"""Unit tests for POST /rembg/cutout."""

from __future__ import annotations

import base64
import io

import pytest
from PIL import Image


def _make_png_b64(color: tuple[int, int, int] = (180, 100, 50), size: int = 64) -> str:
    img = Image.new("RGB", (size, size), color=color)
    buf = io.BytesIO()
    img.save(buf, format="PNG")
    return base64.b64encode(buf.getvalue()).decode("ascii")


def test_rembg_missing_image_returns_400(client) -> None:
    resp = client.post("/rembg/cutout", json={})
    assert resp.status_code == 400


def test_rembg_bad_base64_returns_400(client) -> None:
    resp = client.post("/rembg/cutout", json={"image_base64": "%%%bad%%%"})
    assert resp.status_code == 400


def test_rembg_returns_png_with_alpha(client, red_png_b64) -> None:
    """rembg removes background → output is PNG with alpha channel."""
    resp = client.post("/rembg/cutout", json={"image_base64": red_png_b64})
    assert resp.status_code == 200
    body = resp.json()
    assert body["content_type"] == "image/png"
    assert "image_base64" in body

    raw = base64.b64decode(body["image_base64"])
    img = Image.open(io.BytesIO(raw))
    assert img.mode == "RGBA", f"expected RGBA, got {img.mode}"


def test_rembg_alpha_matting_flag_round_trips(client, red_png_b64) -> None:
    resp = client.post("/rembg/cutout", json={"image_base64": red_png_b64, "alpha_matting": False})
    assert resp.status_code == 200
    assert resp.json()["alpha_matting"] is False