"""muse#54 item 8 -- `muse reflog anchor COMMIT [--json]`.

Given a commit ID, search the HEAD log and every branch's reflog for
entries that moved a ref TO that commit, reporting ref + @{N} index for
each match.
"""
from __future__ import annotations

import json
import pathlib

from tests.cli_test_helper import CliRunner
from muse.core.types import fake_id, Manifest
from muse.core.paths import muse_dir

cli = None
runner = CliRunner()


def _env(root: pathlib.Path) -> Manifest:
    return {"MUSE_REPO_ROOT": str(root)}


def _run(root: pathlib.Path, *args: str):
    return runner.invoke(cli, list(args), env=_env(root))


def _init_repo(tmp_path: pathlib.Path) -> tuple[pathlib.Path, str]:
    dot_muse = muse_dir(tmp_path)
    dot_muse.mkdir()
    repo_id = fake_id("repo")
    (dot_muse / "repo.json").write_text(json.dumps({
        "repo_id": repo_id, "domain": "code", "default_branch": "main",
        "created_at": "2025-01-01T00:00:00+00:00",
    }), encoding="utf-8")
    (dot_muse / "HEAD").write_text("ref: refs/heads/main\n", encoding="utf-8")
    (dot_muse / "refs" / "heads").mkdir(parents=True)
    (dot_muse / "snapshots").mkdir()
    (dot_muse / "commits").mkdir()
    (dot_muse / "objects").mkdir()
    return tmp_path, repo_id


def _commit_file(root: pathlib.Path, content: str, message: str) -> str:
    (root / "f.txt").write_text(content)
    add = _run(root, "code", "add", "f.txt")
    assert add.exit_code == 0, add.output
    commit = _run(root, "commit", "-m", message, "--json")
    assert commit.exit_code == 0, commit.output
    return json.loads(commit.output)["commit_id"]


class TestReflogAnchor:
    def test_finds_commit_on_head_log(self, tmp_path: pathlib.Path) -> None:
        root, repo_id = _init_repo(tmp_path)
        c1 = _commit_file(root, "v1\n", "c1")
        c2 = _commit_file(root, "v2\n", "c2")

        result = _run(root, "reflog", "anchor", c2, "--json")
        assert result.exit_code == 0, result.output
        data = json.loads(result.output)
        assert data["commit_id"] == c2
        assert data["count"] >= 1
        assert any(m["ref"] == "HEAD" and m["index"] == 0 for m in data["matches"])

    def test_finds_commit_on_named_branch_log(self, tmp_path: pathlib.Path) -> None:
        root, repo_id = _init_repo(tmp_path)
        c1 = _commit_file(root, "v1\n", "c1")

        result = _run(root, "reflog", "anchor", c1, "--json")
        assert result.exit_code == 0, result.output
        data = json.loads(result.output)
        assert any(m["ref"] == "refs/heads/main" for m in data["matches"])

    def test_unmatched_commit_returns_empty(self, tmp_path: pathlib.Path) -> None:
        root, repo_id = _init_repo(tmp_path)
        _commit_file(root, "v1\n", "c1")

        fake_commit = "sha256:" + "0" * 64
        result = _run(root, "reflog", "anchor", fake_commit, "--json")
        assert result.exit_code == 0, result.output
        data = json.loads(result.output)
        assert data["count"] == 0
        assert data["matches"] == []

    def test_accepts_bare_hex_without_prefix(self, tmp_path: pathlib.Path) -> None:
        root, repo_id = _init_repo(tmp_path)
        c1 = _commit_file(root, "v1\n", "c1")
        bare_hex = c1.split(":", 1)[1]

        result = _run(root, "reflog", "anchor", bare_hex, "--json")
        assert result.exit_code == 0, result.output
        data = json.loads(result.output)
        assert data["commit_id"] == c1
        assert data["count"] >= 1

    def test_second_commit_not_anchored_at_first_commits_index(self, tmp_path: pathlib.Path) -> None:
        root, repo_id = _init_repo(tmp_path)
        c1 = _commit_file(root, "v1\n", "c1")
        c2 = _commit_file(root, "v2\n", "c2")

        result = _run(root, "reflog", "anchor", c1, "--json")
        assert result.exit_code == 0, result.output
        data = json.loads(result.output)
        # c1 should be found, but not at the newest (@{0}) HEAD index --
        # that belongs to c2.
        head_matches = [m for m in data["matches"] if m["ref"] == "HEAD"]
        assert all(m["index"] != 0 for m in head_matches)