using UnityEngine;

namespace Ashwild.Player
{
    /// <summary>
    /// Drives a humanoid Animator from the local player's PlayerEvents bus so a visible rig
    /// reflects what the player is doing. It is a pure consumer of the bus — it never simulates
    /// anything itself — which lets the exact same component drive two independent rigs from one
    /// shared source of truth: the owner's first-person arms (seen only by the owner, never
    /// networked) and his third-person body (replicated to other players by a sibling FishNet
    /// NetworkAnimator). Because both rigs read the same events at the same frame, the arms the
    /// owner sees and the body everyone else sees stay in lockstep by construction.
    /// This is owner-only local simulation: add every instance to
    /// PlayerNetworkController.ownerOnlyBehaviours so remote puppets never run it — a remote body
    /// is animated by its replicated NetworkAnimator instead. Every parameter name is optional;
    /// leave a field blank to skip that parameter, so a minimal arms rig can ignore the full
    /// locomotion blend that the third-person body uses.
    /// </summary>
    [DisallowMultipleComponent]
    public class PlayerAnimatorDriver : MonoBehaviour
    {
        #region Serialized Fields

        [Header("Target")]
        [SerializeField] private Animator animator;
        [Tooltip("Transform whose facing defines local move direction. Defaults to the Animator's transform when left empty.")]
        [SerializeField] private Transform orientation;

        [Header("Float parameters (leave blank to skip)")]
        [SerializeField] private string speedParam = "Speed";
        [SerializeField] private string moveXParam = "MoveX";
        [SerializeField] private string moveYParam = "MoveY";
        [Tooltip("Planar speed (m/s) above which the player counts as moving rather than idle.")]
        [SerializeField] private float moveThreshold = 0.15f;
        [Tooltip("Damping applied to float parameters for smooth blends.")]
        [SerializeField] private float floatDampTime = 0.1f;

        [Header("Bool parameters (leave blank to skip)")]
        [SerializeField] private string groundedParam = "Grounded";
        [SerializeField] private string crouchingParam = "Crouching";
        [SerializeField] private string sprintingParam = "Sprinting";

        [Header("Int parameters (leave blank to skip)")]
        [Tooltip("Selects which swing variant the attack state plays — 1-based, matching the Attack1/Attack2… slots.")]
        [SerializeField] private string attackIndexParam = "AttackIndex";

        [Header("Trigger parameters (leave blank to skip)")]
        [SerializeField] private string jumpParam = "Jump";
        [SerializeField] private string attackParam = "Attack";
        [SerializeField] private string landParam = "Land";
        [SerializeField] private string grabParam = "Grab";
        [SerializeField] private string equipParam = "Equip";
        [SerializeField] private string unequipParam = "Unequip";

        #endregion

        #region Locomotion Levels

        /// <summary>
        /// The discrete gait the Speed parameter reports, and the thresholds the blend tree is built on.
        /// Deliberately not a measured velocity: a metre-per-second reading makes the animation hostage to
        /// movement tuning (retune sprintSpeed and every rig silently blends wrong), and it lies whenever
        /// the player's actual speed drops without his intent changing — pushing uphill, against a wall,
        /// through a slowing effect — where a sprint would visibly decay into a walk. Reporting intent
        /// instead keeps the gait stable, and the parameter damping still eases each change.
        /// </summary>
        private const float IdleLevel = 0f;
        private const float WalkLevel = 1f;
        private const float RunLevel = 2f;

        #endregion

        #region State

        private Vector3 planarVelocity;
        private bool isSprinting;

        private int speedId, moveXId, moveYId;
        private int groundedId, crouchingId, sprintingId;
        private int attackIndexId;
        private int jumpId, attackId, landId;
        private int grabId, equipId, unequipId;

        #endregion

        #region Unity Lifecycle

        /// <summary>
        /// Caches parameter hashes (0 for blank names, which are then skipped) and defaults the
        /// orientation reference so local move direction works without extra wiring.
        /// </summary>
        private void Awake()
        {
            speedId = Hash(speedParam);
            moveXId = Hash(moveXParam);
            moveYId = Hash(moveYParam);
            groundedId = Hash(groundedParam);
            crouchingId = Hash(crouchingParam);
            sprintingId = Hash(sprintingParam);
            attackIndexId = Hash(attackIndexParam);
            jumpId = Hash(jumpParam);
            attackId = Hash(attackParam);
            landId = Hash(landParam);
            grabId = Hash(grabParam);
            equipId = Hash(equipParam);
            unequipId = Hash(unequipParam);

            if (orientation == null && animator != null)
                orientation = animator.transform;
        }

        /// <summary>
        /// Subscribes to the locomotion/tool events that map onto animation, and seeds the bool
        /// parameters from the bus's current state so a freshly enabled rig starts in the right pose.
        /// </summary>
        private void OnEnable()
        {
            PlayerEvents.VelocityChanged += HandleVelocityChanged;
            PlayerEvents.GroundedChanged += HandleGroundedChanged;
            PlayerEvents.CrouchChanged += HandleCrouchChanged;
            PlayerEvents.SprintChanged += HandleSprintChanged;
            PlayerEvents.Jumped += HandleJumped;
            PlayerEvents.AttackSwung += HandleAttackSwung;
            PlayerEvents.LandingStunStarted += HandleLandingStunStarted;
            PlayerEvents.GrabPerformed += HandleGrabPerformed;
            PlayerEvents.EquipStarted += HandleEquipStarted;
            PlayerEvents.UnequipStarted += HandleUnequipStarted;

            isSprinting = PlayerEvents.IsSprinting;
            SetBool(groundedId, PlayerEvents.IsGrounded);
            SetBool(crouchingId, PlayerEvents.IsCrouching);
            SetBool(sprintingId, isSprinting);
        }

        /// <summary>
        /// Unsubscribes — mirrors OnEnable exactly.
        /// </summary>
        private void OnDisable()
        {
            PlayerEvents.VelocityChanged -= HandleVelocityChanged;
            PlayerEvents.GroundedChanged -= HandleGroundedChanged;
            PlayerEvents.CrouchChanged -= HandleCrouchChanged;
            PlayerEvents.SprintChanged -= HandleSprintChanged;
            PlayerEvents.Jumped -= HandleJumped;
            PlayerEvents.AttackSwung -= HandleAttackSwung;
            PlayerEvents.LandingStunStarted -= HandleLandingStunStarted;
            PlayerEvents.GrabPerformed -= HandleGrabPerformed;
            PlayerEvents.EquipStarted -= HandleEquipStarted;
            PlayerEvents.UnequipStarted -= HandleUnequipStarted;
        }

        /// <summary>
        /// Pushes the smoothed movement floats every frame. The gait itself is a step function, but the
        /// damping on the way to the Animator is what turns idle → walk → run into a blend instead of a
        /// snap, so the discrete parameter still reads as continuous motion.
        /// </summary>
        private void Update()
        {
            if (animator == null) return;

            float level = ComputeLocomotionLevel();
            SetFloat(speedId, level);

            if (moveXId != 0 || moveYId != 0)
            {
                Vector3 direction = planarVelocity.sqrMagnitude > 0.0001f ? planarVelocity.normalized : Vector3.zero;
                Vector3 local = orientation != null
                    ? orientation.InverseTransformDirection(direction)
                    : direction;
                SetFloat(moveXId, local.x * level);
                SetFloat(moveYId, local.z * level);
            }
        }

        #endregion

        #region Event Handlers

        /// <summary>
        /// Caches the planar (horizontal) velocity that Update turns into blend-tree floats.
        /// </summary>
        private void HandleVelocityChanged(Vector3 velocity)
        {
            planarVelocity = new Vector3(velocity.x, 0f, velocity.z);
        }

        private void HandleGroundedChanged(bool grounded, float impactSpeed) => SetBool(groundedId, grounded);
        private void HandleCrouchChanged(bool crouching) => SetBool(crouchingId, crouching);

        /// <summary>
        /// Caches the sprint intent as well as setting the bool, because the gait reported through Speed
        /// is chosen from the player's intent rather than from how fast he happens to be travelling.
        /// </summary>
        private void HandleSprintChanged(bool sprinting)
        {
            isSprinting = sprinting;
            SetBool(sprintingId, sprinting);
        }
        private void HandleJumped() => SetTrigger(jumpId);

        /// <summary>
        /// Selects the combo variant before firing the swing, so the attack state reads an index that is
        /// already correct on the frame it is entered. The parameter is 1-based to match the Attack1/
        /// Attack2… clip slots a designer sees in the controller.
        /// </summary>
        private void HandleAttackSwung(int variant)
        {
            SetInt(attackIndexId, variant + 1);
            SetTrigger(attackId);
        }

        /// <summary>
        /// A landing stun begins on a hard touchdown — the cue for a landing animation.
        /// </summary>
        private void HandleLandingStunStarted(float duration) => SetTrigger(landId);

        private void HandleGrabPerformed() => SetTrigger(grabId);
        private void HandleEquipStarted() => SetTrigger(equipId);
        private void HandleUnequipStarted() => SetTrigger(unequipId);

        #endregion

        #region Internal Helpers

        /// <summary>
        /// Picks the gait to report. Velocity is consulted only to answer "is he moving at all" — the
        /// distinction between walking and running comes from the sprint intent, never from a speed
        /// reading, so the two never disagree. Crouching is not a level of its own: it is a separate bool
        /// so a crouch tree can reuse the same idle/walk distinction underneath it.
        /// </summary>
        private float ComputeLocomotionLevel()
        {
            if (planarVelocity.magnitude < moveThreshold) return IdleLevel;
            return isSprinting ? RunLevel : WalkLevel;
        }

        /// <summary>
        /// Hashes a parameter name, returning 0 for a blank name so the setters can skip it.
        /// </summary>
        private int Hash(string paramName) => string.IsNullOrEmpty(paramName) ? 0 : Animator.StringToHash(paramName);

        private void SetFloat(int id, float value)
        {
            if (id != 0) animator.SetFloat(id, value, floatDampTime, Time.deltaTime);
        }

        private void SetBool(int id, bool value)
        {
            if (id != 0 && animator != null) animator.SetBool(id, value);
        }

        private void SetInt(int id, int value)
        {
            if (id != 0 && animator != null) animator.SetInteger(id, value);
        }

        private void SetTrigger(int id)
        {
            if (id != 0 && animator != null) animator.SetTrigger(id);
        }

        #endregion
    }
}