/*
 * Copyright (c) 2003 Sun Microsystems, Inc. All Rights Reserved.
 * Copyright (c) 2010 JogAmp Community. All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 * 
 * - Redistribution of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * 
 * - Redistribution in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * 
 * Neither the name of Sun Microsystems, Inc. or the names of
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES,
 * INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
 * PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN
 * MICROSYSTEMS, INC. ("SUN") AND ITS LICENSORS SHALL NOT BE LIABLE FOR
 * ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING OR
 * DISTRIBUTING THIS SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR
 * ITS LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR
 * DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE
 * DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY,
 * ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE, EVEN IF
 * SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 * 
 * You acknowledge that this software is not designed or intended for use
 * in the design, construction, operation or maintenance of any nuclear
 * facility.
 * 
 * Sun gratefully acknowledges that this software was originally authored
 * and developed by Kenneth Bradley Russell and Christopher John Kline.
 */

package com.jogamp.gluegen.opengl;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

  /**
   * Builds the StaticGLInfo class from the OpenGL header files (i.e., gl.h
   * and glext.h) whose paths were passed as arguments to {@link
   * #main(String[])}.
   *
   * It relies upon the assumption that a function's membership is scoped by
   * preprocessor blocks in the header files that match the following pattern:
   * <br>
   *
   * <pre>
   * 
   * #ifndef GL_XXXX
   * GLAPI <returnType> <APIENTRY|GLAPIENTRY> glFuncName(<params>)
   * #endif GL_XXXX
   *
   * </pre>
   *
   * For example, if it parses the following data:
   *
   * <pre>
   * 
   * #ifndef GL_VERSION_1_3
   * GLAPI void APIENTRY glActiveTexture (GLenum);
   * GLAPI void APIENTRY glMultiTexCoord1dv (GLenum, const GLdouble *);
   * GLAPI void  <APIENTRY|GLAPIENTRY> glFuncName(<params>)
   * #endif GL_VERSION_1_3
   *
   * #ifndef GL_ARB_texture_compression
   * GLAPI void APIENTRY glCompressedTexImage3DARB (GLenum, GLint, GLenum, GLsizei, GLsizei, GLsizei, GLint, GLsizei, const GLvoid *);
   * GLAPI void APIENTRY glCompressedTexImage2DARB (GLenum, GLint, GLenum, GLsizei, GLsizei, GLint, GLsizei, const GLvoid *);
   * #endif
   * 
   * </pre>
   *
   * It will associate
   *   <code> glActiveTexture </code> and
   *   <code> glMultiTexCoord1dv </code>
   * with the symbol
   *   <code> GL_VERSION_1_3 </code>,
   * and associate
   *   <code> glCompressedTexImage2DARB </code> and
   *   <code> glCompressedTexImage3DARB </code>
   * with the symbol
   *   <code> GL_ARB_texture_compression </code>.
   * */
public class BuildStaticGLInfo {

  // Handles function pointer 
  protected static final int funcIdentifierGroup = 9;
  protected static Pattern funcPattern =
    Pattern.compile("^(GLAPI|GL_API|GL_APICALL|EGLAPI|extern)?(\\s*)((unsigned|const)\\s+)?(\\w+)(\\s+\\*\\s*|\\s*\\*\\s+|\\s+)?(GLAPIENTRY|GL_APIENTRY|APIENTRY|EGLAPIENTRY|WINAPI)?(\\s*)([ew]?gl\\w+)\\s?(\\(.*)");

  protected static Pattern associationPattern =
    Pattern.compile("\\#ifndef ([CEW]?GL[XU]?_[A-Za-z0-9_]+)(.*)");

  protected static Pattern ifPattern =
    Pattern.compile("\\#if(.*)");
  protected static Pattern elsePattern =
    Pattern.compile("\\#(elif|else)(.*)");
  protected static Pattern endifPattern =
    Pattern.compile("\\#endif(.*)");
  
  protected static final int defineIdentifierGroup = 1;
  protected static Pattern definePattern =
    Pattern.compile("\\#define ([CEW]?GL[XU]?_[A-Za-z0-9_]+)\\s*([A-Za-z0-9_]+)(.*)");

  // Maps function / #define names to Set of names of the extensions they're declared in
  protected Map<String, Set<String>> declarationToExtensionMap = new HashMap<String, Set<String>>();

  // Maps extension names to Set of identifiers (both #defines and
  // function names) this extension declares
  protected Map<String, Set<String>> extensionToDeclarationMap = new HashMap<String, Set<String>>();
  protected boolean DEBUG = false;

    /**
     * The first argument is the package to which the StaticGLInfo class
     * belongs, the second is the path to the directory in which that package's
     * classes reside, and the remaining arguments are paths to the C header
     * files that should be parsed
     */
    public static void main(String[] args) throws IOException {
        if (args.length > 0 && args[0].equals("-test")) {
            BuildStaticGLInfo builder = new BuildStaticGLInfo();
            builder.setDebug(true);
            String[] newArgs = new String[args.length - 1];
            System.arraycopy(args, 1, newArgs, 0, args.length - 1);
            builder.parse(newArgs);
            builder.dump();
            System.exit(0);
        }

        String packageName = args[0];
        String packageDir = args[1];

        String[] cHeaderFilePaths = new String[args.length - 2];
        System.arraycopy(args, 2, cHeaderFilePaths, 0, cHeaderFilePaths.length);

        BuildStaticGLInfo builder = new BuildStaticGLInfo();
        try {
            builder.parse(cHeaderFilePaths);

            File file = new File(packageDir + File.separatorChar + "StaticGLInfo.java");
            String parentDir = file.getParent();
            if (parentDir != null) {
                File pDirFile = new File(parentDir);
                pDirFile.mkdirs();
            }

            PrintWriter writer = new PrintWriter(new BufferedWriter(new FileWriter(file)));
            builder.emitJavaCode(writer, packageName);

            writer.flush();
            writer.close();
        } catch (Exception e) {
            StringBuilder buf = new StringBuilder("{ ");
            for (int i = 0; i < cHeaderFilePaths.length; ++i) {
                buf.append(cHeaderFilePaths[i]);
                buf.append(" ");
            }
            buf.append('}');
            throw new RuntimeException(
                    "Error building StaticGLInfo.java from " + buf.toString(), e);
        }
    }

    public void setDebug(boolean v) {
        DEBUG = v;
    }

    /** Parses the supplied C header files and adds the function
    associations contained therein to the internal map. */
    public void parse(String[] cHeaderFilePaths) throws IOException {
        for (int i = 0; i < cHeaderFilePaths.length; i++) {
            parse(cHeaderFilePaths[i]);
        }
    }

    /** Parses the supplied C header file and adds the function
    associations contained therein to the internal map. */
    public void parse(String cHeaderFilePath) throws IOException {
        BufferedReader reader = new BufferedReader(new FileReader(cHeaderFilePath));
        String line, activeAssociation = null;
        Matcher m = null;
        int block = 0;
        while ((line = reader.readLine()) != null) {
            int type = 0; // 1-define, 2-function            
            if ( 0 < block ) { // inside a #ifndef GL_XXX block and matching a function, if block > 0
                String identifier = null;
                if( 2 >= block ) {  // not within sub-blocks > 2, i.e. further typedefs
                    if ((m = funcPattern.matcher(line)).matches()) {
                        identifier = m.group(funcIdentifierGroup).trim();
                        type = 2;
                    } else if ((m = definePattern.matcher(line)).matches()) {
                        identifier = m.group(defineIdentifierGroup).trim();
                        type = 1;
                    }
                }
                if ( identifier != null &&
                     activeAssociation != null &&                     
                     !identifier.equals(activeAssociation) // Handles #ifndef GL_... #define GL_... 
                   ) 
                {
                    addAssociation(identifier, activeAssociation);
                    if (DEBUG) {
                        System.err.println("<"+block+">   ADDING ASSOCIATION: <" + identifier + "> <" + activeAssociation + "> ; type " + type);
                    }
                } else {
                    if ((m = ifPattern.matcher(line)).matches()) {
                        final String comment = m.group(1).trim();
                        block++;
                        if (DEBUG) {
                            System.err.println("<"+block+"> BEGIN IF BLOCK: <" + comment + ">");
                        }
                    } else if ((m = elsePattern.matcher(line)).matches()) {
                        final String comment = m.group(1).trim();
                        if (DEBUG) {
                            System.err.println("<"+block+"> ELSE BLOCK: <" + comment + ">");
                        }
                    } else if ((m = endifPattern.matcher(line)).matches()) {
                        final String comment = m.group(1).trim();
                        block--;
                        if( 0 == block ) {
                            if (DEBUG) {
                                System.err.println("<"+block+"> END ASSOCIATION BLOCK: <" + activeAssociation + " <-> " + comment + ">");
                            }
                            activeAssociation = null;                
                        } else {
                            if (DEBUG) {
                                System.err.println("<"+block+"> END IF BLOCK: <" + comment + ">");
                            }
                        }
                    }
                }
            } else if ((m = associationPattern.matcher(line)).matches()) {                
                // found a new #ifndef GL_XXX block
                activeAssociation = m.group(1).trim();
                block++;
                if (DEBUG) {
                    System.err.println("<"+block+"> BEGIN ASSOCIATION BLOCK: <" + activeAssociation + ">");
                }
            }
        }
        reader.close();
    }

    public void dump() {
        for (String name : extensionToDeclarationMap.keySet()) {
            Set<String> decls = extensionToDeclarationMap.get(name);
            System.out.println("<" + name + "> :");
            List<String> l = new ArrayList<String>();
            l.addAll(decls);
            Collections.sort(l);
            for (String str : l) {
                System.out.println("  <" + str + ">");
            }
        }
    }

    public Set<String> getExtension(String identifier) {
        return declarationToExtensionMap.get(identifier);
    }

    public Set<String> getDeclarations(String extension) {
        return extensionToDeclarationMap.get(extension);
    }

    public Set<String> getExtensions() {
        return extensionToDeclarationMap.keySet();
    }

    public void emitJavaCode(PrintWriter output, String packageName) {
        output.println("package " + packageName + ";");
        output.println();
        output.println("import java.util.*;");
        output.println();
        output.println("public final class StaticGLInfo");
        output.println("{");

        output.println("  // maps function names to the extension string or OpenGL");
        output.println("  // specification version string to which they correspond.");
        output.println("  private static HashMap funcToAssocMap;");
        output.println();

        output.println("  /**");
        output.println("   * Returns the OpenGL extension string or GL_VERSION string with which the");
        output.println("   * given function is associated. <P>");
        output.println("   *");
        output.println("   * If the");
        output.println("   * function is part of the OpenGL core, the returned value will be");
        output.println("   * GL_VERSION_XXX where XXX represents the OpenGL version of which the");
        output.println("   * function is a member (XXX will be of the form \"A\" or \"A_B\" or \"A_B_C\";");
        output.println("   * e.g., GL_VERSION_1_2_1 for OpenGL version 1.2.1).");
        output.println("   *");
        output.println("   * If the function is an extension function, the returned value will the");
        output.println("   * OpenGL extension string for the extension to which the function");
        output.println("   * corresponds. For example, if glLoadTransposeMatrixfARB is the argument,");
        output.println("   * GL_ARB_transpose_matrix will be the value returned.");
        output.println("   * Please see http://oss.sgi.com/projects/ogl-sample/registry/index.html for");
        output.println("   * a list of extension names and the functions they expose.");
        output.println("   *");
        output.println("   * If the function specified is not part of any known OpenGL core version or");
        output.println("   * extension, then NULL will be returned.");
        output.println("   */");
        output.println("  public static String getFunctionAssociation(String glFunctionName)");
        output.println("  {");
        output.println("    String mappedName = null;");
        output.println("    int  funcNamePermNum = com.jogamp.gluegen.runtime.opengl.GLNameResolver.getFuncNamePermutationNumber(glFunctionName);");
        output.println("    for(int i = 0; null==mappedName && i < funcNamePermNum; i++) {");
        output.println("        String tmp = com.jogamp.gluegen.runtime.opengl.GLNameResolver.getFuncNamePermutation(glFunctionName, i);");
        output.println("        try {");
        output.println("          mappedName = (String)funcToAssocMap.get(tmp);");
        output.println("        } catch (Exception e) { }");
        output.println("    }");
        output.println("    return mappedName;");
        output.println("  }");
        output.println();

        output.println("  static");
        output.println("  {");

        // Compute max capacity
        int maxCapacity = 0;
        for (String name : declarationToExtensionMap.keySet()) {
            if (!name.startsWith("GL")) {
                ++maxCapacity;
            }
        }

        output.println("    funcToAssocMap = new HashMap(" + maxCapacity + "); // approximate max capacity");
        output.println("    String group;");
        ArrayList<String> sets = new ArrayList<String>(extensionToDeclarationMap.keySet());
        Collections.sort(sets);
        for (String groupName : sets) {
            Set<String> funcs = extensionToDeclarationMap.get(groupName);
            List<String> l = new ArrayList<String>();
            l.addAll(funcs);
            Collections.sort(l);
            Iterator<String> funcIter = l.iterator();
            boolean printedHeader = false;
            while (funcIter.hasNext()) {
                String funcName = funcIter.next();
                if (!funcName.startsWith("GL")) {
                    if (!printedHeader) {
                        output.println();
                        output.println("    //----------------------------------------------------------------");
                        output.println("    //                 " + groupName);
                        output.println("    //----------------------------------------------------------------");
                        output.println("    group = \"" + groupName + "\";");
                        printedHeader = true;
                    }

                    output.println("    funcToAssocMap.put(\"" + funcName + "\", group);");
                }
            }
        }
        output.println("  }");
        output.println("} // end class StaticGLInfo");
    }

    //----------------------------------------------------------------------
    // Internals only below this point
    //
    protected void addAssociation(String identifier, String association) {
        Set<String> extensions = declarationToExtensionMap.get(identifier);
        if(null == extensions) {
            extensions = new HashSet<String>();
            declarationToExtensionMap.put(identifier, extensions);
        }
        extensions.add(association);
        
        Set<String> identifiers = extensionToDeclarationMap.get(association);
        if (identifiers == null) {
            identifiers = new HashSet<String>();
            extensionToDeclarationMap.put(association, identifiers);
        }
        identifiers.add(identifier);
    }
}