using System.Collections;
using System.Collections.Generic;
using UnityEditor;
using UnityEngine;

public static class GenPolygonCollider
{
    static float tileWidth = 1.0f;
    static float tileHeight = 0.5f;
    static float halfTileWidth = tileWidth / 2;
    static float halfTileHeight = tileHeight / 2;

    [MenuItem("Tools/ResourceEditor/GeneratePolygonCollider")]
    public static void GeneratePolygonCollider()
    {

        GameObject obj = Selection.activeGameObject;

        PolygonCollider2D polygonCollider2D = obj.GetComponent<PolygonCollider2D>();
        if (polygonCollider2D == null)
        {
            polygonCollider2D = obj.AddComponent<PolygonCollider2D>();
        }

        var sprRender = obj.GetComponent<SpriteRenderer>();
        var sprite = sprRender.sprite;
        Bounds bounds = sprite.bounds;
        Vector4 border = sprite.border;
        var minPos = sprRender.transform.TransformPoint(bounds.center - new Vector3(bounds.extents.x - border.x / sprite.pixelsPerUnit, bounds.extents.y - border.y / sprite.pixelsPerUnit));
        var maxPos = sprRender.transform.TransformPoint(bounds.center + new Vector3(bounds.extents.x - border.z / sprite.pixelsPerUnit, bounds.extents.y - border.w / sprite.pixelsPerUnit));

        float sprWidth = maxPos.x - minPos.x;
        float sprHeight = maxPos.y - minPos.y;

        int sizeX = 2;
        int sizeY = 3;

        Vector2 left = MapToLocalPos(sizeX, 0);
        Vector2 top = MapToLocalPos(sizeX, sizeY);
        Vector2 right = MapToLocalPos(0, sizeY);
        Vector2 bottom = Vector2.zero;

        polygonCollider2D.points = new[] { bottom, left, top, right };
    }
    
    public static Vector2 MapToLocalPos(int row, int col)
    {
        Vector2 worldPos = new Vector2();
        worldPos.x = (col - row) * halfTileWidth;
        worldPos.y = (row + col) * halfTileHeight;
        return worldPos;
    }
}