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

/// <summary>
/// Drop this on a sphere primitive to use it as a placeholder NPC:
/// - Sets sphere color per-instance
/// - Spawns a floating TextMeshPro name label that billboards to face the camera
/// - Shows a proximity interaction prompt ("[F]", "(X)", "(✕)") that swaps based on
///   the last input device used, via InputDeviceTracker
/// - Press the interact button while in range to start a Yarn Spinner dialogue node
/// Requires: TextMeshPro Essentials imported, Input System package installed,
/// InputDeviceTracker.cs in the project, and a "Player" tag on your player object
/// (or assign the Player field manually in the Inspector).
/// </summary>
[RequireComponent(typeof(SphereCollider))]
public class NPCStandIn : MonoBehaviour
{
    [Header("Identity")]
    public string npcName = "Unnamed NPC";
    public Color npcColor = Color.white;

    [Header("Dialogue")]
    public DialogueRunner dialogueRunner;
    public string yarnStartNode = "Start";

    [Tooltip("Optional. Left empty, the Canvas under the DialogueRunner is used.")]
    public GameObject dialogueUI;

    [Header("Label")]
    public float labelHeight = 1.2f;
    public float labelFontSize = 4f;
    public Color labelColor = Color.white;

    [Header("Interaction Prompt")]
    public Transform player;              // auto-found by "Player" tag if left empty
    public float interactionRange = 3f;
    public float promptHeight = 0.7f;
    public float promptFontSize = 3f;

    private TextMeshPro labelText;
    private TextMeshPro promptText;
    private Renderer rend;
    private Camera mainCam;
    private InputAction interactAction;
    private bool playerInRange;

    void Awake()
    {
        rend = GetComponent<Renderer>();
        rend.material.color = npcColor;

        // Best-effort only, and silent. The runner lives in the Systems scene, which may
        // not have loaded yet when this level's objects awake — see ResolvedDialogueRunner.
        dialogueRunner = SceneServices.TryResolve(dialogueRunner);

        mainCam = Camera.main;

        if (player == null)
        {
            GameObject found = GameObject.FindGameObjectWithTag("Player");
            if (found != null) player = found.transform;
        }

        CreateLabel();
        CreatePrompt();

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

    /// <summary>
    /// The dialogue runner, resolved on demand.
    ///
    /// Not resolved once in Awake: the runner lives in the Systems scene, and an NPC in
    /// a level scene can wake up before that scene exists — loading the level on its own,
    /// or in a different order, used to log "could not resolve dialogueRunner" and then
    /// stay broken for the rest of the session. Looking it up at the point of use makes
    /// load order irrelevant, and the result is cached, so this costs one search.
    /// </summary>
    public DialogueRunner ResolvedDialogueRunner =>
        dialogueRunner != null
            ? dialogueRunner
            : dialogueRunner = SceneServices.TryResolve<DialogueRunner>(null);

    void OnEnable() => interactAction?.Enable();
    void OnDisable() => interactAction?.Disable();

    void CreateLabel()
    {
        GameObject labelObj = new GameObject($"{npcName}_Label");
        labelObj.transform.SetParent(transform);
        labelObj.transform.localPosition = Vector3.up * labelHeight;

        labelText = labelObj.AddComponent<TextMeshPro>();
        labelText.text = npcName;
        labelText.fontSize = labelFontSize;
        labelText.color = labelColor;
        labelText.alignment = TextAlignmentOptions.Center;
        labelText.rectTransform.sizeDelta = new Vector2(2f, 0.5f);
    }

    void CreatePrompt()
    {
        GameObject promptObj = new GameObject($"{npcName}_Prompt");
        promptObj.transform.SetParent(transform);
        promptObj.transform.localPosition = Vector3.up * promptHeight;

        promptText = promptObj.AddComponent<TextMeshPro>();
        promptText.fontSize = promptFontSize;
        promptText.color = Color.yellow;
        promptText.alignment = TextAlignmentOptions.Center;
        promptText.rectTransform.sizeDelta = new Vector2(1.5f, 0.4f);
        promptObj.SetActive(false); // hidden until player is in range
    }

    void Update()
    {
        if (player == null) return;

        float dist = Vector3.Distance(transform.position, player.position);
        bool inRangeNow = dist <= interactionRange;

        if (inRangeNow != playerInRange)
        {
            playerInRange = inRangeNow;
            promptText.gameObject.SetActive(playerInRange);
        }

        if (playerInRange)
        {
            promptText.text = GlyphFor(InputDeviceTracker.Current);
        }
    }

    void LateUpdate()
    {
        if (mainCam == null) return;

        if (labelText != null)
            labelText.transform.rotation = Quaternion.LookRotation(
                labelText.transform.position - mainCam.transform.position);

        if (promptText != null)
            promptText.transform.rotation = Quaternion.LookRotation(
                promptText.transform.position - mainCam.transform.position);
    }

    static string GlyphFor(InputDeviceTracker.DeviceType type)
    {
        switch (type)
        {
            case InputDeviceTracker.DeviceType.Xbox: return "(X)";
            case InputDeviceTracker.DeviceType.PlayStation: return "(\u2715)"; // Cross button
            default: return "[F]";
        }
    }

    public void Interact()
    {
        var runner = ResolvedDialogueRunner;
        if (runner == null)
        {
            Debug.LogError(
                $"[NPCStandIn] {npcName}: 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 (!runner.IsDialogueRunning)
        {
            StartDialogueAsync();
        }
    }

    async void StartDialogueAsync()
    {
        // The dialogue UI is hidden when the player leaves a conversation via
        // <<enter_environment>>. Make it visible again before the runner
        // renders its first line.
        if (DialogueUIVisibility.Show(ResolveDialogueUI()))
        {
            // 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 ResolvedDialogueRunner.StartDialogue(yarnStartNode);
    }

    /// <summary>
    /// The Canvas under the DialogueRunner, unless one was assigned explicitly.
    /// Resolved at call time (including inactive children) so this works
    /// without any per-NPC Inspector wiring.
    /// </summary>
    GameObject ResolveDialogueUI()
    {
        if (dialogueUI != null)
        {
            return dialogueUI;
        }

        var runner = ResolvedDialogueRunner;
        if (runner == null)
        {
            return null;
        }

        var canvas = runner.GetComponentInChildren<Canvas>(true);
        if (canvas == null)
        {
            Debug.LogWarning($"[NPCStandIn] No Canvas found under {runner.name} for {npcName}");
            return null;
        }

        dialogueUI = canvas.gameObject;
        return dialogueUI;
    }
}