import base64
import unittest
from io import BytesIO

from PIL import Image


def _tiny_png_b64() -> str:
    image = Image.new("RGB", (1, 1), (255, 128, 0))
    buf = BytesIO()
    image.save(buf, format="PNG")
    return base64.b64encode(buf.getvalue()).decode("ascii")


class ApiBridgeTest(unittest.TestCase):
    def test_decode_payload_returns_frontend_culture_decode_shape(self):
        from api_bridge import decode_payload_to_culture_decode

        captured = {}

        def fake_run_decode(image):
            captured["size"] = image.size
            return "raw model text"

        def fake_parse_sections(raw):
            assert raw == "raw model text"
            return {
                "title": "Test Shrine",
                "location": "Kyoto, Japan",
                "category": "Architecture / Religion",
                "flag": "JP",
                "features": ["gate", "path", "shrine", "vermilion"],
                "tourists": "A red gate path.",
                "locals": "A local meaning.",
                "avoid_bullets": ["Do not block.", "Do not climb.", "Ask first."],
                "matters": "It matters culturally.",
            }

        def fake_sections_to_decode(sections, uploaded_b64=None):
            assert uploaded_b64 == _tiny_png_b64()
            return {
                "id": "abc123",
                "title": sections["title"],
                "location": sections["location"],
                "category": sections["category"],
                "flag": sections["flag"],
                "_uploaded_b64": uploaded_b64,
                "scan": {
                    "subject": sections["tourists"],
                    "features": sections["features"],
                    "contextPrompt": "A traveler is looking at Test Shrine.",
                },
                "layers": {
                    "l1": {"key": "l1", "title": "What tourists see", "label": "L1", "tone": "Objective", "text": sections["tourists"], "priority": "standard"},
                    "l2": {"key": "l2", "title": "What locals know", "label": "L2", "tone": "Revealing", "text": sections["locals"], "priority": "highlight"},
                    "l3": {"key": "l3", "title": "What not to do", "label": "L3", "tone": "Protective", "bullets": sections["avoid_bullets"], "priority": "standard"},
                    "l4": {"key": "l4", "title": "Why it matters", "label": "L4", "tone": "Cultural depth", "text": sections["matters"], "priority": "highlight"},
                },
            }

        result = decode_payload_to_culture_decode(
            {"image": _tiny_png_b64(), "mime": "image/png"},
            run_decode=fake_run_decode,
            parse_sections=fake_parse_sections,
            sections_to_decode=fake_sections_to_decode,
        )

        self.assertEqual(captured["size"], (1, 1))
        self.assertEqual(result["id"], "abc123")
        self.assertTrue(result["image"].startswith("data:image/png;base64,"))
        self.assertNotIn("_uploaded_b64", result)
        self.assertEqual(result["layers"]["l3"]["bullets"], ["Do not block.", "Do not climb.", "Ask first."])


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