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

namespace xCommons.Extensions
{
    public static partial class ModelExtensions
    {
        /// <summary>
        /// Retrieve a Binding Flag for Retrieve all Instance Members including
        /// Priate and Public ...
        /// </summary>
        /// <returns></returns>
        public static BindingFlags GetDefaultBindingFlag()
        {
            return BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic;
        }

        /// <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 a Class is Contains a Property or not ...
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="source"></param>
        /// <param name="property"></param>
        /// <param name="bindingAttr"></param>
        /// <returns></returns>
        public static bool HasProperty<T>(
            this T source,
            string property,
            BindingFlags bindingAttr = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic
        )
        where T : class
        {
            //
            var result = source
                .GetType()
                .GetProperties(bindingAttr)
                .Any(prop => prop.Name == property); ;

            //
            return result;
        }

        /// <summary>
        /// Check a Class is Contains a field or not ...
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="source"></param>
        /// <param name="field"></param>
        /// <param name="bindingAttr"></param>
        /// <returns></returns>
        public static bool HasField<T>(
            this T source,
            string field,
            BindingFlags bindingAttr = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic
        )
        where T : class
        {
            //
            var result = source
                .GetType()
                .GetFields(bindingAttr)
                .Any(fld => fld.Name == field);

            //
            return result;
        }

        /// <summary>
        /// Check a Class is Contains a Method or not ...
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="source"></param>
        /// <param name="method"></param>
        /// <param name="bindingAttr"></param>
        /// <returns></returns>
        public static bool HasMethod<T>(
            this T source,
            string method,
            BindingFlags bindingAttr = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic
        )
        where T : class
        {
            //
            var result = source
                .GetType()
                .GetMethods(bindingAttr)
                .Any(mthd => mthd.Name == method);

            //
            return result;
        }

        /// <summary>
        /// Retrieve a Class Properties Names ...
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="source"></param>
        /// <param name="bindingAttr"></param>
        /// <returns></returns>
        public static string[] GetPropertiesNames<T>(
            this T source,
            BindingFlags bindingAttr = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic
        )
        {
            //
            var result = source
                .GetType()
                .GetProperties(bindingAttr)
                .Select(p => p.Name)
                .ToArray();

            //
            return result;
        }

        /// <summary>
        /// Retrieve a Class Fields Names ...
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="source"></param>
        /// <param name="bindingAttr"></param>
        /// <returns></returns>
        public static string[] GetFieldsNames<T>(
            this T source,
            BindingFlags bindingAttr = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic
        )
        {
            //
            var result = source
                .GetType()
                .GetFields(bindingAttr)
                .Select(p => p.Name)
                .ToArray();

            //
            return result;
        }

        /// <summary>
        /// Retrieve a Class Methods Names ...
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="source"></param>
        /// <param name="bindingAttr"></param>
        /// <returns></returns>
        public static string[] GetMethodsNames<T>(
            this T source,
            BindingFlags bindingAttr = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic
        )
        {
            //
            var result = source
                .GetType()
                .GetMethods(bindingAttr)
                .Select(p => p.Name)
                .ToArray();

            //
            return result;
        }

        /// <summary>
        /// Retrieve a Class Members Names ...
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="source"></param>
        /// <param name="bindingAttr"></param>
        /// <returns></returns>
        public static string[] GetMembersNames<T>(
            this T source,
            BindingFlags bindingAttr = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic
        )
        {
            //
            var result = source
                .GetType()
                .GetMembers(bindingAttr)
                .Select(p => p.Name)
                .ToArray();

            //
            return result;
        }

        /// <summary>
        /// Get a Class Property Value using Generic Concept ...
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <typeparam name="TProp"></typeparam>
        /// <param name="source"></param>
        /// <param name="property"></param>
        /// <param name="bindingAttr"></param>
        /// <returns></returns>
        public static TProp GetProperty<T, TProp>(
            this T source,
            string property,
            BindingFlags bindingAttr = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic
        )
        where T : class
        {
            //
            TProp result = default;

            //
            // Check if T Has Property ...
            if (source.HasProperty(property))
            {
                //
                // Access Property ...
                var prop = source
                    .GetType()
                    .GetProperty(
                        property, 
                        bindingAttr
                    );

                //
                // Retrieve Property Value as Object ...
                var propVal = prop.GetValue(source);

                //
                result = (TProp)propVal;
            }

            //
            return result;
        }

        /// <summary>
        /// Get a Class Field Value using Generic Concept ...
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <typeparam name="TField"></typeparam>
        /// <param name="source"></param>
        /// <param name="field"></param>
        /// <param name="bindingAttr"></param>
        /// <returns></returns>
        public static TField GetField<T, TField>(
            this T source,
            string field,
            BindingFlags bindingAttr = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic
        )
        where T : class
        {
            //
            TField result = default;

            //
            if (source.HasField(field))
            {
                //
                var fld = source
                    .GetType()
                    .GetField(
                        field,
                        bindingAttr
                    );

                //
                var fieldVal = fld.GetValue(source);
                result = (TField)fieldVal;
            }

            //
            return result;
        }

        /// <summary>
        /// Set a Class Property Value using Generic Concept ...
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <typeparam name="TProp"></typeparam>
        /// <param name="source"></param>
        /// <param name="property"></param>
        /// <param name="value"></param>
        /// <param name="bindingAttr"></param>
        /// <returns></returns>
        public static bool SetProperty<T, TProp>(
            this T source,
            string property,
            TProp value,
            BindingFlags bindingAttr = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic
        )
        where T : class
        {
            //
            // Check T Has Property ...
            var result = source.HasProperty(property);
            if (!result)
            {
                return result;
            }

            //
            // Access Property ...
            var prop = source
                .GetType()
                .GetProperty(
                    property,
                    bindingAttr
                );

            //
            // Set Property ...
            try
            {
                //
                result = true;
                prop.SetValue(source, value);
            }
            catch
            {
                result = false;
            }

            //
            return result;
        }

        /// <summary>
        /// Set a Class Field Value using Generic Concept ...
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <typeparam name="TField"></typeparam>
        /// <param name="source"></param>
        /// <param name="field"></param>
        /// <param name="value"></param>
        /// <param name="bindingAttr"></param>
        /// <returns></returns>
        public static bool SetField<T, TField>(
            this T source,
            string field,
            TField value,
            BindingFlags bindingAttr = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic
        )
        where T : class
        {
            //
            // Check T Has Field ...
            var result = source.HasField(field);
            if (!result)
            {
                return result;
            }

            //
            // Access Field ...
            var fld = source
                .GetType()
                .GetField(
                    field,
                    bindingAttr
                );

            //
            // Set Value ...
            try
            {
                //
                result = true;
                fld.SetValue(source, value);
            }
            catch
            {
                result = false;
            }

            //
            return result;
        }

        /// <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;
        }
    }
}