/*

 * Copyright (c) 2014, 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.

 *

 * 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.

 */

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

import com.sun.tools.javac.file.JavacFileManager;

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

import java.io.ByteArrayOutputStream;

import java.io.FileWriter;

import java.io.IOException;

import java.io.PrintStream;

import java.io.PrintWriter;

import java.io.StringWriter;

import java.lang.annotation.Annotation;

import java.lang.annotation.Retention;

import java.lang.annotation.RetentionPolicy;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.Paths;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.EnumMap;

import java.util.Iterator;

import java.util.List;

import java.util.Map;

import java.util.stream.Collectors;

import javax.tools.JavaFileManager;

import javax.tools.JavaFileObject;

import javax.tools.StandardJavaFileManager;

import javax.tools.ToolProvider;

public class Tester {

    /** Marker annotation for test methods to be invoked by runTests. */

    @Retention(RetentionPolicy.RUNTIME)

    @interface Test { }

    /**

     * Run all methods annotated with @Test, and throw an exception if any

     * errors are reported..

     * Typically called on a tester object in main()

     * @throws Exception if any errors occurred

     */

    void runTests() throws Exception {

        for (Method m: getClass().getDeclaredMethods()) {

            Annotation a = m.getAnnotation(Test.class);

            if (a != null) {

                try {

                    out.println("Running test " + m.getName());

                    m.invoke(this);

                } catch (InvocationTargetException e) {

                    Throwable cause = e.getCause();

                    throw (cause instanceof Exception) ? ((Exception) cause) : e;

                }

                out.println();

            }

        }

        if (errors > 0)

            throw new Exception(errors + " errors occurred");

    }

    TestResult runMain(String[] opts, String[] files) {

        out.println("Main " + Arrays.toString(opts) + " " + Arrays.toString(files));

        return run(new TestResult(opts), (tr, c, pw) -> {

            com.sun.tools.javac.main.Main compiler =

                new com.sun.tools.javac.main.Main("javac", pw);

            int rc = compiler.compile(join(opts, files), c).exitCode;

            tr.setResult(rc);

        });

    }

    TestResult runCall(String[] opts, String[] files) {

        out.println("Call " + Arrays.toString(opts) + " " + Arrays.toString(files));

        return run(new TestResult(opts), (tr, c, pw) -> {

            boolean ok = JavacTool.create()

                    .getTask(pw, null, null, Arrays.asList(opts), null, getFiles(files), c)

                    .call();

            tr.setResult(ok);

        });

    }

    TestResult runParse(String[] opts, String[] files) {

        out.println("Parse " + Arrays.toString(opts) + " " + Arrays.toString(files));

        return run(new TestResult(opts), (tr, c, pw) -> {

            JavacTool.create()

                    .getTask(pw, null, null, Arrays.asList(opts), null, getFiles(files), c)

                    .parse();

            tr.setResult(true);

        });

    }

    TestResult runAnalyze(String[] opts, String[] files) {

        out.println("Analyze " + Arrays.toString(opts) + " " + Arrays.toString(files));

        return run(new TestResult(opts), (tr, c, pw) -> {

            JavacTool.create()

                    .getTask(pw, null, null, Arrays.asList(opts), null, getFiles(files), c)

                    .analyze();

            tr.setResult(true);

        });

    }

    interface Runnable {

        void run(TestResult tr, Context c, PrintWriter pw) throws IOException;

    }

    TestResult run(TestResult tr, Runnable r) {

        StringWriter sw = new StringWriter();

        PrintWriter pw = new PrintWriter(sw);

        StreamOutput sysOut = new StreamOutput(System.out, System::setOut);

        StreamOutput sysErr = new StreamOutput(System.err, System::setErr);

        Context context = new Context();

        JavacFileManager.preRegister(context);

        try {

            r.run(tr, context, pw);

        } catch (IllegalArgumentException | IllegalStateException | IOException e) {

            tr.setThrown(e);

        } finally {

            ((JavacFileManager) context.get(JavaFileManager.class)).close();

            tr.setLogs(sw.toString(), sysOut.close(), sysErr.close());

        }

        tr.setContext(context);

        tr.show();

        return tr;

    }

    enum Log { DIRECT, STDOUT, STDERR };

    class TestResult {

        final List<String> args;

        Throwable thrown;

        Object rc; // Number or Boolean

        Map<Log, String> logs;

        Context context;

        TestResult(String... args) {

            this.args = Arrays.asList(args);

        }

        TestResult(List<String> args, Iterable<? extends JavaFileObject> files) {

            this.args = new ArrayList<>();

            this.args.addAll(args);

            for (JavaFileObject f: files)

                this.args.add(f.getName());

        }

        void setResult(int rc) {

            this.rc = rc;

        }

        void setResult(boolean ok) {

            this.rc = ok ? 0 : 1;

        }

        void setThrown(Throwable thrown) {

            this.thrown = thrown;

        }

        void setLogs(String direct, String stdOut, String stdErr) {

            logs = new EnumMap<>(Log.class);

            logs.put(Log.DIRECT, direct);

            logs.put(Log.STDOUT, stdOut);

            logs.put(Log.STDERR, stdErr);

        }

        void setContext(Context context) {

            this.context = context;

        }

        final void show() {

            String NL = System.getProperty("line.separator");

            boolean needSep = false;

            if (rc != null) {

                out.print("rc:" + rc);

                needSep = true;

            }

            if (thrown != null) {

                if (needSep) out.print("; ");

                out.print("thrown:" + thrown);

                needSep = true;

            }

            if (needSep)

                out.println();

            logs.forEach((k, v) -> {

                if (!v.isEmpty()) {

                    out.println("javac/" + k + ":");

                    if (v.endsWith(NL))

                        out.print(v);

                    else

                        out.println(v);

                }

            });

        }

        TestResult checkOK() {

            if (thrown != null) {

                error("unexpected exception thrown: " + thrown);

            } else if (rc == null) {

                error("no result set");

            } else if (rc != (Integer) 0 && rc != (Boolean) true) {

                error("compilation failed unexpectedly; rc=" + rc);

            }

            return this;

        }

        TestResult checkResult(int expect) {

            if (thrown != null) {

                error("unexpected exception thrown: " + thrown);

            } else if (rc != (Integer) expect) {

                error("unexpected result: " + rc +", expected:" + expect);

            }

            return this;

        }

        TestResult checkResult(boolean expect) {

            if (thrown != null) {

                error("unexpected exception thrown: " + thrown);

            } else if (rc != (Integer) (expect ? 0 : 1)) {

                error("unexpected result: " + rc +", expected:" + expect);

            }

            return this;

        }

        TestResult checkLog(String... expects) {

            return checkLog(Log.DIRECT, expects);

        }

        TestResult checkLog(Log l, String... expects) {

            for (String e: expects) {

                if (!logs.get(l).contains(e))

                    error("expected string not found: " + e);

            }

            return this;

        }

        TestResult checkIllegalArgumentException() {

            return checkThrown(IllegalArgumentException.class);

        }

        TestResult checkIllegalStateException() {

            return checkThrown(IllegalStateException.class);

        }

        TestResult checkThrown(Class<? extends Throwable> t) {

            if (thrown == null)

                error("expected exception not thrown: " + t);

            else if (!t.isAssignableFrom(thrown.getClass()))

                error("unexpected exception thrown: " + thrown + ";  expected: " + t);

            return this;

        }

        TestResult checkClass(String name) {

            Path p = getOutDir().resolve(name.replace(".", "/") + ".class");

            if (!Files.exists(p))

                error("expected class not found: " + name + " (" + p + ")");

            return this;

        }

        Path getOutDir() {

            Iterator<String> iter = args.iterator();

            while (iter.hasNext()) {

                if (iter.next().equals("-d")) {

                    return Paths.get(iter.next());

                }

            }

            return null;

        }

    }

    /**

     * Utility class to simplify the handling of temporarily setting a

     * new stream for System.out or System.err.

     */

    private static class StreamOutput {

        // functional interface to set a stream.

        private interface Initializer {

            void set(PrintStream s);

        }

        private final ByteArrayOutputStream baos = new ByteArrayOutputStream();

        private final PrintStream ps = new PrintStream(baos);

        private final PrintStream prev;

        private final Initializer init;

        StreamOutput(PrintStream s, Initializer init) {

            prev = s;

            init.set(ps);

            this.init = init;

        }

        String close() {

            init.set(prev);

            ps.close();

            return baos.toString();

        }

    }

    List<JavaFileObject> getFiles(String... paths) {

        List<JavaFileObject> files = new ArrayList<>();

        for (JavaFileObject f : fm.getJavaFileObjects(paths))

            files.add(f);

        return files;

    }

    String toString(List<JavaFileObject> files) {

        return files.stream().map(f -> f.getName()).collect(Collectors.toList()).toString();

    }

    void mkdirs(String path) throws IOException {

        Files.createDirectories(Paths.get(path));

    }

    void writeFile(String path, String body) throws IOException {

        Path p = Paths.get(path);

        if (p.getParent() != null)

            Files.createDirectories(p.getParent());

        try (FileWriter w = new FileWriter(path)) {

            w.write(body);

        }

    }

    String[] join(String[] a, String[] b) {

        String[] result = new String[a.length + b.length];

        System.arraycopy(a, 0, result, 0, a.length);

        System.arraycopy(b, 0, result, a.length, b.length);

        return result;

    }

    void error(String message) {

        out.print(">>>>> ");

        out.println(message);

        errors++;

    }

    StandardJavaFileManager fm =

            ToolProvider.getSystemJavaCompiler().getStandardFileManager(null, null, null);

    PrintStream out = System.err;

    int errors;

}