/*

 * Copyright (c) 2010, 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 java.io.*;

import java.lang.reflect.*;

import java.util.*;

import javax.tools.*;

import com.sun.source.tree.CompilationUnitTree;

import com.sun.source.tree.Tree;

import com.sun.source.util.JavacTask;

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

import com.sun.tools.javac.tree.JCTree;

import com.sun.tools.javac.tree.JCTree.JCCompilationUnit;

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

public abstract class AbstractTreeScannerTest {

    /**

     * Run the program. A base directory can be provided for file arguments.

     * In jtreg mode, the -r option can be given to change the default base

     * directory to the test root directory. For other options, see usage().

     * @param baseDir base directory for any file arguments.

     * @param args command line args

     * @return true if successful or in gui mode

     */

    boolean run(File baseDir, String... args) {

        if (args.length == 0) {

            usage(System.out);

            return true;

        }

        ArrayList<File> files = new ArrayList<File>();

        for (int i = 0; i < args.length; i++) {

            String arg = args[i];

            if (arg.equals("-q"))

                quiet = true;

            else if (arg.equals("-v"))

                verbose = true;

            else if (arg.equals("-r")) {

                File d = baseDir;

                while (!new File(d, "TEST.ROOT").exists()) {

                    d = d.getParentFile();

                    if (d == null)

                        throw new Error("cannot find TEST.ROOT");

                }

                baseDir = d;

            }

            else if (arg.startsWith("-"))

                throw new Error("unknown option: " + arg);

            else {

                while (i < args.length)

                    files.add(new File(baseDir, args[i++]));

            }

        }

        for (File file: files) {

            if (file.exists())

                test(file);

            else

                error("File not found: " + file);

        }

        if (fileCount != 1)

            System.err.println(fileCount + " files read");

        System.err.println(treeCount + " tree nodes compared");

        if (errors > 0)

            System.err.println(errors + " errors");

        return (errors == 0);

    }

    /**

     * Print command line help.

     * @param out output stream

     */

    void usage(PrintStream out) {

        out.println("Usage:");

        out.println("  java " + getClass().getName() + " options... files...");

        out.println("");

        out.println("where options include:");

        out.println("-q        Quiet: don't report on inapplicable files");

        out.println("-v        Verbose: report on files as they are being read");

        out.println("");

        out.println("files may be directories or files");

        out.println("directories will be scanned recursively");

        out.println("non java files, or java files which cannot be parsed, will be ignored");

        out.println("");

    }

    /**

     * Test a file. If the file is a directory, it will be recursively scanned

     * for java files.

     * @param file the file or directory to test

     */

    void test(File file) {

        if (file.isDirectory()) {

            for (File f: file.listFiles()) {

                test(f);

            }

            return;

        }

        if (file.isFile() && file.getName().endsWith(".java")) {

            try {

                if (verbose)

                    System.err.println(file);

                fileCount++;

                treeCount += test(read(file));

            } catch (ParseException e) {

                if (!quiet) {

                    error("Error parsing " + file + "\n" + e.getMessage());

                }

            } catch (IOException e) {

                error("Error reading " + file + ": " + e);

            }

            return;

        }

        if (!quiet)

            error("File " + file + " ignored");

    }

    abstract int test(JCCompilationUnit t);

    /**

     * Read a file.

     * @param file the file to be read

     * @return the tree for the content of the file

     * @throws IOException if any IO errors occur

     * @throws TreePosTest.ParseException if any errors occur while parsing the file

     */

    JCCompilationUnit read(File file) throws IOException, ParseException {

        StringWriter sw = new StringWriter();

        PrintWriter pw = new PrintWriter(sw);

        Reporter r = new Reporter(pw);

        JavacTool tool = JavacTool.create();

        StandardJavaFileManager fm = tool.getStandardFileManager(r, null, null);

        Iterable<? extends JavaFileObject> files = fm.getJavaFileObjects(file);

        JavacTask task = tool.getTask(pw, fm, r, Collections.<String>emptyList(), null, files);

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

        pw.flush();

        if (r.errors > 0)

            throw new ParseException(sw.toString());

        Iterator<? extends CompilationUnitTree> iter = trees.iterator();

        if (!iter.hasNext())

            throw new Error("no trees found");

        JCCompilationUnit t = (JCCompilationUnit) iter.next();

        if (iter.hasNext())

            throw new Error("too many trees found");

        return t;

    }

    /**

     * Report an error. When the program is complete, the program will either

     * exit or throw an Error if any errors have been reported.

     * @param msg the error message

     */

    void error(String msg) {

        System.err.println(msg);

        errors++;

    }

    /**

     *  Report an error for a specific tree node.

     *  @param file the source file for the tree

     *  @param t    the tree node

     *  @param label an indication of the error

     */

    void error(JavaFileObject file, Tree tree, String msg) {

        JCTree t = (JCTree) tree;

        error(file.getName() + ":" + getLine(file, t) + ": " + msg + " " + trim(t, 64));

    }

    /**

     * Get a trimmed string for a tree node, with normalized white space and limited length.

     */

    String trim(Tree tree, int len) {

        JCTree t = (JCTree) tree;

        return (s.length() < len) ? s : s.substring(0, len);

    }

    /** Number of files that have been analyzed. */

    int fileCount;

    /** Number of trees that have been successfully compared. */

    int treeCount;

    /** Number of errors reported. */

    int errors;

    /** Flag: don't report irrelevant files. */

    boolean quiet;

    /** Flag: report files as they are processed. */

    boolean verbose;

    /**

     * Thrown when errors are found parsing a java file.

     */

    private static class ParseException extends Exception {

        ParseException(String msg) {

            super(msg);

        }

    }

    /**

     * DiagnosticListener to report diagnostics and count any errors that occur.

     */

    private static class Reporter implements DiagnosticListener<JavaFileObject> {

        Reporter(PrintWriter out) {

            this.out = out;

        }

        public void report(Diagnostic<? extends JavaFileObject> diagnostic) {

            out.println(diagnostic);

            switch (diagnostic.getKind()) {

                case ERROR:

                    errors++;

            }

        }

        int errors;

        PrintWriter out;

    }

    /**

     * Get the set of fields for a tree node that may contain child tree nodes.

     * These are the fields that are subtypes of JCTree or List.

     * The results are cached, based on the tree's tag.

     */

    Set<Field> getFields(JCTree tree) {

        Set<Field> fields = map.get(tree.getTag());

        if (fields == null) {

            fields = new HashSet<Field>();

            for (Field f: tree.getClass().getFields()) {

                Class<?> fc = f.getType();

                if (JCTree.class.isAssignableFrom(fc) || List.class.isAssignableFrom(fc))

                    fields.add(f);

            }

            map.put(tree.getTag(), fields);

        }

        return fields;

    }

    // where

    Map<Integer, Set<Field>> map = new HashMap<Integer,Set<Field>>();

    /** Get the line number for the primary position for a tree.

     * The code is intended to be simple, although not necessarily efficient.

     * However, note that a file manager such as JavacFileManager is likely

     * to cache the results of file.getCharContent, avoiding the need to read

     * the bits from disk each time this method is called.

     */

    int getLine(JavaFileObject file, JCTree tree) {

        try {

            CharSequence cs = file.getCharContent(true);

            int line = 1;

            for (int i = 0; i < tree.pos; i++) {

                if (cs.charAt(i) == '\n') // jtreg tests always use Unix line endings

                    line++;

            }

            return line;

        } catch (IOException e) {

            return -1;

        }

    }

}