using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using NationalInstruments.VisaNS;

namespace CommonDevHostApp.Devices
{
    public class CommonVisaResource : IDisposable
    {
        private MessageBasedSession mbSession;
        public bool IsOk { get; set; }
        public string ResourceHandle;

        public CommonVisaResource()
        {
            IsOk = false;
        }

        /// <summary>
        /// 对于Visa总线，方法close 与Dispose功能一样
        /// </summary>
        public void Dispose()
        {
            this.Close();
        }

        /// <summary>
        /// 打开设备，在Initilize函数之后，可以Open打开设备，或者Close关闭设备
        /// </summary>
        /// <returns></returns>
        public virtual bool Open(string ResourceHandle)
        {
            if (IsOk)
                return true;

            this.ResourceHandle = ResourceHandle;

            if (mbSession != null)
                Close();

            mbSession = (MessageBasedSession)ResourceManager.GetLocalManager().Open(this.ResourceHandle);
            if (mbSession != null)
            {
                IsOk = true;
                return true;
            }
            else
            {
                IsOk = false;
                return false;
            }
        }

        /// <summary>
        /// 关闭设备
        /// </summary>
        /// <returns></returns>
        public virtual bool Close()
        {
            if (mbSession != null)
            {
                try
                {
                    mbSession.Dispose();
                    mbSession = null;
                }
                catch (Exception)
                {
                }
                finally
                {
                    mbSession = null;
                }
            }

            IsOk = false;
            return true;
        }

        /// <summary>
        /// 写总线
        /// </summary>
        /// <param name="command"></param>
        /// <returns></returns>
        public virtual bool Write(string command)
        {
            if (mbSession != null)
            {
                mbSession.Write(command);
                return true;
            }
            else
            {
                return false;
            }
        }

        /// <summary>
        /// 读总线
        /// </summary>
        /// <returns></returns>
        public virtual string Read()
        {
            if (mbSession != null)
            {
                string responseString = mbSession.ReadString();
                return responseString;
            }
            else
            {
                return null;
            }
        }

        /// <summary>
        /// 查询
        /// </summary>
        /// <param name="command"></param>
        /// <returns></returns>
        public virtual string Query(string command)
        {
            if (mbSession != null)
            {
                mbSession.Write(command);
                string responseString = mbSession.ReadString();
                return responseString;
            }
            else
            {
                return null;
            }
        }
    }
}