using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SQLite;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace JJMediSys
{
    class SQLiteDBHelper
    {
        /// <summary>
        ///  
        /// </summary>
        public string connectionString = string.Empty;


        /// <summary>
        /// 
        /// </summary>
        public  SQLiteConnection connection = null;


        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="dbPath">数据库文件路径</param>
        public SQLiteDBHelper(string dbPath)
        {
            this.connectionString = "Data Source=" + dbPath;
        }

        /// <summary>
        /// 创建数据库文件
        /// </summary>
        /// <param name="dbPath"></param>
        public  void CreateDB(string dbPath,string CreateSql)
        {
            using (SQLiteConnection connection = new SQLiteConnection("Data Source=" + dbPath))
            {
                connection.Open();
                using (SQLiteCommand command = new SQLiteCommand(connection))
                {
                    bool ret = ExecuteCommand(CreateSql);
                }
            }
        }


        /// <summary>
        /// 打开连接
        /// </summary>
        /// <param name="dataSource"></param>
        /// <param name="password"></param>
        public void SetDataSource(string dataSource, string password)
        {
            connectionString = string.Format("Data Source={0};Pooling=true;FailIfMissing=false", dataSource);
            connection = new SQLiteConnection(connectionString);
            if (!string.IsNullOrEmpty(password))
            {
                //connection.SetPassword(password);
            }
            connection.Open();
        }


        #region 通用方法
        /// <summary>
        /// 查询表
        /// </summary>
        /// <param name="sqlStr"></param>
        /// <returns></returns>
        public  DataTable ExecQuery(string sqlStr)
        {
            DataTable dt = new DataTable();
            try
            {
                SQLiteDataAdapter OraDa = new SQLiteDataAdapter(sqlStr, connection);
                OraDa.Fill(dt);
                return dt;
            }
            catch (SQLiteException e)
            {
                string s = e.Message;
                return null;
            }
        }


        /// <summary>
        /// 增、删、改操作  
        /// </summary>
        /// <param name="commandStr">sql语句</param>
        /// <returns>是否成功</returns>
        public  bool ExecuteCommand(string sqlStr)
        {
            using (SQLiteCommand cmd = new SQLiteCommand(sqlStr, connection))
            {
                try
                {
                    if (cmd.ExecuteNonQuery() > 0)
                    {

                        return true;
                    }
                    else
                    {

                        return false;
                    }
                }
                catch (Exception ex)
                {

                    ex.ToString();
                    return false;
                }
            }
        }


        /// <summary>
        /// 根据查询语句，获取表中记录的条数   select count(*) from t_Developer
        /// </summary>
        /// <param name="sqlStr"></param>
        /// <returns></returns>
        public  int GetRecordCount(string sqlStr)
        {
            using (SQLiteCommand cmd = new SQLiteCommand(sqlStr, connection))
            {
                try
                {
                    cmd.CommandText = sqlStr;
                    SQLiteDataReader dr = cmd.ExecuteReader();
                    if (dr.Read())
                    {
                        return dr.FieldCount;
                    }
                    return 0;
                }
                catch (Exception e)
                {
                    e.ToString();
                    return 0;
                }
            }
        }
        #endregion
    }
}