using System;
using System.Collections.Generic;
using System.Data.SQLite;
using System.Linq;
using System.Text;
using System.IO;
using System.Data;
using System.Configuration;

namespace OTSModelSharp.DTLBase
{
  

    namespace Helper
    {
        public class SQLiteHelper3
        {
            /// <summary>
            /// 创建数据库文件
            /// </summary>
            /// <param name="fileName">文件名</param>
            public static void CreateDBFile(string fileName)
            {
                string path = Environment.CurrentDirectory + @"/Data/";
                if (!Directory.Exists(path))
                {
                    Directory.CreateDirectory(path);
                }
                string databaseFileName = path + fileName;
                if (!File.Exists(databaseFileName))
                {
                    SQLiteConnection.CreateFile(databaseFileName);
                }
            }
            /// <summary>
            /// 删除数据库
            /// </summary>
            /// <param name="fileName">文件名</param>
            public static void DeleteDBFile(string fileName)
            {
                string path = Environment.CurrentDirectory + @"/Data/";
                if (File.Exists(path))
                {
                    File.Delete(path);
                }
            }

            /// <summary>
            /// 生成连接字符串
            /// </summary>
            /// <returns></returns>
            private static string CreateConnectionString()
            {
                SQLiteConnectionStringBuilder connectionString = new SQLiteConnectionStringBuilder();
                //connectionString.DataSource = @"data/data.db";//此处文件名可以使用变量表示
                connectionString.DataSource = ConfigurationManager.ConnectionStrings["SQLite"].ConnectionString;
                string conStr = connectionString.ToString();
                return conStr;
            }

            private static SQLiteConnection m_dbConnection;
            /// <summary>
            /// 事务
            /// </summary>
            public static SQLiteTransaction trans = null;


            #region 事务控制

            /// <summary>
            /// 开始事务
            /// </summary>
            public static void BeginTransaction()
            {
                trans = m_dbConnection.BeginTransaction(IsolationLevel.ReadCommitted);
            }

            /// <summary>
            /// 回滚事务
            /// </summary>
            public static void Rollback()
            {
                trans.Rollback();
            }

            /// <summary>
            /// 提交事务
            /// </summary>
            public static void Commit()
            {
                trans.Commit();
            }

            #endregion

            /// <summary>
            /// 连接到数据库
            /// </summary>
            /// <returns></returns>
            public static SQLiteConnection dbConnection()
            {
                m_dbConnection = new SQLiteConnection(CreateConnectionString());

                m_dbConnection.Open();

                return m_dbConnection;
            }

            /// <summary>
            /// 在指定数据库中创建一个table
            /// </summary>
            /// <param name="sql">sql语言，如：create table pat_info (name varchar(20), score int)</param>
            /// <returns></returns>
            public static bool CreateTable(string sql)
            {
                try
                {
                    SQLiteCommand command = new SQLiteCommand(sql, dbConnection());
                    command.ExecuteNonQuery();
                    return true;
                }
                catch (Exception ex)
                {
                    //_ErrorLog.Insert("ExecuteNonQuery(" + sql + ")Err:" + ex);
                    return false;
                }
                finally
                {
                    closeConn();
                }

            }

            /// <summary>
            /// 在指定数据库中删除一个table
            /// </summary>
            /// <param name="tablename">表名称</param>
            /// <returns></returns>
            public static bool DeleteTable(string tablename)
            {
                try
                {
                    SQLiteCommand cmd = new SQLiteCommand("DROP TABLE IF EXISTS " + tablename, dbConnection());
                    cmd.ExecuteNonQuery();
                    return true;
                }
                catch (Exception ex)
                {
                    //_ErrorLog.Insert("ExecuteNonQuery(DROP TABLE IF EXISTS " + tablename + ")Err:" + ex);
                    return false;
                }
                finally
                {
                    closeConn();
                }
            }

            /// <summary>
            /// 在指定表中添加列
            /// </summary>
            /// <param name="tablename">表名</param>
            /// <param name="columnname">列名</param>
            /// <param name="ctype">列的数值类型</param>
            /// <returns></returns>
            public static bool AddColumn(string tablename, string columnname, string ctype)
            {
                try
                {
                    SQLiteCommand cmd = new SQLiteCommand("ALTER TABLE " + tablename + " ADD COLUMN " + columnname + " " + ctype, dbConnection());
                    cmd.ExecuteNonQuery();
                    return true;
                }
                catch (Exception ex)
                {
                    //_ErrorLog.Insert("ExecuteNonQuery(ALTER TABLE " + tablename + " ADD COLUMN " + columnname + " " + ctype + ")Err:" + ex);
                    return false;
                }
                finally
                {
                    closeConn();
                }
            }

            /// <summary>
            /// 执行增删改查操作
            /// </summary>
            /// <param name="sql">查询语言</param>
            /// <returns></returns>
            public static int ExecuteNonQuery(string sql)
            {
                try
                {
                    SQLiteCommand cmd;
                    cmd = new SQLiteCommand(sql, dbConnection());
                    cmd.ExecuteNonQuery().ToString();
                    return 1;
                }
                catch (Exception ex)
                {
                    //_ErrorLog.Insert("ExecuteNonQuery(" + sql + ")Err:" + ex);
                    return 0;
                }
                finally
                {
                    closeConn();
                }
            }

            /// <summary>  
            /// <para>执行SQL,返回受影响的行数</para>  
            /// <para>可用于执行表创建语句</para>  
            /// <para>paramArr == null 表示无参数</para>  
            /// </summary>  
            /// <param name="sql"></param>  
            /// <returns></returns>  
            public static int ExecuteNonQuery(string sql, SQLiteParameter[] paramArr)
            {
                if (sql == null)
                {
                    throw new ArgumentNullException("sql=null");
                }
                SQLiteCommand cmd = new SQLiteCommand();
                cmd.CommandText = sql;
                if (paramArr != null)
                {
                    foreach (SQLiteParameter p in paramArr)
                    {
                        cmd.Parameters.Add(p);
                    }
                }
                cmd.Connection = m_dbConnection;
                int i = cmd.ExecuteNonQuery();
                return i;
            }

            /// <summary>
            /// 返回一条记录查询
            /// </summary>
            /// <param name="sql">sql查询语言</param>
            /// <returns>返回字符串数组</returns>
            public static string[] SqlRow(string sql)
            {
                try
                {
                    SQLiteCommand sqlcmd = new SQLiteCommand(sql, dbConnection());//sql语句
                    SQLiteDataReader reader = sqlcmd.ExecuteReader();
                    if (!reader.Read())
                    {
                        return null;
                    }
                    string[] Row = new string[reader.FieldCount];
                    for (int i = 0; i < reader.FieldCount; i++)
                    {
                        Row[i] = (reader[i].ToString());
                    }
                    reader.Close();
                    return Row;
                }
                catch (Exception ex)
                {
                    //_ErrorLog.Insert("SqlRow(" + sql + ")Err:" + ex);
                    return null;
                }
                finally
                {
                    closeConn();
                }
            }

            /// <summary>
            /// 唯一结果查询
            /// </summary>
            /// <param name="sql">sql查询语言</param>
            /// <returns>返回一个字符串</returns>
            public static string sqlone(string sql)
            {

                try
                {
                    SQLiteCommand sqlcmd = new SQLiteCommand(sql, dbConnection());//sql语句
                    return sqlcmd.ExecuteScalar().ToString();
                }
                catch
                {
                    return "";
                }
                finally
                {
                    closeConn();
                }
            }

            /// <summary>
            /// 获取一列数据
            /// </summary>
            /// <param name="sql">单列查询</param>
            /// <param name="count">返回结果数量</param>
            /// <returns>返回一个数组</returns>
            public static List<string> sqlcolumn(string sql)
            {
                try
                {
                    List<string> Column = new List<string>();
                    SQLiteCommand sqlcmd = new SQLiteCommand(sql, dbConnection());//sql语句
                    SQLiteDataReader reader = sqlcmd.ExecuteReader();
                    while (reader.Read())
                    {
                        Column.Add(reader[0].ToString());
                    }
                    reader.Close();
                    return Column;
                }
                catch (Exception ex)
                {
                    //_ErrorLog.Insert("sqlcolumn(" + sql + ")Err:" + ex);
                    return null;
                }
                finally
                {
                    closeConn();
                }
            }

            /// <summary>
            /// 返回记录集查询
            /// </summary>
            /// <param name="sql">sql查询语言</param>
            /// <returns>返回查询结果集</returns>
            public static DataTable SqlTable(string sql)
            {
                try
                {
                    SQLiteCommand sqlcmd = new SQLiteCommand(sql, dbConnection());//sql语句
                    sqlcmd.CommandTimeout = 120;
                    SQLiteDataReader reader = sqlcmd.ExecuteReader();
                    DataTable dt = new DataTable();
                    if (reader != null)
                    {
                        dt.Load(reader, LoadOption.PreserveChanges, null);
                    }
                    return dt;
                }
                catch (Exception ex)
                {
                    //_ErrorLog.Insert("SqlReader(" + sql + ")Err:" + ex);
                    return null;
                }
                finally
                {
                    closeConn();
                }
            }
            /// <summary>
            /// 关闭数据库连接
            /// </summary>
            public static void closeConn()
            {
                try
                {
                    if (m_dbConnection.State == ConnectionState.Open)
                        m_dbConnection.Close();
                    else if (m_dbConnection.State == ConnectionState.Broken)
                    {
                        m_dbConnection.Close();
                    }
                }
                catch (Exception ex)
                {
                    //_ErrorLog.Insert("closeConnErr:" + ex);
                }
            }
        }
    }
}