using System;
using System.Collections.Generic;
using System.Text;
using System.Reflection;
using System.Data;

namespace Estsh.Web.Util
{
    public static class ModelConvert
    {
        /// <summary>
        /// 根据模板获得该类可读写的字段名数组
        /// </summary>
        /// <typeparam name="T">模版类</typeparam>
        /// <returns>字段名数组</returns>
        public static string[] GetFieldNames<T>()
        {
            List<string> fieldList = new List<string>();
            Type type = typeof(T);
            PropertyInfo[] propertys = type.GetProperties();
            for (int i = 0; i < propertys.Length; i++)
            {
                // 只包含可读写的字段
                if (propertys[i].CanRead && propertys[i].CanWrite)
                {
                    fieldList.Add(propertys[i].Name);
                }
            }
            return fieldList.ToArray();
        }

        /// <summary>
        /// 根据模板类获得实体的字段键值对
        /// </summary>
        /// <typeparam name="T">模版类</typeparam>
        /// <param name="model">实体</param>
        /// <returns>字段键值对</returns>
        public static Dictionary<string, object> GetFieldNameValuePairs<T>(T model)
        {
            Dictionary<string, object> valueDict = new Dictionary<string, object>();
            Type type = typeof(T);
            PropertyInfo[] propertys = type.GetProperties();
            for (int i = 0; i < propertys.Length; i++)
            {
                // 只包含可读写的字段
                if (propertys[i].CanRead && propertys[i].CanWrite)
                {
                    object value = propertys[i].GetValue(model, null);
                    valueDict.Add(propertys[i].Name, value);
                }
            }
            return valueDict;
        }

        /// <summary>
        /// 根据实体的属性构造一张空表
        /// </summary>
        /// <typeparam name="T">模版类</typeparam>
        /// <returns></returns>
        public static DataTable BuildSchema<T>()
        {
            DataTable tbSchema = new DataTable();
            Type type = typeof(T);
            foreach (PropertyInfo property in type.GetProperties())
            {
                tbSchema.Columns.Add(property.Name, property.PropertyType);
            }
            return tbSchema;
        }

        /// <summary>
        /// 实体数组到数据表的赋值
        /// </summary>
        /// <typeparam name="T">模版类</typeparam>
        /// <param name="modelArray"></param>
        /// <returns></returns>
        public static DataTable ToDataTable<T>(T[] modelArray)
        {
            DataTable dt = BuildSchema<T>();
            for (int i = 0; i < modelArray.Length; i++)
            {
                DataRow row = ToDataRow<T>(modelArray[i], dt);
                dt.Rows.Add(row);
            }
            return dt;
        }

        /// <summary>
        /// 实体到数据行的同名字段同步
        /// </summary>
        /// <typeparam name="T">模版类</typeparam>
        /// <param name="model"></param>
        /// <param name="dt"></param>
        /// <returns></returns>
        public static DataRow ToDataRow<T>(T model, DataTable dt)
        {
            DataRow row = dt.NewRow();
            Type type = typeof(T);
            foreach (PropertyInfo property in type.GetProperties())
            {
                if (row.Table.Columns.Contains(property.Name))
                {
                    row[property.Name] = property.GetValue(model, null);
                }
            }
            return row;
        }

        /// <summary>
        /// 数据表到实体数组的赋值
        /// </summary>
        /// <typeparam name="T">模版类</typeparam>
        /// <param name="dt"></param>
        /// <returns></returns>
        public static T[] ToModelArray<T>(DataTable dt)
        {
            T[] modelArray = new T[dt.Rows.Count];
            for (int i = 0; i < dt.Rows.Count; i++)
            {
                modelArray[i] = ToModel<T>(dt.Rows[i]);
            }
            return modelArray;
        }

        /// <summary>
        /// 数据行到实体的同名字段同步
        /// </summary>
        /// <typeparam name="T">模版类</typeparam>
        /// <param name="row"></param>
        /// <param name="model"></param>
        public static T ToModel<T>(DataRow row)
        {
            Type type = typeof(T);
            T model = (T)Activator.CreateInstance(type);
            foreach (PropertyInfo property in type.GetProperties())
            {
                if (row.Table.Columns.Contains(property.Name) && property.CanWrite && row[property.Name] != null && row[property.Name] != DBNull.Value)
                {
                    object value = null;
                    switch (Type.GetTypeCode(property.PropertyType))
                    {
                        case TypeCode.Boolean:
                            value = Convert.ToBoolean(row[property.Name]);
                            break;
                        case TypeCode.DateTime:
                            value = Convert.ToDateTime(row[property.Name]);
                            break;
                        case TypeCode.Decimal:
                            value = Convert.ToDecimal(row[property.Name]);
                            break;
                        case TypeCode.Single:
                            value = Convert.ToSingle(row[property.Name]);
                            break;
                        case TypeCode.Double:
                            value = Convert.ToDouble(row[property.Name]);
                            break;
                        case TypeCode.Int16:
                            value = Convert.ToInt16(row[property.Name]);
                            break;
                        case TypeCode.Int32:
                            value = Convert.ToInt32(row[property.Name]);
                            break;
                        case TypeCode.Int64:
                            value = Convert.ToInt64(row[property.Name]);
                            break;
                        case TypeCode.SByte:
                            value = Convert.ToSByte(row[property.Name]);
                            break;
                        case TypeCode.Byte:
                            value = Convert.ToByte(row[property.Name]);
                            break;
                        case TypeCode.String:
                            value = Convert.ToString(row[property.Name]);
                            break;
                        default:
                            value = row[property.Name];
                            break;
                    }
                    property.SetValue(model, value, null);
                }
            }
            return model;
        }
    }
}