/*******************************************************************************
    * Copyright 2012 Internet2
    * 
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    * 
    *   http://www.apache.org/licenses/LICENSE-2.0
    * 
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   ******************************************************************************/
  /**
   * @author mchyzer
   * $Id$
   */
  package edu.internet2.middleware.grouperInstaller.util;
  
  import java.io.File;
  import java.sql.Connection;
  import java.sql.DriverManager;
  import java.sql.PreparedStatement;
  import java.sql.ResultSet;
  import java.sql.SQLException;
  import java.util.ArrayList;
  import java.util.HashSet;
  import java.util.List;
  import java.util.Set;
  
  import edu.internet2.middleware.grouperInstaller.driverShim.MySqlShim;
  import edu.internet2.middleware.grouperInstaller.driverShim.OracleShim;
  import edu.internet2.middleware.grouperInstaller.driverShim.PostgresShim;
  import edu.internet2.middleware.grouperInstaller.driverShim.SqlServerShim;
  import edu.internet2.middleware.grouperInstallerExt.org.apache.commons.logging.Log;
  
  
  /**
   * the instance can be reused, it doesnt store state except the connection user/pass etc
   */
  public class GiDbUtils {
  
    /**
     * url of db
     */
    private String url;
    
    /**
     * user of db
     */
    private String user;
    
    /**
     * pass of db
     */
    private String pass;
    
    /**
     * construct
     * @param url
     * @param user
     * @param pass
     */
    public GiDbUtils(String url, String user, String pass) {
      super();
      this.url = url;
      this.user = user;
      this.pass = pass;
    }
  
    /**
     * strings of driver classes that are registered
     */
    private static Set<String> driversRegistered = new HashSet<String>();
    
    
    /**
     * 
     * @param appDir where we can find drivers
     */
    public void registerDriverOnce(String appDir) {
      String driver = convertUrlToDriverClassIfNeeded(this.url, null);
      if (driversRegistered.contains(driver)) {
        return;
      }
      //see if its on classpath
      try {
        Class.forName(driver);
        //already on classpath?  thats good
      } catch (ClassNotFoundException e) {
        
        //we need to find jar and add
        String prefix = null;
        if (this.isMysql()) {
          prefix = "mysql";
        } else if (this.isOracle()) {
          prefix = "ojdbc";
       } else if (this.isPostgres()) {
         prefix = "postgres";
       } else {
         throw new RuntimeException("What kind of database is this???? " + this.url);
       }
 
       List<File> allFiles = GrouperInstallerUtils.fileListRecursive(new File(appDir));
       File driverJar = null;
       for (File file : allFiles) {
         if (file.getName().endsWith(".jar") && file.getName().startsWith(prefix)) {
           
           //find the latest file with correct prefix and suffix
           if (driverJar == null || driverJar.lastModified() < file.lastModified()) {
             driverJar = file;
           }
         }
       }
       
       if (driverJar == null) {
         System.out.println("Cant find driver jar that starts with '" + prefix + "' and ends with .jar!!! in directory: " + appDir);
         System.exit(1);
       }
       try {
         if (this.isMysql()) {
           MySqlShim.init(driverJar);
           MySqlShimrInstaller/driverShim/MySqlShim.html#MySqlShim">MySqlShim mysqlShim = new MySqlShim();
           DriverManager.registerDriver(mysqlShim);
         } else if (this.isOracle()) {
           OracleShim.init(driverJar);
           OracleShimnstaller/driverShim/OracleShim.html#OracleShim">OracleShim oracleShim = new OracleShim();
           DriverManager.registerDriver(oracleShim);
         } else if (this.isPostgres()) {
           PostgresShim.init(driverJar);
           PostgresShimller/driverShim/PostgresShim.html#PostgresShim">PostgresShim postgresShim = new PostgresShim();
           DriverManager.registerDriver(postgresShim);
         } else {
           throw new RuntimeException("What kind of database is this???? " + this.url);
         }
       } catch (SQLException sqle) {
         throw new RuntimeException("Problem registering driver: " + this.url, sqle);
       }
     }
     driversRegistered.add(driver);
   }
   
   /** 
    * oracle types
    */
   public static enum DbType {
 
     /** string type */
     STRING {
 
       /**
        * 
        * @see edu.internet2.middleware.GiDbUtils.util.GcDbUtils.DbType#processResultSet(java.sql.ResultSet, int)
        */
       @Override
       public Object processResultSet(ResultSet resultSet, int indexZeroIndexed) {
         try {
           return resultSet.getString(indexZeroIndexed+1);
         } catch (SQLException e) {
           throw new RuntimeException("Error reading col (zero indexed) " + indexZeroIndexed, e);
         }
       }
 
       /**
        * @see edu.internet2.middleware.GiDbUtils.util.GcDbUtils.DbType#attachParam(PreparedStatement, Object, int)
        */
       @Override
       public void attachParam(PreparedStatement preparedStatement, Object arg,
           int indexZeroIndexed) {
         String argString = GrouperInstallerUtils.stringValue(arg);
         try {
           preparedStatement.setString(indexZeroIndexed+1, argString);
         } catch (SQLException e) {
           throw new RuntimeException("Error setting param (zero indexed) " + indexZeroIndexed + ": " + argString, e);
         }
       }
     };
 
     /**
      * get the data
      * @param resultSet
      * @param indexZeroIndexed
      * @return the object or null
      */
     public abstract Object processResultSet(ResultSet resultSet, int indexZeroIndexed);
     
     /**
      * attach a param to a prepared statement
      * @param preparedStatement
      * @param arg
      * @param indexZeroIndexed
      */
     public abstract void attachParam(PreparedStatement preparedStatement, Object arg, int indexZeroIndexed);
     
     /**
      * convert an object arg to a dbtype
      * @param object
      * @return dbtype
      */
     public static DbType fromObject(Object object) {
       
       if (object == null || object instanceof String) {
         return DbType.STRING;
       }
       throw new RuntimeException("Unsupported type: " + GrouperInstallerUtils.className(object) + ", " + object);
     }
     
     /**
      * convert an object arg to a dbtype
      * @param theClass
      * @return dbtype
      */
     public static DbType fromClass(Class<?> theClass) {
       
       if (theClass instanceof Class<?> && String.class.equals(theClass)) {
         return DbType.STRING;
       }
       
       throw new RuntimeException("Unsupported type: " + theClass);
     }
     
   }
   
   /**
    * see if the config file seems to be postgres
    * @return see if postgres
    */
   public boolean isPostgres() {
     return isPostgres(this.url);
   }
   
   /**
    * see if the config file seems to be postgres
    * @param connectionUrl
    * @return see if postgres
    */
   public static boolean isPostgres(String connectionUrl) {
     return GrouperInstallerUtils.defaultString(connectionUrl).toLowerCase().contains(":postgresql:");
   }
   
   /**
    * see if the config file seems to be oracle
    * @return see if oracle
    */
   public boolean isOracle() {
     return isOracle(this.url);
   }
   
   /**
    * see if the config file seems to be oracle
    * @param connectionUrl
    * @return see if oracle
    */
   public static boolean isOracle(String connectionUrl) {
     return GrouperInstallerUtils.defaultString(connectionUrl).toLowerCase().contains(":oracle:");
   }
   
   /**
    * see if the config file seems to be mysql
    * @return see if mysql
    */
   public boolean isMysql() {
     return isMysql(this.url);
   }
   
   /**
    * see if the config file seems to be mysql
    * @param connectionUrl
    * @return see if mysql
    */
   public static boolean isMysql(String connectionUrl) {
     return GrouperInstallerUtils.defaultString(connectionUrl).toLowerCase().contains(":mysql:");
   }
   
   /**
    * if there is no driver class specified, then try to derive it from the URL
    * @param connectionUrl
    * @param driverClassName
    * @return the driver class
    */
   public static String convertUrlToDriverClassIfNeeded(String connectionUrl, String driverClassName) {
     //default some of the stuff
     if (GrouperInstallerUtils.isBlank(driverClassName)) {
       
       if (isMysql(connectionUrl)) {
         driverClassName = "com.mysql.jdbc.Driver";
       } else if (isOracle(connectionUrl)) {
         driverClassName = "oracle.jdbc.driver.OracleDriver";
       } else if (isPostgres(connectionUrl)) { 
         driverClassName = "org.postgresql.Driver";
       } else {
         
         //if this is blank we will figure it out later
         if (!GrouperInstallerUtils.isBlank(connectionUrl)) {
         
           String error = "Cannot determine the driver class from database URL: " + connectionUrl;
           System.err.println(error);
           LOG.error(error);
           return null;
         }
       }
     }
     return driverClassName;
 
   }
 
   /**
    * get a connection to the oracle DB
    * @return a connection
    */
   public Connection connection() {
     
     String oracleUrl = null;
     
     try {
 
       // this should be done with original driver or shim by now
 //      String driverClass = convertUrlToDriverClassIfNeeded(this.url, null);
 //  
 //      GrouperInstallerUtils.forName(driverClass);
       
       Connection conn = DriverManager.getConnection(this.url, this.user, this.pass);
       conn.setAutoCommit(false);
       return conn;
     } catch (Exception e) {
       throw new RuntimeException("Error connecting to: " + oracleUrl, e);
     }
   }
 
   /**
    * run a query and get rows back
    * @param rowType type of each row returned, e.g. String.class or Object[]
    * @param <T> generic type
    * @param query
    * @param returnColTypes
    * @return the list of objects
    */
   public <T> List<T> listSelect(Class<T> rowType, String query, List<DbType> returnColTypes) {
     return listSelect(rowType, query, returnColTypes, null);
   }
 
   /**
    * select a value from the db
    * @param <T>
    * @param colType
    * @param query
    * @return the data
    */
   public <T> T select(Class<T> colType, String query) {
     List<T> rows = listSelect(colType, query, GrouperInstallerUtils.toList(DbType.fromClass(colType)));
     
     T data = GrouperInstallerUtils.listPopOne(rows);
     
     return data;
   }
   
   /**
    * run a query and get rows back
    * @param rowType type of each row returned, e.g. String.class or Object[]
    * @param <T> generic type
    * @param query
    * @param returnColTypes
    * @param args preparedstatement arguments
    * @return the list of objects
    */
   @SuppressWarnings("unchecked")
   public <T> List<T> listSelect(Class<T> rowType, String query, List<DbType> returnColTypes, List<Object> args) {
     Connection connection = null;
     PreparedStatement preparedStatement = null;
     ResultSet resultSet = null;
     List<T> results = new ArrayList<T>();
     
     try {
       
       int returnColTypesLength = GrouperInstallerUtils.length(returnColTypes);
       if (returnColTypesLength==0) {
         throw new RuntimeException("Why is returnColTypesLength == 0???");
       }
       
       connection = this.connection();
       preparedStatement = connection.prepareStatement(query);
       
       //attach arguments
       int argsLength = GrouperInstallerUtils.length(args);
 
       for (int i=0; i<argsLength;i++) {
         Object arg = args.get(i);
         DbType dbType = DbType.fromObject(arg);
         dbType.attachParam(preparedStatement, arg, i);
       }
       
       resultSet = preparedStatement.executeQuery();
 
       if (rowType.isArray() != returnColTypesLength>1) {
         throw new RuntimeException("If returnColTypesLength > 1 (" + returnColTypesLength + ") then you must pass in an array as the return type");
       }
       
       while (resultSet.next()) {
         
         //if array of cols
         if (rowType.isArray()) {
         
           Object[] result = new Object[returnColTypesLength];
           results.add((T)result);
           
           for (int i=0; i<returnColTypesLength;i++) {
             result[i] = returnColTypes.get(i).processResultSet(resultSet, i);
           }
         } else {
           //if one col
           results.add((T)returnColTypes.get(0).processResultSet(resultSet, 0));
         }
         
       }
     } catch (Exception e) {
       throw new RuntimeException("Error with query: " + query, e);
     } 
     finally {
       rollbackQuietly(connection);
       GrouperInstallerUtils.closeQuietly(resultSet);
       GrouperInstallerUtils.closeQuietly(preparedStatement);
       GrouperInstallerUtils.closeQuietly(connection);
     }
     return results;
 
   }
   
   /**
    * rollback quiently
    * @param connection
    */
   public void rollbackQuietly(Connection connection) {
     try {
       if (connection != null) {
         connection.rollback();
       }
     } catch (Exception e) {
       LOG.error("Problem rolling back", e);
       //probably should rethrow but dont want to mess up the other closes...
     }
 
   }
   
   /**
    * execute a query (insert/update/delete/etc)
    * @param query query to execute
    * @param arg preparedstatement argument
    * @return either (1) the row count for SQL Data Manipulation Language (DML) statements
      *         or (2) 0 for SQL statements that return nothing
    */
   public int executeUpdate(String query, Object arg) {
     
     List<Object> args = GrouperInstallerUtils.toList(arg);
     return executeUpdate(query, args);
     
   }
   
   /**
    * execute a query (insert/update/delete/etc)
    * @param query query to execute
    * @return either (1) the row count for SQL Data Manipulation Language (DML) statements
    *         or (2) 0 for SQL statements that return nothing
    */
   public int executeUpdate(String query) {
     
     return executeUpdate(query, null);
     
   }
   
   /**
    * execute a query (insert/update/delete/etc)
    * @param query query to execute
    * @param args preparedstatement arguments
    * @return either (1) the row count for SQL Data Manipulation Language (DML) statements
      *         or (2) 0 for SQL statements that return nothing
    */
   public int executeUpdate(String query, List<Object> args) {
     return executeUpdate(query, args, true);
   }
   
   /**
    * check connection to the db
    * @return exception if there is one
    */
   public Exception checkConnection() {
     
     String query = checkConnectionQuery();
     
     try {
       select(String.class, query);
     } catch (Exception e) {
       return e;
     }
     return null;
   }
 
   /**
    * check connection to the db
    * @return the query to check connection with
    */
   public String checkConnectionQuery() {
     if (this.isMysql()) {
       return "select 1";
     }
     if (this.isOracle()) {
       return "select 1 from dual";
     }
     if (this.isPostgres()) {
       return "select 1";
     }
     throw new RuntimeException("Cant find which database type from URL: " + this.url);
 
   }
 
   /**
    * execute a query (insert/update/delete/etc)
    * @param query query to execute
    * @param args preparedstatement arguments
    * @param commit if we should commit
    * @return either (1) the row count for SQL Data Manipulation Language (DML) statements
      *         or (2) 0 for SQL statements that return nothing
    */
   public int executeUpdate(String query, List<Object> args, boolean commit) {
     Connection connection = null;
     PreparedStatement preparedStatement = null;
 
     try {
       connection = this.connection();
       preparedStatement = connection.prepareStatement(query);
       
       //attach arguments
       int argsLength = GrouperInstallerUtils.length(args);
 
       for (int i=0; i<argsLength;i++) {
         Object arg = args.get(i);
         DbType dbType = DbType.fromObject(arg);
         dbType.attachParam(preparedStatement, arg, i);
       }
       
       int result = preparedStatement.executeUpdate();
       
       if (commit) {
         connection.commit();
       }
       
       return result;
       
     } catch (Exception e) {
       rollbackQuietly(connection);
       throw new RuntimeException("Error with query: " + query, e);
     } 
     finally {
       GrouperInstallerUtils.closeQuietly(preparedStatement);
       GrouperInstallerUtils.closeQuietly(connection);
     }
 
   }
 
   /**
    * 
    */
   private static Log LOG = GrouperInstallerUtils.retrieveLog(GiDbUtils.class);
 }