"""Tests for the streamlit-drawable-canvas compatibility shim.

The shim re-attaches ``image_to_url`` to ``streamlit.elements.image``
on modern Streamlit where the helper was relocated to
``streamlit.elements.lib.image_utils`` and given a new signature
(takes a ``LayoutConfig`` dataclass instead of a plain ``int``
width).

If this test ever fails on a Streamlit upgrade, it almost
certainly means the ``image_to_url`` function moved AGAIN — the
shim's fallback message points to where to look. Update
``_drawable_canvas_compat.py`` to find the new location.
"""

from __future__ import annotations

import sys
import types


def test_shim_attaches_image_to_url():
    """After ``install()`` the old import path resolves to a
    callable, even on modern Streamlit where the original was
    relocated."""
    # Force a fresh import so the module-level _PATCHED guard
    # doesn't short-circuit between tests.
    sys.modules.pop("src.gui._drawable_canvas_compat", None)
    from src.gui._drawable_canvas_compat import install
    install()
    import streamlit.elements.image as old_loc
    assert hasattr(old_loc, "image_to_url")
    assert callable(old_loc.image_to_url)


def test_shim_is_idempotent():
    """Calling ``install()`` twice doesn't double-wrap or break
    anything — important because the page module imports + calls
    it once, and a Streamlit script-rerun re-executes the page
    module top-to-bottom."""
    sys.modules.pop("src.gui._drawable_canvas_compat", None)
    from src.gui._drawable_canvas_compat import install
    install()
    import streamlit.elements.image as old_loc
    first = old_loc.image_to_url
    install()
    second = old_loc.image_to_url
    assert first is second


def test_shim_no_op_when_image_to_url_already_present():
    """If a future Streamlit restores ``image_to_url`` at the old
    location, the shim must not overwrite it — leave the upstream
    function in place so the canvas package gets the official
    version, not our compatibility wrapper."""
    sys.modules.pop("src.gui._drawable_canvas_compat", None)
    import streamlit.elements.image as old_loc

    sentinel = lambda *a, **kw: "sentinel-url"  # noqa: E731
    old_loc.image_to_url = sentinel
    try:
        from src.gui._drawable_canvas_compat import install
        install()
        assert old_loc.image_to_url is sentinel, (
            "Shim must not clobber an existing image_to_url."
        )
    finally:
        # Tidy up so subsequent tests see a clean module.
        delattr(old_loc, "image_to_url")
        sys.modules.pop("src.gui._drawable_canvas_compat", None)


def test_shim_calls_new_function_with_layout_config():
    """The shim's wrapper must translate the old ``(image, width,
    clamp, channels, output_format, image_id)`` call into the new
    ``(image, layout_config, …)`` signature without breaking."""
    sys.modules.pop("src.gui._drawable_canvas_compat", None)
    import streamlit.elements.image as old_loc
    if hasattr(old_loc, "image_to_url"):
        delattr(old_loc, "image_to_url")

    # Replace the new function with a recorder so we can inspect
    # what arguments the shim passed through.
    from streamlit.elements.lib import image_utils
    captured: dict = {}
    original = image_utils.image_to_url

    def recorder(image, layout_config, clamp, channels, output_format, image_id):
        captured["image"] = image
        captured["layout_config"] = layout_config
        captured["clamp"] = clamp
        captured["channels"] = channels
        captured["output_format"] = output_format
        captured["image_id"] = image_id
        return "fake-url"

    image_utils.image_to_url = recorder
    try:
        from src.gui._drawable_canvas_compat import install
        install()
        result = old_loc.image_to_url(
            "fake-image", -1, False, "RGB", "PNG", "test-id",
        )
        assert result == "fake-url"
        assert captured["image"] == "fake-image"
        assert captured["clamp"] is False
        assert captured["channels"] == "RGB"
        assert captured["output_format"] == "PNG"
        assert captured["image_id"] == "test-id"
        # The shim wraps the int width into a LayoutConfig.
        from streamlit.elements.lib.layout_utils import LayoutConfig
        assert isinstance(captured["layout_config"], LayoutConfig)
    finally:
        image_utils.image_to_url = original
        if hasattr(old_loc, "image_to_url"):
            delattr(old_loc, "image_to_url")
        sys.modules.pop("src.gui._drawable_canvas_compat", None)