using System;
using LanLib.UpdateManager.Jobs.Internal;
using UnityEngine;

namespace LanLib.UpdateManager.Jobs
{
    /// <summary>
    /// <see cref="MonoBehaviour"/> abstract class with automatic registration in <see cref="UpdateTransformJobManager{}"/>.
    /// </summary>
    /// <remarks>
    /// Instances will register themselves for job scheduling in the <c>OnEnable</c> message and unregister in the <c>OnDisable</c> message.
    /// </remarks>
    /// <seealso cref="UpdateTransformJobManager{}"/>
    public abstract class AJobBehaviour<TData> : MonoBehaviour, ITransformJobUpdatable<TData>
        where TData : struct, IUpdateTransformJob
    {
        /// <summary>
        /// Whether job data should be synchronized every frame.
        /// By default, returns false.
        /// </summary>
        /// <remarks>
        /// Override in subclasses implementing <see cref="IJobDataSynchronizer{}"/> and return true
        /// to automatically register objects for job data synchronization every frame.
        /// </remarks>
        public virtual bool SynchronizeJobDataEveryFrame => false;

        protected virtual void OnEnable()
        {
            this.RegisterInManager(SynchronizeJobDataEveryFrame);
        }

        protected virtual void OnDisable()
        {
            this.UnregisterInManager();
        }

        public Transform Transform => transform;

        /// <summary>
        /// Returns the job data for the first job run.
        /// </summary>
        /// <remarks>
        /// Override this in child classes to use data other than <see langword="default"/> in the first scheduled job run.
        /// </remarks>
        /// <seealso cref="ITransformJobUpdatable{}.InitialJobData"/>
        public virtual TData InitialJobData => default;

        /// <summary>
        /// Shortcut for <c>UpdateTransformJobManager&lt;TData&gt;.Instance.GetData(this)</c>.
        /// </summary>
        /// <seealso cref="UpdateTransformJobManager{}.GetData"/>
        public TData JobData => this.GetJobData();

#if UNITY_EDITOR
        /// <summary>
        /// Whether job data should be synchronized in the <c>OnValidate</c> message.
        /// By default, returns true.
        /// </summary>
        /// <remarks>
        /// Override in subclasses implementing <see cref="IJobDataSynchronizer{}"/> and return false
        /// to avoid automatic job data synchronization during <c>OnValidate</c>.
        /// </remarks>
        protected virtual bool SynchronizeJobDataOnValidate => true;

        /// <summary>
        /// Synchronizes job data on Play mode if <see cref="SynchronizeJobDataOnValidate"/> returns true.
        /// </summary>
        protected virtual void OnValidate()
        {
            if (Application.isPlaying && SynchronizeJobDataOnValidate)
            {
                this.SynchronizeJobDataOnce();
            }
        }
#endif
    }

    /// <summary>
    /// Alias for <see cref="AJobBehaviour{}"/>.
    /// </summary>
    /// <remarks>
    ///   Deprecated: use <see cref="AJobBehaviour{}"/> instead and implement
    ///   <see cref="IBurstUpdateTransformJob{}"/> in job definition to compile jobs with Burst.
    /// </remarks>
    [Obsolete("Use AJobBehaviour<> and implement IBurstUpdateTransformJob<> in job definition instead.")]
    public abstract class AJobBehaviour<TData, TJob> : AJobBehaviour<TData>
        where TData : struct, IUpdateTransformJob
        where TJob : struct, IInternalUpdateTransformJob<TData>
    {
    }
}