"""Fail-fast startup-contract tests (method-spec §10, §4.1, §8).

The run must refuse to start on a bad config: missing/non-positive caps, a third
decision value on the run path, a profile without a ``default`` model. All of this
is pure config-layer validation — no model client, no API key, no network.
"""

from __future__ import annotations

from typing import Any

import pytest
from pydantic import ValidationError

from portfolio_optimiser_claude.contracts import load_contracts

VALID_DATA_SOURCE: dict[str, Any] = {"docs_dir": "docs", "top_k": 3}
VALID_TERMINATION: dict[str, Any] = {"max_rounds": 4, "max_tokens": 20_000}
VALID_FEEDBACK: dict[str, Any] = {"decision": "approved", "rationale": "sound measure"}
VALID_MODEL_MAP: dict[str, Any] = {
    "profiles": {"anthropic": {"default": "some-model-id", "proposer": "some-model-id"}}
}


def load(**overrides: dict[str, Any]) -> Any:
    kwargs: dict[str, Any] = {
        "data_source": VALID_DATA_SOURCE,
        "termination": VALID_TERMINATION,
        "feedback": VALID_FEEDBACK,
        "model_map": VALID_MODEL_MAP,
    }
    kwargs.update(overrides)
    return load_contracts(
        kwargs["data_source"],
        kwargs["termination"],
        kwargs["feedback"],
        model_map=kwargs["model_map"],
    )


class TestTermination:
    """§8: required at startup, positive caps, never an unbounded loop."""

    def test_missing_max_tokens_rejected(self) -> None:
        with pytest.raises(ValidationError):
            load(termination={"max_rounds": 4})

    def test_missing_max_rounds_rejected(self) -> None:
        with pytest.raises(ValidationError):
            load(termination={"max_tokens": 20_000})

    @pytest.mark.parametrize("bad", [0, -1])
    def test_nonpositive_caps_rejected(self, bad: int) -> None:
        with pytest.raises(ValidationError):
            load(termination={"max_rounds": bad, "max_tokens": 20_000})
        with pytest.raises(ValidationError):
            load(termination={"max_rounds": 4, "max_tokens": bad})


class TestFeedback:
    """§4.1: run-path decision is BINARY — exactly two values."""

    @pytest.mark.parametrize("decision", ["approved", "rejected"])
    def test_binary_decisions_accepted(self, decision: str) -> None:
        contracts = load(feedback={"decision": decision, "rationale": "why"})
        assert contracts.feedback.decision == decision

    def test_third_decision_value_rejected(self) -> None:
        # approved_with_adjustment lives ONLY in bundle-seed frontmatter and the
        # promotion gate's accepted set — the run path must reject it (§4).
        with pytest.raises(ValidationError):
            load(feedback={"decision": "approved_with_adjustment", "rationale": "why"})

    def test_empty_rationale_rejected(self) -> None:
        with pytest.raises(ValidationError):
            load(feedback={"decision": "approved", "rationale": ""})


class TestDataSource:
    """§10: a docs directory + a positive top-k."""

    def test_empty_docs_dir_rejected(self) -> None:
        with pytest.raises(ValidationError):
            load(data_source={"docs_dir": "", "top_k": 3})

    def test_nonpositive_top_k_rejected(self) -> None:
        with pytest.raises(ValidationError):
            load(data_source={"docs_dir": "docs", "top_k": 0})


class TestModelMap:
    """§10: role -> model id per backend profile, each profile REQUIRING a default."""

    def test_profile_without_default_rejected(self) -> None:
        with pytest.raises(ValidationError):
            load(model_map={"profiles": {"anthropic": {"proposer": "some-model-id"}}})

    def test_empty_profiles_rejected(self) -> None:
        with pytest.raises(ValidationError):
            load(model_map={"profiles": {}})

    def test_bundled_model_map_is_valid(self) -> None:
        # model_map=None falls back to the bundled data/model_map.json, which must
        # itself satisfy the contract (fail-fast on the shipped config too).
        contracts = load(model_map=None)  # type: ignore[arg-type]
        assert "default" in contracts.model_map.profiles["anthropic"]


def test_happy_path_validates_all_four() -> None:
    contracts = load()
    assert contracts.data_source.top_k == 3
    assert contracts.termination.max_rounds == 4
    assert contracts.feedback.decision == "approved"
    assert "anthropic" in contracts.model_map.profiles