"""Tests for tools.working_diff.collect_working_diff — the git collection
layer shared by the CLI and gateway ``/diff`` command.

Runs against real temporary git repositories (no mocks) so the staged /
unstaged / untracked semantics are proven against actual git behaviour.
"""

import shutil
import subprocess

import pytest

from tools.working_diff import collect_working_diff

pytestmark = pytest.mark.skipif(
    shutil.which("git") is None, reason="git required for working-diff tests"
)


def _git(repo, *args):
    subprocess.run(
        ["git", *args], cwd=repo, check=True, capture_output=True,
        env={"HOME": str(repo), "GIT_AUTHOR_NAME": "t", "GIT_AUTHOR_EMAIL": "t@t",
             "GIT_COMMITTER_NAME": "t", "GIT_COMMITTER_EMAIL": "t@t",
             "PATH": __import__("os").environ["PATH"]},
    )


@pytest.fixture()
def repo(tmp_path):
    d = tmp_path / "repo"
    d.mkdir()
    _git(d, "init", "-q")
    (d / "tracked.py").write_text("print('hello')\n")
    _git(d, "add", "-A")
    _git(d, "commit", "-q", "-m", "init")
    return d


def test_clean_repo_reports_empty(repo):
    result = collect_working_diff(str(repo))
    assert result["success"] is True
    assert result.get("empty") is True
    assert result["diff"] == ""


def test_unstaged_change_appears_in_default_mode(repo):
    (repo / "tracked.py").write_text("print('changed')\n")
    result = collect_working_diff(str(repo))
    assert result["success"] is True
    assert "-print('hello')" in result["diff"]
    assert "+print('changed')" in result["diff"]
    assert "tracked.py" in result["stat"]


def test_untracked_file_appears_as_addition(repo):
    (repo / "brand_new.py").write_text("x = 1\n")
    result = collect_working_diff(str(repo))
    assert result["success"] is True
    assert "brand_new.py" in result["untracked"]
    assert "+x = 1" in result["diff"]
    assert not result.get("empty")


def test_staged_mode_shows_only_staged(repo):
    (repo / "tracked.py").write_text("print('staged')\n")
    _git(repo, "add", "tracked.py")
    (repo / "unstaged.py").write_text("y = 2\n")  # untracked, must not appear

    result = collect_working_diff(str(repo), mode="staged")
    assert result["success"] is True
    assert "+print('staged')" in result["diff"]
    assert "unstaged.py" not in result["diff"]


def test_all_mode_spans_staged_unstaged_and_untracked(repo):
    (repo / "tracked.py").write_text("print('staged')\n")
    _git(repo, "add", "tracked.py")
    (repo / "extra.py").write_text("z = 3\n")

    result = collect_working_diff(str(repo), mode="all")
    assert result["success"] is True
    assert "+print('staged')" in result["diff"]
    assert "+z = 3" in result["diff"]


def test_paths_filter_restricts_output(repo):
    (repo / "tracked.py").write_text("print('changed')\n")
    (repo / "other.py").write_text("o = 1\n")
    _git(repo, "add", "other.py")
    _git(repo, "commit", "-q", "-m", "add other")
    (repo / "other.py").write_text("o = 2\n")

    result = collect_working_diff(str(repo), paths=["tracked.py"])
    assert result["success"] is True
    assert "tracked.py" in result["diff"]
    assert "other.py" not in result["diff"]


def test_non_git_directory_fails_cleanly(tmp_path):
    plain = tmp_path / "plain"
    plain.mkdir()
    result = collect_working_diff(str(plain))
    assert result["success"] is False
    assert "not a git repository" in result["error"].lower()


def test_unknown_mode_rejected(repo):
    result = collect_working_diff(str(repo), mode="bogus")
    assert result["success"] is False
    assert "bogus" in result["error"]