Syntriax.Engine/Engine.Core/Extensions/UniverseObjectExtensions.cs

using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;

using Syntriax.Engine.Core.Exceptions;

namespace Syntriax.Engine.Core;

public static class UniverseObjectExtensions
{
    public static T SetUniverseObject<T>(this T universeObject, string? name = "", IUniverseObject? parent = null) where T : IUniverseObject
    {
        if (!string.IsNullOrWhiteSpace(name))
            universeObject.Name = name;
        if (parent is not null)
            universeObject.SetParent(parent);
        return universeObject;
    }

    #region Universe Object Search

    public static T? GetUniverseObject<T>(this IEnumerable<IUniverseObject> universeObjects) where T : class
    {
        foreach (IUniverseObject universeObject in universeObjects)
            if (universeObject is T @object)
                return @object;

        return default;
    }

    public static bool TryGetUniverseObject<T>(this IEnumerable<IUniverseObject> universeObjects, [NotNullWhen(returnValue: true)] out T? universeObject) where T : class
    {
        universeObject = GetUniverseObject<T>(universeObjects);
        return universeObject is not null;
    }

    public static void GetUniverseObjects<T>(this IEnumerable<IUniverseObject> universeObjects, IList<T> foundUniverseObjects) where T : class
    {
        foundUniverseObjects.Clear();

        foreach (IUniverseObject universeObject in universeObjects)
            if (universeObject is T @object)
                foundUniverseObjects.Add(@object);
    }

    #endregion

    #region Universe Object Search In Parent

    /// <summary>
    /// Tries to get a <see cref="IUniverseObject"/> of the specified type in it's parents recursively.
    /// </summary>
    /// <typeparam name="T">The type of <see cref="IUniverseObject"/> to get.</typeparam>
    /// <param name="behaviour">When this method returns, contains the <see cref="IUniverseObject"/> of the specified type, if found; otherwise, null.</param>
    /// <returns><see cref="true"/> if a <see cref="IUniverseObject"/> of the specified type was found in the parent universe objects; otherwise, <see cref="false"/>.</returns>
    public static bool TryGetUniverseObjectInParent<T>(this IUniverseObject universeObject, [NotNullWhen(returnValue: true)] out T? behaviour) where T : class
    {
        behaviour = GetUniverseObjectInParent<T>(universeObject);
        return behaviour is not null;
    }

    /// <summary>
    /// Gets a <see cref="IUniverseObject"/> of the specified type in it's parents recursively.
    /// </summary>
    /// <typeparam name="T">The type of <see cref="IUniverseObject"/> to get.</typeparam>
    /// <param name="universeObject">The <see cref="IUniverseObject"/> to start searching from.</param>
    /// <returns>The <see cref="IUniverseObject"/> of the specified type if found; otherwise, null.</returns>
    public static T? GetUniverseObjectInParent<T>(this IUniverseObject universeObject) where T : class
    {
        if (universeObject.GetUniverseObject<T>() is T localUniverseObject)
            return localUniverseObject;

        IUniverseObject? parent = universeObject;

        while (parent is not null)
        {
            if (parent is T behaviour)
                return behaviour;

            parent = universeObject.Parent;
        }

        return default;
    }

    /// <summary>
    /// Gets a <see cref="IUniverseObject"/> of the specified type in the parents recursively. Throws an error if not found.
    /// </summary>
    /// <typeparam name="T">The type of <see cref="IUniverseObject"/> to get.</typeparam>
    /// <param name="universeObject">The <see cref="IUniverseObject"/> to start searching from.</param>
    /// <returns>The <see cref="IUniverseObject"/> of the specified type if found; otherwise, throws <see cref="UniverseObjectNotFoundException"/>.</returns>
    public static T GetRequiredUniverseObjectInParent<T>(this IUniverseObject universeObject) where T : class
        => universeObject.GetUniverseObjectInParent<T>() ?? throw new UniverseObjectNotFoundException($"{universeObject.Name}'s {nameof(IUniverseObject)} does not contain any {typeof(T).FullName} on any parent ");

    #endregion

    #region Universe Object Search In Children
    /// <summary>
    /// Tries to get a <see cref="IUniverseObject"/> of the specified type in it's children recursively.
    /// </summary>
    /// <typeparam name="T">The type of <see cref="IUniverseObject"/> to get.</typeparam>
    /// <param name="behaviour">When this method returns, contains the <see cref="IUniverseObject"/> of the specified type, if found; otherwise, null.</param>
    /// <returns><see cref="true"/> if a <see cref="IUniverseObject"/> of the specified type was found in the child universe objects; otherwise, <see cref="false"/>.</returns>
    public static bool TryGetUniverseObjectInChildren<T>(this IUniverseObject universeObject, [NotNullWhen(returnValue: true)] out T? behaviour) where T : class
    {
        behaviour = GetUniverseObjectInChildren<T>(universeObject);
        return behaviour is not null;
    }

    /// <summary>
    /// Gets a <see cref="IUniverseObject"/> of the specified type in it's children recursively.
    /// </summary>
    /// <typeparam name="T">The type of <see cref="IUniverseObject"/> to get.</typeparam>
    /// <param name="universeObject">The <see cref="IUniverseObject"/> to start searching from.</param>
    /// <returns>The <see cref="IUniverseObject"/> of the specified type if found; otherwise, null.</returns>
    public static T? GetUniverseObjectInChildren<T>(this IUniverseObject universeObject) where T : class
    {
        if (universeObject.GetUniverseObject<T>() is T localUniverseObject)
            return localUniverseObject;

        foreach (IUniverseObject child in universeObject)
            if (GetUniverseObjectInChildren<T>(child) is T behaviour)
                return behaviour;

        return default;
    }

    /// <summary>
    /// Gets a <see cref="IUniverseObject"/> of the specified type in the children recursively. Throws an error if not found.
    /// </summary>
    /// <typeparam name="T">The type of <see cref="IUniverseObject"/> to get.</typeparam>
    /// <param name="universeObject">The <see cref="IUniverseObject"/> to start searching from.</param>
    /// <returns>The <see cref="IUniverseObject"/> of the specified type if found; otherwise, throws <see cref="UniverseObjectNotFoundException"/>.</returns>
    public static T GetRequiredUniverseObjectInChildren<T>(this IUniverseObject universeObject) where T : class
        => universeObject.GetUniverseObjectInChildren<T>() ?? throw new UniverseObjectNotFoundException($"{universeObject.Name}'s {nameof(IUniverseObject)} does not contain any {typeof(T).FullName} on any children ");
    #endregion

    #region Behaviour Search
    public static T? FindBehaviour<T>(this IEnumerable<IUniverseObject> universeObjects) where T : class
    {
        foreach (IUniverseObject universeObject in universeObjects)
            if (universeObject.BehaviourController.GetBehaviour<T>() is T behaviour)
                return behaviour;

        return default;
    }

    public static bool TryFindBehaviour<T>(this IEnumerable<IUniverseObject> universeObjects, [NotNullWhen(returnValue: true)] out T? behaviour) where T : class
    {
        behaviour = FindBehaviour<T>(universeObjects);
        return behaviour is not null;
    }

    public static void FindBehaviours<T>(this IEnumerable<IUniverseObject> universeObjects, IList<T> behaviours) where T : class
    {
        behaviours.Clear();
        List<T> cache = [];

        foreach (IUniverseObject universeObject in universeObjects)
        {
            universeObject.BehaviourController.GetBehaviours(cache);
            foreach (T behaviour in cache)
                behaviours.Add(behaviour);
        }
    }
    #endregion
}