namespace jeanf.propertyDrawer
{
    using System;
    using System.Linq;
    using System.Reflection;
    using System.Collections;
    using System.Collections.Generic;
    public static class ReflectionUtil
    {
        private static Assembly[] _allAssemblies;
        public static Assembly[] AllAssemblies
        {
            get
            {
                if (_allAssemblies == null)
                {
                    _allAssemblies = AppDomain.CurrentDomain.GetAssemblies();
                }

                return _allAssemblies;
            }
        }

        public static IEnumerable<Type> GetAllTypesWithAttributeAsEnumerable(this Assembly assembly, Type attribute)
        {
            foreach (Type type in assembly.GetTypes())
            {
                if (type.GetCustomAttributes(attribute.GetType(), true).Length > 0)
                {
                    yield return type;
                }
            }
        }

        public static Type[] GetAllTypesWithAttribute(this Assembly assembly, Type attribute)
        {
            return assembly.GetAllTypesWithAttributeAsEnumerable(attribute).ToArray();
        }

        /// <summary>
        /// Finds the most nested object inside of an object.
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="obj"></param>
        /// <param name="path"></param>
        /// <returns></returns>
        public static T GetNestedObject<T>(this object obj, string path)
        {
            foreach (string part in path.Split('.'))
            {
                obj = obj.GetFieldOrProperty<T>(part);
            }
            return (T)obj;
        }

        #region Get Variable Methods

        /// <summary>
        /// Gets a property or a field of an object by a name.
        /// </summary>
        /// <typeparam name="T">Type of the field/property.</typeparam>
        /// <param name="obj">Object the field/property should be found in.</param>
        /// <param name="name">Name of the field/property.</param>
        /// <param name="bindingFlags">Filters for the field/property it can find. (optional)</param>
        /// <returns>The field/property.</returns>
        public static T GetFieldOrProperty<T>(this object obj, string name, BindingFlags bindingFlags = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic)
        {
            try
            {
                // Try getting the field. If the property wasn't found...
                return GetField<T>(obj, name, bindingFlags);
            }
            catch (FieldNotFoundException)
            {
                //...try getting the property. If that wasn't found as well, throw an exception
                try
                {
                    return GetProperty<T>(obj, name, bindingFlags);
                }
                catch (PropertyNotFoundException)
                {
                    throw new PropertyOrFieldNotFoundException("Couldn't find a filed nor a property with the name of '" + name + "' inside of the object '" + obj.GetType().Name + "'");
                }
            }

        }

        /// <summary>
        /// Gets a field inside of an object by a name.
        /// </summary>
        /// <typeparam name="T">Type of the field.</typeparam>
        /// <param name="obj">Object the field should be found in.</param>
        /// <param name="name">Name of the field.</param>
        /// <param name="bindingFlags">Filters for the fields it can find. (optional)</param>
        /// <returns>The field.</returns>
        public static T GetField<T>(this object obj, string name, BindingFlags bindingFlags = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic)
        {
            // Try getting the field and returning it.
            FieldInfo field = obj.GetType().GetField(name, bindingFlags);
            if (field != null)
                return (T)field.GetValue(obj);

            // If a field couldn't be found. Throw an exception about it.
            throw new FieldNotFoundException("Couldn't find a field with the name of '" + name + "' inside of the object '" + obj.GetType().Name + "'");
        }

        /// <summary>
        /// Gets a property inside of an object by a name.
        /// </summary>
        /// <typeparam name="T">Type of the property.</typeparam>
        /// <param name="obj">Object the property should be found in.</param>
        /// <param name="name">Name of the property.</param>
        /// <param name="bindingFlags">Filters for the properties it can find. (optional)</param>
        /// <returns>The property.</returns>
        public static T GetProperty<T>(this object obj, string name, BindingFlags bindingFlags = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic)
        {
            // Try getting the field and returning it.
            PropertyInfo property = obj.GetType().GetProperty(name, bindingFlags);
            if (property != null)
                return (T)property.GetValue(obj, null);

            // If a field couldn't be found. Throw an exception about it.
            throw new PropertyNotFoundException("Couldn't find a property with the name of '" + name + "' inside of the object '" + obj.GetType().Name + "'");
        }

        #endregion

        #region Set Variable Methods

        /// <summary>
        /// Sets a field or a property inside of an object by name.
        /// </summary>
        /// <typeparam name="T">Type of the field/property.</typeparam>
        /// <param name="obj">Object contaning the field/property.</param>
        /// <param name="name">Name of the field/property.</param>
        /// <param name="value">New value of the field/property.</param>
        /// <param name="bindingFlags">Filters for the field/property it can find. (optional)</param>
        public static void SetFieldOrProperty<T>(this object obj, string name, T value, BindingFlags bindingFlags = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic)
        {
            try
            {
                // Try getting the field. If the property wasn't found...
                SetField(obj, name, value, bindingFlags);
                return;
            }
            catch (FieldNotFoundException)
            {
                //...try getting the property. If that wasn't found as well, throw an exception
                try
                {
                    SetProperty(obj, name, value, bindingFlags);
                    return;
                }
                catch (PropertyNotFoundException)
                {
                    throw new PropertyOrFieldNotFoundException("Couldn't find a filed nor a property with the name of '" + name + "' inside of the object '" + obj.GetType().Name + "'");
                }
            }

        }

        /// <summary>
        /// Sets a field inside of an object by name.
        /// </summary>
        /// <typeparam name="T">Type of the field.</typeparam>
        /// <param name="obj">Object contaning the field.</param>
        /// <param name="name">Name of the field.</param>
        /// <param name="value">New value of the field.</param
        /// <param name="bindingFlags">Filters for the fields it can find. (optional)</param>>
        public static void SetField<T>(this object obj, string name, T value, BindingFlags bindingFlags = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic)
        {
            // Try getting the field and returning it.
            FieldInfo field = obj.GetType().GetField(name, bindingFlags);
            if (field != null)
            {
                field.SetValue(obj, value);
                return;
            }

            // If a field couldn't be found. Throw an exception about it.
            throw new FieldNotFoundException("Couldn't find a field with the name of '" + name + "' inside of the object '" + obj.GetType().Name + "'");
        }

        /// <summary>
        /// Sets a property inside of an object by name.
        /// </summary>
        /// <typeparam name="T">Type of the property.</typeparam>
        /// <param name="obj">Object contaning the property.</param>
        /// <param name="name">Name of the property.</param>
        /// <param name="value">New value of the property.</param>
        /// <param name="bindingFlags">Filters for the properties it can find. (optional)</param>
        public static void SetProperty<T>(this object obj, string name, T value, BindingFlags bindingFlags = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic)
        {
            // Try getting the field and returning it.
            PropertyInfo property = obj.GetType().GetProperty(name, bindingFlags);
            if (property != null)
            {
                property.SetValue(obj, value, null);
                return;
            }

            // If a field couldn't be found. Throw an exception about it.
            throw new PropertyNotFoundException("Couldn't find a property with the name of '" + name + "' inside of the object '" + obj.GetType().Name + "'");
        }

        #endregion

        #region Get All Variables Methods

        /// <summary>
        /// Gets all the properties and fields in obj of type T.
        /// </summary>
        /// <typeparam name="T">The type of the fields/properties.</typeparam>
        /// <param name="obj">Object to find the fields/properties in.</param>
        /// <param name="bindingFlags">Filters for the types of fields/properties that can be found.</param>
        /// <returns>The fields/properties found.</returns>
        public static IEnumerable<T> GetAllFieldsOrProperties<T>(this object obj, BindingFlags bindingFlags = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic)
        {
            // Get the fields and the properties in the object.
            T[] fields = obj.GetAllFields<T>(bindingFlags).ToArray();
            T[] properties = obj.GetAllProperties<T>(bindingFlags).ToArray();

            // Only return the fields if fields were found.
            if (fields != null && fields.Length != 0)
            {
                // Loop through the fields and return each one.
                for (int i = 0; i < fields.Length; i++)
                {
                    yield return fields[i];
                }
            }

            // Only return the properties if properties were found.
            if (properties != null && properties.Length != 0)
            {
                // Loop through the properties and return each one if they have the right type.
                for (int i = 0; i < properties.Length; i++)
                {
                    yield return properties[i];
                }
            }
        }

        /// <summary>
        /// Gets all the properties and fields in obj.
        /// </summary>
        /// <param name="obj">Object to find the fields/properties in.</param>
        /// <param name="bindingFlags">Filters for the types of fields/properties that can be found.</param>
        /// <returns>The fields/properties found.</returns>
        public static IEnumerable GetAllFieldsOrProperties(this object obj, BindingFlags bindingFlags = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic)
        {
            // Get the fields and the properties in the object.
            object[] fields = obj.GetAllFields(bindingFlags).Cast<object>().ToArray();
            object[] properties = obj.GetAllProperties(bindingFlags).Cast<object>().ToArray();

            // Only return the fields if fields were found.
            if (fields != null && fields.Length != 0)
            {
                // Loop through the fields and return each one.
                for (int i = 0; i < fields.Length; i++)
                {
                    yield return fields[i];
                }
            }

            // Only return the properties if properties were found.
            if (properties != null && properties.Length != 0)
            {
                // Loop through the properties and return each one if they have the right type.
                for (int i = 0; i < properties.Length; i++)
                {
                    yield return properties[i];
                }
            }
        }

        /// <summary>
        /// Gets all the fields in obj of type T.
        /// </summary>
        /// <typeparam name="T">Type of the fields allowed.</typeparam>
        /// <param name="obj">Object to find the fields in.</param>
        /// <param name="bindingFlags">Filters of the fields allowed.</param>
        /// <returns>The fields found.</returns>
        public static IEnumerable<T> GetAllFields<T>(this object obj, BindingFlags bindingFlags = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic)
        {
            // Get all the properties.
            FieldInfo[] fields = obj.GetType().GetFields(bindingFlags);

            // If there are no properties, break.
            if (fields == null || fields.Length == 0)
                yield break;

            // If there are properties in the array, return each element.
            for (int i = 0; i < fields.Length; i++)
            {
                object currentValue = fields[i].GetValue(obj);

                if (currentValue.GetType() == typeof(T))
                    yield return (T)currentValue;
            }
        }

        /// <summary>
        /// Gets all the fields in obj.
        /// </summary>
        /// <param name="obj">Object to find the fields in.</param>
        /// <param name="bindingFlags">Filters of the fields allowed.</param>
        /// <returns>The fields found.</returns>
        public static IEnumerable GetAllFields(this object obj, BindingFlags bindingFlags = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic)
        {
            // Get all the properties.
            FieldInfo[] fields = obj.GetType().GetFields(bindingFlags);

            // If there are no properties, break.
            if (fields == null || fields.Length == 0)
                yield break;

            // If there are properties in the array, return each element.
            for (int i = 0; i < fields.Length; i++)
            {
                yield return fields[i].GetValue(obj);
            }
        }

        /// <summary>
        /// Gets all the properties in obj of type T.
        /// </summary>
        /// <typeparam name="T">Type of the properties allowed.</typeparam>
        /// <param name="obj">Object to find the properties in.</param>
        /// <param name="bindingFlags">Filters of the properties allowed.</param>
        /// <returns>The properties found.</returns>
        public static IEnumerable<T> GetAllProperties<T>(this object obj, BindingFlags bindingFlags = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic)
        {
            // Get all the properties.
            PropertyInfo[] properties = obj.GetType().GetProperties(bindingFlags);

            // If there are no properties, break.
            if (properties == null || properties.Length == 0)
                yield break;

            // If there are properties in the array, return each element.
            for (int i = 0; i < properties.Length; i++)
            {
                object currentValue = properties[i].GetValue(obj, null);

                if (currentValue.GetType() == typeof(T))
                    yield return (T)currentValue;
            }
        }

        /// <summary>
        /// Gets all the properties in obj.
        /// </summary>
        /// <param name="obj">Object to find the properties in.</param>
        /// <param name="bindingFlags">Filters of the properties allowed.</param>
        /// <returns>The properties found.</returns>
        public static IEnumerable GetAllProperties(this object obj, BindingFlags bindingFlags = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic)
        {
            // Get all the properties.
            PropertyInfo[] properties = obj.GetType().GetProperties(bindingFlags);

            // If there are no properties, break.
            if (properties == null || properties.Length == 0)
                yield break;

            // If there are properties in the array, return each element.
            for (int i = 0; i < properties.Length; i++)
            {
                yield return properties[i].GetValue(obj, null);
            }
        }

        #endregion

    }

}