using Unity.Entities;
using Unity.NetCode;

namespace ProjectM.Simulation
{
    /// <summary>
    /// Phase 1.7 mechanic-changer boon state on a player — the run-scoped counterpart to the flat-stat
    /// <see cref="StatModifier"/> band. Stackable counts (<see cref="Pierce"/>/<see cref="Fork"/>/<see cref="Chain"/>)
    /// and boolean <see cref="Flags"/> (see <see cref="BoonFlag"/>) that combat systems read to alter behaviour.
    /// <para>
    /// Replicated <see cref="SendToOwnerType.SendToOwner"/> (matching <c>BoonOffer</c>): rollback-correctness is
    /// provided by the <c>[GhostField]</c>s themselves — the owner is the sole predicting client and needs the
    /// replicated Fork/Pierce/Chain so its OWN predict-spawned projectiles (in <c>AbilityFireSystem</c>, which
    /// filters <c>.WithAll&lt;Simulate&gt;()</c>) don't mispredict. Non-owning clients render forked/pierced/chained
    /// projectiles as interpolated server ghosts and never read the shooter's effects; every other read is
    /// server-only. NOT <see cref="SendToOwnerType.All"/> — the send type is not what enables rollback, the
    /// <c>[GhostField]</c> is.
    /// </para>
    /// Baked INERT (all 0) on the player prefab (the <c>BoonOffer</c> idiom) so a pick is a non-structural mutate;
    /// zeroed on the Returning edge in <c>RunDirectorSystem</c> alongside the StatModifier band strips.
    /// </summary>
    [GhostComponent(OwnerSendType = SendToOwnerType.SendToOwner)]
    public struct BoonEffects : IComponentData
    {
        /// <summary>Extra enemy hits a projectile survives before despawning (stacks).</summary>
        [GhostField] public byte Pierce;
        /// <summary>Extra spread projectiles spawned per shot (stacks).</summary>
        [GhostField] public byte Fork;
        /// <summary>Targets a projectile chains to after a hit (stacks).</summary>
        [GhostField] public byte Chain;
        /// <summary>Boolean effect bits — see <see cref="BoonFlag"/>.</summary>
        [GhostField] public byte Flags;
    }

    /// <summary>Bit masks for <see cref="BoonEffects.Flags"/>. Plain byte consts (never an enum compared in Burst).</summary>
    public static class BoonFlag
    {
        public const byte DashTrail = 1;        // dashing damages enemies passed through
        public const byte FinisherDetonate = 2; // the melee combo finisher blasts an AoE
        public const byte KnockToPull = 4;      // this player's knockback pulls enemies IN instead of away
        public const byte Siphon = 8;           // killing an enemy heals this player
        public const byte Frenzy = 16;          // a kill grants a short cooldown-reduction surge
    }

    /// <summary>
    /// Stable byte discriminator for a <c>BoonDefBlob</c> mechanic-changer effect (0 = a plain stat boon).
    /// Bytes only — Burst-safe, never an enum compared inside a Bursted system.
    /// </summary>
    public static class BoonEffectKind
    {
        public const byte None = 0;
        public const byte Pierce = 1;
        public const byte Fork = 2;
        public const byte Chain = 3;
        public const byte DashTrail = 4;
        public const byte FinisherDetonate = 5;
        public const byte KnockToPull = 6;
        public const byte Siphon = 7;
        public const byte Frenzy = 8;
    }
}