using System;
using System.Data.Entity;
using System.Data.SqlClient;
using System.Text;
using CK.SCP.Utils;


namespace ChangkeTec.SDMS.Model
{
    public static class DbContextFactory
    {
        static DbContextFactory()
        {
            Database.SetInitializer<DataCenterContext>(null);
            Database.SetInitializer<ExchangeCenterContext>(null);
        }


        public static DataCenterContext CreateDataCenterInstance()
        {
            var dbSetting = GlobalConfig.DataCenterDB;
            try
            {
                DataCenterContext db;
                var strConn = GetEfConnectionString(dbSetting);
                db = new DataCenterContext(strConn);

                return db;
            }
            catch (SqlException ex)
            {
                throw new Exception($"系统无法连接到数据库:{dbSetting}，请检查配置的服务器,数据库,用户名和密码等信息是否正确。{Environment.NewLine}{ex}");
            }
        }

        public static ExchangeCenterContext CreateExchangeCenterInstance()
        {
            var dbSetting = GlobalConfig.ExchangeCenterDB;
            try
            {
                ExchangeCenterContext db;
                var strConn = GetEfConnectionString(dbSetting);
                db = new ExchangeCenterContext(strConn);
                return db;
            }
            catch (SqlException ex)
            {
                throw new Exception($"系统无法连接到数据库:{dbSetting}，请检查配置的服务器,数据库,用户名和密码等信息是否正确。{Environment.NewLine}{ex}");
            }
        }

        private static string GetEfConnectionString(DbSetting dbSetting)
        {
            var sbConn = new StringBuilder();

            if (string.IsNullOrEmpty(dbSetting.密码)) throw new Exception("配置文件错误，请检查");
            switch (dbSetting.数据库类型)
            {
                case "SQLServer":
                    sbConn.Append($"Data source ={dbSetting.服务器地址}");
                    sbConn.Append(dbSetting.端口 == "0" ? ";" : $",{dbSetting.端口};");
                    sbConn.Append($"Initial catalog = {dbSetting.数据库名称};");
                    sbConn.Append($"User id = {dbSetting.用户名};");
                    sbConn.Append($"Password = {CK.SCP.Utils.EncryptHelper.Decrypt(dbSetting.密码)};");
                    sbConn.Append("MultipleActiveResultSets = True;");
                    sbConn.Append("persist security info = True;");
                    sbConn.Append("App = EntityFramework;");
                    break;
                case "MySql":
                    sbConn.Append($"server ={dbSetting.服务器地址};");
                    sbConn.Append($"port ={dbSetting.端口};");
                    sbConn.Append($"database = {dbSetting.数据库名称};");
                    sbConn.Append($"user id = {dbSetting.用户名};");
                    sbConn.Append($"password = {EncryptHelper.Decrypt(dbSetting.密码)};");
                    sbConn.Append("persistsecurityinfo =True;");
                    break;
            }

            return sbConn.ToString();
        }
    }
}