using SQLite;
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq.Expressions;
using Vinno.FIS.Sonopost.Common;
using Vinno.FIS.Sonopost.Helpers;

namespace Vinno.FIS.Sonopost.Features.Dicom
{
    public class DicomCacheDB
    {
        private readonly object _dbLock = new object();
        private SQLiteConnection _connection;
        private static DicomCacheDB _instance;

        public static DicomCacheDB Instance => _instance ?? (_instance = new DicomCacheDB());

        private DicomCacheDB()
        {
            var folder = Path.Combine(SonopostConstants.DataFolder, SonopostConstants.RemedicalFolder);
            DirectoryHelper.CreateDirectory(folder);
            var cacheDbPath = Path.Combine(folder, "Sonopost.RemedicalCache.db");
            _connection = new SQLiteConnection(cacheDbPath, false);
            CreateTable<DicomUploadContext>();
        }

        /// <summary>
        /// 创建表
        /// </summary>
        /// <typeparam name="T"></typeparam>
        private void CreateTable<T>()
        {
            lock (_dbLock)
            {
                _connection.CreateTable<T>();
            }
        }

        /// <summary>
        /// 添加数据
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="item"></param>
        public bool Create<T>(T item) where T : class
        {
            lock (_dbLock)
            {
                var ret = _connection.InsertOrReplace(item, typeof(T));
                return ret > 0;
            }
        }

        /// <summary>
        /// 删除数据
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="expr"></param>
        public bool Delete<T>(Expression<Func<T, bool>> expr) where T : class, new()
        {
            lock (_dbLock)
            {
                var existingItems = _connection.Table<T>().Where(expr);
                var ret = 0;
                foreach (var item in existingItems)
                {
                    var temp = _connection.Delete(item);
                    ret += temp;
                }
                return ret > 0;
            }
        }

        /// <summary>
        /// 更新数据
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="item"></param>
        public bool Update<T>(T item) where T : class
        {
            lock (_dbLock)
            {
                var ret = _connection.Update(item);
                return ret > 0;
            }
        }

        /// <summary>
        ///查询所有数据
        /// </summary>
        /// <typeparam name="T">The type of db model</typeparam>
        /// <returns>All items in one table.</returns>
        public IList<T> GetAll<T>() where T : class, new()
        {
            lock (_dbLock)
            {
                return _connection.Table<T>().ToList();
            }
        }

        /// <summary>
        /// 查询指定数据
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="expr"></param>
        /// <returns></returns>
        public T Get<T>(Expression<Func<T, bool>> expr) where T : class, new()
        {
            lock (_dbLock)
            {
                return _connection.Table<T>().Where(expr).FirstOrDefault();
            }
        }

        /// <summary>
        /// 关闭连接
        /// </summary>
        public void Close()
        {
            lock (_dbLock)
            {
                if (_connection != null)
                {
                    _connection.Close();
                    _connection.Dispose();
                    _connection = null;
                }
            }
        }
    }
}