"""
Offline tests for Phase 3 enrichment running only on the top-k slice with
ONE batched related-documents lookup (perf: the old code ran a sequential
Neo4j query per fused result and the final trim discarded most of it).
"""

from unittest.mock import AsyncMock, MagicMock

import pytest

from src.services.hybrid_rag_service import HybridRAGService

TENANT = "llm_tester"


@pytest.fixture
def graph():
    g = MagicMock()
    g.get_related_documents_batch = AsyncMock(return_value={})
    return g


@pytest.fixture
def service(graph):
    settings = MagicMock()
    settings.ollama_llm_model = "test-model"
    return HybridRAGService(
        vector_service=MagicMock(),
        graph_service=graph,
        searxng_client=MagicMock(),
        ollama_client=MagicMock(),
        content_extractor=MagicMock(),
        settings=settings,
    )


def _fused(n):
    return [
        {
            "result": {"page_id": i + 1, "title": f"page {i + 1}"},
            "rrf_score": 1.0 / (i + 1),
            "sources": ["vector"],
        }
        for i in range(n)
    ]


@pytest.mark.unit
class TestTopKEnrichment:
    async def test_only_top_k_enriched_with_single_batched_lookup(
        self, service, graph
    ):
        results = _fused(30)

        enriched = await service._enrich_with_related_dossiers(
            results, user=TENANT, top_k=5
        )

        # ONE batched lookup, only for the top-k page ids
        graph.get_related_documents_batch.assert_awaited_once()
        kwargs = graph.get_related_documents_batch.await_args.kwargs
        assert kwargs["page_ids"] == [1, 2, 3, 4, 5]
        assert kwargs["user"] == TENANT
        # The single-page method must not be used anymore
        graph.get_related_documents.assert_not_called()

        # Every result still carries the key (tail is empty)
        assert all("related_dossiers" in r for r in enriched)
        assert all(r["related_dossiers"] == [] for r in enriched[5:])

    async def test_related_docs_mapped_onto_results(self, service, graph):
        graph.get_related_documents_batch = AsyncMock(return_value={
            1: [{
                "page_id": 9, "title": "rel", "path": "p/rel",
                "tags": ["docker", "infra", "misc", "extra-tag-ignored"],
                "shared_entities": 3,
            }],
        })
        results = _fused(3)

        enriched = await service._enrich_with_related_dossiers(
            results, user=TENANT, top_k=2
        )

        dossiers = enriched[0]["related_dossiers"]
        assert len(dossiers) == 3  # max 3 tags per related doc
        assert dossiers[0] == {
            "page_id": 9, "title": "rel", "path": "p/rel",
            "tag": "docker", "shared_entities": 3,
        }
        assert enriched[1]["related_dossiers"] == []
        assert enriched[2]["related_dossiers"] == []

    async def test_results_without_page_id_are_skipped(self, service, graph):
        results = [
            {"result": {"url": "http://x", "title": "web"}, "sources": ["web"]},
            {"result": {"page_id": 7, "title": "wiki"}, "sources": ["vector"]},
        ]

        enriched = await service._enrich_with_related_dossiers(
            results, user=TENANT, top_k=10
        )

        kwargs = graph.get_related_documents_batch.await_args.kwargs
        assert kwargs["page_ids"] == [7]
        assert enriched[0]["related_dossiers"] == []

    async def test_batch_lookup_failure_degrades_gracefully(self, service, graph):
        graph.get_related_documents_batch = AsyncMock(
            side_effect=RuntimeError("neo4j down")
        )
        results = _fused(3)

        enriched = await service._enrich_with_related_dossiers(
            results, user=TENANT, top_k=3
        )

        assert all(r["related_dossiers"] == [] for r in enriched)