# Copyright (c) Microsoft Corporation.
# Licensed under the MIT license.

import os
import subprocess
from types import SimpleNamespace
from unittest.mock import patch

import pytest

from build_scripts.enforce_alembic_revision_immutability import (
    _on_release_branch,
    has_revision_violations,
)

MODIFIED_REVISION = "M\tpyrit/memory/alembic/versions/b2f4c6a8d1e3_add_conversations_table.py"


def _completed(stdout: str = "", returncode: int = 0) -> subprocess.CompletedProcess:
    return subprocess.CompletedProcess(args=["git"], returncode=returncode, stdout=stdout, stderr="")


@pytest.mark.parametrize(
    "environment, expected",
    [
        ({"GITHUB_REF": "refs/heads/releases/v1.1.0"}, True),
        ({"GITHUB_REF": "refs/heads/releases/v1.0.1"}, True),
        ({"GITHUB_REF": "refs/heads/main"}, False),
        ({"GITHUB_REF": "refs/heads/releases-notes"}, False),
        ({"GITHUB_REF": "refs/tags/v1.1.0"}, False),
        ({"GITHUB_REF": "refs/pull/42/merge", "GITHUB_BASE_REF": "releases/v1.1.0"}, True),
        ({"GITHUB_REF": "refs/pull/42/merge", "GITHUB_BASE_REF": "main"}, False),
        ({"GITHUB_REF": "refs/heads/gh-readonly-queue/releases/v1.1.0/pr-42-abc123"}, True),
        ({"GITHUB_REF": "refs/heads/gh-readonly-queue/main/pr-42-abc123"}, False),
        ({}, False),
    ],
)
def test_on_release_branch_recognizes_release_refs(environment: dict[str, str], expected: bool) -> None:
    """pull_request events carry the target branch in GITHUB_BASE_REF; merge_group embeds it in GITHUB_REF."""
    with patch.dict("os.environ", environment, clear=True):
        with patch("build_scripts.enforce_alembic_revision_immutability._git_stdout", return_value="main"):
            assert _on_release_branch() is expected


@pytest.mark.parametrize(
    "checked_out_branch, expected",
    [("releases/v1.1.0", True), ("main", False), ("HEAD", False)],
)
def test_on_release_branch_falls_back_to_checked_out_branch(checked_out_branch: str, expected: bool) -> None:
    """Runs outside GitHub Actions have no ref variables, leaving the branch name as the only signal."""
    with patch.dict("os.environ", {}, clear=True):
        with patch(
            "build_scripts.enforce_alembic_revision_immutability._git_stdout",
            return_value=checked_out_branch,
        ) as mock_git_stdout:
            assert _on_release_branch() is expected

    assert mock_git_stdout.call_args.args == ("rev-parse", "--abbrev-ref", "HEAD")


def test_on_release_branch_ignores_branch_name_when_ci_refs_are_present() -> None:
    """A PR from a release-named source branch into main must still be enforced."""
    environment = {"GITHUB_REF": "refs/pull/42/merge", "GITHUB_BASE_REF": "main"}
    with patch.dict("os.environ", environment, clear=True):
        with patch(
            "build_scripts.enforce_alembic_revision_immutability._git_stdout",
            return_value="releases/v1.1.0",
        ) as mock_git_stdout:
            assert _on_release_branch() is False

    mock_git_stdout.assert_not_called()


def test_release_branch_push_skips_history_checks() -> None:
    """A release branch push shares neither origin/main nor a comparable previous commit."""

    def _fail_if_called(*args, **kwargs):
        raise AssertionError(f"history check ran on a release branch push: {args}")

    with patch.dict(os.environ, {"GITHUB_BASE_REF": ""}, clear=False):
        with patch("build_scripts.enforce_alembic_revision_immutability._on_release_branch", return_value=True):
            with patch("build_scripts.enforce_alembic_revision_immutability._get_violations", return_value=[]):
                with patch("build_scripts.enforce_alembic_revision_immutability._git", side_effect=_fail_if_called):
                    assert has_revision_violations() is False


def test_release_pull_request_compares_against_its_base() -> None:
    """A pull request into a release branch is comparable against that branch."""
    calls: list[tuple] = []

    def _record(*args, **kwargs):
        calls.append(args)
        return SimpleNamespace(returncode=0, stdout="", stderr="")

    with patch.dict(os.environ, {"GITHUB_BASE_REF": "releases/v1.1.0"}, clear=False):
        with patch("build_scripts.enforce_alembic_revision_immutability._on_release_branch", return_value=True):
            with patch("build_scripts.enforce_alembic_revision_immutability._get_violations", return_value=[]):
                with patch("build_scripts.enforce_alembic_revision_immutability._git", side_effect=_record):
                    assert has_revision_violations() is False

    assert any("origin/releases/v1.1.0...HEAD" in call for call in calls)
    assert not any("origin/main...HEAD" in call for call in calls)


def test_release_pull_request_reports_modified_revision() -> None:
    """The base comparison still catches a revision the pull request itself edits."""

    def _modified(*args, **kwargs):
        if "diff" in args and any(arg == "origin/releases/v1.1.0...HEAD" for arg in args):
            return SimpleNamespace(returncode=0, stdout=f"M\t{MODIFIED_REVISION}\n", stderr="")
        return SimpleNamespace(returncode=0, stdout="", stderr="")

    with patch.dict(os.environ, {"GITHUB_BASE_REF": "releases/v1.1.0"}, clear=False):
        with patch("build_scripts.enforce_alembic_revision_immutability._on_release_branch", return_value=True):
            with patch("build_scripts.enforce_alembic_revision_immutability._get_violations", return_value=[]):
                with patch("build_scripts.enforce_alembic_revision_immutability._git", side_effect=_modified):
                    assert has_revision_violations() is True


def test_release_branch_still_reports_staged_violations() -> None:
    """Skipping the history checks must not stop the staged-change check."""
    with patch("build_scripts.enforce_alembic_revision_immutability._on_release_branch", return_value=True):
        with patch(
            "build_scripts.enforce_alembic_revision_immutability._get_violations",
            return_value=[MODIFIED_REVISION],
        ):
            assert has_revision_violations() is True


def test_branch_comparison_still_runs_off_release_branches() -> None:
    """Positive control: the origin/main comparison must keep catching violations everywhere else."""
    with patch.dict(os.environ, {"GITHUB_BASE_REF": ""}, clear=False):
        with patch("build_scripts.enforce_alembic_revision_immutability._on_release_branch", return_value=False):
            with patch("build_scripts.enforce_alembic_revision_immutability._get_violations", return_value=[]):
                with patch(
                    "build_scripts.enforce_alembic_revision_immutability._git",
                    return_value=_completed(stdout=MODIFIED_REVISION),
                ) as mock_git:
                    assert has_revision_violations() is True

    assert mock_git.call_args.args[:3] == ("diff", "--name-status", "origin/main...HEAD")


def test_previous_commit_check_still_runs_off_release_branches() -> None:
    """Positive control: the HEAD~1..HEAD check must keep catching violations everywhere else."""

    def _violations_for(diff_spec: list[str]) -> list[str]:
        return [MODIFIED_REVISION] if diff_spec == ["HEAD~1..HEAD"] else []

    with patch("build_scripts.enforce_alembic_revision_immutability._on_release_branch", return_value=False):
        with patch(
            "build_scripts.enforce_alembic_revision_immutability._get_violations",
            side_effect=_violations_for,
        ):
            with patch("build_scripts.enforce_alembic_revision_immutability._git", return_value=_completed()):
                assert has_revision_violations() is True


def test_clean_history_off_release_branches_passes() -> None:
    with patch("build_scripts.enforce_alembic_revision_immutability._on_release_branch", return_value=False):
        with patch("build_scripts.enforce_alembic_revision_immutability._get_violations", return_value=[]):
            with patch("build_scripts.enforce_alembic_revision_immutability._git", return_value=_completed()):
                assert has_revision_violations() is False