package cn.datax.common.database.dialect;

import cn.datax.common.database.core.DbColumn;
import cn.datax.common.database.core.DbTable;
import org.springframework.jdbc.core.RowMapper;

import java.sql.ResultSet;

/**
 * Oracle Oracle11g及以下数据库方言
 *
 * @author yuwei
 * @since 2020-03-14
 */
public class OracleDialect extends AbstractDbDialect {

    @Override
    public String columns(String dbName, String tableName) {
        return "select columns.column_name AS colName, columns.data_type AS DATATYPE, columns.data_length AS DATALENGTH, columns.data_precision AS DATAPRECISION, " +
                "columns.data_scale AS DATASCALE, columns.nullable AS NULLABLE, columns.column_id AS COLPOSITION, columns.data_default AS DATADEFAULT, comments.comments AS COLCOMMENT," +
                "case when t.column_name is null then 0 else 1 end as COLKEY " +
                "from sys.user_tab_columns columns LEFT JOIN sys.user_col_comments comments ON columns.table_name = comments.table_name AND columns.column_name = comments.column_name " +
                "left join ( " +
                "select col.column_name as column_name, con.table_name as table_name from user_constraints con, user_cons_columns col " +
                "where con.constraint_name = col.constraint_name and con.constraint_type = 'P' " +
                ") t on t.table_name = columns.table_name and columns.column_name = t.column_name " +
                "where columns.table_name = UPPER('" + tableName + "') order by columns.column_id ";
    }

    @Override
    public String tables(String dbName) {
        return "select tables.table_name AS TABLENAME, comments.comments AS TABLECOMMENT from sys.user_tables tables " +
                "LEFT JOIN sys.user_tab_comments comments ON tables.table_name = comments.table_name ";
    }

    @Override
    public String buildPaginationSql(String originalSql, long offset, long count) {
        StringBuilder sqlBuilder = new StringBuilder();
        sqlBuilder.append("SELECT * FROM ( SELECT TMP.*, ROWNUM ROW_ID FROM ( ");
        sqlBuilder.append(originalSql).append(" ) TMP WHERE ROWNUM <=").append((offset >= 1) ? (offset + count) : count);
        sqlBuilder.append(") WHERE ROW_ID > ").append(offset);
        return sqlBuilder.toString();
    }

    @Override
    public RowMapper<DbColumn> columnMapper() {
        return (ResultSet rs, int rowNum) -> {
            DbColumn entity = new DbColumn();
            entity.setColName(rs.getString("COLNAME"));
            entity.setDataType(rs.getString("DATATYPE"));
            entity.setDataLength(rs.getInt("DATALENGTH"));
            entity.setDataPrecision(rs.getInt("DATAPRECISION"));
            entity.setDataScale(rs.getInt("DATASCALE"));
            entity.setColKey("1".equals(rs.getString("COLKEY")) ? true : false);
            entity.setNullable("Y".equals(rs.getString("NULLABLE")) ? true : false);
            entity.setColPosition(rs.getInt("COLPOSITION"));
            entity.setDataDefault(rs.getString("DATADEFAULT"));
            entity.setColComment(rs.getString("COLCOMMENT"));
            return entity;
        };
    }

    @Override
    public RowMapper<DbTable> tableMapper() {
        return (ResultSet rs, int rowNum) -> {
            DbTable entity = new DbTable();
            entity.setTableName(rs.getString("TABLENAME"));
            entity.setTableComment(rs.getString("TABLECOMMENT"));
            return entity;
        };
    }
}
