# autoimports script requires -scripting mode

/*

 * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 *   - Redistributions of source code must retain the above copyright

 *     notice, this list of conditions and the following disclaimer.

 *

 *   - Redistributions in binary form must reproduce the above copyright

 *     notice, this list of conditions and the following disclaimer in the

 *     documentation and/or other materials provided with the distribution.

 *

 *   - Neither the name of Oracle nor the names of its

 *     contributors may be used to endorse or promote products derived

 *     from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS

 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,

 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF

 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING

 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS

 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

/*

 * It is tedious to import Java classes used in a script. Sometimes it is easier

 * use simple names of java classes and have a script auto import Java classes. 

 * You can load this script at the start of an interactive jjs session or at the

 * start of your script. This script defines a __noSuchProperty__ hook to auto 

 * import Java classes as needed and when they are referred to for the first time

 * in your script. You can also call the "autoimports" function to print script 

 * statements that you need to use in your script, i.e., have the function generate

 * a script to import Java classes used by your script so far. After running your

 * script, you can call autoimports to get the exact Java imports you need and replace

 * the autoimports load with the generated import statements (to avoid costly init of

 * the autoimports script).

 *

 * Example usage of autoimports.js in interactive mode:

 *

 *     jjs -scripting autoimports.js -

 *     jjs> Vector

 *     jjs> [JavaClass java.util.Vector]

 */

(function() {

    var ArrayList = Java.type("java.util.ArrayList");

    var HashMap = Java.type("java.util.HashMap");

    var Files = Java.type("java.nio.file.Files");

    var FileSystems = Java.type("java.nio.file.FileSystems");

    var URI = Java.type("java.net.URI");

    // initialize a class to package map by iterating all

    // classes available in the system by walking through "jrt fs"

    var fs = FileSystems.getFileSystem(URI.create("jrt:/"));

    var root = fs.getPath('/');

    var clsToPkg = new HashMap();

    function addToClsToPkg(c, p) {

        if (clsToPkg.containsKey(c)) {

            var val = clsToPkg.get(c);

            if (val instanceof ArrayList) {

                val.add(p);

            } else {

                var al = new ArrayList();

                al.add(val);

                al.add(p);

                clsToPkg.put(c, al);

            }

        } else {

            clsToPkg.put(c, p);

        }

    }

    // handle collision and allow user to choose package

    function getPkgOfCls(c) {

        var val = clsToPkg.get(c);

        if (val instanceof ArrayList) {

            var count = 1;

            print("Multiple matches for " + c + ", choose package:");

            for each (var v in val) {

                print(count + ". " + v);

                count++;

            }

            var choice = parseInt(readLine());

            if (isNaN(choice) || choice < 1 || choice > val.size()) {

                print("invalid choice: " + choice);

                return undefined;

            }

            return val.get(choice - 1);

        } else {

            return val;

        }

    }

    Files.walk(root).forEach(function(p) {

        if (Files.isRegularFile(p)) {

            var str = p.toString();

            if (str.endsWith(".class") && !str.endsWith("module-info.class")) {

                str = str.substring("/modules/".length);

                var idx = str.indexOf('/');

                if (idx != -1) {

                    str = str.substring(idx + 1);

                    if (str.startsWith("java") ||

                        str.startsWith("javax") ||

                        str.startsWith("org")) {

                        var lastIdx = str.lastIndexOf('/');

                        if (lastIdx != -1) {

                            var pkg = str.substring(0, lastIdx).replaceAll('/', '.');

                            var cls = str.substring(lastIdx + 1, str.lastIndexOf(".class"));

                            addToClsToPkg(cls, pkg);

                        }

                    }

                }

            }

        } 

    });

    var imports = new ArrayList();

    var global = this;

    var oldNoSuchProp = global.__noSuchProperty__;

    this.__noSuchProperty__ = function(name) {

        'use strict';

        if (clsToPkg.containsKey(name)) {

            var pkg = getPkgOfCls(name);

            if (pkg) {

                var clsName = pkg + "." + name;

                imports.add("var " + name + " = Java.type('" + clsName + "');");

                return global[name] = Java.type(clsName);

            }

        } else if (typeof oldNoSuchProp == 'function') {

            return oldNoSuchProp.call(this, name);

        }

        if (typeof this == 'undefined') {

            throw new ReferenceError(name);

        } else {

            return undefined;

        }

    }

    this.autoimports = function() {

        for each (var im in imports) {

            print(im);

        }

    }

})();