"""Tests for configuration module."""

import os
from unittest.mock import patch

import pytest
from pydantic import ValidationError

from llm_inference.config import LLMSettings, SettingsCache


class TestLLMSettings:
    """Tests for LLMSettings."""

    def test_required_fields(self) -> None:
        """Test that required fields must be provided."""
        # Without required fields, should raise ValidationError
        with pytest.raises(ValidationError):
            LLMSettings()

    def test_with_required_fields(self) -> None:
        """Test settings with all required fields provided."""
        settings = LLMSettings(
            default_backend="litellm",
            enable_vllm=False,
            enable_llamacpp=False,
            external_url="http://localhost:8100",
        )

        assert settings.default_backend == "litellm"
        assert settings.enable_vllm is False
        assert settings.enable_llamacpp is False

    def test_optional_defaults(self) -> None:
        """Test optional fields have sensible defaults."""
        settings = LLMSettings(
            default_backend="litellm",
            enable_vllm=False,
            enable_llamacpp=False,
            external_url="http://localhost:8100",
        )

        assert settings.default_model == "qwen3.5"
        assert settings.host == "0.0.0.0"
        assert settings.port == 14011
        assert settings.request_timeout == 120.0
        assert settings.max_retries == 3
        assert settings.rate_limit_rps == 10.0

    def test_env_override(self) -> None:
        """Test environment variable overrides."""
        env_vars = {
            "LLM_DEFAULT_BACKEND": "vllm",
            "LLM_ENABLE_VLLM": "true",
            "LLM_ENABLE_LLAMACPP": "false",
            "LLM_PORT": "8150",
            "LLM_OPENAI_API_KEY": "sk-test-key",
            "LLM_EXTERNAL_URL": "http://localhost:8100",
        }

        with patch.dict(os.environ, env_vars, clear=False):
            settings = LLMSettings()

            assert settings.default_backend == "vllm"
            assert settings.port == 8150
            assert settings.enable_vllm is True
            assert settings.openai_api_key == "sk-test-key"

    def test_vllm_url_default(self) -> None:
        """Test vLLM URL default value."""
        settings = LLMSettings(
            default_backend="litellm",
            enable_vllm=False,
            enable_llamacpp=False,
            external_url="http://localhost:8100",
        )
        assert settings.vllm_base_url == "http://localhost:14001"

    def test_llamacpp_url_default(self) -> None:
        """Test llama.cpp URL default value."""
        settings = LLMSettings(
            default_backend="litellm",
            enable_vllm=False,
            enable_llamacpp=False,
            external_url="http://localhost:8100",
        )
        assert settings.llamacpp_base_url == "http://localhost:8080"

    def test_timeout_settings(self) -> None:
        """Test timeout and retry configuration."""
        settings = LLMSettings(
            default_backend="litellm",
            enable_vllm=False,
            enable_llamacpp=False,
            external_url="http://localhost:8100",
            request_timeout=60.0,
            connect_timeout=5.0,
            max_retries=5,
        )

        assert settings.request_timeout == 60.0
        assert settings.connect_timeout == 5.0
        assert settings.max_retries == 5

    def test_rate_limit_settings(self) -> None:
        """Test rate limiting configuration."""
        settings = LLMSettings(
            default_backend="litellm",
            enable_vllm=False,
            enable_llamacpp=False,
            external_url="http://localhost:8100",
            rate_limit_rps=20.0,
            rate_limit_burst=50,
        )

        assert settings.rate_limit_rps == 20.0
        assert settings.rate_limit_burst == 50


class TestSettingsCache:
    """Tests for SettingsCache class."""

    def test_set_and_get(self) -> None:
        """Test setting and getting cached settings."""
        SettingsCache.clear()

        settings = LLMSettings(
            default_backend="litellm",
            enable_vllm=False,
            enable_llamacpp=False,
            external_url="http://localhost:8100",
        )
        SettingsCache.set(settings)

        retrieved = SettingsCache.get()
        assert retrieved is settings

    def test_get_without_set_creates_instance(self) -> None:
        """Test that get() creates instance from environment if not set."""
        SettingsCache.clear()

        env_vars = {
            "LLM_DEFAULT_BACKEND": "litellm",
            "LLM_ENABLE_VLLM": "false",
            "LLM_ENABLE_LLAMACPP": "false",
            "LLM_EXTERNAL_URL": "http://localhost:8100",
        }

        with patch.dict(os.environ, env_vars, clear=False):
            settings = SettingsCache.get()
            assert isinstance(settings, LLMSettings)
            assert settings.default_backend == "litellm"

    def test_cached_returns_same_instance(self) -> None:
        """Test that SettingsCache returns cached instance."""
        SettingsCache.clear()

        settings = LLMSettings(
            default_backend="litellm",
            enable_vllm=False,
            enable_llamacpp=False,
            external_url="http://localhost:8100",
        )
        SettingsCache.set(settings)

        settings1 = SettingsCache.get()
        settings2 = SettingsCache.get()

        assert settings1 is settings2

    def test_clear_removes_cached_instance(self) -> None:
        """Test that clear() removes the cached instance."""
        settings = LLMSettings(
            default_backend="litellm",
            enable_vllm=False,
            enable_llamacpp=False,
            external_url="http://localhost:8100",
        )
        SettingsCache.set(settings)

        SettingsCache.clear()

        # After clear, _instance should be None
        assert SettingsCache._instance is None