using System;
using System.Data;
using System.Data.SqlClient;
using System.IO;
using System.Threading;


namespace AllBase
{
    public class SqlHelper
    {
        /// <summary>
        /// 数据库链接串
        /// </summary>
        private string ConnString = "";
        /// <summary>
        /// 是否已经链接成功
        /// </summary>
        public bool Connected  {
            get { return Connection != null && Connection.State == ConnectionState.Open; }
        }
        /// <summary>
        /// 数据库链接
        /// </summary>
        private SqlConnection Connection =null;
        /// <summary>
        /// 执行超时
        /// </summary>
        public int TimeOut = 100;

        public SqlHelper(string conn)
        {
            ConnString = conn;
            ConnTo();
        }

        public string Replace(string key)
        {
            return key.Replace("'", "''");
        }

        /// <summary> 
        /// 执行指定数据库连接对象的命令 
        /// </summary> 
        /// <param name="sql">T存储过程名称或T-SQL语句</param> 
        /// <returns>返回影响的行数</returns> 
        public int ExecuteNonQuery(string sql)
        {
            SqlCommand cmd = PrepareCommand(sql);
            try
            {
                // Finally, execute the command 
                int retval = cmd.ExecuteNonQuery();
                return retval;
            }
            catch (Exception e)
            {
                ErrorDoing(e.Message,sql);
                
            }
            return 0;
        }
        /// <summary>
        /// 获取插入ID
        /// </summary>
        /// <param name="sql"></param>
        /// <returns></returns>
        public int InsertId(string sql)
        {
            sql += ";SELECT @@IDENTITY";
            string id = ExecuteFirst(sql);
            int i = 0;
            int.TryParse(id, out i);
            return i;
        }
        /// <summary>
        /// 是否存在
        /// </summary>
        /// <param name="sql"></param>
        /// <returns></returns>
        public bool Exists(string sql)
        {
            string id = ExecuteFirst(sql);
            return !string.IsNullOrEmpty(id);
        }

        /// <summary> 
        /// 执行指定数据库连接对象的命令,指定存储过程参数,返回DataSet. 
        /// </summary> 
        /// <param name="sql">存储过程名或T-SQL语句</param> 
        /// <returns>返回一个包含结果集的DataSet</returns> 
        public DataSet ExecuteDataset(string sql)
        {

            SqlCommand cmd = PrepareCommand(sql);
            try
            {
            // 创建SqlDataAdapter和DataSet. 
                SqlDataAdapter da = new SqlDataAdapter(cmd);
            
                DataSet ds = new DataSet();
                // 填充DataSet. 
                da.Fill(ds);
                cmd.Parameters.Clear();
                return ds;
            }
            catch (Exception e)
            {
                ErrorDoing(e.Message,sql);

            }
            return null;
        }

        /// <summary> 
        /// 执行指定数据库连接对象的命令,指定存储过程参数,返回DataSet. 
        /// </summary> 
        /// <param name="sql">存储过程名或T-SQL语句</param> 
        /// <returns>返回一个包含结果集的DataSet</returns> 
        public DataTable ExecuteDataTable(string sql)
        {

            SqlCommand cmd = PrepareCommand(sql);
            try
            {
                // 创建SqlDataAdapter和DataSet. 
                SqlDataAdapter da = new SqlDataAdapter(cmd);

                DataTable ds = new DataTable();
                // 填充DataSet. 
                da.Fill(ds);
                cmd.Parameters.Clear();
                return ds;
            }
            catch (Exception e)
            {
                ErrorDoing(e.Message,sql);
                
            }
            return null;

        }

        /// <summary> 
        /// 执行指定数据库连接对象的命令,指定存储过程参数,返回DataSet. 
        /// </summary> 
        /// <param name="sql">存储过程名或T-SQL语句</param> 
        /// <returns>返回一个包含结果集的DataSet</returns> 
        public DataRow ExecuteDataTableRow(string sql)
        {

            SqlCommand cmd = PrepareCommand(sql);
            try
            {
                // 创建SqlDataAdapter和DataSet. 
                SqlDataAdapter da = new SqlDataAdapter(cmd);

                DataTable ds = new DataTable();
                // 填充DataSet. 
                da.Fill(ds);
                if (ds.Rows.Count > 0)
                    return ds.Rows[0];
            }
            catch (Exception e)
            {
                ErrorDoing(e.Message,sql);
                
            }
            
            return null;

        }

        /// <summary> 
        /// 执行指定数据库连接对象的命令,指定参数,返回结果集中的第一行第一列. 
        /// </summary> 
        /// <param name="sql">存储过程名称或T-SQL语句</param> 
        /// <returns>返回结果集中的第一行第一列</returns> 
        public string ExecuteFirst(string sql)
        {

            SqlCommand cmd = PrepareCommand(sql);
            try
            {
                SqlDataAdapter da = new SqlDataAdapter(cmd);
                DataTable ds = new DataTable();
                // 填充DataSet. 
                da.Fill(ds);
                // 执行SqlCommand命令,并返回结果. 
                var retval = cmd.ExecuteScalar();

                return retval==null?"": retval.ToString();
            }
            catch (Exception e)
            {
                ErrorDoing(e.Message,sql);
                
            }
            return "";
        }



        /// <summary> 
        /// 预处理用户提供的命令,数据库连接/事务/命令类型/参数 
        /// </summary> 
        /// <param name="commandText">存储过程名或都T-SQL命令文本</param> 
        private SqlCommand PrepareCommand(string commandText)
        {
            SqlCommand command = new SqlCommand();
            if (Connection.State != ConnectionState.Open)
                ConnTo();

            command.Connection = Connection;
            command.CommandText = commandText;
            command.CommandType = CommandType.Text;
            command.CommandTimeout = TimeOut;
            return command;
        }

        /// <summary>
        /// 针对不同错误，执行不同的修正
        /// </summary>
        /// <param name="message"></param>
        private void ErrorDoing(string message, string sql)
        {
            if (string.IsNullOrEmpty(message))
                return;
            if (message.Contains("Incorrect string value"))
                return;
            if (message.Contains("Connection must be valid and open"))
                ConnTo();
            if (message.Contains("There is already an open DataReader"))
            {
                Thread.Sleep(500);
                ConnTo();
            }
            if (message.Contains("Fatal error encountered during command execution."))
                ConnTo();
            if (message.Contains(" StreamWriter ") || message.Contains("未将对象引用设置到对象的实例") || message.Contains("未将对象"))
                ConnTo();
            LogSave.Add("执行SQL："+sql+" 错误："+message);
            Random ra = new Random(Guid.NewGuid().GetHashCode());
            Thread.Sleep(ra.Next(200, 2000));
        }

        /// <summary>
        /// 链接数据库
        /// </summary>
        private void ConnTo()
        {
            try
            {
                Connection = new SqlConnection(ConnString);
                Connection.Open();
            }
            catch (Exception e)
            {
                ErrorDoing(e.Message,ConnString);
            }

        }

        /// <summary>
        /// 关闭链接
        /// </summary>
        public void Close()
        {
            try
            {
                Connection.Close();
            }
            catch (Exception e)
            {
                
                
            }
        }


    }


}