using System;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Reflection;
using XCode.DataAccessLayer;

namespace XCode.Configuration
{
    /// <summary>数据属性元数据以及特性</summary>
    public class FieldItem
    {
        #region 属性
        private PropertyInfo _Property;
        /// <summary>属性元数据</summary>
        [Obsolete("该成员在后续版本中将不再被支持！")]
        public PropertyInfo Property
        {
            get { return _Property; }
            set { _Property = value; }
        }

        private BindColumnAttribute _Column;
        /// <summary>绑定列特性</summary>
        [Obsolete("该成员在后续版本中将不再被支持！")]
        public BindColumnAttribute Column
        {
            get { return _Column; }
            set { _Column = value; }
        }

        private DataObjectFieldAttribute _DataObjectField;
        /// <summary>数据字段特性</summary>
        [Obsolete("该成员在后续版本中将不再被支持！")]
        public DataObjectFieldAttribute DataObjectField
        {
            get { return _DataObjectField; }
            set { _DataObjectField = value; }
        }

        private DescriptionAttribute _Description;
        /// <summary>备注</summary>
        public String Description
        {
            get
            {
                if (_Description != null && !String.IsNullOrEmpty(_Description.Description)) return _Description.Description;
                if (_Column != null && !String.IsNullOrEmpty(_Column.Description)) return _Column.Description;
                return null;
            }
        }
        #endregion

        #region 扩展属性
        /// <summary>属性名</summary>
        public String Name { get { return _Property == null ? null : _Property.Name; } }

        /// <summary>属性类型</summary>
        public Type Type { get { return _Property == null ? null : _Property.PropertyType; } }

        /// <summary>属性类型</summary>
        internal Type DeclaringType { get { return _Property == null ? null : _Property.DeclaringType; } }

        /// <summary>是否标识列</summary>
        public Boolean IsIdentity { get { return _DataObjectField == null ? false : _DataObjectField.IsIdentity; } }

        /// <summary>是否主键</summary>
        public Boolean PrimaryKey { get { return _DataObjectField == null ? false : _DataObjectField.PrimaryKey; } }

        /// <summary>是否允许空</summary>
        public Boolean IsNullable { get { return _DataObjectField == null ? false : _DataObjectField.IsNullable; } }

        /// <summary>长度</summary>
        public Int32 Length { get { return _DataObjectField == null ? 0 : _DataObjectField.Length; } }

        /// <summary>是否数据绑定列</summary>
        internal Boolean IsDataObjectField { get { return _DataObjectField != null; } }

        /// <summary>显示名。如果备注不为空则采用备注，否则采用属性名</summary>
        //[Obsolete("请改为使用Description属性！")]
        public String DisplayName
        {
            get
            {
                //if (Description != null && !String.IsNullOrEmpty(Description.Description)) return Description.Description;
                //if (_Column != null && !String.IsNullOrEmpty(_Column.Description)) return _Column.Description;

                return !String.IsNullOrEmpty(Description) ? Description : Name;
            }
        }

        /// <summary>字段名要过滤掉的标识符，考虑MSSQL、MySql、SQLite、Oracle等</summary>
        static Char[] COLUMNNAME_FLAG = new Char[] { '[', ']', '\'', '"', '`' };

        private String _ColumnName;
        /// <summary>用于数据绑定的字段名。
        /// 默认使用BindColumn特性中指定的字段名，如果没有指定，则使用属性名。
        /// </summary>
        public String ColumnName
        {
            get
            {
                if (_ColumnName != null) return _ColumnName;

                // 字段名可能两边带有方括号等标识符
                if (_Column != null && !String.IsNullOrEmpty(_Column.Name))
                    _ColumnName = _Column.Name.Trim(COLUMNNAME_FLAG);
                else
                    _ColumnName = _Property.Name;

                return _ColumnName;
            }
        }

        /// <summary>默认值</summary>
        public String DefaultValue { get { return _Column == null ? null : _Column.DefaultValue; } }

        private TableItem _Table;
        /// <summary>表</summary>
        public TableItem Table
        {
            get { return _Table; }
            //set { _Field = value; }
        }

        private IDataColumn _Field;
        /// <summary>字段</summary>
        public IDataColumn Field
        {
            get { return _Field; }
            //set { _Field = value; }
        }

        /// <summary>实体操作者</summary>
        public IEntityOperate Factory
        {
            get
            {
                Type type = Table.EntityType;
                if (type.IsInterface) return null;

                return EntityFactory.CreateOperate(type);
            }
        }
        #endregion

        #region 构造
        /// <summary>构造函数</summary>
        /// <param name="table"></param>
        /// <param name="property"></param>
        public FieldItem(TableItem table, PropertyInfo property)
        {
            if (property == null) throw new ArgumentNullException("property");

            _Table = table;

            _Property = property;
            _Column = BindColumnAttribute.GetCustomAttribute(_Property);
            _DataObjectField = DataObjectAttribute.GetCustomAttribute(_Property, typeof(DataObjectFieldAttribute)) as DataObjectFieldAttribute;
            _Description = DescriptionAttribute.GetCustomAttribute(_Property, typeof(DescriptionAttribute)) as DescriptionAttribute;
        }
        #endregion

        #region 方法
        /// <summary>已重载。</summary>
        /// <returns></returns>
        public override string ToString()
        {
            //if (String.IsNullOrEmpty(Description))
            //    return Name;
            //else
            //    return String.Format("{1}（{0}）", Name, Description);

            // 为了保持兼容旧的_.Name等代码，必须只能返回字段名
            return ColumnName;
        }

        /// <summary>填充到XField中去</summary>
        /// <param name="field"></param>
        public void Fill(IDataColumn field)
        {
            _Field = field;

            if (field == null) return;

            IDataColumn xf = field;
            if (xf == null) return;

            xf.Name = ColumnName;
            xf.Alias = Name;
            xf.DataType = _Property.PropertyType;
            xf.Description = Description;

            if (_Column != null)
            {
                xf.ID = _Column.Order;
                xf.RawType = _Column.RawType;
                xf.Precision = _Column.Precision;
                xf.Scale = _Column.Scale;
                xf.IsUnicode = _Column.IsUnicode;
                xf.Default = _Column.DefaultValue;

                // 特别处理，兼容旧版本
                if (xf.DataType == typeof(Decimal))
                {
                    if (xf.Precision == 0) xf.Precision = 18;
                }
            }
            if (_DataObjectField != null)
            {
                xf.Length = _DataObjectField.Length;
                xf.Identity = _DataObjectField.IsIdentity;
                xf.PrimaryKey = _DataObjectField.PrimaryKey;
                xf.Nullable = _DataObjectField.IsNullable;
            }
        }

        /// <summary>建立表达式</summary>
        /// <param name="action"></param>
        /// <param name="value"></param>
        /// <returns></returns>
        public WhereExpression CreateExpression(String action, Object value)
        {
            IEntityOperate op = Factory;
            String sql = null;
            String name = op.FormatName(ColumnName);
            if (!String.IsNullOrEmpty(action) && action.Contains("{0}"))
            {
                if (action.Contains("%"))
                    sql = name + " Like " + op.FormatValue(this, String.Format(action, value));
                else
                    sql = name + String.Format(action, op.FormatValue(this, value));
            }
            else
                sql = String.Format("{0}{1}{2}", name, action, op.FormatValue(this, value));
            return new WhereExpression(sql);
        }
        #endregion

        #region 重载运算符
        /// <summary>等于</summary>
        /// <param name="value"></param>
        /// <returns></returns>
        public WhereExpression Equal(object value) { return MakeCondition(this, value, "="); }

        /// <summary>不等于</summary>
        /// <param name="value"></param>
        /// <returns></returns>
        public WhereExpression NotEqual(object value) { return MakeCondition(this, value, "<>"); }

        //public static String operator ==(FieldItem field, Object value) { return MakeCondition(field, value, "=="); }
        //public static String operator !=(FieldItem field, Object value) { return MakeCondition(field, value, "<>"); }

        /// <summary>以某个字符串开始,{0}%操作</summary>
        /// <param name="value"></param>
        /// <returns></returns>
        public WhereExpression StartsWith(Object value) { return CreateExpression("{0}%", value); }

        /// <summary>以某个字符串结束，%{0}操作</summary>
        /// <param name="value"></param>
        /// <returns></returns>
        public WhereExpression EndsWith(Object value) { return CreateExpression("%{0}", value); }

        /// <summary>包含某个字符串，%{0}%操作</summary>
        /// <param name="value"></param>
        /// <returns></returns>
        public WhereExpression Contains(Object value) { return CreateExpression("%{0}%", value); }

        /// <summary>In操作</summary>
        /// <param name="value">逗号分割的数据</param>
        /// <returns></returns>
        public WhereExpression In(String value)
        {
            return new WhereExpression(String.Format("{0} In({1})", Factory.FormatName(ColumnName), value));
        }

        /// <summary>In操作</summary>
        /// <param name="value">枚举数据，会转化为字符串</param>
        /// <returns></returns>
        public WhereExpression In(IEnumerable value)
        {
            if (value == null) return new WhereExpression();

            IEntityOperate op = Factory;
            String name = op.FormatName(ColumnName);

            List<Object> vs = new List<Object>();
            List<String> list = new List<String>();
            foreach (Object item in value)
            {
                // 避免重复项
                if (vs.Contains(item)) continue;
                vs.Add(item);

                // 格式化数值
                String str = op.FormatValue(this, item);
                list.Add(str);
            }
            if (list.Count <= 0) return new WhereExpression();

            return new WhereExpression(String.Format("{0} In({1})", name, String.Join(",", list.ToArray())));
        }

        /// <summary>NotIn操作</summary>
        /// <param name="value"></param>
        /// <returns></returns>
        public WhereExpression NotIn(String value)
        {
            return new WhereExpression(String.Format("{0} Not In({1})", Factory.FormatName(ColumnName), value));
        }

        /// <summary>NotIn操作</summary>
        /// <param name="value"></param>
        /// <returns></returns>
        public WhereExpression NotIn(IEnumerable value)
        {
            if (value == null) return new WhereExpression();

            IEntityOperate op = Factory;
            String name = op.FormatName(ColumnName);

            List<Object> vs = new List<Object>();
            List<String> list = new List<String>();
            foreach (Object item in value)
            {
                // 避免重复项
                if (vs.Contains(item)) continue;
                vs.Add(item);

                // 格式化数值
                String str = op.FormatValue(this, item);
                list.Add(str);
            }
            if (list.Count <= 0) return new WhereExpression();

            return new WhereExpression(String.Format("{0} Not In({1})", name, String.Join(",", list.ToArray())));
        }

        /// <summary>IsNull操作，不为空，一般用于字符串，但不匹配0长度字符串</summary>
        /// <returns></returns>
        public WhereExpression IsNull()
        {
            return new WhereExpression(String.Format("{0} Is Null", Factory.FormatName(ColumnName)));
        }

        /// <summary>NotIn操作</summary>
        /// <returns></returns>
        public WhereExpression NotIsNull()
        {
            return new WhereExpression(String.Format("Not {0} Is Null", Factory.FormatName(ColumnName)));
        }

        /// <summary>IsNullOrEmpty操作，用于空或者0长度字符串</summary>
        /// <returns></returns>
        public WhereExpression IsNullOrEmpty()
        {
            return IsNull().Or(Equal(""));
        }

        /// <summary>NotIsNullOrEmpty操作</summary>
        /// <returns></returns>
        public WhereExpression NotIsNullOrEmpty()
        {
            return NotIsNull().And(NotEqual(""));
        }

        /// <summary>大于</summary>
        /// <param name="field"></param>
        /// <param name="value"></param>
        /// <returns></returns>
        public static WhereExpression operator >(FieldItem field, Object value) { return MakeCondition(field, value, ">"); }

        /// <summary>小于</summary>
        /// <param name="field"></param>
        /// <param name="value"></param>
        /// <returns></returns>
        public static WhereExpression operator <(FieldItem field, Object value) { return MakeCondition(field, value, "<"); }

        /// <summary>大于等于</summary>
        /// <param name="field"></param>
        /// <param name="value"></param>
        /// <returns></returns>
        public static WhereExpression operator >=(FieldItem field, Object value) { return MakeCondition(field, value, ">="); }

        /// <summary>小于等于</summary>
        /// <param name="field"></param>
        /// <param name="value"></param>
        /// <returns></returns>
        public static WhereExpression operator <=(FieldItem field, Object value) { return MakeCondition(field, value, "<="); }

        internal static WhereExpression MakeCondition(FieldItem field, Object value, String action)
        {
            //IEntityOperate op = EntityFactory.CreateOperate(field.Table.EntityType);
            //return new WhereExpression(String.Format("{0}{1}{2}", op.FormatName(field.ColumnName), action, op.FormatValue(field, value)));
            return field == null ? new WhereExpression() : field.CreateExpression(action, value);
        }
        #endregion

        #region 排序
        /// <summary>升序</summary>
        /// <returns></returns>
        public OrderExpression Asc() { return new OrderExpression(Factory.FormatName(Name)); }

        /// <summary>降序</summary>
        /// <remarks>感谢 树懒（303409914）发现这里的错误</remarks>
        /// <returns></returns>
        public OrderExpression Desc() { return new OrderExpression().Desc(Factory.FormatName(Name)); }
        #endregion

        #region 类型转换
        /// <summary>类型转换</summary>
        /// <param name="obj"></param>
        /// <returns></returns>
        public static implicit operator String(FieldItem obj)
        {
            return !obj.Equals(null) ? obj.ColumnName : null;
        }
        #endregion
    }

    /// <summary>继承FieldItem，仅仅为了重载==和!=运算符</summary>
    [EditorBrowsable(EditorBrowsableState.Never)]
    public class Field : FieldItem
    {
        #region 构造
        /// <summary>构造函数</summary>
        /// <param name="table"></param>
        /// <param name="property"></param>
        public Field(TableItem table, PropertyInfo property) : base(table, property) { }
        #endregion

        /// <summary>等于</summary>
        /// <param name="field"></param>
        /// <param name="value"></param>
        /// <returns></returns>
        public static WhereExpression operator ==(Field field, Object value) { return field.Equal(value); }

        /// <summary>不等于</summary>
        /// <param name="field"></param>
        /// <param name="value"></param>
        /// <returns></returns>
        public static WhereExpression operator !=(Field field, Object value) { return field.NotEqual(value); }

        /// <summary>重写一下</summary>
        /// <returns></returns>
        public override int GetHashCode() { return base.GetHashCode(); }

        /// <summary>重写一下</summary>
        /// <param name="obj"></param>
        /// <returns></returns>
        public override bool Equals(object obj) { return base.Equals(obj); }

        #region 类型转换
        /// <summary>类型转换</summary>
        /// <param name="obj"></param>
        /// <returns></returns>
        public static implicit operator String(Field obj)
        {
            return !obj.Equals(null) ? obj.ColumnName : null;
        }
        #endregion
    }
}