using AcDream.Runtime.Gameplay;

namespace AcDream.App.Net;

/// <summary>
/// C3c-F1 (2026-08-02): the App half of the movement-stats application
/// seam. Every server stat recompute (skills, burden, stamina, PK status —
/// the character-bindings <c>OnSkillsUpdated</c>/<c>OnMovementStatsUpdated</c>
/// callbacks) routes through
/// <see cref="RuntimeLocalPlayerMovementState.ApplyCharacterMovementStats"/>;
/// App holds no controller reference and performs no direct configuration
/// mutation. A recompute displaced past session teardown (the post-logout
/// inbound-Create ingest chain that crashed the connected lifecycle gate)
/// observes a typed dropped outcome and is logged under the existing
/// player diagnostics instead of faulting the session.
/// </summary>
/// <remarks>
/// Stuck-cast fix (2026-07-30): retail fires
/// <c>CPhysicsObj::report_exhaustion</c> from exactly ONE site —
/// <c>CommandInterpreter::HandleExhaustion</c> (0x006b3c70), a
/// notification-handler vtable slot invoked on the stamina-exhaustion
/// EVENT — not on every vitals refresh. The P1 wiring called
/// <c>ReportExhaustion()</c> on EVERY movement-stats application
/// (every stamina regen/drain tick), and each call re-dispatches the
/// current movement state through the animation sink — truncating any
/// in-flight action animation (cast gestures wedged mid-play; the
/// diagnostic session showed 490 spurious stance re-queues). The
/// re-apply fires only when the exhausted state (stamina == 0)
/// actually TRANSITIONS, matching retail's event semantics. Skill/
/// burden changes still reach <c>PlayerWeenie</c> immediately through
/// the owner seam — the next natural dispatch picks up the new rates,
/// exactly as retail. The edge is observed for dormant applications too
/// (the event fired; a player not yet in world has no movement to
/// re-dispatch, and activation starts movement from the already-current
/// stamina gate), but dispatched only on a live controller.
/// </remarks>
internal sealed class LiveMovementStatsApplier(
    RuntimeLocalPlayerMovementState movement,
    RuntimeMovementSkillState skills,
    Action<string> log)
{
    private readonly RuntimeLocalPlayerMovementState _movement = movement
        ?? throw new ArgumentNullException(nameof(movement));
    private readonly RuntimeMovementSkillState _skills = skills
        ?? throw new ArgumentNullException(nameof(skills));
    private readonly Action<string> _log = log
        ?? throw new ArgumentNullException(nameof(log));
    private readonly StaminaExhaustionEdgeTracker _staminaExhaustion = new();

    /// <summary>
    /// Forgets the retiring character/session exhaustion baseline; the next
    /// generation's first sample must not synthesize an edge.
    /// </summary>
    public void Reset() => _staminaExhaustion.Reset();

    public RuntimeMovementStatsApplication Apply(string reason)
    {
        RuntimeMovementStatsApplication outcome =
            _movement.ApplyCharacterMovementStats(_skills);
        switch (outcome)
        {
            case RuntimeMovementStatsApplication.DroppedNoController:
            case RuntimeMovementStatsApplication.DroppedIncompleteSnapshot:
                // Byte-identical to the pre-F1 ApplyTo=false silent skip.
                return outcome;
            case RuntimeMovementStatsApplication.DroppedDisplacedController:
                _log(
                    $"player: dropped displaced movement {reason} — the "
                    + "Runtime movement controller is terminal");
                return outcome;
        }

        RuntimeMovementSkillSnapshot snapshot = _skills.Snapshot;
        if (_staminaExhaustion.Observe(snapshot.CurrentStamina)
            && outcome is RuntimeMovementStatsApplication.AppliedLive)
        {
            _movement.ReportExhaustion();
        }

        _log(
            $"player: applied server movement {reason} "
            + $"run={snapshot.RunSkill} jump={snapshot.JumpSkill} "
            + $"burden={snapshot.Burden:F2} stamina={snapshot.CurrentStamina}");
        return outcome;
    }
}