//! Integration tests for cluster membership.
#![allow(clippy::unwrap_used, clippy::expect_used)]

use std::net::{IpAddr, Ipv4Addr, SocketAddr};
use stemedb_cluster::membership::{
    MembershipEntry, MembershipEvent, NodeId, NodeInfo, NodeState, SwimMembership,
};
use stemedb_cluster::SwimConfig;

fn test_addr(port: u16) -> SocketAddr {
    SocketAddr::new(IpAddr::V4(Ipv4Addr::new(127, 0, 0, 1)), port)
}

fn test_node_info(n: u8) -> NodeInfo {
    let id = NodeId::from_bytes([n; 16]);
    NodeInfo::new(id, test_addr(9090 + n as u16), test_addr(8080 + n as u16))
}

#[tokio::test]
async fn test_three_node_discovery_via_manual_updates() {
    // Simulate 3 nodes discovering each other via gossip updates
    let node1_info = test_node_info(1);
    let node2_info = test_node_info(2);
    let node3_info = test_node_info(3);

    let config = SwimConfig::fast();

    // Create 3 membership instances
    let m1 = SwimMembership::new(node1_info.clone(), config.clone());
    let m2 = SwimMembership::new(node2_info.clone(), config.clone());
    let m3 = SwimMembership::new(node3_info.clone(), config.clone());

    // Bootstrap node1 (first node)
    m1.join(vec![]).await.unwrap();

    // Node2 joins, discovers node1
    m2.alive_node(node1_info.id, node1_info.clone());

    // Node3 joins, discovers node1 and node2
    m3.alive_node(node1_info.id, node1_info.clone());
    m3.alive_node(node2_info.id, node2_info.clone());

    // Node1 discovers node2 and node3
    m1.alive_node(node2_info.id, node2_info.clone());
    m1.alive_node(node3_info.id, node3_info.clone());

    // Node2 discovers node3
    m2.alive_node(node3_info.id, node3_info.clone());

    // All nodes should see 2 members (excluding self)
    assert_eq!(m1.member_count(), 2);
    assert_eq!(m2.member_count(), 2);
    assert_eq!(m3.member_count(), 2);

    // Verify specific members
    assert!(m1.is_member(node2_info.id));
    assert!(m1.is_member(node3_info.id));
    assert!(m2.is_member(node1_info.id));
    assert!(m2.is_member(node3_info.id));
    assert!(m3.is_member(node1_info.id));
    assert!(m3.is_member(node2_info.id));
}

#[tokio::test]
async fn test_node_failure_detection_via_suspicion() {
    let node1_info = test_node_info(1);
    let node2_info = test_node_info(2);
    let node3_info = test_node_info(3);

    let config = SwimConfig::fast();
    let m1 = SwimMembership::new(node1_info.clone(), config);

    // Add node2 and node3 as alive members
    m1.alive_node(node2_info.id, node2_info.clone());
    m1.alive_node(node3_info.id, node3_info.clone());

    assert_eq!(m1.member_count(), 2);

    // Subscribe to events
    let mut events = m1.subscribe();

    // Suspect node2 (simulating failed probe)
    m1.suspect_node(node2_info.id);

    // Node2 should be suspect, not counted as alive
    assert_eq!(m1.member_count(), 1);
    assert!(!m1.is_member(node2_info.id)); // Suspect nodes are not "members"

    // Verify event was emitted
    let event = events.try_recv().unwrap();
    assert!(matches!(event, MembershipEvent::NodeSuspected(_)));

    // Confirm failure (suspicion timeout expired)
    m1.fail_node(node2_info.id);

    let event = events.try_recv().unwrap();
    assert!(matches!(event, MembershipEvent::NodeFailed(_)));

    // Node3 should still be alive
    assert!(m1.is_member(node3_info.id));
    assert_eq!(m1.member_count(), 1);
}

#[tokio::test]
async fn test_node_rejoin_after_failure() {
    let node1_info = test_node_info(1);
    let mut node2_info = test_node_info(2);

    let config = SwimConfig::fast();
    let m1 = SwimMembership::new(node1_info.clone(), config);

    // Add node2
    m1.alive_node(node2_info.id, node2_info.clone());
    assert!(m1.is_member(node2_info.id));

    // Node2 fails
    m1.suspect_node(node2_info.id);
    m1.fail_node(node2_info.id);
    assert!(!m1.is_member(node2_info.id));

    // Node2 restarts with higher incarnation
    node2_info.incarnation = 1;
    m1.alive_node(node2_info.id, node2_info.clone());

    // Node2 should be alive again
    assert!(m1.is_member(node2_info.id));
    assert_eq!(m1.member_count(), 1);
}

#[tokio::test]
async fn test_membership_gossip_propagation() {
    // Simulate gossip propagation across 3 nodes
    let node1_info = test_node_info(1);
    let node2_info = test_node_info(2);
    let node3_info = test_node_info(3);

    let config = SwimConfig::fast();
    let m1 = SwimMembership::new(node1_info.clone(), config.clone());
    let m2 = SwimMembership::new(node2_info.clone(), config.clone());
    let m3 = SwimMembership::new(node3_info.clone(), config);

    // Node1 learns about node2
    m1.alive_node(node2_info.id, node2_info.clone());

    // Node1 gets gossip batch and forwards to node3
    let batch = m1.get_gossip_batch(10);
    assert!(!batch.is_empty());

    // Forward gossip to node3
    for entry in &batch {
        m3.process_membership_update(entry.clone());
    }

    // Node3 should now know about node2
    assert!(m3.is_member(node2_info.id));

    // Node3 learns about node1
    m3.alive_node(node1_info.id, node1_info.clone());

    // Get node3's gossip and forward to node2
    let batch3 = m3.get_gossip_batch(10);
    for entry in &batch3 {
        m2.process_membership_update(entry.clone());
    }

    // Node2 should now know about node1 and node3
    assert!(m2.is_member(node1_info.id));
    // node3 is in m3's gossip batch because m3 called alive_node on node1
    // but node3 itself wouldn't be in the batch unless someone else added it
}

#[test]
fn test_suspicion_timeout_check() {
    let node1_info = test_node_info(1);
    let node2_info = test_node_info(2);

    let config =
        SwimConfig { suspicion_timeout: std::time::Duration::from_millis(1), ..SwimConfig::fast() };

    let m1 = SwimMembership::new(node1_info, config);
    m1.alive_node(node2_info.id, node2_info);

    // Suspect the node
    m1.suspect_node(NodeId::from_bytes([2; 16]));

    // Wait for suspicion timeout
    std::thread::sleep(std::time::Duration::from_millis(10));

    // Check timeouts - should promote to dead
    m1.check_suspicion_timeouts();

    // Node should be dead
    let (_, state) = m1.all_members().into_iter().next().unwrap();
    assert_eq!(state, NodeState::Dead);
}

#[tokio::test]
async fn test_graceful_leave() {
    let node1_info = test_node_info(1);
    let config = SwimConfig::fast();
    let m1 = SwimMembership::new(node1_info, config);

    // Join and leave
    m1.join(vec![]).await.unwrap();
    assert!(m1.is_joined());

    m1.leave().await.unwrap();
    assert!(!m1.is_joined());
}

#[test]
fn test_concurrent_membership_updates() {
    let node1_info = test_node_info(1);
    let config = SwimConfig::default();
    let m1 = SwimMembership::new(node1_info, config);

    // Simulate concurrent updates for the same node
    let mut node2_v1 = test_node_info(2);
    node2_v1.incarnation = 1;

    let mut node2_v2 = test_node_info(2);
    node2_v2.incarnation = 2;
    node2_v2.assign_shard(0);

    // Process older version first
    let entry_v1 = MembershipEntry::new(node2_v1, NodeState::Alive, 1);
    m1.process_membership_update(entry_v1);

    // Process newer version
    let entry_v2 = MembershipEntry::new(node2_v2.clone(), NodeState::Alive, 2);
    m1.process_membership_update(entry_v2);

    // Should have the newer version
    let member = m1.get_member(NodeId::from_bytes([2; 16])).unwrap();
    assert_eq!(member.incarnation, 2);
    assert!(member.shard_assignments.contains(&0));
}

#[test]
fn test_stale_update_ignored() {
    let node1_info = test_node_info(1);
    let config = SwimConfig::default();
    let m1 = SwimMembership::new(node1_info, config);

    // Add node2 with incarnation 2
    let mut node2_new = test_node_info(2);
    node2_new.incarnation = 2;
    let entry_new = MembershipEntry::new(node2_new, NodeState::Alive, 10);
    m1.process_membership_update(entry_new);

    // Try to update with older incarnation
    let mut node2_old = test_node_info(2);
    node2_old.incarnation = 1;
    let entry_old = MembershipEntry::new(node2_old, NodeState::Dead, 5);
    m1.process_membership_update(entry_old);

    // Should still be alive with incarnation 2
    let member = m1.get_member(NodeId::from_bytes([2; 16])).unwrap();
    assert_eq!(member.incarnation, 2);
}