package org.apidesign.livedb.impl;

 import java.io.IOException;

 import java.io.Writer;

 import java.sql.CallableStatement;

 import java.sql.Connection;

 import java.sql.Driver;

 import java.sql.ResultSet;

 import java.sql.ResultSetMetaData;

 import java.sql.SQLException;

 import java.util.Properties;

 import java.util.ServiceLoader;

 import java.util.Set;

 import javax.annotation.processing.AbstractProcessor;

 import javax.annotation.processing.Filer;

 import javax.annotation.processing.Processor;

 import javax.annotation.processing.RoundEnvironment;

 import javax.annotation.processing.SupportedAnnotationTypes;

 import javax.annotation.processing.SupportedSourceVersion;

 import javax.lang.model.SourceVersion;

 import javax.lang.model.element.Element;

 import javax.lang.model.element.PackageElement;

 import javax.lang.model.element.TypeElement;

 import javax.tools.JavaFileObject;

 import org.apidesign.livedb.LiveDB;

 import org.openide.util.lookup.ServiceProvider;

 /**

  *

  * @author Jaroslav Tulach <jtulach@netbeans.org>

  */

 // BEGIN: livedb.processor

 @SupportedAnnotationTypes("org.apidesign.livedb.LiveDB")

 @SupportedSourceVersion(SourceVersion.RELEASE_6)

 @ServiceProvider(service=Processor.class)

 public final class LiveDBProcessor extends AbstractProcessor {

     @Override

     public boolean process(

         Set<? extends TypeElement> annotations, RoundEnvironment roundEnv

     ) {

         final Filer filer = processingEnv.getFiler();

         for (Element e : roundEnv.getElementsAnnotatedWith(LiveDB.class)) {

             LiveDB db = e.getAnnotation(LiveDB.class);

             PackageElement pe = (PackageElement)e;

             String clsName = pe.getQualifiedName() + "." + db.classname();

             try {

                 JavaFileObject src = filer.createSourceFile(clsName, pe);

                 Writer w = src.openWriter();

                 Connection c = getConnection(

                     db.url(), db.user(), db.password()

                 );

                 CallableStatement s = c.prepareCall(db.query());

                 ResultSet rs = s.executeQuery();

                 ResultSetMetaData md = rs.getMetaData();

                 generateClassHeader(w, pe, db);

                 w.append("class " + db.classname() + " {\n");

                 for (int i = 1; i <= md.getColumnCount(); i++) {

                     generateField(w, md, i);

                 }

                 generateConstructor(w, db, md);

                 generateQueryMethod(w, db, md);

                 w.append("}");

                 w.close();

             } catch (IOException ex) {

                 throw new IllegalStateException(ex);

             } catch (SQLException ex) {

                 throw new IllegalStateException(ex);

             }

         }

         return true;

     }

 // FINISH: livedb.processor

     private void generateQueryMethod(Writer w, LiveDB db, ResultSetMetaData md) throws SQLException, IOException {

         w.append("  public static List<" + db.classname() + "> ")

          .append("query() throws SQLException {\n");

         w.append("    Connection c = DriverManager.getConnection(\"")

          .append(db.url()).append("\", \"")

          .append(db.user()).append("\", \"")

          .append(db.password()).append("\");\n");

         w.append("    List<").append(db.classname())

          .append("> res = new ArrayList<")

          .append(db.classname()).append(">();\n");

         w.append("    CallableStatement s = c.prepareCall(\"")

          .append(db.query()).append("\");\n");

         w.append("    ResultSet rs = s.executeQuery();\n");

         w.append("    ResultSetMetaData md = rs.getMetaData();\n");

         w.append("    while (rs.next()) {\n");

         w.append("      res.add(new " + db.classname() + "(\n");

         for (int i = 1; i <= md.getColumnCount(); i++) {

             w.append("        (")

              .append(md.getColumnClassName(i))

              .append(")rs.getObject(" + i).append(")");

             if (i < md.getColumnCount()) {

                 w.append(",\n");

             } else {

                 w.append("\n");

             }

         }

         w.append("      ));\n");

         w.append("    };\n");

         w.append("    return res;\n");

         w.append("  }");

     }

     private void generateConstructor(Writer w, LiveDB db, ResultSetMetaData md) throws SQLException, IOException {

         w.append("  private " + db.classname() + "(\n");

         for (int i = 1; i <= md.getColumnCount(); i++) {

             w.append("    ").append(md.getColumnClassName(i))

              .append(" ").append(md.getColumnName(i));

             if (i < md.getColumnCount()) {

                 w.append(",\n");

             } else {

                 w.append("\n");

             }

         }

         w.append("  ) {\n");

         for (int i = 1; i <= md.getColumnCount(); i++) {

             w.append("    this.")

              .append(md.getColumnName(i))

              .append(" = ")

              .append(md.getColumnName(i))

              .append(";\n");

         }

         w.append("  }\n");

     }

     private void generateField(Writer w, ResultSetMetaData md, int i) throws IOException, SQLException {

         w.append("  public final ")

          .append(md.getColumnClassName(i))

          .append(" ")

          .append(md.getColumnName(i))

          .append(";\n");

     }

     private void generateClassHeader(Writer w, PackageElement pe, LiveDB db) throws IOException {

         w.append("package " + pe.getQualifiedName() + ";\n");

         w.append("import java.util.List;\n");

         w.append("import java.util.ArrayList;\n");

         w.append("import java.sql.*;\n");

     }

     private static Connection getConnection(String url, String user, String password) 

     throws SQLException {

         final ClassLoader cl = LiveDBProcessor.class.getClassLoader();

         for (Driver d : ServiceLoader.load(Driver.class, cl)) {

 //            System.out.println("looked up: " + d);

             if (d.acceptsURL(url)) {

                 //System.out.println("accepts: " + d);

                 Properties p = new Properties();

                 p.put("user", user);

                 p.put("password", password);

                 return d.connect(url, p);

             }

         }

         throw new SQLException("No driver found for " + url);

     }

 }