package frame.object.data;

import java.util.HashMap;
import java.util.Map;

import frame.object.meta.EntityMeta;
import frame.object.meta.Field;
import frame.variant.ValueType;

public class Indexes {
	
	private EntitySet entitySet;
	private Map<String, IIndex> indexMap;
	private boolean dirty;
	
	public Indexes(EntitySet entitySet) {
		indexMap = new HashMap<String, IIndex>();
		this.entitySet = entitySet;
	}
	
	public Entity getEntity(String fieldName, Object value) throws DataException {
		if (fieldName == null) {
			return null;
		}
		
		fieldName = fieldName.toLowerCase();
		IIndex index = indexMap.get(fieldName);
		
		if (dirty || index == null) {
			index = createIndex(fieldName);
			indexMap.put(fieldName, index);
		}
		
		Entity entity = index.get(value);
		return entity;
	}

	private IIndex createIndex(String fieldName) throws DataException {
		EntityMeta meta = entitySet.getEntityMeta();
		Field field = meta.getField(fieldName);
		
		if (field == null) {
			throw new DataException("FieldNotExists", "field not exists: " + fieldName);
		}
		
		ValueType type = field.getValueType();
		
		if (ValueType.String != type && ValueType.Long != type && ValueType.Int != type) {
			throw new DataException("FieldCannotCreateIndex", "filed can not create index: " + fieldName);
		}
		
		Index index = new Index(meta.getTableName(), fieldName);
		index.load(entitySet);
		
 		return index;
	}

	public void setDirty() {
		dirty = true;
	}
}