using Unity.Entities;
using Unity.Mathematics;

namespace ProjectM.Simulation
{
    /// <summary>
    /// SERVER-ONLY transient knockback on a Husk. While <see cref="UntilTick"/> has not elapsed, EnemyAISystem
    /// moves the Husk along <see cref="Dir"/> at <see cref="Speed"/> (REPLACING its seek) and suppresses its strike.
    /// Stamped by ProjectileDamageSystem on a hit (Dir = the projectile's heading). NOT a [GhostField] — the Husk's
    /// displaced position already replicates via the stock LocalTransform default variant, so knockback adds NO
    /// replicated surface (no ghost re-bake). EnemyAISystem must remain the SOLE writer of the Husk's Position, so
    /// knockback is applied INSIDE it (never a competing system). Force/duration live in <see cref="Tuning"/>
    /// (KnockbackSpeed = 0 disables knockback globally).
    /// </summary>
    public struct KnockbackState : IComponentData
    {
        /// <summary>Planar (XZ) knockback heading — the projectile's direction at impact.</summary>
        public float2 Dir;

        /// <summary>Knockback speed (world units/sec) applied for the window; 0 = not knocked.</summary>
        public float Speed;

        /// <summary>Server tick until which the knockback is active (0 = none; scheduled via TickUtil.NonZero).</summary>
        public uint UntilTick;
    }
}