/*

 * Copyright (c) 2015, 2017, 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 static jdk.nashorn.internal.runtime.ScriptRuntime.UNDEFINED;

import java.io.BufferedReader;

import java.io.File;

import java.io.InputStream;

import java.io.InputStreamReader;

import java.io.IOException;

import java.io.UncheckedIOException;

import java.io.OutputStream;

import java.io.PrintWriter;

import java.net.URI;

import java.security.AccessController;

import java.security.PrivilegedAction;

import java.util.concurrent.Callable;

import java.util.function.Consumer;

import java.util.function.Function;

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

import jdk.internal.jline.console.UserInterruptException;

import jdk.nashorn.api.scripting.NashornException;

import jdk.nashorn.internal.objects.Global;

import jdk.nashorn.internal.objects.NativeJava;

import jdk.nashorn.internal.runtime.Context;

import jdk.nashorn.internal.runtime.NativeJavaPackage;

import jdk.nashorn.internal.runtime.Property;

import jdk.nashorn.internal.runtime.ScriptEnvironment;

import jdk.nashorn.internal.runtime.ScriptFunction;

import jdk.nashorn.internal.runtime.ScriptingFunctions;

import jdk.nashorn.internal.runtime.ScriptObject;

import jdk.nashorn.internal.runtime.ScriptRuntime;

import jdk.nashorn.internal.runtime.Source;

import jdk.nashorn.tools.Shell;

/**

 * Interactive command line Shell for Nashorn.

 */

public final class Main extends Shell {

    private Main() {}

    private static final String DOC_PROPERTY_NAME = "__doc__";

    static final boolean DEBUG = Boolean.getBoolean("nashorn.jjs.debug");

    // file where history is persisted.

    private static final File HIST_FILE = new File(new File(System.getProperty("user.home")), ".jjs.history");

    /**

     * Main entry point with the default input, output and error streams.

     *

     * @param args The command line arguments

     */

    public static void main(final String[] args) {

        try {

            final int exitCode = main(System.in, System.out, System.err, args);

            if (exitCode != SUCCESS) {

                System.exit(exitCode);

            }

        } catch (final IOException e) {

            System.err.println(e); //bootstrapping, Context.err may not exist

            System.exit(IO_ERROR);

        }

    }

    /**

     * Starting point for executing a {@code Shell}. Starts a shell with the

     * given arguments and streams and lets it run until exit.

     *

     * @param in input stream for Shell

     * @param out output stream for Shell

     * @param err error stream for Shell

     * @param args arguments to Shell

     *

     * @return exit code

     *

     * @throws IOException if there's a problem setting up the streams

     */

    public static int main(final InputStream in, final OutputStream out, final OutputStream err, final String[] args) throws IOException {

        return new Main().run(in, out, err, args);

    }

    /**

     * read-eval-print loop for Nashorn shell.

     *

     * @param context the nashorn context

     * @param global  global scope object to use

     * @return return code

     */

    protected int readEvalPrint(final Context context, final Global global) {

        final ScriptEnvironment env = context.getEnv();

        final String prompt = bundle.getString("shell.prompt");

        final String prompt2 = bundle.getString("shell.prompt2");

        final PrintWriter err = context.getErr();

        final Global oldGlobal = Context.getGlobal();

        final boolean globalChanged = (oldGlobal != global);

        final PropertiesHelper propsHelper = new PropertiesHelper(context);

        if (globalChanged) {

            Context.setGlobal(global);

        }

        // jjs.js is read and evaluated. The result of the evaluation is an "exports" object. This is done

        // to avoid polluting javascript global scope. These are internal funtions are retrieved from the

        // 'exports' object and used from here.

        final ScriptObject jjsObj = (ScriptObject)context.eval(global, readJJSScript(), global, "<jjs.js>");

        final boolean isHeadless = (boolean) ScriptRuntime.apply((ScriptFunction) jjsObj.get("isHeadless"), null);

        final ScriptFunction fileChooserFunc = isHeadless? null : (ScriptFunction) jjsObj.get("chooseFile");

        final NashornCompleter completer = new NashornCompleter(context, global, this, propsHelper, fileChooserFunc);

        final ScriptFunction browseFunc = isHeadless? null : (ScriptFunction) jjsObj.get("browse");

        final ScriptFunction javadoc = (ScriptFunction) jjsObj.get("javadoc");

        try (final Console in = new Console(System.in, System.out, HIST_FILE, completer,

                str -> {

                    try {

                        final Object res = context.eval(global, str, global, "<shell>");

                        if (res != null && res != UNDEFINED) {

                            // Special case Java types: show the javadoc for the class.

                            if (!isHeadless && NativeJava.isType(UNDEFINED, res)) {

                                final String typeName = NativeJava.typeName(UNDEFINED, res).toString();

                                final String url = typeName.replace('.', '/').replace('$', '.') + ".html";

                                openBrowserForJavadoc(browseFunc, url);

                            } else if (!isHeadless && res instanceof NativeJavaPackage) {

                                final String pkgName = ((NativeJavaPackage)res).getName();

                                final String url = pkgName.replace('.', '/') + "/package-summary.html";

                                openBrowserForJavadoc(browseFunc, url);

                            } else if (NativeJava.isJavaMethod(UNDEFINED, res)) {

                                ScriptRuntime.apply(javadoc, UNDEFINED, res);

                                return ""; // javadoc function already prints javadoc

                            } else if (res instanceof ScriptObject) {

                                final ScriptObject sobj = (ScriptObject)res;

                                if (sobj.has(DOC_PROPERTY_NAME)) {

                                    return toString(sobj.get(DOC_PROPERTY_NAME), global);

                                } else if (sobj instanceof ScriptFunction) {

                                    return ((ScriptFunction)sobj).getDocumentation();

                                }

                            }

                            // FIXME: better than toString for other cases?

                            return toString(res, global);

                        }

                     } catch (Exception ignored) {

                     }

                     return null;

                })) {

            global.addShellBuiltins();

            // redefine readLine to use jline Console's readLine!

            ScriptingFunctions.setReadLineHelper(str-> {

                try {

                    return in.readLine(str);

                } catch (final IOException ioExp) {

                    throw new UncheckedIOException(ioExp);

                }

            });

            if (System.getSecurityManager() == null) {

                final Consumer<String> evaluator = str -> {

                    // could be called from different thread (GUI), we need to handle Context set/reset

                    final Global _oldGlobal = Context.getGlobal();

                    final boolean _globalChanged = (_oldGlobal != global);

                    if (_globalChanged) {

                        Context.setGlobal(global);

                    }

                    try {

                        evalImpl(context, global, str, err, env._dump_on_error);

                    } finally {

                        if (_globalChanged) {

                            Context.setGlobal(_oldGlobal);

                        }

                    }

                };

                // expose history object for reflecting on command line history

                global.addOwnProperty("history", Property.NOT_ENUMERABLE, new HistoryObject(in.getHistory(), err, evaluator));

                // 'edit' command

                global.addOwnProperty("edit", Property.NOT_ENUMERABLE, new EditObject(in, err::println, evaluator));

            }

            while (true) {

                String source = "";

                try {

                    source = in.readLine(prompt);

                } catch (final IOException ioe) {

                    err.println(ioe.toString());

                    if (env._dump_on_error) {

                        ioe.printStackTrace(err);

                    }

                    return IO_ERROR;

                } catch (final UserInterruptException ex) {

                    break;

                }

                if (source == null) {

                    break;

                }

                if (source.isEmpty()) {

                    continue;

                }

                try {

                    final Object res = context.eval(global, source, global, "<shell>");

                    if (res != UNDEFINED) {

                        err.println(toString(res, global));

                    }

                } catch (final Exception exp) {

                    // Is this a ECMAScript SyntaxError at last column (of the single line)?

                    // If so, it is because parser expected more input but got EOF. Try to

                    // to more lines from the user (multiline edit support).

                    if (completer.isSyntaxErrorAt(exp, 1, source.length())) {

                        final String fullSrc = completer.readMoreLines(source, exp, in, prompt2, err);

                        // check if we succeeded in getting complete code.

                        if (fullSrc != null && !fullSrc.isEmpty()) {

                            evalImpl(context, global, fullSrc, err, env._dump_on_error);

                        } // else ignore, error reported already by 'completer.readMoreLines'

                    } else {

                        // can't read more lines to have parseable/complete code.

                        err.println(exp);

                        if (env._dump_on_error) {

                            exp.printStackTrace(err);

                        }

                    }

                }

            }

        } catch (final Exception e) {

            err.println(e);

            if (env._dump_on_error) {

                e.printStackTrace(err);

            }

        } finally {

            if (globalChanged) {

                Context.setGlobal(oldGlobal);

            }

            try {

                propsHelper.close();

            } catch (final Exception exp) {

                if (DEBUG) {

                    exp.printStackTrace();

                }

            }

        }

        return SUCCESS;

    }

    static String getMessage(final String id) {

        return bundle.getString(id);

    }

    private void evalImpl(final Context context, final Global global, final String source,

            final PrintWriter err, final boolean doe) {

        try {

            final Object res = context.eval(global, source, global, "<shell>");

            if (res != UNDEFINED) {

                err.println(toString(res, global));

            }

        } catch (final Exception e) {

            err.println(e);

            if (doe) {

                e.printStackTrace(err);

            }

        }

    }

    private static String JAVADOC_BASE = "https://docs.oracle.com/javase/%d/docs/api/";

    private static void openBrowserForJavadoc(ScriptFunction browse, String relativeUrl) {

        try {

            final URI uri = new URI(String.format(JAVADOC_BASE, Runtime.version().feature()) + relativeUrl);

            ScriptRuntime.apply(browse, null, uri);

        } catch (Exception ignored) {

        }

    }

    private static String readJJSScript() {

        return AccessController.doPrivileged(

            new PrivilegedAction<String>() {

                @Override

                public String run() {

                    try {

                        final InputStream resStream = Main.class.getResourceAsStream("resources/jjs.js");

                        if (resStream == null) {

                            throw new RuntimeException("resources/jjs.js is missing!");

                        }

                        return new String(Source.readFully(resStream));

                    } catch (final IOException exp) {

                        throw new RuntimeException(exp);

                    }

                }

            });

    }

}