using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using JetBrains.Annotations;
using Kyoo.Models.Attributes;
namespace Kyoo
{
///
/// A class containing helper methods to merge objects.
///
public static class Merger
{
///
/// Merge two lists, can keep duplicates or remove them.
///
/// The first enumerable to merge
/// The second enumerable to merge, if items from this list are equals to one from the first, they are not kept
/// Equality function to compare items. If this is null, duplicated elements are kept
/// The two list merged as an array
public static T[] MergeLists(IEnumerable first,
IEnumerable second,
Func isEqual = null)
{
if (first == null)
return second.ToArray();
if (second == null)
return first.ToArray();
if (isEqual == null)
return first.Concat(second).ToArray();
List list = first.ToList();
return list.Concat(second.Where(x => !list.Any(y => isEqual(x, y)))).ToArray();
}
///
/// Set every fields of first to those of second. Ignore fields marked with the attribute
/// At the end, the OnMerge method of first will be called if first is a
///
/// The object to assign
/// The object containing new values
/// Fields of T will be used
///
public static T Assign(T first, T second)
{
Type type = typeof(T);
IEnumerable properties = type.GetProperties()
.Where(x => x.CanRead && x.CanWrite
&& Attribute.GetCustomAttribute(x, typeof(NotMergeableAttribute)) == null);
foreach (PropertyInfo property in properties)
{
object value = property.GetValue(second);
property.SetValue(first, value);
}
if (first is IOnMerge merge)
merge.OnMerge(second);
return first;
}
///
/// Set every default values of first to the value of second. ex: {id: 0, slug: "test"}, {id: 4, slug: "foo"} -> {id: 4, slug: "test"}.
/// At the end, the OnMerge method of first will be called if first is a
///
/// The object to complete
/// Missing fields of first will be completed by fields of this item. If second is null, the function no-op.
/// Filter fields that will be merged
/// Fields of T will be completed
///
/// If first is null
public static T Complete([NotNull] T first, [CanBeNull] T second, Func where = null)
{
if (first == null)
throw new ArgumentNullException(nameof(first));
if (second == null)
return first;
Type type = typeof(T);
IEnumerable properties = type.GetProperties()
.Where(x => x.CanRead && x.CanWrite
&& Attribute.GetCustomAttribute(x, typeof(NotMergeableAttribute)) == null);
if (where != null)
properties = properties.Where(where);
foreach (PropertyInfo property in properties)
{
object value = property.GetValue(second);
object defaultValue = property.PropertyType.IsValueType
? Activator.CreateInstance(property.PropertyType)
: null;
if (value?.Equals(defaultValue) == false && value != property.GetValue(first))
property.SetValue(first, value);
}
if (first is IOnMerge merge)
merge.OnMerge(second);
return first;
}
///
/// An advanced function.
/// This will set missing values of to the corresponding values of .
/// Enumerable will be merged (concatenated).
/// At the end, the OnMerge method of first will be called if first is a .
///
/// The object to complete
/// Missing fields of first will be completed by fields of this item. If second is null, the function no-op.
/// Fields of T will be merged
///
public static T Merge(T first, T second)
{
if (first == null)
return second;
if (second == null)
return first;
Type type = typeof(T);
IEnumerable properties = type.GetProperties()
.Where(x => x.CanRead && x.CanWrite
&& Attribute.GetCustomAttribute(x, typeof(NotMergeableAttribute)) == null);
foreach (PropertyInfo property in properties)
{
object oldValue = property.GetValue(first);
object newValue = property.GetValue(second);
object defaultValue = property.PropertyType.IsValueType
? Activator.CreateInstance(property.PropertyType)
: null;
if (oldValue?.Equals(defaultValue) != false)
property.SetValue(first, newValue);
else if (typeof(IEnumerable).IsAssignableFrom(property.PropertyType)
&& property.PropertyType != typeof(string))
{
Type enumerableType = Utility.GetGenericDefinition(property.PropertyType, typeof(IEnumerable<>))
.GenericTypeArguments
.First();
property.SetValue(first, Utility.RunGenericMethod