"""Tests for Cascade LLM Router."""

import time
from pathlib import Path
from unittest.mock import AsyncMock, patch

import pytest
import yaml

from infrastructure.router.cascade import (
    CascadeRouter,
    CircuitState,
    Provider,
    ProviderMetrics,
    ProviderStatus,
    RouterConfig,
)


class TestProviderMetrics:
    """Test provider metrics tracking."""

    def test_empty_metrics(self):
        """Test metrics with no requests."""
        metrics = ProviderMetrics()
        assert metrics.total_requests == 0
        assert metrics.avg_latency_ms == 0.0
        assert metrics.error_rate == 0.0

    def test_avg_latency_calculation(self):
        """Test average latency calculation."""
        metrics = ProviderMetrics(
            total_requests=4,
            total_latency_ms=1000.0,  # 4 requests, 1000ms total
        )
        assert metrics.avg_latency_ms == 250.0

    def test_error_rate_calculation(self):
        """Test error rate calculation."""
        metrics = ProviderMetrics(
            total_requests=10,
            successful_requests=7,
            failed_requests=3,
        )
        assert metrics.error_rate == 0.3


class TestProvider:
    """Test Provider dataclass."""

    def test_get_default_model(self):
        """Test getting default model."""
        provider = Provider(
            name="test",
            type="ollama",
            enabled=True,
            priority=1,
            models=[
                {"name": "llama3", "default": True},
                {"name": "mistral"},
            ],
        )
        assert provider.get_default_model() == "llama3"

    def test_get_default_model_no_default(self):
        """Test getting first model when no default set."""
        provider = Provider(
            name="test",
            type="ollama",
            enabled=True,
            priority=1,
            models=[
                {"name": "llama3"},
                {"name": "mistral"},
            ],
        )
        assert provider.get_default_model() == "llama3"

    def test_get_default_model_empty(self):
        """Test with no models."""
        provider = Provider(
            name="test",
            type="ollama",
            enabled=True,
            priority=1,
            models=[],
        )
        assert provider.get_default_model() is None


class TestRouterConfig:
    """Test router configuration."""

    def test_default_config(self):
        """Test default configuration values."""
        config = RouterConfig()
        assert config.timeout_seconds == 30
        assert config.max_retries_per_provider == 2
        assert config.retry_delay_seconds == 1
        assert config.circuit_breaker_failure_threshold == 5


class TestCascadeRouterInit:
    """Test CascadeRouter initialization."""

    def test_init_without_config(self, tmp_path):
        """Test initialization without config file."""
        router = CascadeRouter(config_path=tmp_path / "nonexistent.yaml")
        assert len(router.providers) == 0
        assert router.config.timeout_seconds == 30

    def test_init_with_config(self, tmp_path):
        """Test initialization with config file."""
        config = {
            "cascade": {
                "timeout_seconds": 60,
                "max_retries_per_provider": 3,
            },
            "providers": [
                {
                    "name": "test-ollama",
                    "type": "ollama",
                    "enabled": False,  # Disabled to avoid availability check
                    "priority": 1,
                    "url": "http://localhost:11434",
                }
            ],
        }
        config_path = tmp_path / "providers.yaml"
        config_path.write_text(yaml.dump(config))

        router = CascadeRouter(config_path=config_path)
        assert router.config.timeout_seconds == 60
        assert router.config.max_retries_per_provider == 3
        assert len(router.providers) == 0  # Provider is disabled

    def test_env_var_expansion(self, tmp_path, monkeypatch):
        """Test environment variable expansion in config."""
        monkeypatch.setenv("TEST_API_KEY", "secret123")

        config = {
            "cascade": {},
            "providers": [
                {
                    "name": "test-openai",
                    "type": "openai",
                    "enabled": True,
                    "priority": 1,
                    "api_key": "${TEST_API_KEY}",
                }
            ],
        }
        config_path = tmp_path / "providers.yaml"
        config_path.write_text(yaml.dump(config))

        router = CascadeRouter(config_path=config_path)
        assert len(router.providers) == 1
        assert router.providers[0].api_key == "secret123"


class TestCascadeRouterMetrics:
    """Test metrics tracking."""

    def test_record_success(self):
        """Test recording successful request."""
        provider = Provider(name="test", type="ollama", enabled=True, priority=1)

        router = CascadeRouter(config_path=Path("/nonexistent"))
        router._record_success(provider, 150.0)

        assert provider.metrics.total_requests == 1
        assert provider.metrics.successful_requests == 1
        assert provider.metrics.total_latency_ms == 150.0
        assert provider.metrics.consecutive_failures == 0

    def test_record_failure(self):
        """Test recording failed request."""
        provider = Provider(name="test", type="ollama", enabled=True, priority=1)

        router = CascadeRouter(config_path=Path("/nonexistent"))
        router._record_failure(provider)

        assert provider.metrics.total_requests == 1
        assert provider.metrics.failed_requests == 1
        assert provider.metrics.consecutive_failures == 1

    def test_circuit_breaker_opens(self):
        """Test circuit breaker opens after failures."""
        provider = Provider(name="test", type="ollama", enabled=True, priority=1)

        router = CascadeRouter(config_path=Path("/nonexistent"))
        router.config.circuit_breaker_failure_threshold = 3

        # Record 3 failures
        for _ in range(3):
            router._record_failure(provider)

        assert provider.circuit_state == CircuitState.OPEN
        assert provider.status == ProviderStatus.UNHEALTHY
        assert provider.circuit_opened_at is not None

    def test_circuit_breaker_can_close(self):
        """Test circuit breaker can transition to closed."""
        provider = Provider(name="test", type="ollama", enabled=True, priority=1)

        router = CascadeRouter(config_path=Path("/nonexistent"))
        router.config.circuit_breaker_failure_threshold = 3
        router.config.circuit_breaker_recovery_timeout = 0.1

        # Open the circuit
        for _ in range(3):
            router._record_failure(provider)

        assert provider.circuit_state == CircuitState.OPEN

        # Wait for recovery timeout (reduced for faster tests)
        import time

        time.sleep(0.2)

        # Check if can close
        assert router._can_close_circuit(provider) is True

    def test_half_open_to_closed(self):
        """Test circuit breaker closes after successful test calls."""
        provider = Provider(name="test", type="ollama", enabled=True, priority=1)

        router = CascadeRouter(config_path=Path("/nonexistent"))
        router.config.circuit_breaker_half_open_max_calls = 2

        # Manually set to half-open
        provider.circuit_state = CircuitState.HALF_OPEN
        provider.half_open_calls = 0

        # Record successful calls
        router._record_success(provider, 100.0)
        assert provider.circuit_state == CircuitState.HALF_OPEN  # Still half-open

        router._record_success(provider, 100.0)
        assert provider.circuit_state == CircuitState.CLOSED  # Now closed
        assert provider.status == ProviderStatus.HEALTHY


class TestCascadeRouterGetMetrics:
    """Test get_metrics method."""

    def test_get_metrics_empty(self):
        """Test getting metrics with no providers."""
        router = CascadeRouter(config_path=Path("/nonexistent"))
        metrics = router.get_metrics()

        assert "providers" in metrics
        assert len(metrics["providers"]) == 0

    def test_get_metrics_with_providers(self):
        """Test getting metrics with providers."""
        router = CascadeRouter(config_path=Path("/nonexistent"))

        # Add a test provider
        provider = Provider(
            name="test",
            type="ollama",
            enabled=True,
            priority=1,
        )
        provider.metrics.total_requests = 10
        provider.metrics.successful_requests = 8
        provider.metrics.failed_requests = 2
        provider.metrics.total_latency_ms = 2000.0

        router.providers = [provider]

        metrics = router.get_metrics()

        assert len(metrics["providers"]) == 1
        p_metrics = metrics["providers"][0]
        assert p_metrics["name"] == "test"
        assert p_metrics["metrics"]["total_requests"] == 10
        assert p_metrics["metrics"]["error_rate"] == 0.2
        assert p_metrics["metrics"]["avg_latency_ms"] == 200.0


class TestCascadeRouterGetStatus:
    """Test get_status method."""

    def test_get_status(self):
        """Test getting router status."""
        router = CascadeRouter(config_path=Path("/nonexistent"))

        provider = Provider(
            name="test",
            type="ollama",
            enabled=True,
            priority=1,
            models=[{"name": "llama3", "default": True}],
        )
        router.providers = [provider]

        status = router.get_status()

        assert status["total_providers"] == 1
        assert status["healthy_providers"] == 1
        assert status["degraded_providers"] == 0
        assert status["unhealthy_providers"] == 0
        assert len(status["providers"]) == 1


@pytest.mark.asyncio
class TestCascadeRouterComplete:
    """Test complete method with failover."""

    async def test_complete_with_ollama(self):
        """Test successful completion with Ollama."""
        router = CascadeRouter(config_path=Path("/nonexistent"))

        provider = Provider(
            name="ollama-local",
            type="ollama",
            enabled=True,
            priority=1,
            url="http://localhost:11434",
            models=[{"name": "llama3.2", "default": True}],
        )
        router.providers = [provider]

        # Mock the Ollama call
        with patch.object(router, "_call_ollama") as mock_call:
            mock_call.return_value = AsyncMock()()
            mock_call.return_value = {
                "content": "Hello, world!",
                "model": "llama3.2",
            }

            result = await router.complete(
                messages=[{"role": "user", "content": "Hi"}],
            )

        assert result["content"] == "Hello, world!"
        assert result["provider"] == "ollama-local"
        assert result["model"] == "llama3.2"

    async def test_failover_to_second_provider(self):
        """Test failover when first provider fails."""
        router = CascadeRouter(config_path=Path("/nonexistent"))

        provider1 = Provider(
            name="ollama-failing",
            type="ollama",
            enabled=True,
            priority=1,
            url="http://localhost:11434",
            models=[{"name": "llama3.2", "default": True}],
        )
        provider2 = Provider(
            name="ollama-backup",
            type="ollama",
            enabled=True,
            priority=2,
            url="http://backup:11434",
            models=[{"name": "llama3.2", "default": True}],
        )
        router.providers = [provider1, provider2]

        # First provider fails, second succeeds
        call_count = [0]

        async def side_effect(*args, **kwargs):
            call_count[0] += 1
            # First 2 retries for provider1 fail, then provider2 succeeds
            if call_count[0] <= router.config.max_retries_per_provider:
                raise RuntimeError("Connection failed")
            return {"content": "Backup response", "model": "llama3.2"}

        with patch.object(router, "_call_ollama") as mock_call:
            mock_call.side_effect = side_effect

            result = await router.complete(
                messages=[{"role": "user", "content": "Hi"}],
            )

        assert result["content"] == "Backup response"
        assert result["provider"] == "ollama-backup"

    async def test_all_providers_fail(self):
        """Test error when all providers fail."""
        router = CascadeRouter(config_path=Path("/nonexistent"))

        provider = Provider(
            name="failing",
            type="ollama",
            enabled=True,
            priority=1,
            models=[{"name": "llama3.2", "default": True}],
        )
        router.providers = [provider]

        with patch.object(router, "_call_ollama") as mock_call:
            mock_call.side_effect = RuntimeError("Always fails")

            with pytest.raises(RuntimeError) as exc_info:
                await router.complete(messages=[{"role": "user", "content": "Hi"}])

            assert "All providers failed" in str(exc_info.value)

    async def test_skips_unhealthy_provider(self):
        """Test that unhealthy providers are skipped."""
        router = CascadeRouter(config_path=Path("/nonexistent"))

        provider1 = Provider(
            name="unhealthy",
            type="ollama",
            enabled=True,
            priority=1,
            status=ProviderStatus.UNHEALTHY,
            circuit_state=CircuitState.OPEN,
            circuit_opened_at=time.time(),  # Just opened
            models=[{"name": "llama3.2", "default": True}],
        )
        provider2 = Provider(
            name="healthy",
            type="ollama",
            enabled=True,
            priority=2,
            models=[{"name": "llama3.2", "default": True}],
        )
        router.providers = [provider1, provider2]

        with patch.object(router, "_call_ollama") as mock_call:
            mock_call.return_value = {"content": "Success", "model": "llama3.2"}

            result = await router.complete(
                messages=[{"role": "user", "content": "Hi"}],
            )

        # Should use the healthy provider
        assert result["provider"] == "healthy"


class TestProviderAvailabilityCheck:
    """Test provider availability checking."""

    def test_check_ollama_without_requests(self):
        """Test Ollama returns True when requests not available (fallback)."""
        router = CascadeRouter(config_path=Path("/nonexistent"))

        provider = Provider(
            name="ollama",
            type="ollama",
            enabled=True,
            priority=1,
            url="http://localhost:11434",
        )

        # When requests is None, assume available
        import infrastructure.router.cascade as cascade_module

        old_requests = cascade_module.requests
        cascade_module.requests = None
        try:
            assert router._check_provider_available(provider) is True
        finally:
            cascade_module.requests = old_requests

    def test_check_openai_with_key(self):
        """Test OpenAI with API key."""
        router = CascadeRouter(config_path=Path("/nonexistent"))

        provider = Provider(
            name="openai",
            type="openai",
            enabled=True,
            priority=1,
            api_key="sk-test123",
        )

        assert router._check_provider_available(provider) is True

    def test_check_openai_without_key(self):
        """Test OpenAI without API key."""
        router = CascadeRouter(config_path=Path("/nonexistent"))

        provider = Provider(
            name="openai",
            type="openai",
            enabled=True,
            priority=1,
            api_key=None,
        )

        assert router._check_provider_available(provider) is False

    def test_check_vllm_mlx_without_requests(self):
        """Test vllm-mlx returns True when requests not available (fallback)."""
        router = CascadeRouter(config_path=Path("/nonexistent"))

        provider = Provider(
            name="vllm-mlx-local",
            type="vllm_mlx",
            enabled=True,
            priority=2,
            base_url="http://localhost:8000/v1",
        )

        import infrastructure.router.cascade as cascade_module

        old_requests = cascade_module.requests
        cascade_module.requests = None
        try:
            assert router._check_provider_available(provider) is True
        finally:
            cascade_module.requests = old_requests

    def test_check_vllm_mlx_server_healthy(self):
        """Test vllm-mlx when health check succeeds."""
        from unittest.mock import MagicMock, patch

        router = CascadeRouter(config_path=Path("/nonexistent"))

        provider = Provider(
            name="vllm-mlx-local",
            type="vllm_mlx",
            enabled=True,
            priority=2,
            base_url="http://localhost:8000/v1",
        )

        mock_response = MagicMock()
        mock_response.status_code = 200

        with patch("infrastructure.router.cascade.requests") as mock_requests:
            mock_requests.get.return_value = mock_response
            result = router._check_provider_available(provider)

        assert result is True
        mock_requests.get.assert_called_once_with("http://localhost:8000/health", timeout=5)

    def test_check_vllm_mlx_server_down(self):
        """Test vllm-mlx when server is not running."""
        from unittest.mock import patch

        router = CascadeRouter(config_path=Path("/nonexistent"))

        provider = Provider(
            name="vllm-mlx-local",
            type="vllm_mlx",
            enabled=True,
            priority=2,
            base_url="http://localhost:8000/v1",
        )

        with patch("infrastructure.router.cascade.requests") as mock_requests:
            mock_requests.get.side_effect = ConnectionRefusedError("Connection refused")
            result = router._check_provider_available(provider)

        assert result is False

    def test_check_vllm_mlx_default_url(self):
        """Test vllm-mlx uses default localhost:8000 when no URL configured."""
        from unittest.mock import MagicMock, patch

        router = CascadeRouter(config_path=Path("/nonexistent"))

        provider = Provider(
            name="vllm-mlx-local",
            type="vllm_mlx",
            enabled=True,
            priority=2,
        )

        mock_response = MagicMock()
        mock_response.status_code = 200

        with patch("infrastructure.router.cascade.requests") as mock_requests:
            mock_requests.get.return_value = mock_response
            router._check_provider_available(provider)

        mock_requests.get.assert_called_once_with("http://localhost:8000/health", timeout=5)


@pytest.mark.asyncio
class TestVllmMlxProvider:
    """Test vllm-mlx provider integration."""

    async def test_complete_with_vllm_mlx(self):
        """Test successful completion via vllm-mlx."""
        router = CascadeRouter(config_path=Path("/nonexistent"))

        provider = Provider(
            name="vllm-mlx-local",
            type="vllm_mlx",
            enabled=True,
            priority=2,
            base_url="http://localhost:8000/v1",
            models=[{"name": "Qwen/Qwen2.5-14B-Instruct-MLX", "default": True}],
        )
        router.providers = [provider]

        with patch.object(router, "_call_vllm_mlx") as mock_call:
            mock_call.return_value = {
                "content": "MLX response",
                "model": "Qwen/Qwen2.5-14B-Instruct-MLX",
            }

            result = await router.complete(
                messages=[{"role": "user", "content": "Hi"}],
            )

        assert result["content"] == "MLX response"
        assert result["provider"] == "vllm-mlx-local"
        assert result["model"] == "Qwen/Qwen2.5-14B-Instruct-MLX"

    async def test_vllm_mlx_base_url_normalization(self):
        """Test _call_vllm_mlx appends /v1 when missing."""
        from unittest.mock import AsyncMock, MagicMock, patch

        router = CascadeRouter(config_path=Path("/nonexistent"))

        provider = Provider(
            name="vllm-mlx-local",
            type="vllm_mlx",
            enabled=True,
            priority=2,
            base_url="http://localhost:8000",  # No /v1
            models=[{"name": "qwen-mlx", "default": True}],
        )

        mock_choice = MagicMock()
        mock_choice.message.content = "hello"
        mock_response = MagicMock()
        mock_response.choices = [mock_choice]
        mock_response.model = "qwen-mlx"

        async def fake_create(**kwargs):
            return mock_response

        with patch("openai.AsyncOpenAI") as mock_openai_cls:
            mock_client = MagicMock()
            mock_client.chat.completions.create = AsyncMock(side_effect=fake_create)
            mock_openai_cls.return_value = mock_client

            await router._call_vllm_mlx(
                provider=provider,
                messages=[{"role": "user", "content": "hi"}],
                model="qwen-mlx",
                temperature=0.7,
                max_tokens=None,
            )

            call_kwargs = mock_openai_cls.call_args
            base_url_used = call_kwargs.kwargs.get("base_url") or call_kwargs[1].get("base_url")
            assert base_url_used.endswith("/v1")

    async def test_vllm_mlx_is_local_not_cloud(self):
        """Confirm vllm_mlx is not subject to metabolic protocol cloud skip."""
        router = CascadeRouter(config_path=Path("/nonexistent"))

        provider = Provider(
            name="vllm-mlx-local",
            type="vllm_mlx",
            enabled=True,
            priority=2,
            base_url="http://localhost:8000/v1",
            models=[{"name": "qwen-mlx", "default": True}],
        )
        router.providers = [provider]

        # Quota monitor downshifts to local (ACTIVE tier) — vllm_mlx should still be tried
        with patch("infrastructure.router.cascade._quota_monitor") as mock_qm:
            mock_qm.select_model.return_value = "qwen3:14b"
            mock_qm.check.return_value = None

            with patch.object(router, "_call_vllm_mlx") as mock_call:
                mock_call.return_value = {
                    "content": "Local MLX response",
                    "model": "qwen-mlx",
                }
                result = await router.complete(
                    messages=[{"role": "user", "content": "hi"}],
                )

        assert result["content"] == "Local MLX response"


class TestMetabolicProtocol:
    """Test metabolic protocol: cloud providers skip when quota is ACTIVE/RESTING."""

    def _make_anthropic_provider(self) -> "Provider":
        return Provider(
            name="anthropic-primary",
            type="anthropic",
            enabled=True,
            priority=1,
            api_key="test-key",
            models=[{"name": "claude-sonnet-4-6", "default": True}],
        )

    async def test_cloud_provider_allowed_in_burst_tier(self):
        """BURST tier (quota healthy): cloud provider is tried."""
        router = CascadeRouter(config_path=Path("/nonexistent"))
        router.providers = [self._make_anthropic_provider()]

        with patch("infrastructure.router.cascade._quota_monitor") as mock_qm:
            # select_model returns cloud model → BURST tier
            mock_qm.select_model.return_value = "claude-sonnet-4-6"
            mock_qm.check.return_value = None

            with patch.object(router, "_call_anthropic") as mock_call:
                mock_call.return_value = {"content": "Cloud response", "model": "claude-sonnet-4-6"}
                result = await router.complete(
                    messages=[{"role": "user", "content": "hard question"}],
                )

        mock_call.assert_called_once()
        assert result["content"] == "Cloud response"

    async def test_cloud_provider_skipped_in_active_tier(self):
        """ACTIVE tier (5-hour >= 50%): cloud provider is skipped."""
        router = CascadeRouter(config_path=Path("/nonexistent"))
        router.providers = [self._make_anthropic_provider()]

        with patch("infrastructure.router.cascade._quota_monitor") as mock_qm:
            # select_model returns local 14B → ACTIVE tier
            mock_qm.select_model.return_value = "qwen3:14b"
            mock_qm.check.return_value = None

            with patch.object(router, "_call_anthropic") as mock_call:
                with pytest.raises(RuntimeError, match="All providers failed"):
                    await router.complete(
                        messages=[{"role": "user", "content": "question"}],
                    )

        mock_call.assert_not_called()

    async def test_cloud_provider_skipped_in_resting_tier(self):
        """RESTING tier (7-day >= 80%): cloud provider is skipped."""
        router = CascadeRouter(config_path=Path("/nonexistent"))
        router.providers = [self._make_anthropic_provider()]

        with patch("infrastructure.router.cascade._quota_monitor") as mock_qm:
            # select_model returns local 8B → RESTING tier
            mock_qm.select_model.return_value = "qwen3:8b"
            mock_qm.check.return_value = None

            with patch.object(router, "_call_anthropic") as mock_call:
                with pytest.raises(RuntimeError, match="All providers failed"):
                    await router.complete(
                        messages=[{"role": "user", "content": "simple question"}],
                    )

        mock_call.assert_not_called()

    async def test_local_provider_always_tried_regardless_of_quota(self):
        """Local (ollama/vllm_mlx) providers bypass the metabolic protocol."""
        router = CascadeRouter(config_path=Path("/nonexistent"))
        provider = Provider(
            name="ollama-local",
            type="ollama",
            enabled=True,
            priority=1,
            url="http://localhost:11434",
            models=[{"name": "qwen3:14b", "default": True}],
        )
        router.providers = [provider]

        with patch("infrastructure.router.cascade._quota_monitor") as mock_qm:
            mock_qm.select_model.return_value = "qwen3:8b"  # RESTING tier

            with patch.object(router, "_call_ollama") as mock_call:
                mock_call.return_value = {"content": "Local response", "model": "qwen3:14b"}
                result = await router.complete(
                    messages=[{"role": "user", "content": "hi"}],
                )

        mock_call.assert_called_once()
        assert result["content"] == "Local response"

    async def test_no_quota_monitor_allows_cloud(self):
        """When quota monitor is None (unavailable), cloud providers are allowed."""
        router = CascadeRouter(config_path=Path("/nonexistent"))
        router.providers = [self._make_anthropic_provider()]

        with patch("infrastructure.router.cascade._quota_monitor", None):
            with patch.object(router, "_call_anthropic") as mock_call:
                mock_call.return_value = {"content": "Cloud response", "model": "claude-sonnet-4-6"}
                result = await router.complete(
                    messages=[{"role": "user", "content": "question"}],
                )

        mock_call.assert_called_once()
        assert result["content"] == "Cloud response"


class TestCascadeRouterReload:
    """Test hot-reload of providers.yaml."""

    def test_reload_preserves_metrics(self, tmp_path):
        """Test that reload preserves metrics for existing providers."""
        config = {
            "providers": [
                {
                    "name": "test-openai",
                    "type": "openai",
                    "enabled": True,
                    "priority": 1,
                    "api_key": "sk-test",
                }
            ],
        }
        config_path = tmp_path / "providers.yaml"
        config_path.write_text(yaml.dump(config))

        router = CascadeRouter(config_path=config_path)
        assert len(router.providers) == 1

        # Simulate some traffic
        router._record_success(router.providers[0], 150.0)
        router._record_success(router.providers[0], 250.0)
        assert router.providers[0].metrics.total_requests == 2

        # Reload
        result = router.reload_config()

        assert result["total_providers"] == 1
        assert result["preserved"] == 1
        assert result["added"] == []
        assert result["removed"] == []
        # Metrics survived
        assert router.providers[0].metrics.total_requests == 2
        assert router.providers[0].metrics.total_latency_ms == 400.0

    def test_reload_preserves_circuit_breaker(self, tmp_path):
        """Test that reload preserves circuit breaker state."""
        config = {
            "cascade": {"circuit_breaker": {"failure_threshold": 2}},
            "providers": [
                {
                    "name": "test-openai",
                    "type": "openai",
                    "enabled": True,
                    "priority": 1,
                    "api_key": "sk-test",
                }
            ],
        }
        config_path = tmp_path / "providers.yaml"
        config_path.write_text(yaml.dump(config))

        router = CascadeRouter(config_path=config_path)

        # Open circuit breaker
        for _ in range(2):
            router._record_failure(router.providers[0])
        assert router.providers[0].circuit_state == CircuitState.OPEN

        # Reload
        router.reload_config()

        # Circuit breaker state preserved
        assert router.providers[0].circuit_state == CircuitState.OPEN
        assert router.providers[0].status == ProviderStatus.UNHEALTHY

    def test_reload_detects_added_provider(self, tmp_path):
        """Test that reload detects newly added providers."""
        config = {
            "providers": [
                {
                    "name": "openai-1",
                    "type": "openai",
                    "enabled": True,
                    "priority": 1,
                    "api_key": "sk-test",
                }
            ],
        }
        config_path = tmp_path / "providers.yaml"
        config_path.write_text(yaml.dump(config))

        router = CascadeRouter(config_path=config_path)
        assert len(router.providers) == 1

        # Add a second provider to config
        config["providers"].append(
            {
                "name": "anthropic-1",
                "type": "anthropic",
                "enabled": True,
                "priority": 2,
                "api_key": "sk-ant-test",
            }
        )
        config_path.write_text(yaml.dump(config))

        result = router.reload_config()

        assert result["total_providers"] == 2
        assert result["preserved"] == 1
        assert result["added"] == ["anthropic-1"]
        assert result["removed"] == []

    def test_reload_detects_removed_provider(self, tmp_path):
        """Test that reload detects removed providers."""
        config = {
            "providers": [
                {
                    "name": "openai-1",
                    "type": "openai",
                    "enabled": True,
                    "priority": 1,
                    "api_key": "sk-test",
                },
                {
                    "name": "anthropic-1",
                    "type": "anthropic",
                    "enabled": True,
                    "priority": 2,
                    "api_key": "sk-ant-test",
                },
            ],
        }
        config_path = tmp_path / "providers.yaml"
        config_path.write_text(yaml.dump(config))

        router = CascadeRouter(config_path=config_path)
        assert len(router.providers) == 2

        # Remove anthropic
        config["providers"] = [config["providers"][0]]
        config_path.write_text(yaml.dump(config))

        result = router.reload_config()

        assert result["total_providers"] == 1
        assert result["preserved"] == 1
        assert result["removed"] == ["anthropic-1"]

    def test_reload_re_sorts_by_priority(self, tmp_path):
        """Test that providers are re-sorted by priority after reload."""
        config = {
            "providers": [
                {
                    "name": "low-priority",
                    "type": "openai",
                    "enabled": True,
                    "priority": 10,
                    "api_key": "sk-test",
                },
                {
                    "name": "high-priority",
                    "type": "openai",
                    "enabled": True,
                    "priority": 1,
                    "api_key": "sk-test2",
                },
            ],
        }
        config_path = tmp_path / "providers.yaml"
        config_path.write_text(yaml.dump(config))

        router = CascadeRouter(config_path=config_path)
        assert router.providers[0].name == "high-priority"

        # Swap priorities
        config["providers"][0]["priority"] = 1
        config["providers"][1]["priority"] = 10
        config_path.write_text(yaml.dump(config))

        router.reload_config()

        assert router.providers[0].name == "low-priority"
        assert router.providers[1].name == "high-priority"