using UnityEngine;

/// <summary>
/// Attached to the group leader's GameObject.
/// Scales the leader's sphere to reflect group size and renders a floating
/// count label above it using a World-Space Canvas + TextMesh.
/// Follower agents are hidden (renderer disabled) while in the group.
/// </summary>
[RequireComponent(typeof(MeshRenderer))]
public class AgentGroupVisual : MonoBehaviour
{
    private AgentGroup group;
    private MeshRenderer meshRenderer;
    private GameObject labelObject;
    private TextMesh countLabel;

    // Base scale of a solo agent is 0.5 (set in CreateDefaultAgentPrefab)
    private const float BASE_SCALE = 0.5f;
    // Each additional member adds 10% to radius (so group of 9 is ~1.4× base)
    private const float SCALE_GROWTH = 0.1f;

    private static readonly Color SOLO_COLOR = Color.cyan;
    private static readonly Color GROUP_COLOR = new Color(1f, 0.55f, 0f); // orange

    public void Init(AgentGroup g)
    {
        group = g;
        meshRenderer = GetComponent<MeshRenderer>();
        CreateLabel();
        Refresh();
    }

    public void Refresh()
    {
        if (group == null) return;

        int size = group.Size;

        // Scale sphere
        float scale = BASE_SCALE + BASE_SCALE * SCALE_GROWTH * (size - 1);
        transform.localScale = Vector3.one * scale;

        // Color: solo = cyan, grouped = orange, larger group = brighter orange
        meshRenderer.material.color = size > 1 ? GROUP_COLOR : SOLO_COLOR;

        // Count label – only show for groups of 2+
        if (labelObject != null)
        {
            labelObject.SetActive(size > 1);
            if (countLabel != null) countLabel.text = size.ToString();
        }

        // Hide/show follower renderers
        foreach (var member in group.Members)
        {
            if (member == group.Leader) continue;
            var mr = member.GetComponent<MeshRenderer>();
            if (mr != null) mr.enabled = false;

            var lr = member.GetComponent<LineRenderer>();
            if (lr != null) lr.enabled = false;
        }
    }

    private void CreateLabel()
    {
        labelObject = new GameObject("GroupCountLabel");
        labelObject.transform.SetParent(transform, false);
        // Float above the sphere
        labelObject.transform.localPosition = new Vector3(0f, 0.8f, 0f);

        countLabel = labelObject.AddComponent<TextMesh>();
        countLabel.text = "1";
        countLabel.fontSize = 48;
        countLabel.alignment = TextAlignment.Center;
        countLabel.anchor = TextAnchor.MiddleCenter;
        countLabel.color = Color.white;
        countLabel.characterSize = 0.05f;

        // Always face camera
        labelObject.AddComponent<BillboardLabel>();
    }

    void OnDestroy()
    {
        if (labelObject != null) Destroy(labelObject);

        // Restore solo scale/color if visual is removed (member left group)
        transform.localScale = Vector3.one * BASE_SCALE;
        if (meshRenderer != null) meshRenderer.material.color = SOLO_COLOR;
    }
}

/// <summary>Keeps the TextMesh facing the main camera.</summary>
public class BillboardLabel : MonoBehaviour
{
    void LateUpdate()
    {
        if (Camera.main == null) return;
        transform.forward = Camera.main.transform.forward;
    }
}