/*

 * Copyright (c) 2014, 2015, 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.jshell;

import com.sun.source.tree.CompilationUnitTree;

import com.sun.source.tree.Tree;

import com.sun.source.util.Trees;

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

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

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

import java.util.ArrayList;

import java.util.Arrays;

import java.util.List;

import javax.tools.Diagnostic;

import javax.tools.DiagnosticCollector;

import javax.tools.JavaCompiler;

import javax.tools.JavaFileManager;

import javax.tools.JavaFileObject;

import javax.tools.ToolProvider;

import static jdk.jshell.Util.*;

import com.sun.source.tree.ImportTree;

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

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

import jdk.jshell.MemoryFileManager.OutputMemoryJavaFileObject;

import java.util.Collections;

import java.util.Locale;

import static javax.tools.StandardLocation.CLASS_OUTPUT;

import static jdk.internal.jshell.debug.InternalDebugControl.DBG_GEN;

import java.io.File;

import java.util.Collection;

import java.util.HashMap;

import java.util.LinkedHashMap;

import java.util.Map;

import java.util.stream.Collectors;

import static java.util.stream.Collectors.toList;

import java.util.stream.Stream;

import javax.lang.model.util.Elements;

import javax.tools.FileObject;

import jdk.jshell.MemoryFileManager.SourceMemoryJavaFileObject;

import jdk.jshell.ClassTracker.ClassInfo;

/**

 * The primary interface to the compiler API.  Parsing, analysis, and

 * compilation to class files (in memory).

 * @author Robert Field

 */

class TaskFactory {

    private final JavaCompiler compiler;

    private final MemoryFileManager fileManager;

    private final JShell state;

    private String classpath = System.getProperty("java.class.path");

    TaskFactory(JShell state) {

        this.state = state;

        this.compiler = ToolProvider.getSystemJavaCompiler();

        if (compiler == null) {

            throw new UnsupportedOperationException("Compiler not available, must be run with full JDK 9.");

        }

        if (!System.getProperty("java.specification.version").equals("9"))  {

            throw new UnsupportedOperationException("Wrong compiler, must be run with full JDK 9.");

        }

        this.fileManager = new MemoryFileManager(

                compiler.getStandardFileManager(null, null, null), state);

    }

    void addToClasspath(String path) {

        classpath = classpath + File.pathSeparator + path;

        List<String> args = new ArrayList<>();

        args.add(classpath);

        fileManager().handleOption("-classpath", args.iterator());

    }

    MemoryFileManager fileManager() {

        return fileManager;

    }

    private interface SourceHandler<T> {

        JavaFileObject sourceToFileObject(MemoryFileManager fm, T t);

        Diag diag(Diagnostic<? extends JavaFileObject> d);

    }

    private class StringSourceHandler implements SourceHandler<String> {

        @Override

        public JavaFileObject sourceToFileObject(MemoryFileManager fm, String src) {

            return fm.createSourceFileObject(src, "$NeverUsedName$", src);

        }

        @Override

        public Diag diag(final Diagnostic<? extends JavaFileObject> d) {

            return new Diag() {

                @Override

                public boolean isError() {

                    return d.getKind() == Diagnostic.Kind.ERROR;

                }

                @Override

                public long getPosition() {

                    return d.getPosition();

                }

                @Override

                public long getStartPosition() {

                    return d.getStartPosition();

                }

                @Override

                public long getEndPosition() {

                    return d.getEndPosition();

                }

                @Override

                public String getCode() {

                    return d.getCode();

                }

                @Override

                public String getMessage(Locale locale) {

                    return expunge(d.getMessage(locale));

                }

                @Override

                Unit unitOrNull() {

                    return null;

                }

            };

        }

    }

    private class WrapSourceHandler implements SourceHandler<OuterWrap> {

        final OuterWrap wrap;

        WrapSourceHandler(OuterWrap wrap) {

            this.wrap = wrap;

        }

        @Override

        public JavaFileObject sourceToFileObject(MemoryFileManager fm, OuterWrap w) {

            return fm.createSourceFileObject(w, w.classFullName(), w.wrapped());

        }

        @Override

        public Diag diag(Diagnostic<? extends JavaFileObject> d) {

            return wrap.wrapDiag(d);

        }

    }

    private class UnitSourceHandler implements SourceHandler<Unit> {

        @Override

        public JavaFileObject sourceToFileObject(MemoryFileManager fm, Unit u) {

            return fm.createSourceFileObject(u,

                    state.maps.classFullName(u.snippet()),

                    u.snippet().outerWrap().wrapped());

        }

        @Override

        public Diag diag(Diagnostic<? extends JavaFileObject> d) {

            SourceMemoryJavaFileObject smjfo = (SourceMemoryJavaFileObject) d.getSource();

            Unit u = (Unit) smjfo.getOrigin();

            return u.snippet().outerWrap().wrapDiag(d);

        }

    }

    /**

     * Parse a snippet of code (as a String) using the parser subclass.  Return

     * the parse tree (and errors).

     */

    class ParseTask extends BaseTask {

        private final Iterable<? extends CompilationUnitTree> cuts;

        private final List<? extends Tree> units;

        ParseTask(final String source) {

            super(Stream.of(source),

                    new StringSourceHandler(),

                    "-XDallowStringFolding=false", "-proc:none");

            ReplParserFactory.instance(getContext());

            cuts = parse();

            units = Util.stream(cuts)

                    .flatMap(cut -> {

                        List<? extends ImportTree> imps = cut.getImports();

                        return (!imps.isEmpty() ? imps : cut.getTypeDecls()).stream();

                    })

                    .collect(toList());

        }

        private Iterable<? extends CompilationUnitTree> parse() {

            try {

                return task.parse();

            } catch (Exception ex) {

                throw new InternalError("Exception during parse - " + ex.getMessage(), ex);

            }

        }

        List<? extends Tree> units() {

            return units;

        }

        @Override

        Iterable<? extends CompilationUnitTree> cuTrees() {

            return cuts;

        }

    }

    /**

     * Run the normal "analyze()" pass of the compiler over the wrapped snippet.

     */

    class AnalyzeTask extends BaseTask {

        private final Iterable<? extends CompilationUnitTree> cuts;

        AnalyzeTask(final OuterWrap wrap) {

            this(Stream.of(wrap),

                    new WrapSourceHandler(wrap),

                    "-XDshouldStopPolicy=FLOW", "-proc:none");

        }

        AnalyzeTask(final Collection<Unit> units) {

            this(units.stream(), new UnitSourceHandler(),

                    "-XDshouldStopPolicy=FLOW", "-Xlint:unchecked", "-proc:none");

        }

        <T>AnalyzeTask(final Stream<T> stream, SourceHandler<T> sourceHandler,

                String... extraOptions) {

            super(stream, sourceHandler, extraOptions);

            cuts = analyze();

        }

        private Iterable<? extends CompilationUnitTree> analyze() {

            try {

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

                task.analyze();

                return cuts;

            } catch (Exception ex) {

                throw new InternalError("Exception during analyze - " + ex.getMessage(), ex);

            }

        }

        @Override

        Iterable<? extends CompilationUnitTree> cuTrees() {

            return cuts;

        }

        Elements getElements() {

            return task.getElements();

        }

        javax.lang.model.util.Types getTypes() {

            return task.getTypes();

        }

    }

    /**

     * Unit the wrapped snippet to class files.

     */

    class CompileTask extends BaseTask {

        private final Map<Unit, List<OutputMemoryJavaFileObject>> classObjs = new HashMap<>();

        CompileTask(Collection<Unit> units) {

            super(units.stream(), new UnitSourceHandler(),

                    "-Xlint:unchecked", "-proc:none");

        }

        boolean compile() {

            fileManager.registerClassFileCreationListener(this::listenForNewClassFile);

            boolean result = task.call();

            fileManager.registerClassFileCreationListener(null);

            return result;

        }

        List<ClassInfo> classInfoList(Unit u) {

            List<OutputMemoryJavaFileObject> l = classObjs.get(u);

            if (l == null) return Collections.emptyList();

            return l.stream()

                    .map(fo -> state.classTracker.classInfo(fo.getName(), fo.getBytes()))

                    .collect(Collectors.toList());

        }

        private void listenForNewClassFile(OutputMemoryJavaFileObject jfo, JavaFileManager.Location location,

                String className, JavaFileObject.Kind kind, FileObject sibling) {

            //debug("listenForNewClassFile %s loc=%s kind=%s\n", className, location, kind);

            if (location == CLASS_OUTPUT) {

                state.debug(DBG_GEN, "Compiler generating class %s\n", className);

                Unit u = ((sibling instanceof SourceMemoryJavaFileObject)

                        && (((SourceMemoryJavaFileObject) sibling).getOrigin() instanceof Unit))

                        ? (Unit) ((SourceMemoryJavaFileObject) sibling).getOrigin()

                        : null;

                classObjs.compute(u, (k, v) -> (v == null)? new ArrayList<>() : v)

                        .add(jfo);

            }

        }

        @Override

        Iterable<? extends CompilationUnitTree> cuTrees() {

            throw new UnsupportedOperationException("Not supported.");

        }

    }

    abstract class BaseTask {

        final DiagnosticCollector<JavaFileObject> diagnostics = new DiagnosticCollector<>();

        final JavacTaskImpl task;

        private DiagList diags = null;

        private final SourceHandler<?> sourceHandler;

        private final Context context = new Context();

        private Types types;

        private JavacMessages messages;

        private Trees trees;

        private <T>BaseTask(Stream<T> inputs,

                //BiFunction<MemoryFileManager, T, JavaFileObject> sfoCreator,

                SourceHandler<T> sh,

                String... extraOptions) {

            this.sourceHandler = sh;

            List<String> options = Arrays.asList(extraOptions);

            Iterable<? extends JavaFileObject> compilationUnits = inputs

                            .map(in -> sh.sourceToFileObject(fileManager, in))

                            .collect(Collectors.toList());

            this.task = (JavacTaskImpl) ((JavacTool) compiler).getTask(null,

                    fileManager, diagnostics, options, null,

                    compilationUnits, context);

        }

        abstract Iterable<? extends CompilationUnitTree> cuTrees();

        CompilationUnitTree firstCuTree() {

            return cuTrees().iterator().next();

        }

        Diag diag(Diagnostic<? extends JavaFileObject> diag) {

            return sourceHandler.diag(diag);

        }

        Context getContext() {

            return context;

        }

        Types types() {

            if (types == null) {

                types = Types.instance(context);

            }

            return types;

        }

        JavacMessages messages() {

            if (messages == null) {

                messages = JavacMessages.instance(context);

            }

            return messages;

        }

        Trees trees() {

            if (trees == null) {

                trees = Trees.instance(task);

            }

            return trees;

        }

        // ------------------ diags functionality

        DiagList getDiagnostics() {

            if (diags == null) {

                LinkedHashMap<String, Diag> diagMap = new LinkedHashMap<>();

                for (Diagnostic<? extends JavaFileObject> in : diagnostics.getDiagnostics()) {

                    Diag d = diag(in);

                    diagMap.put(uniqueKey, d);

                }

                diags = new DiagList(diagMap.values());

            }

            return diags;

        }

        boolean hasErrors() {

            return getDiagnostics().hasErrors();

        }

        String shortErrorMessage() {

            StringBuilder sb = new StringBuilder();

            for (Diag diag : getDiagnostics()) {

                    if (!line.trim().startsWith("location:")) {

                        sb.append(line);

                    }

                }

            }

            return sb.toString();

        }

        void debugPrintDiagnostics(String src) {

            for (Diag diag : getDiagnostics()) {

                state.debug(DBG_GEN, "ERROR --\n");

                    if (!line.trim().startsWith("location:")) {

                        state.debug(DBG_GEN, "%s\n", line);

                    }

                }

                int start = (int) diag.getStartPosition();

                int end = (int) diag.getEndPosition();

                if (src != null) {

                    String[] srcLines = src.split("\\r?\\n");

                    for (String line : srcLines) {

                        state.debug(DBG_GEN, "%s\n", line);

                    }

                    StringBuilder sb = new StringBuilder();

                    for (int i = 0; i < start; ++i) {

                        sb.append(' ');

                    }

                    sb.append('^');

                    if (end > start) {

                        for (int i = start + 1; i < end; ++i) {

                            sb.append('-');

                        }

                        sb.append('^');

                    }

                    state.debug(DBG_GEN, "%s\n", sb.toString());

                }

                state.debug(DBG_GEN, "printDiagnostics start-pos = %d ==> %d -- wrap = %s\n",

                        diag.getStartPosition(), start, this);

                state.debug(DBG_GEN, "Code: %s\n", diag.getCode());

                state.debug(DBG_GEN, "Pos: %d (%d - %d) -- %s\n", diag.getPosition(),

                        diag.getStartPosition(), diag.getEndPosition(), diag.getMessage(null));

            }

        }

    }

}