using NightclubArcadia.Core;
using NightclubArcadia.Dialogue;
using NightclubArcadia.UI;
using UnityEngine;
using UnityEngine.InputSystem;
using Yarn.Unity;

namespace NightclubArcadia.Interaction
{
    /// <summary>
    /// Anything the player can walk up to and talk to: a character, or an object with
    /// something to say.
    ///
    /// Replaces NPCStandIn, which was written to be dropped on a sphere primitive and
    /// carried its identity in per-instance public fields. Two objects could claim the
    /// same character and disagree, and in practice did — the scene's second "Bartender"
    /// was the chair, renamed in the data but not in the hierarchy.
    ///
    /// Identity now comes from an InteractableDefinition asset, so a prefab is the thing
    /// and the scene only places it. Also replaces DialogueInteractable, a trigger-zone
    /// variant of the same idea that was in no scene at all.
    /// </summary>
    [RequireComponent(typeof(SphereCollider))]
    public sealed class DialogueInteractor : MonoBehaviour, IClickInteractable
    {
        [Header("Identity")]
        [SerializeField] InteractableDefinition definition;

        [Header("Presentation (optional)")]
        [SerializeField] WorldSpaceLabel label;
        [SerializeField] InteractionPrompt prompt;

        [Header("Overrides")]
        [Tooltip("Leave empty to use the Canvas under the DialogueRunner.")]
        [SerializeField] GameObject dialogueUI;

        DialogueRunner runner;
        Transform player;
        InputAction interact;
        bool playerInRange;

        public Transform ApproachPoint => transform;

        public float ApproachRadius =>
            definition != null ? Mathf.Max(0.15f, definition.InteractionRange - 0.5f) : 0.15f;

        /// <summary>
        /// The dialogue runner, resolved on demand and cached only on success.
        ///
        /// Never resolved once in Awake: the runner lives in the Systems scene and this
        /// object lives in a level, so it can wake up before the runner exists. Caching a
        /// failure there left NPCs permanently mute for the session. See SceneOrderTests.
        /// </summary>
        public DialogueRunner ResolvedRunner =>
            runner != null ? runner : runner = SceneServices.TryResolve<DialogueRunner>(null);

        Transform Player =>
            player != null ? player : player = SceneServices.Player;

        void Awake()
        {
            if (definition == null)
            {
                Debug.LogError($"[Interactor] {name} has no InteractableDefinition; it will do nothing.", this);
                enabled = false;
                return;
            }

            GetComponent<SphereCollider>().isTrigger = false;

            if (label != null)
            {
                label.gameObject.SetActive(definition.ShowLabel);
                label.SetText(definition.DisplayName);
            }

            prompt?.SetShown(false);

            interact = new InputAction("Interact");
            interact.AddBinding("<Keyboard>/f");
            interact.AddBinding("<Gamepad>/buttonSouth");
            interact.performed += _ =>
            {
                if (playerInRange)
                {
                    Interact();
                }
            };
        }

        void OnEnable() => interact?.Enable();

        void OnDisable() => interact?.Disable();

        void Update()
        {
            var target = Player;
            if (target == null)
            {
                return;
            }

            var inRange = Vector3.Distance(transform.position, target.position) <= definition.InteractionRange;
            if (inRange == playerInRange)
            {
                return;
            }

            playerInRange = inRange;
            prompt?.SetShown(inRange);
        }

        /// <summary>Entry point for both the proximity keypress and click-to-move arrival.</summary>
        public void Interact()
        {
            var dialogue = ResolvedRunner;
            if (dialogue == null)
            {
                Debug.LogError(
                    $"[Interactor] {definition.DisplayName}: no DialogueRunner in any loaded scene. " +
                    "It lives in Systems.unity — open Bootstrap, or Tools → Nightclub Arcadia → " +
                    "Open Game Scenes.", this);
                return;
            }

            if (UIStateController.Instance != null && UIStateController.Instance.IsMenuOpen)
            {
                return;
            }

            if (!dialogue.IsDialogueRunning)
            {
                StartDialogueAsync(dialogue);
            }
        }

        public void OnApproached() => Interact();

        async void StartDialogueAsync(DialogueRunner dialogue)
        {
            // The dialogue UI is hidden when the player leaves a conversation via
            // <<enter_environment>>. Make it visible again before the first line renders.
            if (DialogueUIVisibility.Show(ResolveDialogueUI(dialogue)))
            {
                // Only reached if the UI was found deactivated; give TMP a frame to
                // re-cache its Canvas in OnEnable before any text is generated.
                await Awaitable.NextFrameAsync();
            }

            await dialogue.StartDialogue(definition.YarnNode);
        }

        GameObject ResolveDialogueUI(DialogueRunner dialogue)
        {
            if (dialogueUI != null)
            {
                return dialogueUI;
            }

            var canvas = dialogue.GetComponentInChildren<Canvas>(true);
            if (canvas == null)
            {
                Debug.LogWarning(
                    $"[Interactor] No Canvas under {dialogue.name} for {definition.DisplayName}", this);
                return null;
            }
            return canvas.gameObject;
        }
    }
}