//! Cypher query execution correctness tests
//!
//! Tests to verify that Cypher queries execute correctly and return expected results.

use ruvector_graph::{Edge, GraphDB, Label, Node, Properties, PropertyValue};

fn setup_test_graph() -> GraphDB {
    let db = GraphDB::new();

    // Create people
    let mut alice_props = Properties::new();
    alice_props.insert(
        "name".to_string(),
        PropertyValue::String("Alice".to_string()),
    );
    alice_props.insert("age".to_string(), PropertyValue::Integer(30));

    let mut bob_props = Properties::new();
    bob_props.insert("name".to_string(), PropertyValue::String("Bob".to_string()));
    bob_props.insert("age".to_string(), PropertyValue::Integer(35));

    let mut charlie_props = Properties::new();
    charlie_props.insert(
        "name".to_string(),
        PropertyValue::String("Charlie".to_string()),
    );
    charlie_props.insert("age".to_string(), PropertyValue::Integer(28));

    db.create_node(Node::new(
        "alice".to_string(),
        vec![Label {
            name: "Person".to_string(),
        }],
        alice_props,
    ))
    .unwrap();

    db.create_node(Node::new(
        "bob".to_string(),
        vec![Label {
            name: "Person".to_string(),
        }],
        bob_props,
    ))
    .unwrap();

    db.create_node(Node::new(
        "charlie".to_string(),
        vec![Label {
            name: "Person".to_string(),
        }],
        charlie_props,
    ))
    .unwrap();

    // Create relationships
    db.create_edge(Edge::new(
        "e1".to_string(),
        "alice".to_string(),
        "bob".to_string(),
        "KNOWS".to_string(),
        Properties::new(),
    ))
    .unwrap();

    db.create_edge(Edge::new(
        "e2".to_string(),
        "bob".to_string(),
        "charlie".to_string(),
        "KNOWS".to_string(),
        Properties::new(),
    ))
    .unwrap();

    db
}

#[test]
fn test_execute_simple_match_all_nodes() {
    let db = setup_test_graph();

    // TODO: Implement query execution
    // let results = db.execute("MATCH (n) RETURN n").unwrap();
    // assert_eq!(results.len(), 3);

    // For now, just verify the graph was set up correctly
    assert!(db.get_node("alice").is_some());
    assert!(db.get_node("bob").is_some());
    assert!(db.get_node("charlie").is_some());
}

#[test]
fn test_execute_match_with_label_filter() {
    let db = setup_test_graph();

    // TODO: Implement
    // let results = db.execute("MATCH (n:Person) RETURN n").unwrap();
    // assert_eq!(results.len(), 3);

    assert!(db.get_node("alice").is_some());
}

#[test]
fn test_execute_match_with_property_filter() {
    let db = setup_test_graph();

    // TODO: Implement
    // let results = db.execute("MATCH (n:Person {name: 'Alice'}) RETURN n").unwrap();
    // assert_eq!(results.len(), 1);

    let alice = db.get_node("alice").unwrap();
    assert_eq!(
        alice.properties.get("name"),
        Some(&PropertyValue::String("Alice".to_string()))
    );
}

#[test]
fn test_execute_match_with_where_clause() {
    let db = setup_test_graph();

    // TODO: Implement
    // let results = db.execute("MATCH (n:Person) WHERE n.age > 30 RETURN n").unwrap();
    // Should return Bob (35)
    // assert_eq!(results.len(), 1);

    let bob = db.get_node("bob").unwrap();
    if let Some(PropertyValue::Integer(age)) = bob.properties.get("age") {
        assert!(*age > 30);
    }
}

#[test]
fn test_execute_match_relationship() {
    let db = setup_test_graph();

    // TODO: Implement
    // let results = db.execute("MATCH (a)-[r:KNOWS]->(b) RETURN a, r, b").unwrap();
    // Should return 2 relationships

    assert!(db.get_edge("e1").is_some());
    assert!(db.get_edge("e2").is_some());
}

#[test]
fn test_execute_create_node() {
    let db = GraphDB::new();

    // TODO: Implement
    // db.execute("CREATE (n:Person {name: 'David', age: 40})").unwrap();

    // For now, create manually
    let mut props = Properties::new();
    props.insert(
        "name".to_string(),
        PropertyValue::String("David".to_string()),
    );
    props.insert("age".to_string(), PropertyValue::Integer(40));

    db.create_node(Node::new(
        "david".to_string(),
        vec![Label {
            name: "Person".to_string(),
        }],
        props,
    ))
    .unwrap();

    let david = db.get_node("david").unwrap();
    assert_eq!(
        david.properties.get("name"),
        Some(&PropertyValue::String("David".to_string()))
    );
}

#[test]
fn test_execute_count_aggregation() {
    let db = setup_test_graph();

    // TODO: Implement
    // let results = db.execute("MATCH (n:Person) RETURN COUNT(n) AS count").unwrap();
    // assert_eq!(results[0]["count"], 3);

    // Manual verification
    assert!(db.get_node("alice").is_some());
    assert!(db.get_node("bob").is_some());
    assert!(db.get_node("charlie").is_some());
}

#[test]
fn test_execute_sum_aggregation() {
    let db = setup_test_graph();

    // TODO: Implement
    // let results = db.execute("MATCH (n:Person) RETURN SUM(n.age) AS total_age").unwrap();
    // assert_eq!(results[0]["total_age"], 93); // 30 + 35 + 28

    // Manual verification
    let ages: Vec<i64> = ["alice", "bob", "charlie"]
        .iter()
        .filter_map(|id| {
            db.get_node(*id).and_then(|n| {
                if let Some(PropertyValue::Integer(age)) = n.properties.get("age") {
                    Some(*age)
                } else {
                    None
                }
            })
        })
        .collect();

    assert_eq!(ages.iter().sum::<i64>(), 93);
}

#[test]
fn test_execute_avg_aggregation() {
    let db = setup_test_graph();

    // TODO: Implement
    // let results = db.execute("MATCH (n:Person) RETURN AVG(n.age) AS avg_age").unwrap();
    // assert_eq!(results[0]["avg_age"], 31.0); // (30 + 35 + 28) / 3

    let ages: Vec<i64> = ["alice", "bob", "charlie"]
        .iter()
        .filter_map(|id| {
            db.get_node(*id).and_then(|n| {
                if let Some(PropertyValue::Integer(age)) = n.properties.get("age") {
                    Some(*age)
                } else {
                    None
                }
            })
        })
        .collect();

    let avg = ages.iter().sum::<i64>() as f64 / ages.len() as f64;
    assert!((avg - 31.0).abs() < 0.1);
}

#[test]
fn test_execute_order_by() {
    let db = setup_test_graph();

    // TODO: Implement
    // let results = db.execute("MATCH (n:Person) RETURN n ORDER BY n.age ASC").unwrap();
    // First should be Charlie (28), last should be Bob (35)

    let mut ages: Vec<i64> = ["alice", "bob", "charlie"]
        .iter()
        .filter_map(|id| {
            db.get_node(*id).and_then(|n| {
                if let Some(PropertyValue::Integer(age)) = n.properties.get("age") {
                    Some(*age)
                } else {
                    None
                }
            })
        })
        .collect();

    ages.sort();
    assert_eq!(ages, vec![28, 30, 35]);
}

#[test]
fn test_execute_limit() {
    let db = setup_test_graph();

    // TODO: Implement
    // let results = db.execute("MATCH (n:Person) RETURN n LIMIT 2").unwrap();
    // assert_eq!(results.len(), 2);

    assert!(db.get_node("alice").is_some());
}

#[test]
fn test_execute_path_query() {
    let db = setup_test_graph();

    // TODO: Implement
    // let results = db.execute("MATCH p = (a:Person)-[:KNOWS*1..2]->(b:Person) RETURN p").unwrap();
    // Should find paths: Alice->Bob, Bob->Charlie, Alice->Bob->Charlie

    let e1 = db.get_edge("e1").unwrap();
    let e2 = db.get_edge("e2").unwrap();

    assert_eq!(e1.from, "alice");
    assert_eq!(e1.to, "bob");
    assert_eq!(e2.from, "bob");
    assert_eq!(e2.to, "charlie");
}

// ============================================================================
// Complex Query Execution Tests
// ============================================================================

#[test]
fn test_execute_multi_hop_traversal() {
    let db = setup_test_graph();

    // TODO: Implement
    // Find all people connected to Alice within 2 hops
    // let results = db.execute("
    //     MATCH (alice:Person {name: 'Alice'})-[:KNOWS*1..2]->(connected)
    //     RETURN DISTINCT connected.name
    // ").unwrap();

    // Should find Bob (1 hop) and Charlie (2 hops)

    assert!(db.get_node("bob").is_some());
    assert!(db.get_node("charlie").is_some());
}

#[test]
fn test_execute_pattern_matching() {
    let db = setup_test_graph();

    // TODO: Implement
    // let results = db.execute("
    //     MATCH (a:Person)-[:KNOWS]->(b:Person)-[:KNOWS]->(c:Person)
    //     RETURN a.name, c.name
    // ").unwrap();

    // Should find Alice knows Charlie through Bob

    assert!(db.get_edge("e1").is_some());
    assert!(db.get_edge("e2").is_some());
}

#[test]
fn test_execute_collect_aggregation() {
    let db = setup_test_graph();

    // TODO: Implement
    // let results = db.execute("
    //     MATCH (p:Person)-[:KNOWS]->(friend)
    //     RETURN p.name, COLLECT(friend.name) AS friends
    // ").unwrap();

    // Alice: [Bob], Bob: [Charlie], Charlie: []

    assert!(db.get_edge("e1").is_some());
}

#[test]
fn test_execute_optional_match() {
    let db = setup_test_graph();

    // TODO: Implement
    // let results = db.execute("
    //     MATCH (p:Person)
    //     OPTIONAL MATCH (p)-[:KNOWS]->(friend)
    //     RETURN p.name, friend.name
    // ").unwrap();

    // Should return all people, some with null friends

    assert!(db.get_node("charlie").is_some());
}

// ============================================================================
// Result Verification Tests
// ============================================================================

#[test]
fn test_query_result_schema() {
    // TODO: Implement
    // Verify that query results have correct schema
    // let db = setup_test_graph();
    // let results = db.execute("MATCH (n:Person) RETURN n.name AS name, n.age AS age").unwrap();
    // assert!(results.has_column("name"));
    // assert!(results.has_column("age"));
}

#[test]
fn test_query_result_ordering() {
    // TODO: Implement
    // Verify that ORDER BY is correctly applied
}

#[test]
fn test_query_result_pagination() {
    // TODO: Implement
    // Verify SKIP and LIMIT work correctly together
}

// ============================================================================
// Error Handling Tests
// ============================================================================

#[test]
fn test_execute_invalid_property_access() {
    // TODO: Implement
    // let db = setup_test_graph();
    // let result = db.execute("MATCH (n:Person) WHERE n.nonexistent > 5 RETURN n");
    // Should handle gracefully (return no results or error depending on semantics)
}

#[test]
fn test_execute_type_mismatch() {
    // TODO: Implement
    // let db = setup_test_graph();
    // let result = db.execute("MATCH (n:Person) WHERE n.name > 5 RETURN n");
    // Should handle type mismatch error
}