/*
 * Copyright 1998-2008 Sun Microsystems, Inc.  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.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */

package com.sun.tools.javadoc;

import com.sun.javadoc.*;

import static com.sun.javadoc.LanguageVersion.*;

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

import java.net.*;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.InvocationTargetException;

import java.io.File;
import java.io.IOException;
import java.util.StringTokenizer;

/**
 * Class creates, controls and invokes doclets.
 * @author Neal Gafter (rewrite)
 */
public class DocletInvoker {

    private final Class<?> docletClass;

    private final String docletClassName;

    private final ClassLoader appClassLoader;

    private final Messager messager;

    private static class DocletInvokeException extends Exception {
        private static final long serialVersionUID = 0;
    }

    private String appendPath(String path1, String path2) {
        if (path1 == null || path1.length() == 0) {
            return path2 == null ? "." : path2;
        } else if (path2 == null || path2.length() == 0) {
            return path1;
        } else {
            return path1  + File.pathSeparator + path2;
        }
    }

    public DocletInvoker(Messager messager,
                         String docletClassName, String docletPath,
                         ClassLoader docletParentClassLoader) {
        this.messager = messager;
        this.docletClassName = docletClassName;

        // construct class loader
        String cpString = null;   // make sure env.class.path defaults to dot

        // do prepends to get correct ordering
        cpString = appendPath(System.getProperty("env.class.path"), cpString);
        cpString = appendPath(System.getProperty("java.class.path"), cpString);
        cpString = appendPath(docletPath, cpString);
        URL[] urls = pathToURLs(cpString);
        if (docletParentClassLoader == null)
            appClassLoader = new URLClassLoader(urls);
        else
            appClassLoader = new URLClassLoader(urls, docletParentClassLoader);

        // attempt to find doclet
        Class dc = null;
        try {
            dc = appClassLoader.loadClass(docletClassName);
        } catch (ClassNotFoundException exc) {
            messager.error(null, "main.doclet_class_not_found", docletClassName);
            messager.exit();
        }
        docletClass = dc;
    }

    /**
     * Generate documentation here.  Return true on success.
     */
    public boolean start(RootDoc root) {
        Object retVal;
        String methodName = "start";
        Class[] paramTypes = new Class[1];
        Object[] params = new Object[1];
        paramTypes[0] = RootDoc.class;
        params[0] = root;
        try {
            retVal = invoke(methodName, null, paramTypes, params);
        } catch (DocletInvokeException exc) {
            return false;
        }
        if (retVal instanceof Boolean) {
            return ((Boolean)retVal).booleanValue();
        } else {
            messager.error(null, "main.must_return_boolean",
                           docletClassName, methodName);
            return false;
        }
    }

    /**
     * Check for doclet added options here. Zero return means
     * option not known.  Positive value indicates number of
     * arguments to option.  Negative value means error occurred.
     */
    public int optionLength(String option) {
        Object retVal;
        String methodName = "optionLength";
        Class[] paramTypes = new Class[1];
        Object[] params = new Object[1];
        paramTypes[0] = option.getClass();
        params[0] = option;
        try {
            retVal = invoke(methodName, new Integer(0), paramTypes, params);
        } catch (DocletInvokeException exc) {
            return -1;
        }
        if (retVal instanceof Integer) {
            return ((Integer)retVal).intValue();
        } else {
            messager.error(null, "main.must_return_int",
                           docletClassName, methodName);
            return -1;
        }
    }

    /**
     * Let doclet check that all options are OK. Returning true means
     * options are OK.  If method does not exist, assume true.
     */
    public boolean validOptions(List<String[]> optlist) {
        Object retVal;
        String options[][] = optlist.toArray(new String[optlist.length()][]);
        String methodName = "validOptions";
        DocErrorReporter reporter = messager;
        Class[] paramTypes = new Class[2];
        Object[] params = new Object[2];
        paramTypes[0] = options.getClass();
        paramTypes[1] = DocErrorReporter.class;
        params[0] = options;
        params[1] = reporter;
        try {
            retVal = invoke(methodName, Boolean.TRUE, paramTypes, params);
        } catch (DocletInvokeException exc) {
            return false;
        }
        if (retVal instanceof Boolean) {
            return ((Boolean)retVal).booleanValue();
        } else {
            messager.error(null, "main.must_return_boolean",
                           docletClassName, methodName);
            return false;
        }
    }

    /**
     * Return the language version supported by this doclet.
     * If the method does not exist in the doclet, assume version 1.1.
     */
    public LanguageVersion languageVersion() {
        try {
            Object retVal;
            String methodName = "languageVersion";
            Class[] paramTypes = new Class[0];
            Object[] params = new Object[0];
            try {
                retVal = invoke(methodName, JAVA_1_1, paramTypes, params);
            } catch (DocletInvokeException exc) {
                return JAVA_1_1;
            }
            if (retVal instanceof LanguageVersion) {
                return (LanguageVersion)retVal;
            } else {
                messager.error(null, "main.must_return_languageversion",
                               docletClassName, methodName);
                return JAVA_1_1;
            }
        } catch (NoClassDefFoundError ex) { // for boostrapping, no Enum class.
            return null;
        }
    }

    /**
     * Utility method for calling doclet functionality
     */
    private Object invoke(String methodName, Object returnValueIfNonExistent,
                          Class[] paramTypes, Object[] params)
        throws DocletInvokeException {
            Method meth;
            try {
                meth = docletClass.getMethod(methodName, paramTypes);
            } catch (NoSuchMethodException exc) {
                if (returnValueIfNonExistent == null) {
                    messager.error(null, "main.doclet_method_not_found",
                                   docletClassName, methodName);
                    throw new DocletInvokeException();
                } else {
                    return returnValueIfNonExistent;
                }
            } catch (SecurityException exc) {
                messager.error(null, "main.doclet_method_not_accessible",
                               docletClassName, methodName);
                throw new DocletInvokeException();
            }
            if (!Modifier.isStatic(meth.getModifiers())) {
                messager.error(null, "main.doclet_method_must_be_static",
                               docletClassName, methodName);
                throw new DocletInvokeException();
            }
            try {
                Thread.currentThread().setContextClassLoader(appClassLoader);
                return meth.invoke(null , params);
            } catch (IllegalArgumentException exc) {
                messager.error(null, "main.internal_error_exception_thrown",
                               docletClassName, methodName, exc.toString());
                throw new DocletInvokeException();
            } catch (IllegalAccessException exc) {
                messager.error(null, "main.doclet_method_not_accessible",
                               docletClassName, methodName);
                throw new DocletInvokeException();
            } catch (NullPointerException exc) {
                messager.error(null, "main.internal_error_exception_thrown",
                               docletClassName, methodName, exc.toString());
                throw new DocletInvokeException();
            } catch (InvocationTargetException exc) {
                Throwable err = exc.getTargetException();
                if (err instanceof java.lang.OutOfMemoryError) {
                    messager.error(null, "main.out.of.memory");
                } else {
                messager.error(null, "main.exception_thrown",
                               docletClassName, methodName, exc.toString());
                    exc.getTargetException().printStackTrace();
                }
                throw new DocletInvokeException();
            }
    }

    /**
     * Utility method for converting a search path string to an array
     * of directory and JAR file URLs.
     *
     * @param path the search path string
     * @return the resulting array of directory and JAR file URLs
     */
    static URL[] pathToURLs(String path) {
        StringTokenizer st = new StringTokenizer(path, File.pathSeparator);
        URL[] urls = new URL[st.countTokens()];
        int count = 0;
        while (st.hasMoreTokens()) {
            URL url = fileToURL(new File(st.nextToken()));
            if (url != null) {
                urls[count++] = url;
            }
        }
        if (urls.length != count) {
            URL[] tmp = new URL[count];
            System.arraycopy(urls, 0, tmp, 0, count);
            urls = tmp;
        }
        return urls;
    }

    /**
     * Returns the directory or JAR file URL corresponding to the specified
     * local file name.
     *
     * @param file the File object
     * @return the resulting directory or JAR file URL, or null if unknown
     */
    static URL fileToURL(File file) {
        String name;
        try {
            name = file.getCanonicalPath();
        } catch (IOException e) {
            name = file.getAbsolutePath();
        }
        name = name.replace(File.separatorChar, '/');
        if (!name.startsWith("/")) {
            name = "/" + name;
        }
        // If the file does not exist, then assume that it's a directory
        if (!file.isFile()) {
            name = name + "/";
        }
        try {
            return new URL("file", "", name);
        } catch (MalformedURLException e) {
            throw new IllegalArgumentException("file");
        }
    }
}
