/*
 * Copyright 2008-2011 the original author or authors.
 * 
 * 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.
 * 
 */
package com.nominanuda.dataobject;

import java.util.Stack;

import com.nominanuda.lang.Check;
import static com.nominanuda.dataobject.DataStructHelper.STRUCT;

public class DataStructContentHandler implements JsonContentHandler {
	private volatile boolean finished = false;
	private DataStruct result;
	private DataStruct cur;
	private String pendingKey;
	private Stack<DataStruct> parentHierarchy = null;

	public void startJSON() throws RuntimeException {
		parentHierarchy = new Stack<DataStruct>();
	}

	public void endJSON() throws RuntimeException {
		finished = true;
		parentHierarchy = null;
	}

	public boolean startObject() throws RuntimeException {
		if(result == null) {
			result = new DataObjectImpl();
			cur = result;
		} else {
			if(STRUCT.isDataArray(cur)) {
				cur = ((Arr)cur).addNewObject();
			} else {
				cur = ((Obj)cur).putNewObject(pendingKey);
			}
		}
		parentHierarchy.push(cur);
		return true;
	}

	public boolean endObject() throws RuntimeException {
		parentHierarchy.pop();
		cur = parentHierarchy.isEmpty() ? null : parentHierarchy.peek();
		return true;
	}

	public boolean startObjectEntry(String key) throws RuntimeException {
		pendingKey = key;
		return true;
	}

	public boolean endObjectEntry() throws RuntimeException {
		return true;
	}

	public boolean startArray() throws RuntimeException {
		if(result == null) {
			result = new DataArrayImpl();
			cur = result;
		} else {
			if(STRUCT.isDataArray(cur)) {
				cur = ((Arr)cur).addNewArray();
			} else {
				cur = ((Obj)cur).putNewArray(pendingKey);
			}
		}
		parentHierarchy.push(cur);
		return true;
	}

	public boolean endArray() throws RuntimeException {
		parentHierarchy.pop();
		cur = parentHierarchy.isEmpty() ? null : parentHierarchy.peek();
		return true;
	}

	public boolean primitive(Object value) throws RuntimeException {
		Check.illegalargument.assertTrue(STRUCT.isPrimitiveOrNull(value));
		if(STRUCT.isDataArray(cur)) {
			((Arr)cur).add(value);
		} else {
			((Obj)cur).put(pendingKey, value);
		}
		return true;
	}

	public DataStruct getResult() {
		Check.illegalstate.assertTrue(finished);
		return result;
	}
}