using Npgsql;
using System;
using System.Collections.Generic;
using System.Data.Common;
using System.Data.SQLite;
using System.Linq;
using System.Reflection;
using System.Web;

namespace JiangSu.cs
{
    public class Tools
    {
        private static PostgreHelper _pgHelper;

        /// <summary>
        /// DB帮助类
        /// </summary>
        public static PostgreHelper PGHelper
        {
            get
            {
                if (null == _pgHelper)
                {
                    _pgHelper = new PostgreHelper();
                }

                return _pgHelper;
            }
        }

        /// <summary>
        /// 获取参数列表
        /// </summary>
        public static DbParameter[] GetPGParams<T>(string sql, T t)
        {
            List<DbParameter> list = new List<DbParameter>();
            Type tType = typeof(T);
            BindingFlags flags = BindingFlags.Public | BindingFlags.IgnoreCase | BindingFlags.Instance;

            int start = sql.IndexOf("@");
            while (start != -1)
            {
                int end = sql.IndexOf(",", start);
                if (end == -1) end = sql.IndexOf(")", start);
                if (end == -1) end = sql.IndexOf(" ", start);
                if (end == -1) end = sql.Length;

                string name = sql.Substring(start + 1, end - start - 1);
                PropertyInfo pi = tType.GetProperty(name, flags);
                if (pi != null)
                {
                    object value = pi.GetValue(t, null);
                    NpgsqlParameter dp = new NpgsqlParameter("@" + name, value);
                    list.Add(dp);
                }

                start = sql.IndexOf("@", end);
            }

            return list.ToArray();
        }

        /// <summary>
        /// 获取参数列表
        /// </summary>
        public static SQLiteParameter[] GetSQLiteParams<T>(string sql, T t)
        {
            List<SQLiteParameter> list = new List<SQLiteParameter>();
            Type tType = typeof(T);
            BindingFlags flags = BindingFlags.Public | BindingFlags.IgnoreCase | BindingFlags.Instance;

            int start = sql.IndexOf("@");
            while (start != -1)
            {
                int end = sql.IndexOf(",", start);
                if (end == -1) end = sql.IndexOf(")", start);
                if (end == -1) end = sql.IndexOf(" ", start);
                if (end == -1) end = sql.Length;

                string name = sql.Substring(start + 1, end - start - 1);
                PropertyInfo pi = tType.GetProperty(name, flags);
                if (pi != null)
                {
                    object value = pi.GetValue(t, null);
                    SQLiteParameter dp = new SQLiteParameter("@" + name, value);
                    list.Add(dp);
                }

                start = sql.IndexOf("@", end);
            }

            return list.ToArray();
        }
    }
}