/*

 * Copyright (c) 2016, 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

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import java.io.File;

import java.io.IOException;

import java.util.Arrays;

import java.util.HashMap;

import java.util.Locale;

import java.util.Map;

import javax.lang.model.element.Element;

import javax.lang.model.element.ElementKind;

import javax.lang.model.type.TypeMirror;

import javax.tools.JavaCompiler;

import javax.tools.JavaFileObject;

import javax.tools.StandardJavaFileManager;

import javax.tools.ToolProvider;

import com.sun.source.tree.CompilationUnitTree;

import com.sun.source.tree.Tree;

import com.sun.source.tree.VariableTree;

import com.sun.source.util.JavacTask;

import com.sun.source.util.TreePathScanner;

import com.sun.tools.javac.api.JavacTaskImpl;

import com.sun.tools.javac.api.JavacTrees;

import com.sun.tools.javac.code.Printer;

import com.sun.tools.javac.code.Type;

import com.sun.tools.javac.code.Type.CapturedType;

import com.sun.tools.javac.code.Type.ClassType;

import com.sun.tools.javac.code.Types;

import com.sun.tools.javac.util.Log;

import static javax.tools.StandardLocation.SOURCE_PATH;

public class LocalVariableInferenceTester {

    public static void main(String[] args) throws IOException {

        try {

            if (args.length != 1) {

                System.err.println("Usage: LocalVariableInferenceTester <sourcefile>");

                System.exit(1);

            }

            File path = new File(System.getProperty("test.src"));

            fm.setLocation(SOURCE_PATH, Arrays.asList(path));

            File input = new File(path, args[0]);

            JavaFileObject jfo = fm.getJavaFileObjects(input).iterator().next();

            new LocalVariableInferenceTester().compileAndCheck(jfo);

        } finally {

            fm.close();

        }

    }

    int errors = 0;

    int checks = 0;

    void compileAndCheck(JavaFileObject input) throws IOException {

        JavaCompiler c = ToolProvider.getSystemJavaCompiler();

        JavacTask task = (JavacTask) c.getTask(null, fm, null, Arrays.asList("-g"), null, Arrays.asList(input));

        JavacTrees trees = JavacTrees.instance(task);

        Types types = Types.instance(((JavacTaskImpl)task).getContext());

        Iterable<? extends CompilationUnitTree> roots = task.parse();

        Log log = Log.instance(((JavacTaskImpl)task).getContext());

        //force code generation (to shake out non-denotable issues)

        boolean hasClasses = task.generate().iterator().hasNext();

        if (!hasClasses) {

            throw new AssertionError("Errors occurred during compilation!");

        }

        errors += log.nerrors;

        new LocalVarTypeChecker(trees, types).scan(roots, null);

        System.err.println("Checks executed: " + checks);

        if (errors != 0) {

            throw new AssertionError("Errors were found");

        }

    }

    void error(Tree node, String msg) {

        System.err.println(node);

        System.err.println("ERROR: " + msg);

        errors++;

    }

    class LocalVarTypeChecker extends TreePathScanner<Void, Void> {

        JavacTrees trees;

        Types types;

        LocalVarTypeChecker(JavacTrees trees, Types types) {

            this.trees = trees;

            this.types = types;

        }

        @Override

        public Void visitVariable(VariableTree node, Void aVoid) {

            Element e = trees.getElement(getCurrentPath());

            if (e.getKind() == ElementKind.LOCAL_VARIABLE) {

                TypeMirror type = e.asType();

                InferredType inferredAnno = e.getAnnotation(InferredType.class);

                if (inferredAnno != null) {

                    checks++;

                    String req = inferredAnno.value();

                    String found = new TypePrinter().visit((Type)type, null);

                    if (!req.equals(found)) {

                        error(node, "Inferred type mismatch; expected: " + req + " - found: " + found);

                    }

                }

            }

            return super.visitVariable(node, null);

        }

        class TypePrinter extends Printer {

            Map<Type, Integer> capturedIdMap = new HashMap<>();

            @Override

            protected String localize(Locale locale, String key, Object... args) {

                throw new UnsupportedOperationException();

            }

            @Override

            public String visitCapturedType(CapturedType t, Locale locale) {

                return "CAP#" + capturedVarId(t, locale);

            }

            @Override

            protected String capturedVarId(CapturedType t, Locale locale) {

                return String.valueOf(capturedIdMap.getOrDefault(t, capturedIdMap.size()));

            }

            @Override

            public String visitClassType(ClassType t, Locale locale) {

                if (!t.isCompound() && t.tsym.name.isEmpty()) {

                    return "#ANON(" + types.directSupertypes(t) + ")";

                } else if (t.isCompound()) {

                    return "#INT(" + types.directSupertypes(t) + ")";

                } else {

                    return super.visitClassType(t, locale);

                }

            }

        }

    }

}