/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2014-2023 abel533@gmail.com
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

package com.github.pagehelper.dialect.helper;

import com.github.pagehelper.Page;
import com.github.pagehelper.dialect.AbstractHelperDialect;
import com.github.pagehelper.util.MetaObjectUtil;
import org.apache.ibatis.cache.CacheKey;
import org.apache.ibatis.mapping.BoundSql;
import org.apache.ibatis.mapping.MappedStatement;
import org.apache.ibatis.mapping.ParameterMapping;
import org.apache.ibatis.reflection.MetaObject;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

/**
 * PostgreSQL 方言.
 *
 * @author liym
 * @since 2021-02-06
 */
public class PostgreSqlDialect extends AbstractHelperDialect {

    @Override
    public Object processPageParameter(MappedStatement ms, Map<String, Object> paramMap, Page page, BoundSql boundSql, CacheKey pageKey) {
        paramMap.put(PAGEPARAMETER_SECOND, page.getPageSize());
        paramMap.put(PAGEPARAMETER_FIRST, page.getStartRow());
        //处理pageKey
        pageKey.update(page.getPageSize());
        pageKey.update(page.getStartRow());
        //处理参数配置
        if (boundSql.getParameterMappings() != null) {
            List<ParameterMapping> newParameterMappings = new ArrayList<ParameterMapping>(boundSql.getParameterMappings());
            if (page.getStartRow() == 0) {
                newParameterMappings.add(new ParameterMapping.Builder(ms.getConfiguration(), PAGEPARAMETER_SECOND, int.class).build());
            } else {
                newParameterMappings.add(new ParameterMapping.Builder(ms.getConfiguration(), PAGEPARAMETER_SECOND, int.class).build());
                newParameterMappings.add(new ParameterMapping.Builder(ms.getConfiguration(), PAGEPARAMETER_FIRST, long.class).build());
            }
            MetaObject metaObject = MetaObjectUtil.forObject(boundSql);
            metaObject.setValue("parameterMappings", newParameterMappings);
        }
        return paramMap;
    }

    /**
     * 构建 <a href="https://www.postgresql.org/docs/current/queries-limit.html">PostgreSQL</a>分页查询语句
     */
    @Override
    public String getPageSql(String sql, Page page, CacheKey pageKey) {
        StringBuilder sqlStr = new StringBuilder(sql.length() + 17);
        sqlStr.append(sql);
        if (page.getStartRow() == 0) {
            sqlStr.append(" LIMIT ?");
        } else {
            sqlStr.append(" LIMIT ? OFFSET ?");
        }
        return sqlStr.toString();
    }

}
