using System;
using NightclubArcadia.Interaction;
using NightclubArcadia.UI;
using UnityEngine;
using UnityEngine.EventSystems;

namespace NightclubArcadia.Player
{
    /// <summary>
    /// Converts pointer clicks into click-to-move destinations or interactable
    /// approach targets.
    /// </summary>
    public sealed class PointerNavigationInput : MonoBehaviour
    {
        const float DoubleClickWindow = 0.35f;
        const float DoubleClickPixelThreshold = 40f;

        [SerializeField] Camera brainCamera;
        [SerializeField] LayerMask clickMask = ~0;
        [SerializeField] PlayerPointerInput pointerInput;
        [SerializeField] ClickToMoveController clickToMove;
        [SerializeField] PlayerMotionArbiter motionArbiter;

        float lastClickTime = -1f;
        Vector2 lastClickPosition;
        bool pendingClick;
        Vector2 pendingClickPosition;

        void Awake()
        {
            if (pointerInput == null)
            {
                pointerInput = GetComponent<PlayerPointerInput>();
            }

            if (clickToMove == null)
            {
                clickToMove = GetComponent<ClickToMoveController>();
            }

            if (motionArbiter == null)
            {
                motionArbiter = GetComponent<PlayerMotionArbiter>();
            }

            if (brainCamera == null)
            {
                brainCamera = Camera.main;
            }

            if (clickMask.value == ~0)
            {
                clickMask = LayerMask.GetMask("Default", "Ground", "Interactable");
            }
        }

        void OnEnable()
        {
            if (pointerInput != null)
            {
                pointerInput.Clicked += OnClicked;
            }
        }

        void OnDisable()
        {
            if (pointerInput != null)
            {
                pointerInput.Clicked -= OnClicked;
            }

            pendingClick = false;
        }

        // Input System callbacks fire during event processing, where
        // IsPointerOverGameObject() is invalid (queries last frame's UI).
        // Queue the click and resolve it in Update instead.
        void OnClicked()
        {
            if (pointerInput == null)
            {
                return;
            }

            pendingClick = true;
            pendingClickPosition = pointerInput.ScreenPosition;
        }

        void Update()
        {
            if (!pendingClick)
            {
                return;
            }

            pendingClick = false;
            ProcessClick(pendingClickPosition);
        }

        void ProcessClick(Vector2 screenPos)
        {
            if (!CanNavigate())
            {
                return;
            }

            if (EventSystem.current != null && EventSystem.current.IsPointerOverGameObject())
            {
                return;
            }

            if (brainCamera == null)
            {
                brainCamera = Camera.main;
            }

            if (brainCamera == null || clickToMove == null)
            {
                return;
            }

            var ray = brainCamera.ScreenPointToRay(screenPos);
            var hits = Physics.RaycastAll(ray, 200f, clickMask, QueryTriggerInteraction.Collide);
            Array.Sort(hits, (a, b) => a.distance.CompareTo(b.distance));

            var isDoubleClick = IsDoubleClick(screenPos);
            lastClickTime = Time.unscaledTime;
            lastClickPosition = screenPos;

            foreach (var hit in hits)
            {
                var interactable = FindInteractable(hit.collider);
                if (interactable != null)
                {
                    if (isDoubleClick)
                    {
                        clickToMove.RequestRun();
                    }

                    if (clickToMove.SetInteractionTarget(interactable))
                    {
                        return;
                    }
                }
            }

            foreach (var hit in hits)
            {
                if (isDoubleClick)
                {
                    clickToMove.RequestRun();
                }

                if (clickToMove.SetDestination(hit.point))
                {
                    return;
                }
            }
        }

        bool CanNavigate()
        {
            if (GetComponent<PlayerControlLock>() is { IsLocked: true })
            {
                return false;
            }

            if (UIStateController.Instance == null)
            {
                return true;
            }

            return !UIStateController.Instance.IsDialogueActive
                   && !UIStateController.Instance.IsMenuOpen;
        }

        bool IsDoubleClick(Vector2 screenPos)
        {
            if (lastClickTime < 0f)
            {
                return false;
            }

            var withinTime = Time.unscaledTime - lastClickTime <= DoubleClickWindow;
            var withinDistance = Vector2.Distance(screenPos, lastClickPosition) <= DoubleClickPixelThreshold;
            return withinTime && withinDistance;
        }

        static IClickInteractable FindInteractable(Collider collider)
        {
            var behaviours = collider.GetComponentsInParent<MonoBehaviour>();
            foreach (var behaviour in behaviours)
            {
                if (behaviour is IClickInteractable interactable)
                {
                    return interactable;
                }
            }

            return null;
        }
    }
}