from fastapi.testclient import TestClient

from serving.api import app


client = TestClient(app)


def test_health_endpoint() -> None:
    response = client.get("/health")

    assert response.status_code == 200
    payload = response.json()
    assert payload["status"] == "ok"
    assert "verifier_backend" in payload
    assert "fallback_used" in payload
    assert "retrieval_backend" in payload
    assert "embedding_model" in payload
    assert "retrieval_fallback_used" in payload
    assert "reranker_backend" in payload
    assert "cross_encoder_model" in payload
    assert "reranker_fallback_used" in payload
    assert "checkpoint_path" in payload


def test_verify_endpoint_rejects_empty_claim() -> None:
    response = client.post("/verify", json={"claim": "   ", "top_k": 5})

    assert response.status_code == 422


def test_verify_endpoint_returns_grounded_response() -> None:
    response = client.post("/verify", json={"claim": "Paris is in France", "top_k": 2})

    assert response.status_code == 200
    payload = response.json()
    assert payload["verdict"] in {"SUPPORTED", "REFUTED", "NOT ENOUGH INFO"}
    assert "explanation" in payload
    assert isinstance(payload["evidence"], list)
    assert "backend_used" in payload
    assert "retrieval_backend" in payload
    assert "retrieval_fallback_used" in payload
    assert "reranker_backend" in payload
    assert "reranker_fallback_used" in payload


def test_metrics_endpoint_reports_snapshot() -> None:
    client.post("/verify", json={"claim": "Paris is in France", "top_k": 2})
    response = client.get("/metrics")

    assert response.status_code == 200
    payload = response.json()
    assert "requests" in payload
    assert "cache_entries" in payload
    assert "average_latency_ms" in payload
    assert "p95_latency_ms" in payload
    assert "verifier_backend" in payload
    assert "retrieval_backend" in payload
    assert "embedding_model" in payload
    assert "retrieval_fallback_used" in payload
    assert "reranker_backend" in payload
    assert "cross_encoder_model" in payload
    assert "reranker_fallback_used" in payload
    assert "checkpoint_path" in payload
    assert "backend_usage_counts" in payload