/*
Copyright (c) 2008  Franklin Schmidt <fschmidt@gmail.com>

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/

package fschmidt.db.base;

import java.sql.SQLException;
import java.sql.PreparedStatement;
import java.sql.Connection;
import java.util.Map;
import java.util.HashMap;
import java.util.Iterator;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import fschmidt.db.DbTable;
import fschmidt.db.DbKey;
import fschmidt.db.DbKeySetter;
import fschmidt.db.DbObject;
import fschmidt.db.DbRecord;
import fschmidt.db.SQLRuntimeException;
import fschmidt.db.DbExpression;
import fschmidt.db.LongKey;
import fschmidt.db.DbUtils;
import fschmidt.db.DbArcana;
import fschmidt.db.ListenerList;
import fschmidt.db.extend.DbRecordExt;
import fschmidt.db.extend.DbTableExt;
import fschmidt.db.extend.DbTransaction;


final class DbRecordImpl<K extends DbKey,V extends DbObject<K,V>> implements DbRecordExt<K,V> {
	private static final Logger logger = LoggerFactory.getLogger(DbRecordImpl.class);

	public static boolean hasStackTrace = false;
	private final V obj;
	private K key;
	private final DbTableExt<K,V> table;
	private Map<String,Object> fields = new HashMap<String,Object>();
	private boolean isInDb;
	private boolean isStale = false;
//	private final long whenLoaded = System.currentTimeMillis();
	private DbTransaction trans;

	public DbRecordImpl(DbTableExt<K,V> table,V obj,K key) {
		this.table = table;
		this.obj = obj;
		this.key = key;
		this.isInDb = true;
		this.trans = table.getDbDatabaseExt().getTransaction();
	}

	public DbRecordImpl(DbTableExt<K,V> table,V obj) {
		this.table = table;
		this.obj = obj;
		this.key = null;
		this.isInDb = false;
		this.trans = table.getDbDatabaseExt().getTransaction();
	}

	public V getDbObject() {
		return obj;
	}

	public K getPrimaryKey() {
		return key;
	}

	public DbTable<K,V> getDbTable() {
		return table;
	}

	public Map<String,Object> fields() {
		return fields;
	}

/*
	public long whenLoaded() {
		return whenLoaded;
	}
*/
	private void checkTrans() {
		if( trans != table.getDbDatabaseExt().getTransaction() ) {
			if( trans==null )
				throw new IllegalStateException("record read outside of a transaction cannot be updated inside a transaction");
			else
				throw new IllegalStateException("transaction mismatch");
		}
	}

	public void insert() {
		if( isInDb() )
			throw new IllegalStateException("already in database");
		try {
			ListenerList<V> list = table.getPreInsertListeners();
			list.event(obj);
			store();
			this.trans = table.getDbDatabaseExt().getTransaction();
			final Map<String,Object> updatedFields = fields;
			final Exception ex = hasStackTrace ? new Exception("in "+Thread.currentThread()) : null;
			table.getDbDatabaseExt().runBeforeCommit( new Runnable() {
				public void run() {
					ListenerList<V> list = table.getPostInsertListeners();
					if( !list.isEmpty() ) {
						V obj2 = DbUtils.getGoodCopy(obj);
						if( obj2==null ) {
							DbRecord<K,V> rec = obj.getDbRecord();
							K key = rec.getPrimaryKey();
							if( ex != null )
								logger.error("insert null in "+Thread.currentThread()+" table="+table+" key="+key, ex);
							throw new NullPointerException("in "+Thread.currentThread()+" table="+table+" key="+key);
						}
						DbRecordImpl rec2 = (DbRecordImpl)obj2.getDbRecord();
						try {
							list.event(obj2);
						} finally {
							updatedFields.clear();
						}
					}
				}
			} );
		} finally {
			fields = new HashMap<String,Object>();
			makeStale();
		}
	}

	public void update() {
		checkTrans();
		if( !isInDb() )
			throw new IllegalStateException("not in database");
		try {
			ListenerList<V> list = table.getPreUpdateListeners();
			list.event(obj);
			if( fields.isEmpty() ) {
				table.uncache(key);
			} else {
				store();
			}
			final Map<String,Object> updatedFields = fields;
			table.getDbDatabaseExt().runBeforeCommit( new Runnable() {
				public void run() {
					ListenerList<V> list = table.getPostUpdateListeners();
					if( !list.isEmpty() && isInDb ) {
						V obj2 = DbUtils.getGoodCopy(obj);
						if( obj2==null )
							return;  // presumably deleted later in transaction
						DbRecordImpl rec2 = (DbRecordImpl)obj2.getDbRecord();
						try {
							list.event(obj2);
						} finally {
							updatedFields.clear();
						}
					}
				}
			} );
		} finally {
			fields = new HashMap<String,Object>();
		}
	}

	private void store() {
		StringBuilder buf = new StringBuilder();
		try {
			DbArcana arcana = table.getDbDatabase().arcana();
			int n = 0;
			if( isInDb() ) {  // update
				buf.append( "update " );
				buf.append( table.getTableName() );
				buf.append( " set " );
				boolean first = true;
				for( Map.Entry<String,Object> entry : fields.entrySet() ) {
					if( first ) {
						first = false;
					} else {
						buf.append( ',' );
					}
					buf.append( arcana.quoteIdentifier(entry.getKey()) );
					if( entry.getValue() instanceof DbExpression ) {
						buf.append( '=' );
						buf.append( entry.getValue() );
					} else {
						buf.append( "=?" );
						n++;
					}
				}
			} else {  // insert
				buf.append( "insert into " );
				buf.append( table.getTableName() );
				if( fields.isEmpty() ) {
					buf.append( " DEFAULT VALUES" );
				} else {
					buf.append( " (" );
					boolean first = true;
					for( Map.Entry<String,Object> entry : fields.entrySet() ) {
						if( first ) {
							first = false;
						} else {
							buf.append( ',' );
						}
						buf.append( arcana.quoteIdentifier(entry.getKey()) );
					}
					buf.append( ") values (" );
					first = true;
					for( Map.Entry<String,Object> entry : fields.entrySet() ) {
						if( first ) {
							first = false;
						} else {
							buf.append(',');
						}
						if( entry.getValue() instanceof DbExpression ) {
							buf.append( entry.getValue() );
						} else {
							buf.append( '?' );
							n++;
						}
					}
					buf.append( ")" );
				}
			}
			Connection con = table.getDbDatabaseExt().getConnection();
			try {
				DbKeySetter<K> keySetter = table.getKeySetter();
				PreparedStatement stmt;
				if( isInDb() ) {
					stmt = keySetter.prepareStatement(
						con, key, buf.toString(), 1+n
					);
				} else {
					stmt = con.prepareStatement( buf.toString() );
				}
				int idx = 1;
				for( Map.Entry<String,Object> entry : fields.entrySet() ) {
					Object value = entry.getValue();
					if( value instanceof DbExpression )
						continue;
					try {
						arcana.setValue(stmt,idx++,value);
					} catch(SQLException e) {
						throw new SQLRuntimeException("field="+entry.getKey()+" value="+value,e);
					}
				}
				stmt.executeUpdate();
				boolean wasInDb = isInDb;
				isInDb = true;
				stmt.close();
				if( !wasInDb ) {
					key = keySetter.refreshKeyAfterInsert(con,this);
				}
			} finally {
				try {
					con.close();
				} catch(SQLException e) {
					logger.error("couldn't close connection",e);
					throw e;
				} catch(RuntimeException e) {
					logger.error("couldn't close connection",e);
					throw e;
				}
			}
		} catch(SQLException e) {
			throw new SQLRuntimeException("key = "+key+"  sql = "+buf.toString(),e);
		} finally {
			table.uncache(key);
		}
	}

	public void delete() {
		checkTrans();
		ListenerList<V> list = table.getPreDeleteListeners();
		list.event(obj);
		if( !isInDb() )
			throw new IllegalStateException("not in database");
		try {
			Connection con = table.getDbDatabaseExt().getConnection();
			PreparedStatement stmt = table.getKeySetter().prepareStatement(
				con, key, "delete from "+table.getTableName(), 1
			);
			stmt.executeUpdate();
			isInDb = false;
			stmt.close();
			con.close();
/*
			table.getDbDatabaseExt().runBeforeCommit( new Runnable() {
				public void run() {
					table.getPostDeleteListeners().event(obj);
				}
			} );
*/
		} catch(SQLException e) {
			throw new SQLRuntimeException("key = "+key,e);
		} finally {
			table.uncache(key);
			fields.clear();
		}
		table.getDbDatabaseExt().runBeforeCommit( new Runnable() {
			public void run() {
				ListenerList<V> list = table.getPostDeleteListeners();
				list.event(obj);
			}
		} );
	}

	public boolean isStale() {
		return isStale || (isInDb || trans!=null) && trans != table.getDbDatabaseExt().getTransaction();
	}

	public void makeStale() {
		isStale = true;
	}

	public boolean isInDb() {
		return isInDb;
	}

}