"""muse#53 item 12 -- `muse symlog prune-orphans [--dry-run] [--json]`.

Finds and removes symlog journals whose symbol no longer exists at HEAD
(file deleted, or symbol removed from a file that still exists).
"""

from __future__ import annotations

import json
import os
import pathlib
import textwrap

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 _init_repo(repo: pathlib.Path) -> None:
    repo.mkdir(parents=True, exist_ok=True)
    _invoke(repo, ["init"])


def _write_file(repo: pathlib.Path, rel: str, content: str) -> None:
    p = repo / rel
    p.parent.mkdir(parents=True, exist_ok=True)
    p.write_text(textwrap.dedent(content))


def _commit(repo: pathlib.Path, msg: str) -> str:
    _invoke(repo, ["code", "add", "."])
    result = _invoke(repo, [
        "commit", "-m", msg,
        "--agent-id", "claude-code",
        "--model-id", "claude-sonnet-4-6",
        "--author", "claude-code",
        "--json",
    ])
    data = json.loads(result.stdout)
    return data["commit_id"]


def _make_repo(tmp_path: pathlib.Path) -> pathlib.Path:
    _init_repo(tmp_path)
    return tmp_path


def _symlog(repo: pathlib.Path, *args: str):
    return _invoke(repo, ["symlog", *args])


class TestPruneOrphans:
    def test_no_orphans_in_clean_repo(self, tmp_path: pathlib.Path) -> None:
        repo = _make_repo(tmp_path)
        _write_file(repo, "src/billing.py", "def compute_total(items):\n    return sum(items)\n")
        _commit(repo, "add compute_total")

        result = _symlog(repo, "prune-orphans", "--json")
        assert result.exit_code == 0, result.stdout
        data = json.loads(result.stdout)
        assert data["pruned"] == 0
        assert data["symbols"] == []

        # The live symbol's journal must still exist afterward.
        exists_result = _symlog(repo, "exists", "src/billing.py::compute_total")
        assert exists_result.exit_code == 0

    def test_orphan_from_deleted_symbol_is_pruned(self, tmp_path: pathlib.Path) -> None:
        repo = _make_repo(tmp_path)
        _write_file(repo, "src/billing.py", (
            "def compute_total(items):\n    return sum(items)\n\n"
            "def apply_discount(total, pct):\n    return total * (1 - pct)\n"
        ))
        _commit(repo, "add two functions")
        # Remove apply_discount entirely.
        _write_file(repo, "src/billing.py", "def compute_total(items):\n    return sum(items)\n")
        _commit(repo, "remove apply_discount")

        result = _symlog(repo, "prune-orphans", "--json")
        assert result.exit_code == 0, result.stdout
        data = json.loads(result.stdout)
        assert data["pruned"] == 1
        assert data["symbols"] == ["src/billing.py::apply_discount"]

        # Surviving symbol's journal must be untouched.
        exists_result = _symlog(repo, "exists", "src/billing.py::compute_total")
        assert exists_result.exit_code == 0
        # Orphaned symbol's journal must now be gone.
        orphan_exists = _symlog(repo, "exists", "src/billing.py::apply_discount")
        assert orphan_exists.exit_code == 1

    def test_orphan_from_deleted_file_is_pruned(self, tmp_path: pathlib.Path) -> None:
        repo = _make_repo(tmp_path)
        _write_file(repo, "src/billing.py", "def compute_total(items):\n    return sum(items)\n")
        _commit(repo, "add compute_total")
        (repo / "src" / "billing.py").unlink()
        _invoke(repo, ["rm", "src/billing.py"])
        _commit(repo, "remove billing.py")

        result = _symlog(repo, "prune-orphans", "--json")
        data = json.loads(result.stdout)
        assert data["pruned"] == 1
        assert data["symbols"] == ["src/billing.py::compute_total"]

    def test_dry_run_does_not_delete(self, tmp_path: pathlib.Path) -> None:
        repo = _make_repo(tmp_path)
        _write_file(repo, "src/billing.py", (
            "def compute_total(items):\n    return sum(items)\n\n"
            "def apply_discount(total, pct):\n    return total * (1 - pct)\n"
        ))
        _commit(repo, "add two functions")
        _write_file(repo, "src/billing.py", "def compute_total(items):\n    return sum(items)\n")
        _commit(repo, "remove apply_discount")

        result = _symlog(repo, "prune-orphans", "--dry-run", "--json")
        data = json.loads(result.stdout)
        assert data["pruned"] == 1
        assert data["dry_run"] is True

        # Still present after a dry-run.
        still_there = _symlog(repo, "exists", "src/billing.py::apply_discount")
        assert still_there.exit_code == 0