"""
Unit tests for backend selection (Ollama primary, Claude fallback).

These tests set the cached health-check globals directly so they are
deterministic regardless of which services are reachable.
"""

import pytest

from src.anthropic import model_selector
from src.core.config import config


@pytest.fixture
def local_first(monkeypatch):
    """Baseline: local-first config, both backends healthy."""
    monkeypatch.setattr(config, "PREFER_CLOUD_BACKEND", False)
    monkeypatch.setattr(config, "ANTHROPIC_API_KEY", "sk-test-fake")
    monkeypatch.setattr(model_selector, "_claude_available", True)
    monkeypatch.setattr(model_selector, "_ollama_available", True)


class TestResolveBackend:
    def test_default_is_ollama(self, local_first):
        assert model_selector.resolve_backend() == "ollama"

    def test_prefer_cloud_config_selects_claude(self, local_first, monkeypatch):
        monkeypatch.setattr(config, "PREFER_CLOUD_BACKEND", True)
        assert model_selector.resolve_backend() == "claude"

    def test_prefer_cloud_override_selects_claude(self, local_first):
        assert model_selector.resolve_backend(prefer_cloud=True) == "claude"

    def test_prefer_cloud_without_claude_falls_back_to_ollama(self, local_first, monkeypatch):
        monkeypatch.setattr(config, "PREFER_CLOUD_BACKEND", True)
        monkeypatch.setattr(model_selector, "_claude_available", False)
        assert model_selector.resolve_backend() == "ollama"

    def test_ollama_down_falls_back_to_claude(self, local_first, monkeypatch):
        monkeypatch.setattr(model_selector, "_ollama_available", False)
        assert model_selector.resolve_backend() == "claude"

    def test_ollama_down_without_claude_stays_ollama(self, local_first, monkeypatch):
        monkeypatch.setattr(model_selector, "_ollama_available", False)
        monkeypatch.setattr(model_selector, "_claude_available", False)
        assert model_selector.resolve_backend() == "ollama"

    def test_unknown_ollama_state_counts_as_available(self, local_first, monkeypatch):
        monkeypatch.setattr(model_selector, "_ollama_available", None)
        assert model_selector.resolve_backend() == "ollama"


class TestGetModel:
    def test_ollama_backend_returns_openai_chat_model(self, local_first):
        from pydantic_ai.models.openai import OpenAIChatModel

        model = model_selector.get_model()
        assert isinstance(model, OpenAIChatModel)
        assert model.model_name == config.OLLAMA_DEFAULT_MODEL

    def test_claude_backend_returns_anthropic_model(self, local_first):
        from pydantic_ai.models.anthropic import AnthropicModel

        model = model_selector.get_model(prefer_cloud=True)
        assert isinstance(model, AnthropicModel)
        assert model.model_name == config.ANTHROPIC_MODEL


class TestToolChoiceSettings:
    def test_ollama_forces_tool_choice(self, local_first):
        settings = model_selector.get_tool_choice_settings()
        assert settings.get("extra_body") == {"tool_choice": "required"}

    def test_claude_uses_native_tool_choice(self, local_first, monkeypatch):
        monkeypatch.setattr(config, "PREFER_CLOUD_BACKEND", True)
        settings = model_selector.get_tool_choice_settings()
        assert not settings.get("extra_body")


class TestGetModelInfo:
    def test_reports_ollama_primary(self, local_first):
        info = model_selector.get_model_info()
        assert info["backend"] == "ollama"
        assert info["model"] == config.OLLAMA_DEFAULT_MODEL
        assert info["ollama_available"] is True
        assert info["claude_available"] is True
        assert info["prefer_cloud"] is False

    def test_reports_claude_when_ollama_down(self, local_first, monkeypatch):
        monkeypatch.setattr(model_selector, "_ollama_available", False)
        info = model_selector.get_model_info()
        assert info["backend"] == "claude"
        assert info["model"] == config.ANTHROPIC_MODEL


class TestWithSlotPinning:
    def test_disabled_returns_settings_unchanged(self, local_first, monkeypatch):
        monkeypatch.setattr(config, "BACKEND_SLOT_PINNING", False)
        base = model_selector.get_tool_choice_settings()
        assert model_selector.with_slot_pinning(base, slot=1) is base
        assert model_selector.with_slot_pinning(None, slot=2) is None

    def test_enabled_merges_slot_with_existing_extra_body(self, local_first, monkeypatch):
        monkeypatch.setattr(config, "BACKEND_SLOT_PINNING", True)
        settings = model_selector.with_slot_pinning(
            model_selector.get_tool_choice_settings(), slot=1
        )
        extra_body = settings["extra_body"]
        assert extra_body["id_slot"] == 1
        # tool_choice from the base settings survives the merge
        assert extra_body["tool_choice"] == "required"

    def test_enabled_pins_bare_settings(self, local_first, monkeypatch):
        monkeypatch.setattr(config, "BACKEND_SLOT_PINNING", True)
        settings = model_selector.with_slot_pinning(None, slot=2)
        assert settings["extra_body"] == {"id_slot": 2}

    def test_claude_backend_never_pinned(self, local_first, monkeypatch):
        monkeypatch.setattr(config, "BACKEND_SLOT_PINNING", True)
        monkeypatch.setattr(config, "PREFER_CLOUD_BACKEND", True)
        base = model_selector.get_tool_choice_settings()
        assert model_selector.with_slot_pinning(base, slot=1) is base