package com.avaje.ebeaninternal.server.loadcontext;

import java.util.List;

import com.avaje.ebean.bean.BeanCollection;
import com.avaje.ebean.bean.BeanCollectionLoader;
import com.avaje.ebean.bean.ObjectGraphNode;
import com.avaje.ebean.bean.PersistenceContext;
import com.avaje.ebeaninternal.api.LoadManyContext;
import com.avaje.ebeaninternal.api.LoadManyRequest;
import com.avaje.ebeaninternal.api.SpiQuery;
import com.avaje.ebeaninternal.server.core.OrmQueryRequest;
import com.avaje.ebeaninternal.server.deploy.BeanDescriptor;
import com.avaje.ebeaninternal.server.deploy.BeanPropertyAssocMany;
import com.avaje.ebeaninternal.server.querydefn.OrmQueryProperties;

public class DLoadManyContext implements LoadManyContext, BeanCollectionLoader {

	protected final DLoadContext parent;

	protected final String fullPath;

	private final BeanDescriptor<?> desc;
	
	private final BeanPropertyAssocMany<?> property;
	
	private final String path;

	private final int batchSize;

	private final OrmQueryProperties queryProps;
	
	private final DLoadList<BeanCollection<?>> weakList;
	
	public DLoadManyContext(DLoadContext parent, BeanPropertyAssocMany<?> p, 
			String path, int batchSize, OrmQueryProperties queryProps, DLoadList<BeanCollection<?>> weakList) {
		
		this.parent = parent;
		this.property = p;
		this.desc = p.getBeanDescriptor();
		this.path = path;
		this.batchSize = batchSize;
		this.queryProps = queryProps;
		this.weakList = weakList;//new DLoadWeakList<BeanCollection<?>>();

		if (parent.getRelativePath() == null){
			this.fullPath = path;
		} else {
			this.fullPath = parent.getRelativePath()+"."+path;
		}

	}
	
    public void configureQuery(SpiQuery<?> query){
		
		// propagate the readOnly state
    	if (parent.isReadOnly() != null){
    		query.setReadOnly(parent.isReadOnly());
    	}
		query.setParentNode(getObjectGraphNode());
		
		if (queryProps != null){
			queryProps.configureManyQuery(query);
		}
				
		if (parent.isUseAutofetchManager()){
			query.setAutofetch(true);
		}
	}

	public ObjectGraphNode getObjectGraphNode() {
		
		// we return the parent node ... as we actually
		// query on the parent selecting just it's id
		
		int pos = path.lastIndexOf('.');
		if (pos == -1){
			return parent.getObjectGraphNode(null);			
		} else {
			String parentPath = path.substring(0, pos);
			return parent.getObjectGraphNode(parentPath);
		}
	}

	public String getFullPath() {
		return fullPath;
	}

	public PersistenceContext getPersistenceContext() {
		return parent.getPersistenceContext();
	}

	public int getBatchSize() {
		return batchSize;
	}

	public BeanPropertyAssocMany<?> getBeanProperty() {
		return property;
	}

	public BeanDescriptor<?> getBeanDescriptor() {
		return desc;
	}

	public String getPath() {
		return path;
	}
	
	public String getName() {
		return parent.getEbeanServer().getName();
	}

	public void register(BeanCollection<?> bc){
		int pos = weakList.add(bc);
		bc.setLoader(pos, this);
	}

	public void loadMany(BeanCollection<?> bc, boolean onlyIds) {
				
		int position = bc.getLoaderIndex();
			
		LoadManyRequest req;
		synchronized (weakList) {
			boolean hitCache = desc.isBeanCaching() && !onlyIds && !parent.isExcludeBeanCache();
		    if (hitCache){
		    	Object ownerBean = bc.getOwnerBean();
		    	BeanDescriptor<? extends Object> parentDesc = desc.getBeanDescriptor(ownerBean.getClass());
		    	Object parentId = parentDesc.getId(ownerBean);
		    	if (parentDesc.cacheLoadMany(property, bc, parentId, parent.isReadOnly(), false)) {
		    		// we loaded the bean from cache
		    		weakList.removeEntry(position);
		    		return;	    			    		
		    	}	    	
		    }
		    
			List<BeanCollection<?>> loadBatch = weakList.getLoadBatch(position, batchSize);
			req = new LoadManyRequest(this, loadBatch, null, batchSize, true, onlyIds, hitCache);
		}		
		parent.getEbeanServer().loadMany(req);
	}
	
	public void loadSecondaryQuery(OrmQueryRequest<?> parentRequest, int requestedBatchSize, boolean all){

	    do {
	    	LoadManyRequest req;
			synchronized (weakList) {
				List<BeanCollection<?>> batch = weakList.getNextBatch(requestedBatchSize);
				if (batch.size() == 0){
					return;
				}
        		req = new LoadManyRequest(this, batch, parentRequest.getTransaction(), requestedBatchSize, false, false, false);
			}
    		parent.getEbeanServer().loadMany(req);
    		if (!all){
    		    // queryFirst(batch)
    		    break;
    		}
	    } while (true);
	}

}