//! Integration tests: multi-node scenarios over real
//! UDP sockets on loopback.

use std::time::Duration;

use tesseras_dht::Node;
use tesseras_dht::nat::NatState;

/// Poll all nodes once each (non-blocking best-effort).
fn poll_all(nodes: &mut [Node], rounds: usize) {
    let fast = Duration::from_millis(1);
    for _ in 0..rounds {
        for n in nodes.iter_mut() {
            n.poll_timeout(fast).ok();
        }
    }
}

/// Create N nodes, join them to the first.
fn make_network(n: usize) -> Vec<Node> {
    let mut nodes = Vec::with_capacity(n);
    let bootstrap = Node::bind(0).unwrap();
    let bp = bootstrap.local_addr().unwrap().port();
    nodes.push(bootstrap);
    nodes[0].set_nat_state(NatState::Global);

    for _ in 1..n {
        let mut node = Node::bind(0).unwrap();
        node.set_nat_state(NatState::Global);
        node.join("127.0.0.1", bp).unwrap();
        nodes.push(node);
    }

    // Small sleep to let packets arrive, then poll
    std::thread::sleep(Duration::from_millis(50));
    poll_all(&mut nodes, 5);
    nodes
}

// ── Bootstrap tests ─────────────────────────────────

#[test]
fn two_nodes_discover_each_other() {
    let nodes = make_network(2);

    assert!(
        nodes[0].routing_table_size() >= 1,
        "Node 0 should have at least 1 peer in routing table"
    );
    assert!(
        nodes[1].routing_table_size() >= 1,
        "Node 1 should have at least 1 peer in routing table"
    );
}

#[test]
fn three_nodes_form_network() {
    let nodes = make_network(3);

    // All nodes should know at least 1 other node
    for (i, node) in nodes.iter().enumerate() {
        assert!(
            node.routing_table_size() >= 1,
            "Node {i} routing table empty"
        );
    }
}

#[test]
fn five_nodes_routing_tables() {
    let nodes = make_network(5);

    // With 5 nodes, most should know 2+ peers
    let total_peers: usize = nodes.iter().map(|n| n.routing_table_size()).sum();
    assert!(
        total_peers >= 5,
        "Total routing entries ({total_peers}) too low"
    );
}

// ── Put/Get tests ───────────────────────────────────

#[test]
fn put_get_local() {
    let mut node = Node::bind(0).unwrap();
    node.put(b"key1", b"value1", 300, false);
    let vals = node.get(b"key1");
    assert_eq!(vals.len(), 1);
    assert_eq!(vals[0], b"value1");
}

#[test]
fn put_get_across_two_nodes() {
    let mut nodes = make_network(2);

    // Node 0 stores
    nodes[0].put(b"hello", b"world", 300, false);

    // Poll to deliver STORE
    std::thread::sleep(Duration::from_millis(50));
    poll_all(&mut nodes, 5);

    // Node 1 should have the value (received via STORE)
    let vals = nodes[1].get(b"hello");
    assert_eq!(vals.len(), 1, "Node 1 should have received the value");
    assert_eq!(vals[0], b"world");
}

#[test]
fn put_multiple_values() {
    let mut nodes = make_network(3);

    // Store 10 key-value pairs from node 0
    for i in 0..10u32 {
        let key = format!("k{i}");
        let val = format!("v{i}");
        nodes[0].put(key.as_bytes(), val.as_bytes(), 300, false);
    }

    std::thread::sleep(Duration::from_millis(50));
    poll_all(&mut nodes, 5);

    // Node 0 should have all 10
    let mut found = 0;
    for i in 0..10u32 {
        let key = format!("k{i}");
        if !nodes[0].get(key.as_bytes()).is_empty() {
            found += 1;
        }
    }
    assert_eq!(found, 10, "Node 0 should have all 10 values");
}

#[test]
fn put_unique_replaces() {
    let mut node = Node::bind(0).unwrap();
    node.put(b"uk", b"first", 300, true);
    node.put(b"uk", b"second", 300, true);

    let vals = node.get(b"uk");
    assert_eq!(vals.len(), 1);
    assert_eq!(vals[0], b"second");
}

#[test]
fn put_get_distributed() {
    let mut nodes = make_network(5);

    // Each node stores one value
    for i in 0..5u32 {
        let key = format!("node{i}-key");
        let val = format!("node{i}-val");
        nodes[i as usize].put(key.as_bytes(), val.as_bytes(), 300, false);
    }

    std::thread::sleep(Duration::from_millis(50));
    poll_all(&mut nodes, 5);

    // Each node should have its own value at minimum
    for i in 0..5u32 {
        let key = format!("node{i}-key");
        let vals = nodes[i as usize].get(key.as_bytes());
        assert!(!vals.is_empty(), "Node {i} should have its own value");
    }
}

// ── Identity tests ──────────────────────────────────

#[test]
fn set_id_deterministic() {
    let mut n1 = Node::bind(0).unwrap();
    let mut n2 = Node::bind(0).unwrap();
    n1.set_id(b"same-seed");
    n2.set_id(b"same-seed");
    assert_eq!(n1.id(), n2.id());
}

#[test]
fn node_id_is_unique() {
    let n1 = Node::bind(0).unwrap();
    let n2 = Node::bind(0).unwrap();
    assert_ne!(n1.id(), n2.id());
}

// ── NAT state tests ────────────────────────────────

#[test]
fn nat_state_transitions() {
    let mut node = Node::bind(0).unwrap();
    assert_eq!(node.nat_state(), NatState::Unknown);

    node.set_nat_state(NatState::Global);
    assert_eq!(node.nat_state(), NatState::Global);

    node.set_nat_state(NatState::ConeNat);
    assert_eq!(node.nat_state(), NatState::ConeNat);

    node.set_nat_state(NatState::SymmetricNat);
    assert_eq!(node.nat_state(), NatState::SymmetricNat);
}

// ── RDP tests ───────────────────────────────────────

#[test]
fn rdp_listen_connect_close() {
    let mut node = Node::bind(0).unwrap();
    let desc = node.rdp_listen(5000).unwrap();
    node.rdp_close(desc);
    // Should be able to re-listen
    let desc2 = node.rdp_listen(5000).unwrap();
    node.rdp_close(desc2);
}

#[test]
fn rdp_connect_state() {
    use tesseras_dht::rdp::RdpState;
    let mut node = Node::bind(0).unwrap();
    let dst = tesseras_dht::NodeId::from_bytes([0x01; 32]);
    let desc = node.rdp_connect(0, &dst, 5000).unwrap();
    assert_eq!(node.rdp_state(desc).unwrap(), RdpState::SynSent);
    node.rdp_close(desc);
}

// ── Resilience tests ────────────────────────────────

#[test]
fn poll_with_no_peers() {
    let mut node = Node::bind(0).unwrap();
    // Should not panic or block
    node.poll().unwrap();
}

#[test]
fn join_invalid_address() {
    let mut node = Node::bind(0).unwrap();
    let result = node.join("this-does-not-exist.invalid", 9999);
    assert!(result.is_err());
}

#[test]
fn empty_get() {
    let mut node = Node::bind(0).unwrap();
    assert!(node.get(b"nonexistent").is_empty());
}

#[test]
fn put_zero_ttl_removes() {
    let mut node = Node::bind(0).unwrap();
    node.put(b"temp", b"data", 300, false);
    assert!(!node.get(b"temp").is_empty());

    // Store with TTL 0 is a delete in the protocol
    // (handled at the wire level in handle_dht_store,
    // but locally we'd need to call storage.remove).
    // This test validates the local storage.
}

// ── Scale test ──────────────────────────────────────

#[test]
fn ten_nodes_put_get() {
    let mut nodes = make_network(10);

    // Node 0 stores
    nodes[0].put(b"scale-key", b"scale-val", 300, false);
    std::thread::sleep(Duration::from_millis(50));
    poll_all(&mut nodes, 5);

    // Count how many nodes received the value
    let mut count = 0;
    for node in &mut nodes {
        if !node.get(b"scale-key").is_empty() {
            count += 1;
        }
    }
    assert!(
        count >= 2,
        "At least 2 nodes should have the value, got {count}"
    );
}

// ── Remote get via FIND_VALUE ───────────────────────

#[test]
fn remote_get_via_find_value() {
    let mut nodes = make_network(3);

    // Node 0 stores locally
    nodes[0].put(b"remote-key", b"remote-val", 300, false);
    std::thread::sleep(Duration::from_millis(50));
    poll_all(&mut nodes, 5);

    // Node 2 does remote get
    let before = nodes[2].get(b"remote-key");
    // Might already have it from STORE, or empty
    if before.is_empty() {
        // Poll to let FIND_VALUE propagate
        std::thread::sleep(Duration::from_millis(100));
        poll_all(&mut nodes, 10);

        let after = nodes[2].get(b"remote-key");
        assert!(
            !after.is_empty(),
            "Node 2 should find the value via FIND_VALUE"
        );
        assert_eq!(after[0], b"remote-val");
    }
}

// ── NAT detection tests ────────────────────────────

#[test]
fn nat_state_default_unknown() {
    let node = Node::bind(0).unwrap();
    assert_eq!(node.nat_state(), NatState::Unknown);
}

#[test]
fn nat_state_set_persists() {
    let mut node = Node::bind(0).unwrap();
    node.set_nat_state(NatState::SymmetricNat);
    assert_eq!(node.nat_state(), NatState::SymmetricNat);
    node.poll().unwrap();
    assert_eq!(node.nat_state(), NatState::SymmetricNat);
}

// ── DTUN tests ──────────────────────────────────────

#[test]
fn dtun_find_node_exchange() {
    // Two nodes: node2 sends DtunFindNode to node1
    // by joining. The DTUN table should be populated.
    let nodes = make_network(2);

    // Both nodes should have peers after join
    assert!(nodes[0].routing_table_size() >= 1);
    assert!(nodes[1].routing_table_size() >= 1);
}

// ── Proxy tests ─────────────────────────────────────

#[test]
fn proxy_dgram_forwarded() {
    use std::sync::{Arc, Mutex};

    let mut nodes = make_network(2);

    let received: Arc<Mutex<Vec<Vec<u8>>>> = Arc::new(Mutex::new(Vec::new()));

    let recv_clone = received.clone();
    nodes[1].set_dgram_callback(move |data, _from| {
        recv_clone.lock().unwrap().push(data.to_vec());
    });

    // Node 0 sends dgram to Node 1
    let id1 = *nodes[1].id();
    nodes[0].send_dgram(b"proxy-test", &id1);

    std::thread::sleep(Duration::from_millis(50));
    poll_all(&mut nodes, 5);

    let msgs = received.lock().unwrap();
    assert!(!msgs.is_empty(), "Node 1 should receive the dgram");
    assert_eq!(msgs[0], b"proxy-test");
}

// ── Advertise tests ─────────────────────────────────

#[test]
fn nodes_peer_count_after_join() {
    let nodes = make_network(3);

    // All nodes should have at least 1 peer
    for (i, node) in nodes.iter().enumerate() {
        assert!(
            node.peer_count() >= 1,
            "Node {i} should have at least 1 peer"
        );
    }
}

// ── Storage tests ───────────────────────────────────

#[test]
fn storage_count_after_put() {
    let mut node = Node::bind(0).unwrap();
    assert_eq!(node.storage_count(), 0);

    node.put(b"k1", b"v1", 300, false);
    node.put(b"k2", b"v2", 300, false);
    assert_eq!(node.storage_count(), 2);
}

#[test]
fn put_from_multiple_nodes() {
    let mut nodes = make_network(3);

    nodes[0].put(b"from-0", b"val-0", 300, false);
    nodes[1].put(b"from-1", b"val-1", 300, false);
    nodes[2].put(b"from-2", b"val-2", 300, false);

    std::thread::sleep(Duration::from_millis(50));
    poll_all(&mut nodes, 5);

    // Each node should have its own value
    assert!(!nodes[0].get(b"from-0").is_empty());
    assert!(!nodes[1].get(b"from-1").is_empty());
    assert!(!nodes[2].get(b"from-2").is_empty());
}

// ── Config tests ────────────────────────────────────

#[test]
fn config_default_works() {
    let config = tesseras_dht::config::Config::default();
    assert_eq!(config.num_find_node, 10);
    assert_eq!(config.bucket_size, 20);
    assert_eq!(config.default_ttl, 300);
}

#[test]
fn config_pastebin_preset() {
    let config = tesseras_dht::config::Config::pastebin();
    assert_eq!(config.default_ttl, 65535);
    assert!(config.require_signatures);
}

// ── Metrics tests ───────────────────────────────────

#[test]
fn metrics_after_put() {
    let mut nodes = make_network(2);
    let before = nodes[0].metrics();
    nodes[0].put(b"m-key", b"m-val", 300, false);
    std::thread::sleep(Duration::from_millis(50));
    poll_all(&mut nodes, 5);
    let after = nodes[0].metrics();
    assert!(
        after.messages_sent > before.messages_sent,
        "messages_sent should increase after put"
    );
}

#[test]
fn metrics_bytes_tracked() {
    let mut node = Node::bind(0).unwrap();
    let m = node.metrics();
    assert_eq!(m.bytes_sent, 0);
    assert_eq!(m.bytes_received, 0);
}

// ── Builder tests ───────────────────────────────────

#[test]
fn builder_basic() {
    use tesseras_dht::node::NodeBuilder;
    let node = NodeBuilder::new()
        .port(0)
        .nat(NatState::Global)
        .build()
        .unwrap();
    assert_eq!(node.nat_state(), NatState::Global);
}

#[test]
fn builder_with_seed() {
    use tesseras_dht::node::NodeBuilder;
    let n1 = NodeBuilder::new()
        .port(0)
        .seed(b"same-seed")
        .build()
        .unwrap();
    let n2 = NodeBuilder::new()
        .port(0)
        .seed(b"same-seed")
        .build()
        .unwrap();
    assert_eq!(n1.id(), n2.id());
}

#[test]
fn builder_with_config() {
    use tesseras_dht::node::NodeBuilder;
    let config = tesseras_dht::config::Config::pastebin();
    let node = NodeBuilder::new().port(0).config(config).build().unwrap();
    assert!(node.config().require_signatures);
}

// ── Persistence mock test ───────────────────────────

#[test]
fn persistence_nop_save_load() {
    let mut node = Node::bind(0).unwrap();
    node.put(b"persist-key", b"persist-val", 300, false);
    // With NoPersistence, save does nothing
    node.save_state();
    // load_persisted with NoPersistence loads nothing
    node.load_persisted();
    // Value still there from local storage
    assert!(!node.get(b"persist-key").is_empty());
}

// ── Ban list tests ────────────────────────────────────

#[test]
fn ban_list_initially_empty() {
    let node = Node::bind(0).unwrap();
    assert_eq!(node.ban_count(), 0);
}

#[test]
fn ban_list_unit() {
    use tesseras_dht::banlist::BanList;
    let mut bl = BanList::new();
    let addr: std::net::SocketAddr = "127.0.0.1:9999".parse().unwrap();

    assert!(!bl.is_banned(&addr));
    bl.record_failure(addr);
    bl.record_failure(addr);
    assert!(!bl.is_banned(&addr)); // 2 < threshold 3
    bl.record_failure(addr);
    assert!(bl.is_banned(&addr)); // 3 >= threshold
}

#[test]
fn ban_list_success_resets() {
    use tesseras_dht::banlist::BanList;
    let mut bl = BanList::new();
    let addr: std::net::SocketAddr = "127.0.0.1:9999".parse().unwrap();

    bl.record_failure(addr);
    bl.record_failure(addr);
    bl.record_success(&addr);
    bl.record_failure(addr); // starts over from 1
    assert!(!bl.is_banned(&addr));
}

// ── Store tracker tests ───────────────────────────────

#[test]
fn store_tracker_initially_empty() {
    let node = Node::bind(0).unwrap();
    assert_eq!(node.pending_stores(), 0);
    assert_eq!(node.store_stats(), (0, 0));
}

#[test]
fn store_tracker_counts_after_put() {
    let mut nodes = make_network(3);

    nodes[0].put(b"tracked-key", b"tracked-val", 300, false);
    std::thread::sleep(Duration::from_millis(50));
    poll_all(&mut nodes, 5);

    // Node 0 should have pending stores (sent to peers)
    // or acks if peers responded quickly
    let (acks, _) = nodes[0].store_stats();
    let pending = nodes[0].pending_stores();
    assert!(
        acks > 0 || pending > 0,
        "Should have tracked some stores (acks={acks}, pending={pending})"
    );
}

// ── Node activity monitor tests ──────────────────────

#[test]
fn activity_check_does_not_crash() {
    let mut node = Node::bind(0).unwrap();
    node.set_nat_state(NatState::Global);
    // Calling poll runs the activity check — should
    // not crash even with no peers
    node.poll().unwrap();
}

// ── Batch operations tests ───────────────────────────

#[test]
fn put_batch_stores_locally() {
    let mut node = Node::bind(0).unwrap();

    let entries: Vec<(&[u8], &[u8], u16, bool)> = vec![
        (b"b1", b"v1", 300, false),
        (b"b2", b"v2", 300, false),
        (b"b3", b"v3", 300, false),
    ];
    node.put_batch(&entries);

    assert_eq!(node.storage_count(), 3);
    assert_eq!(node.get(b"b1"), vec![b"v1".to_vec()]);
    assert_eq!(node.get(b"b2"), vec![b"v2".to_vec()]);
    assert_eq!(node.get(b"b3"), vec![b"v3".to_vec()]);
}

#[test]
fn get_batch_returns_local() {
    let mut node = Node::bind(0).unwrap();
    node.put(b"gb1", b"v1", 300, false);
    node.put(b"gb2", b"v2", 300, false);

    let results = node.get_batch(&[b"gb1", b"gb2", b"gb-missing"]);
    assert_eq!(results.len(), 3);
    assert_eq!(results[0].1, vec![b"v1".to_vec()]);
    assert_eq!(results[1].1, vec![b"v2".to_vec()]);
    assert!(results[2].1.is_empty()); // not found
}

#[test]
fn put_batch_distributes_to_peers() {
    let mut nodes = make_network(3);

    let entries: Vec<(&[u8], &[u8], u16, bool)> = vec![
        (b"dist-1", b"val-1", 300, false),
        (b"dist-2", b"val-2", 300, false),
        (b"dist-3", b"val-3", 300, false),
        (b"dist-4", b"val-4", 300, false),
        (b"dist-5", b"val-5", 300, false),
    ];
    nodes[0].put_batch(&entries);

    std::thread::sleep(Duration::from_millis(100));
    poll_all(&mut nodes, 10);

    // All 5 values should be stored locally on node 0
    for i in 1..=5 {
        let key = format!("dist-{i}");
        let vals = nodes[0].get(key.as_bytes());
        assert!(!vals.is_empty(), "Node 0 should have {key}");
    }

    // At least some should be distributed to other nodes
    let total: usize = nodes.iter().map(|n| n.storage_count()).sum();
    assert!(total > 5, "Total stored {total} should be > 5 (replicated)");
}

// ── Proactive replication tests ──────────────────

#[test]
fn proactive_replicate_on_new_node() {
    // Node 0 stores a value, then node 2 joins.
    // After routing table sync, node 2 should receive
    // the value proactively (§2.5).
    let mut nodes = make_network(2);
    nodes[0].put(b"proactive-key", b"proactive-val", 300, false);

    std::thread::sleep(Duration::from_millis(100));
    poll_all(&mut nodes, 10);

    // Add a third node
    let bp = nodes[0].local_addr().unwrap().port();
    let mut node2 = Node::bind(0).unwrap();
    node2.set_nat_state(NatState::Global);
    node2.join("127.0.0.1", bp).unwrap();
    nodes.push(node2);

    // Poll to let proactive replication trigger
    std::thread::sleep(Duration::from_millis(100));
    poll_all(&mut nodes, 20);

    // At least the original 2 nodes should have the value;
    // the new node may also have it via proactive replication
    let total: usize = nodes.iter().map(|n| n.storage_count()).sum();
    assert!(
        total >= 2,
        "Total stored {total} should be >= 2 after proactive replication"
    );
}

// ── Republish on access tests ────────────────────

#[test]
fn republish_on_find_value() {
    // Store on node 0, retrieve from node 2 via FIND_VALUE.
    // After the value is found, it should be cached on
    // the nearest queried node without it (§2.3).
    let mut nodes = make_network(3);

    nodes[0].put(b"republish-key", b"republish-val", 300, false);

    std::thread::sleep(Duration::from_millis(100));
    poll_all(&mut nodes, 10);

    // Node 2 triggers FIND_VALUE
    let _ = nodes[2].get(b"republish-key");

    // Poll to let the lookup and republish propagate
    for _ in 0..30 {
        poll_all(&mut nodes, 5);
        std::thread::sleep(Duration::from_millis(20));

        let vals = nodes[2].get(b"republish-key");
        if !vals.is_empty() {
            break;
        }
    }

    // Count total stored across all nodes — should be
    // more than 1 due to republish-on-access caching
    let total: usize = nodes.iter().map(|n| n.storage_count()).sum();
    assert!(
        total >= 2,
        "Total stored {total} should be >= 2 after republish-on-access"
    );
}