/**
 * Copyright (c) 2011-2020, hubin (jobob@qq.com).
 *
 * 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.baomidou.mybatisplus.toolkit;

import com.baomidou.mybatisplus.entity.CountOptimize;
import com.baomidou.mybatisplus.enums.Optimize;
import com.baomidou.mybatisplus.plugins.pagination.Pagination;

/**
 * <p>
 * SqlUtils工具类
 * </p>
 *
 * @author Caratacus
 * @Date 2016-11-13
 */
public class SqlUtils {
	private final static SQLFormatter sqlFormatter = new SQLFormatter();
	public static final String SQL_BASE_COUNT = "SELECT COUNT(1) FROM ( %s ) TOTAL";

	/**
	 * 获取CountOptimize
	 * 
	 * @param originalSql
	 *            需要计算Count SQL
	 * @param optimizeType
	 *            count优化方式
	 * @param isOptimizeCount
	 *            是否需要优化Count
	 * @return CountOptimize
	 */
	public static CountOptimize getCountOptimize(String originalSql, String optimizeType, String dialectType,
			boolean isOptimizeCount) {
		CountOptimize countOptimize = CountOptimize.newInstance();
		// 获取优化类型
		Optimize opType = Optimize.getOptimizeType(optimizeType);
		// 调整SQL便于解析
		String tempSql = originalSql.replaceAll("(?i)ORDER[\\s]+BY", "ORDER BY").replaceAll("(?i)GROUP[\\s]+BY", "GROUP BY");
		String indexOfSql = tempSql.toUpperCase();
		// 有排序情况
		int orderByIndex = indexOfSql.lastIndexOf("ORDER BY");
		// 只针对 ALI_DRUID DEFAULT 这2种情况
		if (orderByIndex > -1) {
			countOptimize.setOrderBy(false);
		}
		if (!isOptimizeCount && opType.equals(Optimize.DEFAULT)) {
			countOptimize.setCountSQL(String.format(SQL_BASE_COUNT, originalSql));
			return countOptimize;
		}

		switch (opType) {
		case ALI_DRUID:
			/**
			 * 调用ali druid方式 插件dbType一定要设置为小写与JdbcConstants保持一致
			 * 
			 * @see com.alibaba.druid.util.JdbcConstants
			 */
			String aliCountSql = DruidUtils.count(originalSql, dialectType);
			countOptimize.setCountSQL(aliCountSql);
			break;
		case JSQLPARSER:
			/**
			 * 调用JsqlParser方式
			 */
			JsqlParserUtils.jsqlparserCount(countOptimize, originalSql);
			break;
		default:
			StringBuffer countSql = new StringBuffer("SELECT COUNT(1) ");
			boolean optimize = false;
			if (!indexOfSql.contains("DISTINCT") && !indexOfSql.contains("GROUP BY")) {
				int formIndex = indexOfSql.indexOf("FROM");
				if (formIndex > -1) {
					if (orderByIndex > -1) {
						tempSql = tempSql.substring(0, orderByIndex);
						countSql.append(tempSql.substring(formIndex));
						// 无排序情况
					} else {
						countSql.append(tempSql.substring(formIndex));
					}
					// 执行优化
					optimize = true;
				}
			}
			if (!optimize) {
				// 无优化SQL
				countSql.append("FROM ( ").append(originalSql).append(" ) TOTAL");
			}
			countOptimize.setCountSQL(countSql.toString());
		}

		return countOptimize;
	}

	/**
	 * 查询SQL拼接Order By
	 * 
	 * @param originalSql
	 *            需要拼接的SQL
	 * @param page
	 *            page对象
	 * @param orderBy
	 *            是否需要拼接Order By
	 * @return
	 */
	public static String concatOrderBy(String originalSql, Pagination page, boolean orderBy) {
		if (orderBy && StringUtils.isNotEmpty(page.getOrderByField())) {
			StringBuffer buildSql = new StringBuffer(originalSql);
			buildSql.append(" ORDER BY ").append(page.getOrderByField());
			buildSql.append(page.isAsc() ? " ASC " : " DESC ");
			return buildSql.toString();
		}
		return originalSql;
	}

	/**
	 * 格式sql
	 * 
	 * @param boundSql
	 * @param format
	 * @return
	 */
	public static String sqlFormat(String boundSql, boolean format) {
		if (format) {
			return sqlFormatter.format(boundSql);
		} else {
			return boundSql.replaceAll("[\\s]+", " ");
		}
	}

}