using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Linq.Expressions;

namespace xCommons.Extensions {
    public static partial class ModelExtensions {
        /// <summary>
        /// Update an Instance of a Typed Object with Data Provided by another Instance of Typed Object
        /// </summary>
        /// <param name="source"></param>
        /// <param name="updateWith"></param>
        /// <param name="propertyWhiteList"></param>
        /// <param name="propertyBlackList"></param>
        /// <param name="propertyValueProviders"></param>
        /// <param name="updateWithNullOrEmptyValues"></param>
        /// <param name="throwExceptionOnFails"></param>
        /// <typeparam name="T"></typeparam>
        /// <typeparam name="D"></typeparam>
        /// <returns></returns>
        public static T UpdateData<T, D> (
            this T source,
            D updateWith,
            ICollection<string> propertyWhiteList = null,
            ICollection<string> propertyBlackList = null,
            ICollection<KeyValuePair<string, Func<D, object>>> propertyValueProviders = null,
            bool updateWithNullOrEmptyValues = false,
            bool throwExceptionOnFails = false
        )
        where T : class
        where D : class {
            //
            var hasWhiteList = propertyWhiteList.HasChild<string> ();
            var hasBlackList = propertyBlackList.HasChild<string> ();
            var hasValueProvider = propertyValueProviders.HasChild<KeyValuePair<string, Func<D, object>>> ();

            //
            var fullPropertyList = updateWith.GetType ().GetProperties ().Select (prop => prop.Name);
            var mustSetProps = (hasWhiteList ? propertyWhiteList : fullPropertyList);

            //
            if (hasBlackList) {
                mustSetProps = mustSetProps.Where (propName => !propertyBlackList.Contains (propName));
            }

            //
            mustSetProps.ToList ().ForEach (propName => {
                //
                try {
                    //
                    var sourceProp = source.GetType ().GetProperty (propName);
                    var sourceValue = sourceProp.GetValue (source);
                    var sourceValueType = sourceValue.IsNull () ? null : sourceValue.GetType ();

                    //
                    var updateWithProp = updateWith.GetType ().GetProperty (propName);
                    var updateWithValue = updateWithProp.GetValue (updateWith);
                    var updateWithValueType = updateWithValue.IsNull () ? null : updateWithValue.GetType ();

                    //
                    var valueProviderValue = hasValueProvider ? propertyValueProviders
                        .FirstOrDefault (p => p.Key == propName).Value : null;
                    var updateVal = !valueProviderValue.IsNull () ?
                        valueProviderValue.Invoke (updateWith) :
                        (updateWithValue.IsNull () && !updateWithNullOrEmptyValues) ?
                        sourceValue : updateWithValue;
                    var updateValType = updateVal.IsNull () ? null : updateVal.GetType ();

                    //
                    Type t = Nullable.GetUnderlyingType (sourceProp.PropertyType) ?? sourceProp.PropertyType;
                    object safeValue =
                        (updateVal == null) ?
                        null :
                        !updateValType.IsCollectionType () ?
                        Convert.ChangeType (updateVal, t) :
                        updateVal;

                    //
                    sourceProp.SetValue (source, safeValue);
                } catch (Exception ex) {
                    //
                    if (throwExceptionOnFails) {
                        throw ex;
                    }
                }
            });

            //
            return source;
        }


        /// <summary>
        /// Check two Instance of Typed Object Values are Same or not
        /// </summary>
        /// <param name="source"></param>
        /// <param name="dest"></param>
        /// <param name="propertyWhiteList"></param>
        /// <param name="propertyBlackList"></param>
        /// <param name="throwExceptionOnFails"></param>
        /// <param name="propertyValueCheckers"></param>
        /// /// <typeparam name="T"></typeparam>
        /// <typeparam name="D"></typeparam>
        /// <returns></returns>
        public static bool IsSameContent<T, D> (
            this T source,
            D dest,
            ICollection<string> propertyWhiteList = null,
            ICollection<string> propertyBlackList = null,
            ICollection<KeyValuePair<string, Func<T, D, bool>>> propertyValueCheckers = null,
            bool throwExceptionOnFails = false
        )
        where T : class
        where D : class {
            //
            var hasWhiteList = propertyWhiteList.HasChild<string> ();
            var hasBlackList = propertyBlackList.HasChild<string> ();
            var hasCheckerProvider = propertyValueCheckers.HasChild<KeyValuePair<string, Func<T, D, bool>>> ();

            //
            var fullPropertyList = dest.GetType ().GetProperties ().Select (prop => prop.Name);
            var mustCheckProps = (hasWhiteList ? propertyWhiteList : fullPropertyList);
            if (hasBlackList) {
                mustCheckProps = mustCheckProps.Where (propName => !propertyBlackList.Contains (propName));
            }

            //
            var result = true;
            mustCheckProps.ToList ().ForEach (propName => {
                //
                try {
                    //
                    var sourceProp = source.GetType ().GetProperty (propName);
                    var destProp = dest.GetType ().GetProperty (propName);

                    //
                    // Check Types ...
                    var isSameType = true;

                    //
                    // Check
                    var isSameValue = false;
                    var mustDoCustomCheck = hasCheckerProvider && propertyValueCheckers.Any (p => p.Key == propName);
                    if (mustDoCustomCheck) {
                        //
                        // Check Values ...
                        var valueChecker = propertyValueCheckers.FirstOrDefault (p => p.Key == propName).Value;
                        isSameValue = valueChecker.Invoke (source, dest);
                    } else {
                        // //
                        // isSameType = (sourceProp.PropertyType == destProp.PropertyType &&
                        // sourceProp.ReflectedType == destProp.ReflectedType);

                        //
                        // Check Values ...
                        isSameValue = Equals (sourceProp.GetValue (source), destProp.GetValue (dest));
                    }

                    //
                    if (!isSameType || !isSameValue) {
                        result = false;
                    }
                } catch (Exception ex) {
                    //
                    if (throwExceptionOnFails) {
                        throw ex;
                    }
                }
            });

            //
            return result;
        }

        /// <summary>
        /// Check specific type is Collection Type or not
        /// </summary>
        /// <param name="source"></param>
        /// <returns></returns>
        public static bool IsCollectionType (this Type source) {
            //
            if (source.IsNull () || !source.IsGenericType) {
                return false;
            }

            //
            var genericTypeDefinition = source.GetGenericTypeDefinition ();
            var result = genericTypeDefinition == typeof (List<>) ||
                genericTypeDefinition == typeof (HashSet<>) ||
                genericTypeDefinition == typeof (Collection<>) ||
                genericTypeDefinition == typeof (ICollection<>) ||
                genericTypeDefinition == typeof (IEnumerable<>);

            //
            return result;
        }

        /// <summary>
        /// Retrieve a Property Value in Generic
        /// </summary>
        /// <param name="item"></param>
        /// <typeparam name="T"></typeparam>
        /// <returns></returns>
        public static string GetPropValues<T> (this T item)
        where T : class {
            //
            var props = item.GetType ().GetProperties ();
            var vals = props.Select (p => p.GetValue (item));

            //
            return vals.ToJSON ();
        }

        /// <summary>
        /// Check a Property Value Contains specific value
        /// </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 : class {
            //
            return item.GetPropValues ()
                .ToNormalString ()
                .Contains (value
                    .ToNormalString ());
        }

        /// <summary>
        /// Generate Default Column Map 
        /// </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 : class {
            //
            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>
        /// Generate Default Column Map 
        /// </summary>
        /// <param name="item"></param>
        /// <typeparam name="T"></typeparam>
        /// <returns></returns>
        public static IDictionary<string, string> GetPropValuesDictionary<T> (this T item)
        where T : class {
            //
            if (item.IsNull ()) {
                return null;
            }

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

            //
            foreach (var prop in props) {
                result.Add (prop.Name, prop.GetValue (item).ToJSON ());
            }

            //
            return result;
        }
    }
}