"""muse#53 item 1 -- `muse symlog hotspots` and `muse symlog coupling`.

Analytics commands reading purely from the already-written symlog
journal, with no commit-history scan.
"""

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 TestSymlogHotspots:
    def test_ranks_by_modification_count(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")
        # Modify compute_total twice, apply_discount once.
        _write_file(repo, "src/billing.py", (
            "def compute_total(items):\n    return sum(items) + 1\n\n"
            "def apply_discount(total, pct):\n    return total * (1 - pct) - 1\n"
        ))
        _commit(repo, "modify both")
        _write_file(repo, "src/billing.py", (
            "def compute_total(items):\n    return sum(items) + 2\n\n"
            "def apply_discount(total, pct):\n    return total * (1 - pct) - 1\n"
        ))
        _commit(repo, "modify compute_total again")

        result = _symlog(repo, "hotspots", "--json")
        assert result.exit_code == 0, result.stdout
        data = json.loads(result.stdout)
        assert data["count"] == 2
        assert data["hotspots"][0]["symbol"] == "src/billing.py::compute_total"
        assert data["hotspots"][0]["modifications"] == 2
        assert data["hotspots"][1]["symbol"] == "src/billing.py::apply_discount"
        assert data["hotspots"][1]["modifications"] == 1

    def test_creation_only_excluded(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, "hotspots", "--json")
        data = json.loads(result.stdout)
        assert data["count"] == 0

    def test_file_scoping(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")
        _write_file(repo, "src/other.py", "def unrelated():\n    pass\n")
        _commit(repo, "add two files")
        _write_file(repo, "src/billing.py", "def compute_total(items):\n    return sum(items) + 1\n")
        _write_file(repo, "src/other.py", "def unrelated():\n    return 1\n")
        _commit(repo, "modify both")

        result = _symlog(repo, "hotspots", "--file", "src/billing.py", "--json")
        data = json.loads(result.stdout)
        assert data["count"] == 1
        assert data["hotspots"][0]["symbol"] == "src/billing.py::compute_total"

    def test_top_limits_results(self, tmp_path: pathlib.Path) -> None:
        repo = _make_repo(tmp_path)
        _write_file(repo, "src/billing.py", (
            "def a():\n    return 1\n\ndef b():\n    return 2\n"
        ))
        _commit(repo, "add")
        _write_file(repo, "src/billing.py", (
            "def a():\n    return 11\n\ndef b():\n    return 22\n"
        ))
        _commit(repo, "modify both")

        result = _symlog(repo, "hotspots", "--top", "1", "--json")
        data = json.loads(result.stdout)
        assert len(data["hotspots"]) == 1


class TestSymlogCoupling:
    def test_finds_symbols_that_change_together(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) + 1\n\n"
            "def apply_discount(total, pct):\n    return total * (1 - pct) - 1\n"
        ))
        _commit(repo, "modify both together")

        result = _symlog(repo, "coupling", "--json")
        assert result.exit_code == 0, result.stdout
        data = json.loads(result.stdout)
        assert data["count"] == 1
        pair = data["pairs"][0]
        assert {pair["symbol_a"], pair["symbol_b"]} == {
            "src/billing.py::compute_total", "src/billing.py::apply_discount",
        }
        assert pair["co_changes"] == 2  # both created + both modified together

    def test_below_min_threshold_excluded(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")

        # Only one shared commit (the creation) -- below the default min of 2.
        result = _symlog(repo, "coupling", "--json")
        data = json.loads(result.stdout)
        assert data["count"] == 0

    def test_min_flag_lowers_threshold(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")

        result = _symlog(repo, "coupling", "--min", "1", "--json")
        data = json.loads(result.stdout)
        assert data["count"] == 1

    def test_no_coupling_in_empty_repo(self, tmp_path: pathlib.Path) -> None:
        repo = _make_repo(tmp_path)
        result = _symlog(repo, "coupling", "--json")
        data = json.loads(result.stdout)
        assert data["count"] == 0