import os
import sys
import tempfile
import unittest

sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
import uv_preview as up
from PIL import Image


class TestToPx(unittest.TestCase):
    def test_origin_bottom_left_maps_to_bottom_left_pixel(self):
        # UV(0,0) 原点在左下 -> 图像左下角（x=pad, y=size-pad）
        x, y = up._to_px(0.0, 0.0, size=100, pad=10)
        self.assertAlmostEqual(x, 10.0)
        self.assertAlmostEqual(y, 90.0)

    def test_top_right(self):
        x, y = up._to_px(1.0, 1.0, size=100, pad=10)
        self.assertAlmostEqual(x, 90.0)
        self.assertAlmostEqual(y, 10.0)


class TestRenderUvPng(unittest.TestCase):
    def setUp(self):
        self.tmp = tempfile.mkdtemp()

    def _out(self, name="uv.png"):
        return os.path.join(self.tmp, name)

    def test_writes_png_of_requested_size(self):
        polys = [[[0.1, 0.1], [0.4, 0.1], [0.25, 0.4]],
                 [[0.6, 0.6], [0.9, 0.6], [0.9, 0.9], [0.6, 0.9]]]
        out = up.render_uv_png(polys, self._out(), size=128)
        self.assertTrue(os.path.isfile(out))
        with Image.open(out) as im:
            self.assertEqual(im.size, (128, 128))
            self.assertEqual(im.format, "PNG")

    def test_empty_polygons_still_writes_blank(self):
        out = up.render_uv_png([], self._out("blank.png"), size=64)
        self.assertTrue(os.path.isfile(out))
        with Image.open(out) as im:
            self.assertEqual(im.size, (64, 64))

    def test_degenerate_polygon_skipped_no_crash(self):
        out = up.render_uv_png([[[0.5, 0.5]]], self._out("deg.png"), size=64)
        self.assertTrue(os.path.isfile(out))