using System;
using System.Collections.Generic;

namespace Umbraco.Cms.Core.Events
{
    /// <summary>
    /// Represent event data, for events that support cancellation, and expose an impacted object.
    /// </summary>
    /// <typeparam name="TEventObject">The type of the exposed, impacted object.</typeparam>
    public class CancellableObjectEventArgs<TEventObject> : CancellableObjectEventArgs, IEquatable<CancellableObjectEventArgs<TEventObject>>
    {
        public CancellableObjectEventArgs(TEventObject? eventObject, bool canCancel, EventMessages messages, IDictionary<string, object> additionalData)
            : base(eventObject, canCancel, messages, additionalData)
        {
        }

        public CancellableObjectEventArgs(TEventObject? eventObject, bool canCancel, EventMessages eventMessages)
            : base(eventObject, canCancel, eventMessages)
        {
        }

        public CancellableObjectEventArgs(TEventObject? eventObject, EventMessages eventMessages)
            : base(eventObject, eventMessages)
        {
        }

        public CancellableObjectEventArgs(TEventObject? eventObject, bool canCancel)
            : base(eventObject, canCancel)
        {
        }

        public CancellableObjectEventArgs(TEventObject? eventObject)
            : base(eventObject)
        {
        }

        /// <summary>
        /// Gets or sets the impacted object.
        /// </summary>
        /// <remarks>
        /// This is protected so that inheritors can expose it with their own name
        /// </remarks>
        protected new TEventObject? EventObject
        {
            get => (TEventObject?) base.EventObject;
            set => base.EventObject = value;
        }

        public bool Equals(CancellableObjectEventArgs<TEventObject>? other)
        {
            if (other is null) return false;
            if (ReferenceEquals(this, other)) return true;
            return base.Equals(other) && EqualityComparer<TEventObject>.Default.Equals(EventObject, other.EventObject);
        }

        public override bool Equals(object? obj)
        {
            if (obj is null) return false;
            if (ReferenceEquals(this, obj)) return true;
            if (obj.GetType() != this.GetType()) return false;
            return Equals((CancellableObjectEventArgs<TEventObject>)obj);
        }

        public override int GetHashCode()
        {
            unchecked
            {
                if (EventObject is not null)
                {
                    return (base.GetHashCode() * 397) ^ EqualityComparer<TEventObject>.Default.GetHashCode(EventObject);
                }

                return base.GetHashCode() * 397;
            }
        }

        public static bool operator ==(CancellableObjectEventArgs<TEventObject> left, CancellableObjectEventArgs<TEventObject> right)
        {
            return Equals(left, right);
        }

        public static bool operator !=(CancellableObjectEventArgs<TEventObject> left, CancellableObjectEventArgs<TEventObject> right)
        {
            return !Equals(left, right);
        }
    }
}