using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Data.Common;
using System.Data.SqlClient;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace NFine.Data.Extensions
{
    public class ERPSqlServerHelper
    {
        #region [ 连接串相关 ]
        /// <summary>
        /// 数据中心DB的连接字符串
        /// </summary>
        public static string ConnectionString = ConfigurationManager.ConnectionStrings["ERPconnstr"].ConnectionString;
        /// <summary>
        /// 获取同步服务器的连接
        /// </summary>
        /// <returns></returns>
        private static SqlConnection GetConnectionString()
        {
            return new SqlConnection(ConnectionString);
        }

        /// <summary>
        /// 根据连接串获取连接
        /// </summary>
        /// <returns></returns>
        private static SqlConnection GetConnByString(string conn)
        {
            return new SqlConnection(conn);
        }

        
        #endregion

        #region 数据分页
        /// <summary>
        /// 摘要:
        ///     数据分页
        /// 参数：
        ///     sql：传入要执行sql语句
        ///     param：参数化
        ///     orderField：排序字段
        ///     orderType：排序类型
        ///     pageIndex：当前页
        ///     pageSize：页大小
        ///     count：返回查询条数
        /// </summary>
        public static DataTable GetPageTable(string sql, DbParameter[] param, string orderField, string orderType, int pageIndex, int pageSize, ref int count)
        {
            StringBuilder strSql = new StringBuilder();
            if (pageIndex == 0)
            {
                pageIndex = 1;
            }
            int num = (pageIndex - 1) * pageSize;
            int num1 = (pageIndex) * pageSize;
            string OrderBy = "";
            if (!string.IsNullOrEmpty(orderField))
                OrderBy = "Order By " + orderField + " " + orderType + "";
            else
                OrderBy = "order by (select 0)";
            strSql.Append("Select * From (Select ROW_NUMBER() Over (" + OrderBy + ")");
            strSql.Append(" As rowNum, * From (" + sql + ") As T ) As N Where rowNum > " + num + " And rowNum <= " + num1 + "");
            count = Convert.ToInt32(ExecuteScalar(CommandType.Text, "Select Count(1) From (" + sql + ") As t", param));
            IDataReader dr =  ExecuteReader(CommandType.Text, strSql.ToString(), param);
            return DatabaseReader.ReaderToDataTable(dr);
        }

        /// <summary>
        /// 根据sql语句和参数，返回DataTable
        /// </summary>
        /// <param name="sql">sql语句</param>
        /// <param name="spArr">可变参数</param>
        /// <returns>DataTable</returns>
        public static DataTable GetDataTableBySql(string sql, params SqlParameter[] spArr)
        {
            using (SqlConnection conn = GetConnectionString())
            {
                conn.Open();
                SqlCommand cmd = new SqlCommand(sql, conn).AddTimeout();
                if (spArr != null && spArr.Length > 0)
                    cmd.Parameters.AddRange(spArr.SetDBNull());
                DataTable dt = cmd.ExecuteDataTable();
                return dt;
            }
        }

        /// <summary>
        /// 使用提供的参数，执行有结果集返回的数据库操作命令、并返回SqlDataReader对象
        /// </summary>
        /// <param name="commandType">执行命令的类型（存储过程或T-SQL，等等）</param>
        /// <param name="commandText">存储过程名称或者T-SQL命令行<</param>
        /// <param name="parameters">执行命令所需的sql语句对应参数</param>
        /// <returns>返回SqlDataReader对象</returns>
        private static IDataReader ExecuteReader(CommandType cmdType, string cmdText, params DbParameter[] parameters)
        {
            DbCommand cmd = DbFactory.CreateDbCommand();
            DbConnection conn = DbFactory.CreateDbConnection(ConnectionString);
            try
            {
                PrepareCommand(cmd, conn, null, cmdType, cmdText, parameters);
                IDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
                cmd.Parameters.Clear();
                return rdr;
            }
            catch (Exception ex)
            {
                conn.Close();
                cmd.Dispose();
                //log.Error(ex.Message);
                throw;
            }
        }

        /// <summary>
        /// 依靠数据库连接字符串connectionString,
        /// 使用所提供参数，执行返回首行首列命令
        /// </summary>
        /// <param name="commandType">执行命令的类型（存储过程或T-SQL，等等）</param>
        /// <param name="commandText">存储过程名称或者T-SQL命令行</param>
        /// <param name="parameters">执行命令所需的sql语句对应参数</param>
        /// <returns>返回一个对象，使用Convert.To{Type}将该对象转换成想要的数据类型。</returns>
        private static object ExecuteScalar(CommandType cmdType, string cmdText, params DbParameter[] parameters)
        {
            try
            {
                DbCommand cmd = DbFactory.CreateDbCommand();
                using (DbConnection connection = DbFactory.CreateDbConnection(ConnectionString))
                {
                    PrepareCommand(cmd, connection, null, cmdType, cmdText, parameters);
                    object val = cmd.ExecuteScalar();
                    cmd.Parameters.Clear();
                    return val;
                }
            }
            catch (Exception ex)
            {
                //log.Error(ex.Message);
                throw;
            }
        }


        /// <summary>
        /// 为即将执行准备一个命令
        /// </summary>
        /// <param name="cmd">SqlCommand对象</param>
        /// <param name="conn">SqlConnection对象</param>
        /// <param name="isOpenTrans">DbTransaction对象</param>
        /// <param name="cmdType">执行命令的类型（存储过程或T-SQL，等等）</param>
        /// <param name="cmdText">存储过程名称或者T-SQL命令行, e.g. Select * from Products</param>
        /// <param name="cmdParms">SqlParameters to use in the command</param>
        private static void PrepareCommand(DbCommand cmd, DbConnection conn, DbTransaction isOpenTrans, CommandType cmdType, string cmdText, DbParameter[] cmdParms)
        {
            if (conn.State != ConnectionState.Open)
                conn.Open();
            cmd.Connection = conn;
            cmd.CommandText = cmdText;
            if (isOpenTrans != null)
                cmd.Transaction = isOpenTrans;
            cmd.CommandType = cmdType;
            if (cmdParms != null)
            {
                cmd.Parameters.AddRange(cmdParms);
            }
        }
        #endregion


        
    }
}