package foundation.dao.version;

import foundation.data.entity.Entity;
import foundation.data.entity.EntitySet;
import foundation.json.IJSONProvider;
import foundation.json.IJSONWriter;
import foundation.util.MapList;

public class PackageChange implements IJSONProvider {

	private MapList<String, IDataChange> items;
	
	public PackageChange() {
		items = new MapList<String, IDataChange>();
	}

	public void compareEntity(String name, Entity one, Entity another) throws Exception {
		EntityChange entityChanges = doCompareEntity(name, one, another);
		
		if (entityChanges == null) {
			return;
		}
		
		items.add(name, entityChanges);
	}

	public void compareEntitySet(String name, EntitySet one, EntitySet another) throws Exception {
		if (one == null && another == null) {
			return;
		}
		
		EntitySetChange entitySetChanges = new EntitySetChange(name);
		items.add(name, entitySetChanges);
		
		//1. 如果当前记录没有--已经删除
		if (one == null) {
			entitySetChanges.setChangeType(ChangeType.Delete);
			return;
		}
		
		//2. 如果对照记录没有--新增加
		if (another == null) {
			entitySetChanges.setChangeType(ChangeType.Add);
			return;
		}
		
		//3. 按Entity: one-->another 对比
		for (Entity oneEntity: one) {
			String id = oneEntity.getId();
			Entity anotherEntity = another.getEntity("id", id);
			
			EntityChange entityChange = doCompareEntity(id, oneEntity, anotherEntity);
			
			if (entityChange == null) {
				continue;
			}
			
			entitySetChanges.addOneEntityChange(id, entityChange);
		}

		//4. 按Entity: another-->one 对比
		for (Entity anotherEntity: another) {
			String id = anotherEntity.getId();
			
			if (!one.contains("id", id)) {
				EntityChange entityChange = new EntityChange(name);
				entityChange.setChangeType(ChangeType.Delete);
				
				entitySetChanges.addOneEntityChange(id, entityChange);
			}
		}
	}

	private EntityChange doCompareEntity(String name, Entity one, Entity another) throws Exception {
		EntityChange entityChange = new EntityChange(name);
		
		if (one == null && another == null) {
			return null;
		}
		
		//1. 如果当前记录没有--已经删除
		if (one == null) {
			entityChange.setChangeType(ChangeType.Delete);
			return entityChange;
		}
		
		//2. 如果对照记录没有--新增加
		if (another == null) {
			entityChange.setChangeType(ChangeType.Add);
			return entityChange;
		}
		
		//3. 按字段对比数据
		String[] fields = one.getFieldsMeta().getFieldNames();
		int max = fields.length;
		
		for (int i = 0; i < max; i++) {
			Object oneValue = one.getValue(i);
			Object anotherValue = another.getValue(i);
			
			if (valueEquals(oneValue, anotherValue)) {
				continue;
			}
			
			String oneJSON = one.getJSONString(i);
			String anotherJSON = another.getJSONString(i);
					
			entityChange.addOneFieldChange(fields[i], ChangeType.Change, oneValue, anotherValue, oneJSON, anotherJSON);
		}
		
		if (entityChange.isEmpty()) {
			entityChange.setChangeType(ChangeType.NoChange);
			return null;
		}
		
		entityChange.setChangeType(ChangeType.Change);
		return entityChange;
	}
	
	private boolean valueEquals(Object oneValue, Object anotherValue) {
		if (oneValue == null) {
			if (anotherValue == null) {
				return true;
			}
			else {
				return false;
			}
		}
		else {
			if (anotherValue == null) {
				return false;
			}
			
			return oneValue.equals(anotherValue);
		}
	}

	@Override
	public void writeJSON(IJSONWriter writer) {
		writer.beginObject();
		
		//1. write list
		writer.beginArray("list");
		
		for (IDataChange dataChange: items) {
			writer.write(dataChange.getDataName());
		}
		
		writer.endArray();
		
		//2. write changes
		writer.beginArray("changes");
		
		for (IDataChange dataChange: items) {
			dataChange.writeJSON(writer);
		}
		
		writer.endArray();
	}

}