"""Unit tests for the `undercooked` CLI (task 03): precedence, exit codes, wiring.

`_resolve` and `_uvicorn_log_config` are pure, so precedence is testable without
a socket. `main()` is tested with uvicorn's `run` replaced by a recorder — the
real server is started by the integration/phase criteria, not by a unit test.
"""

from __future__ import annotations

import copy
import os
import subprocess
import sys
from pathlib import Path
from typing import TYPE_CHECKING, Any

import pytest
import uvicorn
import uvicorn.config

from undercooked.__main__ import (
    APP_IMPORT_STRING,
    EXIT_CONFIG_ERROR,
    EXIT_OK,
    RunOptions,
    _cli_overrides,
    _resolve,
    _uvicorn_log_config,
    build_parser,
    main,
)
from undercooked.config import (
    ENV_KEYS,
    ConfigError,
    Settings,
    apply_cli_overrides,
    get_settings,
    reset_settings_cache,
)

if TYPE_CHECKING:
    from collections.abc import Iterator

pytestmark = pytest.mark.unit

REPO_ROOT = Path(__file__).resolve().parents[2]
# A string in an assertion, never a socket bind: the CLI flag is what is under test.
ALL_INTERFACES = "0.0.0.0"  # noqa: S104 - a test assertion, not a socket bind


@pytest.fixture(autouse=True)
def pristine_env() -> Iterator[None]:
    """`main()` publishes CLI flags into `os.environ`; nothing may leak out."""
    saved = dict(os.environ)
    reset_settings_cache()
    yield
    os.environ.clear()
    os.environ.update(saved)
    reset_settings_cache()


@pytest.fixture
def uvicorn_calls(monkeypatch: pytest.MonkeyPatch) -> list[dict[str, Any]]:
    """Replace uvicorn's `run` with a recorder; returns the recorded invocations."""
    calls: list[dict[str, Any]] = []

    def fake_run(target: str, **kwargs: Any) -> None:
        calls.append({"target": target, **kwargs})

    monkeypatch.setattr(uvicorn, "run", fake_run)
    return calls


@pytest.fixture
def bare_env(monkeypatch: pytest.MonkeyPatch) -> None:
    """No `UNDERCOOKED_*`/`DEBUGPY*` in the environment: defaults are observable."""
    for key in list(os.environ):
        if key.startswith(("UNDERCOOKED_", "DEBUGPY")):
            monkeypatch.delenv(key, raising=False)
    monkeypatch.setenv("PYTHON_DOTENV_DISABLED", "true")


def parse(argv: list[str]) -> Any:
    """Parse ``argv`` the way `main` would, without serving anything."""
    return build_parser().parse_args(argv)


# ----------------------------------------------------------------------------- parser


def test_every_flag_defaults_to_unset() -> None:
    args = parse([])
    assert (args.host, args.port, args.reload, args.levels_dir) == (None, None, False, None)


def test_flags_are_parsed() -> None:
    args = parse(
        ["--host", ALL_INTERFACES, "--port", "9000", "--reload", "--levels-dir", "kitchens"]
    )
    assert (args.host, args.port, args.reload) == (ALL_INTERFACES, 9000, True)
    assert args.levels_dir == Path("kitchens")


def test_help_names_the_env_fallback() -> None:
    text = build_parser().format_help()
    assert "--levels-dir" in text
    assert "UNDERCOOKED_PORT" in text


# ----------------------------------------------------------------------------- precedence


def test_cli_beats_environment_and_defaults() -> None:
    settings = Settings(host="10.0.0.1", port=8123, levels_dir=Path("env-levels"))
    options = _resolve(
        parse(["--host", "127.0.0.1", "--port", "9999", "--levels-dir", "cli-levels"]), settings
    )
    assert options == RunOptions(
        host="127.0.0.1", port=9999, reload=False, levels_dir=Path("cli-levels")
    )


def test_settings_supply_everything_the_cli_left_unset() -> None:
    settings = Settings(host=ALL_INTERFACES, port=8123, levels_dir=Path("env-levels"))
    options = _resolve(parse([]), settings)
    assert options == RunOptions(
        host=ALL_INTERFACES, port=8123, reload=False, levels_dir=Path("env-levels")
    )


def test_settings_default_to_the_documented_defaults_in_a_bare_environment(
    bare_env: None,
) -> None:
    options = _resolve(parse([]), get_settings())
    assert options == RunOptions(
        host="127.0.0.1", port=8000, reload=False, levels_dir=Path("levels")
    )


def test_environment_beats_the_builtin_default(monkeypatch: pytest.MonkeyPatch) -> None:
    monkeypatch.setenv("UNDERCOOKED_PORT", "8123")
    monkeypatch.setenv("UNDERCOOKED_HOST", ALL_INTERFACES)
    reset_settings_cache()
    options = _resolve(parse([]), get_settings())
    assert (options.host, options.port) == (ALL_INTERFACES, 8123)


def test_reload_is_a_flag_not_an_environment_variable() -> None:
    assert _resolve(parse(["--reload"]), Settings()).reload is True
    assert _resolve(parse([]), Settings()).reload is False


def test_cli_overrides_only_report_flags_that_were_given() -> None:
    assert _cli_overrides(parse([])) == {}
    assert _cli_overrides(parse(["--port", "9000", "--levels-dir", "x"])) == {
        "port": 9000,
        "levels_dir": Path("x"),
    }


# ----------------------------------------------------------------------------- main()


def test_main_serves_the_app_string_with_resolved_options(
    uvicorn_calls: list[dict[str, Any]], bare_env: None
) -> None:
    assert main([]) == EXIT_OK
    assert len(uvicorn_calls) == 1
    call = uvicorn_calls[0]
    assert call["target"] == APP_IMPORT_STRING  # reload-capable "module:attribute" form
    assert (call["host"], call["port"], call["reload"]) == ("127.0.0.1", 8000, False)
    assert "undercooked" in call["log_config"]["loggers"]


def test_main_passes_cli_flags_to_uvicorn(
    uvicorn_calls: list[dict[str, Any]], bare_env: None
) -> None:
    assert main(["--host", ALL_INTERFACES, "--port", "9123", "--reload"]) == EXIT_OK
    call = uvicorn_calls[0]
    assert (call["host"], call["port"], call["reload"]) == (ALL_INTERFACES, 9123, True)


def test_main_publishes_cli_flags_to_the_environment(
    uvicorn_calls: list[dict[str, Any]], bare_env: None
) -> None:
    """A uvicorn --reload child re-reads the environment, so flags must live there."""
    assert main(["--levels-dir", "kitchens", "--port", "9124"]) == EXIT_OK
    assert os.environ[ENV_KEYS["levels_dir"]] == "kitchens"
    assert os.environ[ENV_KEYS["port"]] == "9124"
    assert get_settings().levels_dir == Path("kitchens")
    assert get_settings().port == 9124


def test_main_validates_cli_values_like_environment_values(
    uvicorn_calls: list[dict[str, Any]], capsys: pytest.CaptureFixture[str]
) -> None:
    assert main(["--port", "0"]) == EXIT_CONFIG_ERROR
    assert uvicorn_calls == []
    err = capsys.readouterr().err
    assert err.strip().startswith("undercooked:")
    assert "UNDERCOOKED_PORT" in err
    assert err.count("\n") == 1  # a one-line message, not a traceback


def test_main_reports_an_invalid_environment(
    uvicorn_calls: list[dict[str, Any]],
    monkeypatch: pytest.MonkeyPatch,
    capsys: pytest.CaptureFixture[str],
) -> None:
    monkeypatch.setenv("UNDERCOOKED_TICK_HZ", "99")
    reset_settings_cache()
    assert main([]) == EXIT_CONFIG_ERROR
    assert uvicorn_calls == []
    assert "UNDERCOOKED_TICK_HZ=99" in capsys.readouterr().err


def test_unknown_flag_is_an_argument_error() -> None:
    with pytest.raises(SystemExit) as excinfo:
        main(["--nope"])
    assert excinfo.value.code == EXIT_CONFIG_ERROR


def test_an_unknown_settings_field_is_a_config_error() -> None:
    with pytest.raises(ConfigError, match="not a configuration field"):
        apply_cli_overrides(**{"nonsense": 1})


# ----------------------------------------------------------------------------- logging


def test_uvicorn_log_config_adds_our_loggers_without_touching_uvicorns() -> None:
    base = copy.deepcopy(uvicorn.config.LOGGING_CONFIG)
    config = _uvicorn_log_config(base)
    assert config is not base
    assert set(base["loggers"]) == {"uvicorn", "uvicorn.error", "uvicorn.access"}
    ours = config["loggers"]["undercooked"]
    assert ours["handlers"] == ["default"]
    assert ours["level"] == "INFO"
    assert config["loggers"]["uvicorn"] is base["loggers"]["uvicorn"]
    assert set(config["formatters"]) == set(base["formatters"])  # the handler exists


# ----------------------------------------------------------------------------- the console script


def test_python_m_undercooked_prints_usage_and_exits_zero() -> None:
    result = subprocess.run(  # fixed argv, the repo's own interpreter
        [sys.executable, "-m", "undercooked", "--help"],
        cwd=REPO_ROOT,
        capture_output=True,
        text=True,
        check=False,
        timeout=120,
    )
    assert result.returncode == EXIT_OK, result.stderr
    assert "usage: undercooked" in result.stdout
    assert "--reload" in result.stdout