using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Expressions;
using xCommons.Extensions;
using xModels.Base;

namespace xDataService.Extensions {
    public static class EntityExtensions {
        /// <summary>
        /// return all values of an entity properties as a json string ...
        /// </summary>
        /// <param name="item"></param>
        /// <typeparam name="T"></typeparam>
        /// <returns></returns>
        public static string GetPropValues<T> (this T item)
        where T : XBaseEntity<T> {
            //
            var props = item.GetType ().GetProperties ();
            var vals = props.Select (p => p.GetValue (item));

            //
            return vals.ToJSON ();
        }

        /// <summary>
        /// check values of all properties of an Entity contains specific value or not ...
        /// </summary>
        /// <param name="item"></param>
        /// <param name="value"></param>
        /// <typeparam name="T"></typeparam>
        /// <returns></returns>
        public static bool PropValuesContains<T> (this T item, string value)
        where T : XBaseEntity<T> => item.GetPropValues ()
            .ToNormalString ()
            .Contains (value);

        /// <summary>
        /// Retrieve Default Column Map of specific Entity ...
        /// </summary>
        /// <param name="item"></param>
        /// <typeparam name="T"></typeparam>
        /// <returns></returns>
        public static IDictionary<string, Expression<Func<T, object>>> GetDefaultColumnsMap<T> (this T item)
        where T : XBaseEntity<T> {
            //
            if (item.IsNull ()) {
                return null;
            }

            //
            var result = new Dictionary<string, Expression<Func<T, object>>> ();
            var props = item.GetType ().GetProperties ();

            //
            foreach (var prop in props) {
                result.Add (
                    prop.Name,
                    t => t.GetType ().GetProperty (prop.Name).GetValue (t, null));
            }

            //
            return result;
        }

        /// <summary>
        /// Check a Type is XBaseEntity or not ...
        /// </summary>
        /// <param name="source"></param>
        /// <returns></returns>
        public static bool IsXEntity(this Type source)
        {
            //
            var result = !source.IsNull();
            if (!result)
            {
                return result;
            }

            //
            var baseType = source.BaseType;
            while(!baseType.IsNull() && baseType != typeof(object))
            {
                //
                if (baseType.IsGenericType &&
                    baseType.GetGenericTypeDefinition() == typeof(XBaseEntity<>))
                {
                    result = true;
                    break;
                }

                //
                baseType = baseType.BaseType;
            }

            //
            return result;
        }
    }
}