using System.Collections.Generic;
using UnityEngine;

public static class PlanRecentering
{
    public static Vector2 ComputeBoundsCenter(IList<Vector2> pts)
    {
        if (pts == null || pts.Count == 0) return Vector2.zero;

        float minX = pts[0].x, maxX = pts[0].x;
        float minY = pts[0].y, maxY = pts[0].y;

        for (int i = 1; i < pts.Count; i++)
        {
            var p = pts[i];
            if (p.x < minX) minX = p.x;
            if (p.x > maxX) maxX = p.x;
            if (p.y < minY) minY = p.y;
            if (p.y > maxY) maxY = p.y;
        }

        return new Vector2((minX + maxX) * 0.5f, (minY + maxY) * 0.5f);
    }

    static void OffsetList(List<Vector2> pts, Vector2 delta)
    {
        if (pts == null) return;
        for (int i = 0; i < pts.Count; i++) pts[i] -= delta;
    }

    /// <summary>
    /// Recentre le plan à (0,0) en bougeant les WallPoint UI (enfants du container)
    /// + met à jour les listes _G.WallsPointStart/Center + force les WallLine à se recalculer.
    /// </summary>
    public static Vector2 RecenterNow_FromCurrentUIAndLists()
    {
        RectTransform pointContainer = WallCreationManager.GetWallPointContainer();
        if (pointContainer == null || pointContainer.childCount == 0) return Vector2.zero;

        // 1) delta basé sur les positions UI (source de vérité pour WallLine)
        List<Vector2> uiPts = new(pointContainer.childCount);
        foreach (RectTransform rt in pointContainer)
            uiPts.Add(rt.anchoredPosition);

        Vector2 delta = ComputeBoundsCenter(uiPts);
        if (delta == Vector2.zero) return Vector2.zero;

        Debug.Log($"[PlanRecentering] delta={delta}");

        // 2) bouger les points UI
        foreach (RectTransform rt in pointContainer)
            rt.anchoredPosition -= delta;

        // 3) bouger les listes globales (cohérence)
        OffsetList(_G.WallsPointStart,  delta);
        OffsetList(_G.WallsPointCenter, delta);

        // 4) forcer refresh des WallLine
        RectTransform lineContainer = WallCreationManager.GetWallLineContainer();
        if (lineContainer != null)
        {
            foreach (RectTransform lr in lineContainer)
            {
                WallLine wl = lr.GetComponent<WallLine>();
                if (wl != null) wl.UpdateValuesFromPoints();
            }
        }

        return delta;
    }
}