Umbraco-CMS/src/Umbraco.Abstractions/Composing/SetCollectionBuilderBase.cs

using System;
using System.Collections.Generic;

namespace Umbraco.Core.Composing
{
    /// <summary>
    /// Implements an un-ordered collection builder.
    /// </summary>
    /// <typeparam name="TBuilder">The type of the builder.</typeparam>
    /// <typeparam name="TCollection">The type of the collection.</typeparam>
    /// <typeparam name="TItem">The type of the items.</typeparam>
    /// <remarks>
    /// <para>A set collection builder is the most basic collection builder,
    /// where items are not ordered.</para>
    /// </remarks>
    public abstract class SetCollectionBuilderBase<TBuilder, TCollection, TItem> : CollectionBuilderBase<TBuilder, TCollection, TItem>
        where TBuilder : SetCollectionBuilderBase<TBuilder, TCollection, TItem>
        where TCollection : class, IBuilderCollection<TItem>
    {
        protected abstract TBuilder This { get; }

        /// <summary>
        /// Clears all types in the collection.
        /// </summary>
        /// <returns>The builder.</returns>
        public TBuilder Clear()
        {
            Configure(types => types.Clear());
            return This;
        }

        /// <summary>
        /// Adds a type to the collection.
        /// </summary>
        /// <typeparam name="T">The type to append.</typeparam>
        /// <returns>The builder.</returns>
        public TBuilder Add<T>()
            where T : TItem
        {
            Configure(types =>
            {
                var type = typeof(T);
                if (types.Contains(type)) types.Remove(type);
                types.Add(type);
            });
            return This;
        }

        /// <summary>
        /// Adds a type to the collection.
        /// </summary>
        /// <param name="type">The type to append.</param>
        /// <returns>The builder.</returns>
        public TBuilder Add(Type type)
        {
            Configure(types =>
            {
                EnsureType(type, "register");
                if (types.Contains(type)) types.Remove(type);
                types.Add(type);
            });
            return This;
        }

        /// <summary>
        ///  Adds types to the collections.
        /// </summary>
        /// <param name="types">The types to append.</param>
        /// <returns>The builder.</returns>
        public TBuilder Add(IEnumerable<Type> types)
        {
            Configure(list =>
            {
                foreach (var type in types)
                {
                    // would be detected by CollectionBuilderBase when registering, anyways, but let's fail fast
                    EnsureType(type, "register");
                    if (list.Contains(type)) list.Remove(type);
                    list.Add(type);
                }
            });
            return This;
        }

        /// <summary>
        /// Removes a type from the collection.
        /// </summary>
        /// <typeparam name="T">The type to remove.</typeparam>
        /// <returns>The builder.</returns>
        public TBuilder Remove<T>()
            where T : TItem
        {
            Configure(types =>
            {
                var type = typeof(T);
                if (types.Contains(type)) types.Remove(type);
            });
            return This;
        }

        /// <summary>
        /// Removes a type from the collection.
        /// </summary>
        /// <param name="type">The type to remove.</param>
        /// <returns>The builder.</returns>
        public TBuilder Remove(Type type)
        {
            Configure(types =>
            {
                EnsureType(type, "remove");
                if (types.Contains(type)) types.Remove(type);
            });
            return This;
        }

        /// <summary>
        /// Replaces a type in the collection.
        /// </summary>
        /// <typeparam name="TReplaced">The type to replace.</typeparam>
        /// <typeparam name="T">The type to insert.</typeparam>
        /// <returns>The builder.</returns>
        /// <remarks>Throws if the type to replace does not already belong to the collection.</remarks>
        public TBuilder Replace<TReplaced, T>()
            where TReplaced : TItem
            where T : TItem
        {
            Configure(types =>
            {
                var typeReplaced = typeof(TReplaced);
                var type = typeof(T);
                if (typeReplaced == type) return;

                var index = types.IndexOf(typeReplaced);
                if (index < 0) throw new InvalidOperationException();

                if (types.Contains(type)) types.Remove(type);
                index = types.IndexOf(typeReplaced); // in case removing type changed index
                types.Insert(index, type);
                types.Remove(typeReplaced);
            });
            return This;
        }

        /// <summary>
        /// Replaces a type in the collection.
        /// </summary>
        /// <param name="typeReplaced">The type to replace.</param>
        /// <param name="type">The type to insert.</param>
        /// <returns>The builder.</returns>
        /// <remarks>Throws if the type to replace does not already belong to the collection.</remarks>
        public TBuilder Replace(Type typeReplaced, Type type)
        {
            Configure(types =>
            {
                EnsureType(typeReplaced, "find");
                EnsureType(type, "register");

                if (typeReplaced == type) return;

                var index = types.IndexOf(typeReplaced);
                if (index < 0) throw new InvalidOperationException();

                if (types.Contains(type)) types.Remove(type);
                index = types.IndexOf(typeReplaced); // in case removing type changed index
                types.Insert(index, type);
                types.Remove(typeReplaced);
            });
            return This;
        }
    }
}