/*
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*/

package key.sql;

import key.*;
import java.sql.*;
import java.io.ByteArrayOutputStream;
import java.io.ByteArrayInputStream;
import java.io.ObjectOutputStream;
import java.lang.reflect.*;
import java.util.Vector;

import postgresql.largeobject.*;

public final class Storage
{
	public static final String JDBC_DRIVER = "postgresql.Driver";
	public static final String JDBC_URL = "jdbc:postgresql:key";
	public static final String JDBC_USER = "subtle";
	public static final String JDBC_PASSWORD = "just";
	
	private static boolean enabled = false;
	
	static Connection db;
	static Statement st;
	static LargeObjectManager blobManager;
	
	static
	{
		if( key.Main.CONNECT_TO_DATABASE )
		{
			try
			{
				Class.forName( JDBC_DRIVER );
				
				try
				{
					db = DriverManager.getConnection( JDBC_URL, JDBC_USER, JDBC_PASSWORD );
					st = db.createStatement();
					blobManager = ((postgresql.Connection)db).getLargeObjectAPI();
					Log.bootLog( "Connected to " + JDBC_URL );
					enabled = true;
				}
				catch( Exception e )
				{
					Log.debug( Storage.class, "Could not connect to database: " + e.getMessage() );
				}
			}
			catch( ClassCastException e )
			{
				Log.debug( Storage.class, "SQL driver not found, database support disabled" );
			}
			catch( Exception e )
			{
				Log.debug( Storage.class, "Miscellaneous exception initialising SQL: " + e.toString() );
			}
		}
	}
	
	public static void initialiseDB()
	{
	}
	
	public static void storeObject( Atom a )
	{
		if( !enabled )
			return;
		
		final StringBuffer fieldNames = new StringBuffer();
		final Vector fieldValues = new Vector();
		
		try
		{
			scanAllFields( a.getClass(), a, fieldNames, fieldValues );
			
			//System.err.println( "Stored object: " + a.getId() );
			//System.err.println( "Fields:\n" + fieldNames.toString() + "\n" );
			//System.err.println( "Values:\n" + fieldValues.toString() + "\n" );
			
			//  Table definition:
			//  -----------------
			//      create table atoms
			//      (
			//        index int,
			//        timestamp int,
			//        serialisedData bytea
			//      );
			//  -----------------
			
			byte[] ba;
			
			{
				ByteArrayOutputStream baos = new ByteArrayOutputStream();
				ObjectOutputStream oos = new ObjectOutputStream( baos );
				oos.writeObject( a );
				ba = baos.toByteArray();
				oos.close();
				baos.close();
			}
			
			PreparedStatement ps = db.prepareStatement( "insert into atoms values (?,?,?)" );
			ps.setInt( 1, a.getIndex() );
			ps.setInt( 2, a.getTimestamp() );
			ps.setBytes( 3, ba );
			ps.executeUpdate();
			ps.close();
		}
		catch( Exception e )
		{
			e.printStackTrace( System.out );
			throw new UnexpectedResult( e.toString() );
		}
	}
	
	public static void scanAllFields( Class start, Object parent,
	                                  StringBuffer fieldNames,
									  Vector fieldValues )
	throws Exception
	{
		{
			Field[] fields;
			
			fields = start.getDeclaredFields();
			
			for( int i = 0; i < fields.length; i++ )
			{
				Field f = fields[i];
				
				try
				{
					int mod = f.getModifiers();
					
					if( !Modifier.isTransient( mod ) && !Modifier.isStatic( mod ) )
					{
						Object sub = null;
						
						try
						{
							sub = f.get( parent );
						}
						catch( IllegalAccessException e )
						{
							if( parent instanceof SQLStorable )
								sub = ((SQLStorable)parent).retrieveField( f );
							else
								System.err.println( "WARNING: Field skipped in storage due to access exception.  Field " + f.toString() + " on " + parent.getClass().getName() );
						}
						
						fieldNames.append( f.getName() );
						fieldNames.append( "," );
						
						if( sub == null )
							fieldValues.addElement( null );
						else
							fieldValues.addElement( sub );
					}
				}
				catch( Exception e )
				{
					Log.error( "Factory", e );
					throw new UnexpectedResult( e );  //  this line temporary
				}
			}
		}
		
		{
			Class root;
			
			root = start.getSuperclass();
			
			if( root != null )
			{
				scanAllFields( root, parent, fieldNames, fieldValues );
			}
		}
	}
}