments (including options), if any
Throws:
Exception – an unexpected fatal exception
Returns:
the exit code/**
     * 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
     * @return the exit code
     */
    @Override
    public int start(String... arguments) throws Exception {
        return rawTool().start(arguments);
    }

    
Persistence stored in Preferences.
/**
     * 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.
/**
     * 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
        }
    }

}