using NightclubArcadia.UI;
using UnityEngine;

namespace NightclubArcadia.Cinematics
{
    public enum CameraState
    {
        Follow,
        ManualPan,
        PointOfInterest,
        Reveal,
        Dialogue,
        Menu
    }

    /// <summary>
    /// Resolves which camera subsystem may write each frame.
    /// </summary>
    public sealed class CameraStateDirector : MonoBehaviour
    {
        [SerializeField] CameraRigAnchor anchor;
        [SerializeField] float dialogueRecenterTime = 0.5f;

        int activeRevealCount;
        float dialogueRecenterTimer;
        bool wasDialogueActive;
        bool wasMenuOpen;

        public CameraState Current { get; private set; } = CameraState.Follow;

        public bool AllowsManualPan =>
            Current != CameraState.Dialogue
            && Current != CameraState.Menu
            && Current != CameraState.Reveal;

        public bool AllowsPointOfInterest =>
            Current == CameraState.Follow || Current == CameraState.PointOfInterest;

        void Awake()
        {
            if (anchor == null)
            {
                anchor = GetComponent<CameraRigAnchor>();
            }
        }

        void Start()
        {
            if (UIStateController.Instance != null)
            {
                UIStateController.Instance.StateChanged += OnUiStateChanged;
            }

            ResolveState(false);
        }

        void OnDestroy()
        {
            if (UIStateController.Instance != null)
            {
                UIStateController.Instance.StateChanged -= OnUiStateChanged;
            }
        }

        void Update()
        {
            ResolveState(true);

            if (Current == CameraState.Dialogue && anchor != null)
            {
                dialogueRecenterTimer += Time.deltaTime;
                var t = Mathf.Clamp01(dialogueRecenterTimer / dialogueRecenterTime);
                anchor.ManualPanOffset = Vector3.Lerp(anchor.ManualPanOffset, Vector3.zero, t);
            }
        }

        void OnUiStateChanged() => ResolveState(true);

        public void RegisterReveal() => activeRevealCount++;

        public void UnregisterReveal() => activeRevealCount = Mathf.Max(0, activeRevealCount - 1);

        void ResolveState(bool allowManualPanPromotion)
        {
            var ui = UIStateController.Instance;
            var menuOpen = ui != null && ui.IsMenuOpen;
            var dialogueActive = ui != null && ui.IsDialogueActive;

            if (menuOpen)
            {
                Current = CameraState.Menu;
            }
            else if (dialogueActive)
            {
                if (!wasDialogueActive)
                {
                    dialogueRecenterTimer = 0f;
                }

                Current = CameraState.Dialogue;
            }
            else if (activeRevealCount > 0)
            {
                Current = CameraState.Reveal;
            }
            else if (allowManualPanPromotion && IsManualPanActive())
            {
                Current = CameraState.ManualPan;
            }
            else if (HasActivePointOfInterest())
            {
                Current = CameraState.PointOfInterest;
            }
            else
            {
                Current = CameraState.Follow;
            }

            wasDialogueActive = dialogueActive;
            wasMenuOpen = menuOpen;
        }

        bool IsManualPanActive()
        {
            var pan = GetComponent<CameraPanInput>();
            return pan != null && pan.IsManualPanActive;
        }

        bool HasActivePointOfInterest()
        {
            var director = GetComponent<CameraPointOfInterestDirector>();
            return director != null && director.HasActivePoi;
        }
    }
}