"""Regression tests for muse branch #21.

``muse branch --merged``/``--no-merged`` crashed with a ``ValueError`` from
``validate_branch_name`` when given a ``sha256:``-prefixed commit ID instead
of a branch name — the argument was passed unconditionally to
``get_head_commit_id``, which validates its input as a branch name.  A commit
ID is a legitimate argument for both flags (e.g. checking against the tip of
a remote-tracking ref by ID rather than by local branch name).
"""

from __future__ import annotations

import json
import os
import pathlib

from tests.cli_test_helper import CliRunner

runner = CliRunner()


def _invoke(repo: pathlib.Path, args: list[str]):
    saved = os.getcwd()
    try:
        os.chdir(repo)
        return runner.invoke(None, args)
    finally:
        os.chdir(saved)


def _commit(repo: pathlib.Path, *extra: str):
    _invoke(repo, ["code", "add", "."])
    return _invoke(repo, ["commit", *extra])


def _head_commit_id(repo: pathlib.Path) -> str:
    result = _invoke(repo, ["rev-parse", "HEAD", "--json"])
    return json.loads(result.output.strip().splitlines()[-1])["commit_id"]


def _init_repo(tmp_path: pathlib.Path) -> pathlib.Path:
    saved = os.getcwd()
    try:
        os.chdir(tmp_path)
        runner.invoke(None, ["init"])
    finally:
        os.chdir(saved)
    (tmp_path / "a.py").write_text("x = 1\n")
    _commit(tmp_path, "-m", "initial")
    return tmp_path


class TestBranchMergedAcceptsCommitId:
    def test_merged_accepts_sha256_commit_id(self, tmp_path: pathlib.Path) -> None:
        """--merged <sha256:...> must not crash — MRG_01."""
        repo = _init_repo(tmp_path)
        tip = _head_commit_id(repo)

        result = _invoke(repo, ["branch", "--merged", tip, "--json"])

        assert result.exit_code == 0, result.output
        branches = json.loads(result.output.strip().splitlines()[-1])
        names = {b["name"] for b in branches}
        assert "main" in names

    def test_no_merged_accepts_sha256_commit_id(self, tmp_path: pathlib.Path) -> None:
        """--no-merged <sha256:...> must not crash — MRG_02."""
        repo = _init_repo(tmp_path)
        tip = _head_commit_id(repo)

        result = _invoke(repo, ["branch", "--no-merged", tip, "--json"])

        assert result.exit_code == 0, result.output
        # main is merged into its own tip, so it must be excluded.
        branches = json.loads(result.output.strip().splitlines()[-1])
        names = {b["name"] for b in branches}
        assert "main" not in names

    def test_merged_still_accepts_branch_name(self, tmp_path: pathlib.Path) -> None:
        """Existing branch-name behaviour is unchanged — MRG_03."""
        repo = _init_repo(tmp_path)

        result = _invoke(repo, ["branch", "--merged", "main", "--json"])

        assert result.exit_code == 0, result.output
        branches = json.loads(result.output.strip().splitlines()[-1])
        names = {b["name"] for b in branches}
        assert "main" in names

    def test_merged_with_diverged_branch_by_commit_id(
        self, tmp_path: pathlib.Path
    ) -> None:
        """A branch not yet merged into the given commit ID is excluded — MRG_04."""
        repo = _init_repo(tmp_path)
        base_tip = _head_commit_id(repo)

        _invoke(repo, ["checkout", "-b", "feat/unmerged"])
        (repo / "b.py").write_text("y = 2\n")
        _commit(repo, "-m", "unmerged work")

        result = _invoke(repo, ["branch", "--merged", base_tip, "--json"])

        assert result.exit_code == 0, result.output
        branches = json.loads(result.output.strip().splitlines()[-1])
        names = {b["name"] for b in branches}
        assert "feat/unmerged" not in names
        assert "main" in names