/*
   
       dsh-codegen  Source code generation suite.
       Copyright (c) 2004-2013 held jointly by the individual authors.
   
       This library is free software; you can redistribute it and/or modify it
       under the terms of the GNU Lesser General Public License as published
       by the Free Software Foundation; either version 3 of the License, or (at
       your option) any later version.
  
      This library is distributed in the hope that it will be useful, but WITHOUT
      ANY WARRANTY; with out even the implied warranty of MERCHANTABILITY or
      FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
      License for more details.
  
      You should have received a copy of the GNU Lesser General Public License
      along with this library;  if not, write to the Free Software Foundation,
      Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA.
  
      > http://www.fsf.org/licensing/licenses/lgpl.html
      > http://www.opensource.org/licenses/lgpl-license.php
  
  */
  package org.dishevelled.codegen;
  
  import java.io.File;
  import java.io.FileWriter;
  import java.io.IOException;
  
  import java.util.Properties;
  
  import org.apache.commons.lang.StringUtils;
  
  import org.apache.commons.io.FileUtils;
  
  import org.apache.velocity.Template;
  import org.apache.velocity.VelocityContext;
  
  import org.apache.velocity.app.Velocity;
  
  /**
   * Static source code generation methods.
   *
   * @author  Michael Heuer
   */
  public final class Codegen
  {
  
      /**
       * Private default constructor.
       */
      private Codegen()
      {
          // empty
      }
  
  
      /**
       * Read license text from the specified file.
       *
       * @param license license file to read
       * @return license text from the specified file or null if the
       *   specified license file cannot be read
       */
      public static String readLicense(final String license)
      {
          String text = null;
          try
          {
              text = FileUtils.readFileToString(new File(license));
          }
          catch (IOException e)
          {
              // ignore
          }
          return text;
      }
  
      /**
       * Generate a java source file for the specified interface
       * description.
       *
       * @param id interface description, must not be null
       */
      public static void generateSource(final InterfaceDescription id)
      {
          if (id == null)
          {
              throw new IllegalArgumentException("id must not be null");
          }
  
          FileWriter fw = null;
          try
          {
              Properties p = new Properties();
              p.setProperty("resource.loader", "class");
              p.setProperty("class.resource.loader.class",
                            "org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader");
  
             Velocity.init(p);
 
             fw = new FileWriter(id.getUpper() + ".java");
 
             VelocityContext context = new VelocityContext();
             context.put("id", id);
             context.put("CodegenUtils", new CodegenUtils());
             context.put("StringUtils", new StringUtils());
 
             Template template = Velocity.getTemplate("org/dishevelled/codegen/Interface.wm");
             template.merge(context, fw);
         }
         catch (Exception e)
         {
             e.printStackTrace();
             System.exit(1);
         }
         finally
         {
             try
             {
                 fw.close();
             }
             catch (Exception e)
             {
                 // empty
             }
         }
     }
 
     /**
      * Generate an abstract unit test java source file for the specified interface
      * description.
      *
      * @param id interface description, must not be null
      */
     public static void generateAbstractUnitTest(final InterfaceDescription id)
     {
         if (id == null)
         {
             throw new IllegalArgumentException("id must not be null");
         }
 
         FileWriter fw = null;
         try
         {
             Properties p = new Properties();
             p.setProperty("resource.loader", "class");
             p.setProperty("class.resource.loader.class",
                           "org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader");
 
             Velocity.init(p);
 
             fw = new FileWriter("Abstract" + id.getUpper() + "Test.java");
 
             VelocityContext context = new VelocityContext();
             context.put("id", id);
             context.put("CodegenUtils", new CodegenUtils());
             context.put("StringUtils", new StringUtils());
 
             Template template = Velocity.getTemplate("org/dishevelled/codegen/AbstractInterfaceTest.wm");
             template.merge(context, fw);
         }
         catch (Exception e)
         {
             e.printStackTrace();
             System.exit(1);
         }
         finally
         {
             try
             {
                 fw.close();
             }
             catch (Exception e)
             {
                 // empty
             }
         }
     }
 
     /**
      * Generate a java source file for the specified class
      * description and style.
      *
      * @param cd class description, must not be null
      * @param style style, must not be null
      */
     public static void generateSource(final ClassDescription cd, final Style style)
     {
         if (cd == null)
         {
             throw new IllegalArgumentException("cd must not be null");
         }
         if (style == null)
         {
             throw new IllegalArgumentException("style must not be null");
         }
 
         FileWriter fw = null;
         try
         {
             Properties p = new Properties();
             p.setProperty("resource.loader", "class");
             p.setProperty("class.resource.loader.class",
                           "org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader");
 
             Velocity.init(p);
 
             fw = new FileWriter(cd.getUpper() + ".java");
 
             VelocityContext context = new VelocityContext();
             context.put("cd", cd);
             context.put("CodegenUtils", new CodegenUtils());
             context.put("StringUtils", new StringUtils());
 
             Template template = Velocity.getTemplate("org/dishevelled/codegen/" + style + ".wm");
             template.merge(context, fw);
         }
         catch (Exception e)
         {
             e.printStackTrace();
             System.exit(1);
         }
         finally
         {
             try
             {
                 fw.close();
             }
             catch (Exception e)
             {
                 // empty
             }
         }
     }
 
     /**
      * Generate a java source file for a fluent builder API for the specified class
      * description and style.
      *
      * @param cd class description, must not be null
      * @param style style, must not be null
      */
     public static void generateBuilderSource(final ClassDescription cd, final Style style)
     {
         // TODO:  perhaps style doesn't matter here, if all the templates are the same
         if (cd == null)
         {
             throw new IllegalArgumentException("cd must not be null");
         }
         if (style == null)
         {
             throw new IllegalArgumentException("style must not be null");
         }
 
         FileWriter fw = null;
         try
         {
             Properties p = new Properties();
             p.setProperty("resource.loader", "class");
             p.setProperty("class.resource.loader.class",
                           "org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader");
 
             Velocity.init(p);
 
             fw = new FileWriter(cd.getUpper() + "Builder.java");
 
             VelocityContext context = new VelocityContext();
             context.put("cd", cd);
             context.put("CodegenUtils", new CodegenUtils());
             context.put("StringUtils", new StringUtils());
 
             Template template = Velocity.getTemplate("org/dishevelled/codegen/" + style + "Builder.wm");
             template.merge(context, fw);
         }
         catch (Exception e)
         {
             e.printStackTrace();
             System.exit(1);
         }
         finally
         {
             try
             {
                 fw.close();
             }
             catch (Exception e)
             {
                 // empty
             }
         }
     }
 
     /**
      * Generate a unit test source file for the specified class
      * description and style.
      *
      * @param cd class description, must not be null
      * @param style style, must not be null
      */
     public static void generateUnitTest(final ClassDescription cd, final Style style)
     {
         if (cd == null)
         {
             throw new IllegalArgumentException("cd must not be null");
         }
         if (style == null)
         {
             throw new IllegalArgumentException("style must not be null");
         }
 
         FileWriter fw = null;
         try
         {
             Properties p = new Properties();
             p.setProperty("resource.loader", "class");
             p.setProperty("class.resource.loader.class",
                           "org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader");
 
             Velocity.init(p);
 
             fw = new FileWriter(cd.getUpper() + "Test.java");
 
             VelocityContext context = new VelocityContext();
             context.put("cd", cd);
             context.put("CodegenUtils", new CodegenUtils());
             context.put("StringUtils", new StringUtils());
 
             Template template = Velocity.getTemplate("org/dishevelled/codegen/" + style + "Test.wm");
             template.merge(context, fw);
         }
         catch (Exception e)
         {
             e.printStackTrace();
             System.exit(1);
         }
         finally
         {
             try
             {
                 fw.close();
             }
             catch (Exception e)
             {
                 // empty
             }
         }
     }
 
     /**
      * Generate an enum source file for the specified class description.
      *
      * @param cd class description, must not be null
      */
     public static void generateEnum(final ClassDescription cd)
     {
         if (cd == null)
         {
             throw new IllegalArgumentException("cd must not be null");
         }
 
         FileWriter fw = null;
         try
         {
             Properties p = new Properties();
             p.setProperty("resource.loader", "class");
             p.setProperty("class.resource.loader.class",
                           "org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader");
 
             Velocity.init(p);
 
             fw = new FileWriter(cd.getUpper() + ".java");
 
             VelocityContext context = new VelocityContext();
             context.put("cd", cd);
             context.put("CodegenUtils", new CodegenUtils());
             context.put("StringUtils", new StringUtils());
 
             Template template = Velocity.getTemplate("org/dishevelled/codegen/Enum.wm");
             template.merge(context, fw);
         }
         catch (Exception e)
         {
             e.printStackTrace();
             System.exit(1);
         }
         finally
         {
             try
             {
                 fw.close();
             }
             catch (Exception e)
             {
                 // empty
             }
         }
     }
 
     /**
      * Generate an enum with lookup source file for the specified class description.
      *
      * @param cd class description, must not be null
      */
     public static void generateEnumWithLookup(final ClassDescription cd)
     {
         if (cd == null)
         {
             throw new IllegalArgumentException("cd must not be null");
         }
 
         FileWriter fw = null;
         try
         {
             Properties p = new Properties();
             p.setProperty("resource.loader", "class");
             p.setProperty("class.resource.loader.class",
                           "org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader");
 
             Velocity.init(p);
 
             fw = new FileWriter(cd.getUpper() + ".java");
 
             VelocityContext context = new VelocityContext();
             context.put("cd", cd);
             context.put("CodegenUtils", new CodegenUtils());
             context.put("StringUtils", new StringUtils());
 
             Template template = Velocity.getTemplate("org/dishevelled/codegen/EnumWithLookup.wm");
             template.merge(context, fw);
         }
         catch (Exception e)
         {
             e.printStackTrace();
             System.exit(1);
         }
         finally
         {
             try
             {
                 fw.close();
             }
             catch (Exception e)
             {
                 // empty
             }
         }
     }
 }