"""Unit tests for ``MatchingConfig.default_method`` validation in ``load_config``.

Covers the three cases from spec task 5.3:

* ``default_method`` missing  -> default ``"score"``.
* ``default_method = "llm_fulltext"`` -> accepted as-is.
* ``default_method = "irgendwas"``    -> ``ConfigError`` with helpful message.

Validates: Requirements 12.3, 12.4
"""

from __future__ import annotations

import pytest

from teamlandkarte_mcp.config import ConfigError, load_config


def _write_config(tmp_path, *, default_method_line: str = ""):
    """Write a minimal valid ``config.toml`` for ``load_config`` tests.

    ``default_method_line`` is inserted into the ``[matching]`` section as a
    raw TOML line (e.g. ``'default_method = "llm_fulltext"'``) or left empty
    to omit the key entirely.
    """

    content = f"""\
[database]
backend = "trino"
host = "trino.example"
port = 443
http_scheme = "https"
verify_ssl = true
catalog = "hive"
schema = "tier1_open_lake"
connect_timeout = 10
pool_size = 4

[matching]
competence_weight = 0.8
role_weight = 0.2
require_confirmation = true
{default_method_line}

[matching.thresholds]
top = 0.8
good = 0.65
partial = 0.5
low = 0.3

[matching.fuzzy]
min_similarity = 0.7

[cache]
db_ttl_hours = 12
search_ttl_minutes = 60
max_size = 100

[azure_openai]
endpoint = "https://example.openai.azure.com"
api_version = "2024-02-15-preview"
chat_deployment = "gpt-4"
show_costs_in_output = false
"""
    p = tmp_path / "config.toml"
    p.write_text(content)
    return p


@pytest.fixture(autouse=True)
def _set_env(monkeypatch):
    """Provide the credentials required by ``load_config``."""

    monkeypatch.setenv("DATA_LAKE_USERNAME", "u")
    monkeypatch.setenv("DATA_LAKE_PASSWORD", "p")
    monkeypatch.setenv("AZURE_OPENAI_LLM_API_KEY", "k")


def test_default_method_missing_falls_back_to_score(tmp_path):
    path = _write_config(tmp_path)
    cfg = load_config(path)
    assert cfg.matching.default_method == "score"


def test_default_method_llm_fulltext_is_accepted(tmp_path):
    path = _write_config(
        tmp_path, default_method_line='default_method = "llm_fulltext"'
    )
    cfg = load_config(path)
    assert cfg.matching.default_method == "llm_fulltext"


def test_default_method_score_is_accepted_explicit(tmp_path):
    path = _write_config(
        tmp_path, default_method_line='default_method = "score"'
    )
    cfg = load_config(path)
    assert cfg.matching.default_method == "score"


def test_default_method_case_insensitive(tmp_path):
    path = _write_config(
        tmp_path, default_method_line='default_method = "LLM_FULLTEXT"'
    )
    cfg = load_config(path)
    assert cfg.matching.default_method == "llm_fulltext"


def test_default_method_invalid_raises_config_error(tmp_path):
    path = _write_config(
        tmp_path, default_method_line='default_method = "irgendwas"'
    )
    with pytest.raises(ConfigError) as exc:
        load_config(path)
    msg = str(exc.value)
    assert "default_method" in msg
    assert "score" in msg
    assert "llm_fulltext" in msg