# Copyright 2024 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

from __future__ import annotations

import os
import sys
import threading
from typing import Iterable

from unittest import mock
import unittest

# This is to be able to import scm from the root of the repo.
sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))

import scm


def GIT(
    test: unittest.TestCase,
    *,
    branchref: str | None = None,
    system_config: dict[str, list[str]] | None = None,
) -> Iterable[tuple[str, list[str]]]:
    """Installs fakes/mocks for scm.GIT so that:

      * GetBranch will just return a fake branchname starting with the value of
        branchref.
      * git_new_branch.create_new_branch will be mocked to update the value
        returned by GetBranch.

    If provided, `system_config` allows you to set the 'system' scoped
    git-config which will be visible as the immutable base configuration layer
    for all git config scopes.

    NOTE: The dependency on git_new_branch.create_new_branch seems pretty
    circular - this functionality should probably move to scm.GIT?
    """
    _branchref = [branchref or "refs/heads/main"]

    global_lock = threading.Lock()
    global_state = {}

    def _newBranch(branchref):
        _branchref[0] = branchref

    patches: list[mock._patch] = [
        mock.patch(
            "scm.GIT._new_config_state",
            side_effect=lambda _: scm.GitConfigStateTest(
                global_lock, global_state, system_state=system_config
            ),
        ),
        mock.patch("scm.GIT.GetBranchRef", side_effect=lambda _: _branchref[0]),
        mock.patch("git_new_branch.create_new_branch", side_effect=_newBranch),
    ]

    for p in patches:
        p.start()
        test.addCleanup(p.stop)

    test.addCleanup(scm.GIT.drop_config_cache)

    return global_state.items()