package foundation.data.object;

import java.util.Date;

import foundation.data.entity.Entity;
import foundation.data.meta.field.FieldsRuntime;
import foundation.util.ContentBuilder;
import foundation.util.Util;

public class DataJoin {
	
	public static String TableJoinConnector = "__";
	public static String EmptySelectFields = "empty";
	private static Date emptyUpdateTime = new Date(0);
	private String id;
	private String dataName;
	private String field;
	private String joinDataName;
	private String joinAsName;
	private String joinField;
	private String joinSelelctFields;
	private String joinSQL;
	private boolean active;
	private Date updateTime;
	private FieldsRuntime joinFieldsMeta;

	public DataJoin() {
		
	}
	
	public void load(Entity entity) {
		id = entity.getString("id");
		dataName = entity.getString("dataname");
		field = entity.getString("field_name");
		joinDataName = entity.getString("join_dataname");
		joinAsName = entity.getString("join_as_name", joinDataName);
		joinField = entity.getString("join_field_name", "id");
		joinSelelctFields = entity.getString("join_select_fields");
		joinSQL = entity.getString("join_sql");
		active = entity.getBoolean("is_active", true);
		updateTime = entity.getDate("last_update_time", emptyUpdateTime);
	}
	
	public void build() {
		if (!Util.isEmpty(joinSQL)) {
			return;
		}
		
		joinSQL = createJoinSQL();
	}

	public void getJoinFields(ContentBuilder result) throws Exception {
		//1. 如果配置了 join select fields
		if (!Util.isEmpty(joinSelelctFields)) {
			//1.1 如果配置为Empty，就不选择任何字段
			if (EmptySelectFields.equalsIgnoreCase(joinSelelctFields)) {
				return;
			}
			
			//1.2 如果配置了字段，根据配置选择字段
			joinSelelctFields = joinSelelctFields.replace(";", ",").replace("，", ",").replace("；", ",");
			String[] segments = joinSelelctFields.split(",");
			
			int max = segments.length;
			for (int i = 0; i < max; i++) {
				String joinField = segments[i];
				joinField = joinField.trim();
				
				result.append(joinDataName + "." + joinField + " as " + joinAsName + TableJoinConnector + joinField);
			}
			
			return;
		}
		
		//2. 自动生成全量 fields
		DataObject joinObject = DataObject.getInstance(joinDataName);
		
		if (joinObject == null) {
			throw new Exception("data object " + joinDataName + " not exits, join skip");
		}
		
		joinFieldsMeta = joinObject.getTableFieldMetas();
		String[] joinFields = joinFieldsMeta.getFieldNames();
		
		int max = joinFields.length;
		for (int i = 0; i < max; i++) {
			String joinField = joinFields[i];
			result.append(joinDataName + "." + joinField + " as " + joinAsName + TableJoinConnector + joinField);
		}
	}
	
	private String createJoinSQL() {
		StringBuilder builder = new StringBuilder();
		
		//1. 添加 left join 关键字
		builder.append(" left join ").append(joinDataName);
		
		//2. 添加左面字段
		if (field.indexOf(".") <= 0) {
			//如果字段没有指定表名，添加表明
			DataObject dataObject = DataObject.getInstance(dataName);
			builder.append(" on ").append(dataObject.getTableOrViewName()).append(".").append(field);
		}
		else {
			//如果字段中指定表名称直接使用
			builder.append(" on ").append(field);
		}
		
		//3. 添加右面字段
		if (joinField.indexOf(".") <= 0) {
			//如果字段没有指定表名，添加表明
			DataObject joinDataObject = DataObject.getInstance(joinDataName);
			builder.append(" = ").append(joinDataObject.getTableOrViewName()).append(".").append(joinField);
		}
		else {
			//如果字段中指定表名称直接使用
			builder.append(" = ").append(joinField);
		}		
		
		return builder.toString();
	}

	public String getDataName() {
		return dataName;
	}

	public String getJoinDataName() {
		return joinDataName;
	}

	public String getJoinAsName() {
		return joinAsName;
	}

	public String getJoinSQL() {
		return joinSQL;
	}

	public String getId() {
		return id;
	}

	public boolean isActive() {
		return active;
	}

	public FieldsRuntime getJoinFieldsMeta() {
		return joinFieldsMeta;
	}

	public Date getUpdateTime() {
		return updateTime;
	}

}