using System.Collections.Generic;
using TMPro;
using UnityEngine;

/// <summary>
/// Screen-space nameplate overlay: one pooled TMP label per spawned avatar (<see cref="NetworkPlayerSetup.Active"/>),
/// projected above the head via Camera.main each LateUpdate - NOT world-space, so names always draw over the
/// scene and (via this canvas's sortingOrder) over the normal HUD. No GraphicRaycaster and every label is
/// raycastTarget=false, so it never eats clicks. Font size scales inversely with camera distance, clamped to
/// [minFontSize, maxFontSize]. Visibility: a label shows only while its avatar's body is rendered locally
/// (own first-person self-hide, the per-client hide-phase matrix, found hiders, paint-reveal gate - a name
/// floating over an invisible body would leak the position), and hider names are additionally suppressed for
/// a local HUNTER viewer during Seek, where bodies ARE rendered but a label would defeat the camouflage hunt.
/// </summary>
[DisallowMultipleComponent]
public class PlayerNameplates : MonoBehaviour
{
    [Tooltip("Disabled label prototype under this canvas; cloned once per avatar. Author pivot (0.5, 0) + " +
             "bottom-center alignment so the text sits on top of the head anchor.")]
    [SerializeField] private GameObject labelContainerTemplate;

    [Tooltip("Metres above the avatar's capsule top where the name anchors.")]
    [SerializeField] private float heightOffset = 0.1f;

    [Tooltip("Font size at Reference Distance; scales inversely with camera distance from there.")]
    [SerializeField] private float referenceFontSize = 28f;

    [Tooltip("Distance (m) at which the font renders at Reference Font Size.")]
    [Min(0.01f)]
    [SerializeField] private float referenceDistance = 3f;

    [Tooltip("Lower font-size clamp (far players).")]
    [SerializeField] private float minFontSize = 12f;

    [Tooltip("Upper font-size clamp (near players).")]
    [SerializeField] private float maxFontSize = 40f;

    private class Entry
    {
        public NetworkPlayerSetup setup;
        public GameObject labelContainer;
        public TMP_Text[] labels;
        public CharacterController capsule; // head-anchor height (present but disabled on remotes)
        public Renderer body;               // own-avatar gate: first-person self-hides the mesh
        public string lastText;
        public float lastSize = -1f;
    }

    private readonly List<Entry> _entries = new List<Entry>();
    private int _seenVersion = -1;

    private void Awake()
    {
        if (labelContainerTemplate) labelContainerTemplate.SetActive(false);
    }

    private void LateUpdate()
    {
        if (!labelContainerTemplate) return;

        if (_seenVersion != NetworkPlayerSetup.ActiveVersion)
        {
            _seenVersion = NetworkPlayerSetup.ActiveVersion;
            Rebuild();
        }

        var cam = Camera.main;
        // Seek is the one window where a hider's body is rendered for a hunter but its name must not be
        // (spotting the camouflage IS the game); everywhere else the body-rendered gate below suffices.
        var match = MatchManager.Instance;
        bool hunterSeek = match && match.LocalSubPhase == MatchManager.MatchSubPhase.Seek &&
                          NetworkPlayerSetup.LocalViewerIsHunter();

        for (int i = 0; i < _entries.Count; i++)
        {
            Entry e = _entries[i];
            if (!e.setup || !e.labelContainer || e.labels is null || e.labels.Length == 0) continue;

            bool show = cam;

            // Label only while the body is rendered locally: covers the own first-person self-hide AND every
            // per-client hide (hide-phase matrix, found hiders, paint-reveal/conversion gates) in one check.
            if (show && (!e.body || !e.body.enabled))
                show = false;

            if (show && hunterSeek && e.setup.Role == PlayerRole.Hider)
                show = false;

            Vector3 screen = default;
            float distance = 0f;
            if (show)
            {
                Vector3 anchor = HeadAnchor(e);
                screen = cam.WorldToScreenPoint(anchor);
                if (screen.z <= 0f) show = false; // behind the camera
                else distance = Vector3.Distance(cam.transform.position, anchor);
            }

            if (e.labelContainer.activeSelf != show)
                e.labelContainer.SetActive(show);
            if (!show) continue;

            e.labelContainer.transform.position = new Vector3(screen.x, screen.y, 0f);

            float size = Mathf.Clamp(referenceFontSize * referenceDistance / Mathf.Max(distance, 0.01f),
                                     minFontSize, maxFontSize);
            // TMP re-layouts on every fontSize/text write, so only touch them on real changes.
            if (Mathf.Abs(size - e.lastSize) > 0.05f)
            {
                e.lastSize = size;
                foreach (var label in e.labels) label.fontSize = size;
            }
            string text = e.setup.DisplayName; // same instance until renamed -> reference compare suffices
            if (!ReferenceEquals(text, e.lastText))
            {
                e.lastText = text;
                foreach (var label in e.labels) label.text = text;
            }
        }
    }

    private Vector3 HeadAnchor(Entry e)
    {
        Transform tf = e.setup.transform;
        Vector3 top = e.capsule
            ? tf.TransformPoint(e.capsule.center + Vector3.up * (e.capsule.height * 0.5f))
            : tf.position;
        return top + Vector3.up * heightOffset;
    }

    private void Rebuild()
    {
        for (int i = 0; i < _entries.Count; i++)
            if (_entries[i].labelContainer) Destroy(_entries[i].labelContainer);
        _entries.Clear();

        var avatars = NetworkPlayerSetup.Active;
        for (int i = 0; i < avatars.Count; i++)
        {
            var setup = avatars[i];
            if (!setup) continue;

            var labelContainer = Instantiate(labelContainerTemplate, labelContainerTemplate.transform.parent);
            _entries.Add(new Entry
            {
                setup = setup,
                labelContainer = labelContainer,
                labels = labelContainer.GetComponentsInChildren<TMP_Text>(),
                capsule = setup.GetComponent<CharacterController>(),
                body = setup.GetComponentInChildren<SkinnedMeshRenderer>(true),
            });
        }
    }
}