"""Tests for the GraphQueryEngine — Cypher validation and safety guardrails."""

import pytest
from unittest.mock import AsyncMock, MagicMock, patch

from reachy_mini_conversation_app.graph_query_engine import (
    validate_cypher,
    GraphQueryEngine,
)


class TestCypherValidation:
    """Test the Cypher safety validation function."""

    def test_rejects_create(self):
        assert validate_cypher("CREATE (n:Person {name: 'test'})") is False

    def test_rejects_merge(self):
        assert validate_cypher("MERGE (n:Person {name: 'test'})") is False

    def test_rejects_delete(self):
        assert validate_cypher("MATCH (n) DELETE n") is False

    def test_rejects_detach_delete(self):
        assert validate_cypher("MATCH (n) DETACH DELETE n") is False

    def test_rejects_set(self):
        assert validate_cypher("MATCH (n) SET n.name = 'test'") is False

    def test_rejects_remove(self):
        assert validate_cypher("MATCH (n) REMOVE n.name") is False

    def test_rejects_drop(self):
        assert validate_cypher("DROP INDEX ON :Person(name)") is False

    def test_rejects_call(self):
        assert validate_cypher("CALL db.labels()") is False

    def test_rejects_load_csv(self):
        assert validate_cypher("LOAD CSV FROM 'file:///data.csv' AS line") is False

    def test_rejects_foreach(self):
        assert (
            validate_cypher("MATCH (n) FOREACH (x IN [1,2] | SET n.val = x)") is False
        )

    def test_rejects_empty_string(self):
        assert validate_cypher("") is False

    def test_rejects_whitespace_only(self):
        assert validate_cypher("   ") is False

    def test_allows_simple_match(self):
        assert validate_cypher("MATCH (n) RETURN n") is True

    def test_allows_match_with_where(self):
        assert (
            validate_cypher(
                "MATCH (p:Person {name: $patient_name})-[:TAKES]->(m:Medication) "
                "WHERE m.dose IS NOT NULL RETURN m.name, m.dose"
            )
            is True
        )

    def test_allows_optional_match(self):
        assert (
            validate_cypher(
                "OPTIONAL MATCH (p:Person)-[:EXPERIENCED]->(e:Event) RETURN count(e)"
            )
            is True
        )

    def test_allows_with_clause(self):
        assert (
            validate_cypher(
                "MATCH (p:Person {name: $patient_name}) "
                "WITH p "
                "MATCH (p)-[:TAKES]->(m:Medication) "
                "RETURN m.name"
            )
            is True
        )

    def test_allows_aggregation(self):
        assert (
            validate_cypher(
                "MATCH (p:Person)-[:EXPERIENCED]->(e:Event {type: 'headache'}) "
                "RETURN count(e) AS headache_count, avg(e.severity) AS avg_severity"
            )
            is True
        )

    def test_allows_order_by_limit(self):
        assert (
            validate_cypher(
                "MATCH (p:Person)-[:EXPERIENCED]->(e:Event) "
                "RETURN e.type, e.timestamp "
                "ORDER BY e.timestamp DESC LIMIT 10"
            )
            is True
        )

    def test_allows_unwind(self):
        assert (
            validate_cypher(
                "UNWIND $names AS name " "MATCH (p:Person {name: name}) RETURN p"
            )
            is True
        )

    def test_rejects_create_case_insensitive(self):
        """Mutations should be caught regardless of case."""
        assert validate_cypher("match (n) Create (m:Test)") is False
        assert validate_cypher("MATCH (n) create (m:Test)") is False
        assert validate_cypher("match (n) CREATE (m:Test)") is False

    def test_rejects_query_not_starting_with_match(self):
        """Queries must start with MATCH, WITH, RETURN, or UNWIND."""
        assert validate_cypher("RETURN 1") is True
        assert validate_cypher("EXPLAIN MATCH (n) RETURN n") is False


class TestGraphQueryEngineSchemaDescription:
    """Test schema description from GraphMemory."""

    def test_fallback_schema_when_not_connected(self):
        """Schema description should return a fallback when not connected."""
        mock_graph = MagicMock()
        mock_graph.is_connected = False
        mock_graph.get_schema_description.return_value = (
            "## Neo4j Graph Schema\n\n### Node Labels\n  (:Person)"
        )

        engine = GraphQueryEngine(mock_graph)
        schema = engine._get_schema()

        assert "Neo4j Graph Schema" in schema

    def test_schema_caching(self):
        """Schema should only be fetched once."""
        mock_graph = MagicMock()
        mock_graph.get_schema_description.return_value = "cached schema"

        engine = GraphQueryEngine(mock_graph)
        _ = engine._get_schema()
        _ = engine._get_schema()

        # Should only be called once
        mock_graph.get_schema_description.assert_called_once()

    def test_cache_invalidation(self):
        """After invalidation, schema should be re-fetched."""
        mock_graph = MagicMock()
        mock_graph.get_schema_description.return_value = "schema v1"

        engine = GraphQueryEngine(mock_graph)
        s1 = engine._get_schema()
        assert s1 == "schema v1"

        mock_graph.get_schema_description.return_value = "schema v2"
        engine.invalidate_schema_cache()
        s2 = engine._get_schema()
        assert s2 == "schema v2"


@pytest.mark.asyncio
class TestGraphQueryEngineExecution:
    """Test query execution path (mocked)."""

    async def test_execute_uses_read_session(self):
        """Ensure execute() calls execute_read, not _execute."""
        mock_graph = MagicMock()
        mock_graph.is_connected = True
        mock_graph.execute_read.return_value = [{"count": 3}]

        engine = GraphQueryEngine(mock_graph)
        results = await engine.execute(
            "MATCH (n:Person)-[:EXPERIENCED]->(e:Event) RETURN count(e) AS count",
            patient_name="Elena",
        )

        mock_graph.execute_read.assert_called_once()
        assert results == [{"count": 3}]

    async def test_execute_returns_empty_when_disconnected(self):
        """Ensure execute() returns empty list when graph is not connected."""
        mock_graph = MagicMock()
        mock_graph.is_connected = False

        engine = GraphQueryEngine(mock_graph)
        results = await engine.execute("MATCH (n) RETURN n")

        assert results == []
        mock_graph.execute_read.assert_not_called()

    async def test_query_handles_generation_error_gracefully(self):
        """Full query() should return a friendly error message on failure."""
        mock_graph = MagicMock()
        mock_graph.is_connected = True
        mock_graph.get_schema_description.return_value = "test schema"

        engine = GraphQueryEngine(mock_graph)

        # Mock the OpenAI client to raise an error
        with patch.object(engine, "_get_client") as mock_client:
            mock_client.return_value.chat.completions.create = AsyncMock(
                side_effect=Exception("API error")
            )
            result = await engine.query("How many headaches?", "Elena")

        assert "error" in result
        assert "answer" in result
        assert result["result_count"] == 0