import sys
import importlib
from unittest.mock import patch

import spacy
from spacy import about

# `from spacy.cli import download` resolves to the *function*, not the module,
# because of an alias in cli/__init__.py. Force-import the module:
importlib.import_module("spacy.cli.download")
dl = sys.modules["spacy.cli.download"]

captured = {}
def fake_run(cmd):
    captured["url"] = next(arg for arg in cmd if arg.startswith("http"))

# Case 1: --url WITHOUT trailing slash
captured.clear()
with patch.object(dl, "run_command", fake_run), \
     patch.object(dl, "_get_pip_install_cmd", lambda: ["pip", "install"]):
    dl.download_model("foo-1.0.tar.gz", custom_url="https://my-mirror.example.com/models")
print(captured["url"])
# → https://github.com/explosion/spacy-models/releases/download/foo-1.0.tar.gz
#   (the user's mirror was silently discarded)

# Case 2: --url WITH trailing slash
with patch.object(dl, "run_command", fake_run), \
     patch.object(dl, "_get_pip_install_cmd", lambda: ["pip", "install"]):
    dl.download_model("foo-1.0.tar.gz", custom_url="https://my-mirror.example.com/models/")
# → ValueError: Download from foo-1.0.tar.gz rejected. Was it a relative path?

base_url = custom_url if custom_url else about.__download_url__
# urljoin requires that the path ends with /, or the last path part will be dropped
if not base_url.endswith("/"):
    base_url = about.__download_url__ + "/"      # ← clobbers custom_url
download_url = urljoin(base_url, filename)
if not download_url.startswith(about.__download_url__):
    raise ValueError(f"Download from {filename} rejected. Was it a relative path?")