import sys
import tempfile
import unittest
from pathlib import Path

from PIL import Image

SCRIPTS = Path(__file__).resolve().parents[1] / "scripts"
sys.path.insert(0, str(SCRIPTS))

from build_g01_backgrounds import process_chroma_image, process_opaque_image, save_png


class G01BackgroundBuilderTests(unittest.TestCase):
    def config(self):
        return {
            "dominanceStart": 30,
            "dominanceEnd": 220,
            "despillAllowance": 10,
        }

    def test_pure_green_becomes_clean_transparency(self):
        source = Image.new("RGB", (2, 1), (0, 255, 0))
        output = process_chroma_image(source, self.config())
        self.assertEqual((0, 0, 0, 0), output.getpixel((0, 0)))

    def test_warm_artwork_remains_opaque(self):
        source = Image.new("RGB", (1, 1), (210, 190, 150))
        output = process_chroma_image(source, self.config())
        self.assertEqual((210, 190, 150, 255), output.getpixel((0, 0)))

    def test_antialiased_green_edge_is_translucent_and_despilled(self):
        source = Image.new("RGB", (1, 1), (100, 200, 90))
        output = process_chroma_image(source, self.config())
        red, green, blue, alpha = output.getpixel((0, 0))
        self.assertGreater(alpha, 0)
        self.assertLess(alpha, 255)
        self.assertLessEqual(green, max(red, blue) + 10)

    def test_opaque_master_is_normalized_to_rgba_without_transparency(self):
        source = Image.new("RGB", (1, 1), (240, 235, 220))
        output = process_opaque_image(source)
        self.assertEqual("RGBA", output.mode)
        self.assertEqual((240, 235, 220, 255), output.getpixel((0, 0)))

    def test_saved_png_declares_srgb_color_profile(self):
        with tempfile.TemporaryDirectory() as directory:
            path = Path(directory) / "asset.png"
            save_png(Image.new("RGBA", (1, 1), (240, 235, 220, 255)), path)
            with Image.open(path) as opened:
                self.assertIn("srgb", opened.info)

    def test_saved_png_bytes_are_deterministic(self):
        with tempfile.TemporaryDirectory() as directory:
            first = Path(directory) / "first.png"
            second = Path(directory) / "second.png"
            image = Image.new("RGBA", (2, 2), (240, 235, 220, 255))
            save_png(image, first)
            save_png(image, second)
            self.assertEqual(first.read_bytes(), second.read_bytes())


if __name__ == "__main__":
    unittest.main()