using UnityEngine;

namespace Unheimlich.Features.Player
{
    /// <summary>
    /// Manages the player's stress level and forwards it to <see cref="Unheimlich.World.CameraSystem.LostFootageRig"/>.
    /// Stress rises instantly to the requested target and decays back to zero over time when not sustained.
    ///
    /// Intended to sit on <c>OctoPlayerFP</c> alongside other player-level components.
    /// Call <see cref="AddStress"/>, <see cref="SetStress"/>, or <see cref="CalmDown"/> from
    /// gameplay systems (proximity triggers, jump-scares, scripted events, etc.).
    /// </summary>
    public class StressController : MonoBehaviour
    {
        // ── Inspector ─────────────────────────────────────────────────────────────

        [Header("References")]
        [Tooltip("The LostFootageRig component on CameraPivot.")]
        [SerializeField] private Unheimlich.World.CameraSystem.LostFootageRig _rig;

        [Header("Decay")]
        [Tooltip("Rate at which stress falls back to zero per second when not sustained.")]
        [SerializeField] private float _decaySpeed = 0.3f;

        [Tooltip("Stress must stay below this threshold for the rig to auto-deactivate.")]
        [SerializeField] private float _deactivateThreshold = 0.05f;

        [Header("Debug")]
        [SerializeField] private bool _debugSustainStress;
        [SerializeField] [Range(0f, 1f)] private float _debugStressValue;

        // ── Runtime state ─────────────────────────────────────────────────────────

        private float _currentStress;
        private float _targetStress;
        private bool  _sustained;   // true while an external system holds a target this frame

        // ── Unity lifecycle ───────────────────────────────────────────────────────

        private void Update()
        {
            if (_debugSustainStress)
                SetStress(_debugStressValue);
                
            _sustained = false;

            if (_currentStress > _targetStress)
                _currentStress = Mathf.MoveTowards(_currentStress, _targetStress, _decaySpeed * Time.deltaTime);
            else
                _currentStress = _targetStress;

            _targetStress = 0f; // reset each frame; callers must re-assert every Update if sustained

            if (_rig == null)
                return;

            _rig.StressLevel = _currentStress;

            // Auto-toggle the rig based on stress level.
            if (!_rig.IsActive && _currentStress > _deactivateThreshold)
                _rig.SetActive(true);
            else if (_rig.IsActive && _currentStress <= _deactivateThreshold)
                _rig.SetActive(false);
        }

        // ── Public API ────────────────────────────────────────────────────────────

        /// <summary>
        /// Sets a one-shot stress spike that will decay naturally next frame.
        /// For sustained stress, call this every frame from a trigger zone or event.
        /// </summary>
        public void SetStress(float value)
        {
            _targetStress = Mathf.Max(_targetStress, Mathf.Clamp01(value));
            _currentStress = Mathf.Max(_currentStress, _targetStress);
        }

        /// <summary>Adds <paramref name="delta"/> on top of the current target stress.</summary>
        public void AddStress(float delta) => SetStress(_targetStress + delta);

        /// <summary>Immediately zeroes stress and deactivates the rig.</summary>
        public void CalmDown()
        {
            _currentStress = 0f;
            _targetStress  = 0f;
            _rig?.SetActive(false);
        }

        /// <summary>
        /// Directly activates or deactivates the rig regardless of stress level.
        /// Useful for scripted sequences where you want the effect without the stress system.
        /// </summary>
        public void ForceRig(bool active) => _rig?.SetActive(active);
    }
}