using System;

namespace Umbraco.Cms.Core.Scoping
{
    /// <summary>
    /// Represents a scope context.
    /// </summary>
    /// <remarks>A scope context can enlist objects that will be attached to the scope, and available
    /// for the duration of the scope. In addition, it can enlist actions, that will run when the
    /// scope is exiting, and after the database transaction has been committed.</remarks>
    public interface IScopeContext : IInstanceIdentifiable
    {
        /// <summary>
        /// Enlists an action.
        /// </summary>
        /// <param name="key">The action unique identifier.</param>
        /// <param name="action">The action.</param>
        /// <param name="priority">The optional action priority (default is 100, lower runs first).</param>
        /// <remarks>
        /// <para>It is ok to enlist multiple action with the same key but only the first one will run.</para>
        /// <para>The action boolean parameter indicates whether the scope completed or not.</para>
        /// </remarks>
        void Enlist(string key, Action<bool> action, int priority = 100);

        /// <summary>
        /// Enlists an object and action.
        /// </summary>
        /// <typeparam name="T">The type of the object.</typeparam>
        /// <param name="key">The object unique identifier.</param>
        /// <param name="creator">A function providing the object.</param>
        /// <param name="action">The optional action.</param>
        /// <param name="priority">The optional action priority (default is 100, lower runs first).</param>
        /// <returns>The object.</returns>
        /// <remarks>
        /// <para>On the first time an object is enlisted with a given key, the object is actually
        /// created. Next calls just return the existing object. It is ok to enlist multiple objects
        /// and action with the same key but only the first one is used, the others are ignored.</para>
        /// <para>The action boolean parameter indicates whether the scope completed or not.</para>
        /// </remarks>
        T? Enlist<T>(string key, Func<T> creator, Action<bool, T?>? action = null, int priority = 100);

        /// <summary>
        /// Gets an enlisted object.
        /// </summary>
        /// <typeparam name="T">The type of the object.</typeparam>
        /// <param name="key">The object unique identifier.</param>
        /// <returns>The enlisted object, if any, else the default value.</returns>
        T? GetEnlisted<T>(string key);

        void ScopeExit(bool completed);
    }
}
