using System;
using System.Reflection;

namespace  YC.DapperFrameWork.Mapper
{
    /// <summary>
    /// Maps an entity property / field to its corresponding column in the database.
    /// </summary>
    public interface IMemberMap
    {
        string Name { get; }
        string ColumnName { get; }
        bool Ignored { get; }
        bool IsReadOnly { get; }
        KeyType KeyType { get; }
        MemberInfo MemberInfo { get; }
        object GetValue(object obj);
        void SetValue(object obj, object value);
        Type MemberType { get; }
    }

    /// <summary>
    /// Maps an entity property to its corresponding column in the database.
    /// </summary>
    public class MemberMap : IMemberMap
    {
        public MemberMap(PropertyInfo memberInfo)
        {
            MemberInfo = memberInfo;
            ColumnName = MemberInfo.Name;
        }

        public MemberMap(FieldInfo memberInfo)
        {
            MemberInfo = memberInfo;
            ColumnName = MemberInfo.Name;
        }

        /// <summary>
        /// Gets the name of the property by using the specified propertyInfo.
        /// </summary>
        public string Name
        {
            get { return MemberInfo.Name; }
        }

        /// <summary>
        /// Gets the column name for the current property.
        /// </summary>
        public string ColumnName { get; private set; }

        /// <summary>
        /// Gets the key type for the current property.
        /// </summary>
        public KeyType KeyType { get; private set; }

        /// <summary>
        /// Gets the ignore status of the current property. If ignored, the current property will not be included in queries.
        /// </summary>
        public bool Ignored { get; private set; }

        /// <summary>
        /// Gets the read-only status of the current property. If read-only, the current property will not be included in INSERT and UPDATE queries.
        /// </summary>
        public bool IsReadOnly { get; private set; }

        /// <summary>
        /// Gets the property info for the current property.
        /// </summary>
		public MemberInfo MemberInfo { get; private set; }

        /// <summary>
        /// Fluently sets the column name for the property.
        /// </summary>
        /// <param name="columnName">The column name as it exists in the database.</param>
        public MemberMap Column(string columnName)
        {
            ColumnName = columnName;
            return this;
        }

        /// <summary>
        /// Fluently sets the key type of the property.
        /// </summary>
        /// <param name="columnName">The column name as it exists in the database.</param>
        public MemberMap Key(KeyType keyType)
        {
            if (Ignored)
            {
                throw new ArgumentException(string.Format("'{0}' is ignored and cannot be made a key field. ", Name));
            }

            if (IsReadOnly)
            {
                throw new ArgumentException(string.Format("'{0}' is readonly and cannot be made a key field. ", Name));
            }

            KeyType = keyType;
            return this;
        }

        /// <summary>
        /// Fluently sets the ignore status of the property.
        /// </summary>
        public MemberMap Ignore()
        {
            if (KeyType != KeyType.NotAKey)
            {
                throw new ArgumentException(string.Format("'{0}' is a key field and cannot be ignored.", Name));
            }

            Ignored = true;
            return this;
        }

        /// <summary>
        /// Fluently sets the read-only status of the property.
        /// </summary>
        public MemberMap ReadOnly()
        {
            if (KeyType != KeyType.NotAKey)
            {
                throw new ArgumentException(string.Format("'{0}' is a key field and cannot be marked readonly.", Name));
            }

            IsReadOnly = true;
            return this;
        }

        public object GetValue(object obj)
        {
            if (MemberInfo is FieldInfo)
            {
                return ((FieldInfo)MemberInfo).GetValue(obj);
            }
            else
            {
                return ((PropertyInfo)MemberInfo).GetValue(obj, null);
            }
        }

        public void SetValue(object obj, object value)
        {
            if (MemberInfo is FieldInfo)
            {
                ((FieldInfo)MemberInfo).SetValue(obj, value);
            }
            else
            {
                ((PropertyInfo)MemberInfo).SetValue(obj, value, null);
            }
        }

        public Type MemberType
        {
            get
            {
                if (MemberInfo is FieldInfo)
                {
                    return ((FieldInfo)MemberInfo).FieldType;
                }
                else
                {
                    return ((PropertyInfo)MemberInfo).PropertyType;
                }
            }
        }
    }

    /// <summary>
    /// Used by ClassMapper to determine which entity property represents the key.
    /// </summary>
    public enum KeyType
    {
        /// <summary>
        /// The property is not a key and is not automatically managed.
        /// </summary>
        NotAKey,

        /// <summary>
        /// The property is an integery-based identity generated from the database.
        /// </summary>
        Identity,

        /// <summary>
        /// The property is an identity generated by the database trigger.
        /// </summary>
        TriggerIdentity,

        /// <summary>
        /// The property is a Guid identity which is automatically managed.
        /// </summary>
        Guid,

        /// <summary>
        /// The property is a key that is not automatically managed.
        /// </summary>
        Assigned
    }
}