//! Integration tests for TcpBridge over TCP localhost (D-030 Layer 2: IPC roundtrip).

use settled_reach_server::bridge::framing::{read_framed, write_framed};
use settled_reach_server::bridge::tcp::TcpBridge;
use settled_reach_server::bridge::types::*;
use settled_reach_server::bridge::SimBridge;
use settled_reach_server::simulation::time::{DayPhase, TickRate};
use std::net::{TcpListener, TcpStream};
use std::thread;

#[test]
fn snapshot_roundtrip_over_tcp() {
    // Bind listener first — port is guaranteed ready before spawning threads
    let listener = TcpListener::bind("127.0.0.1:0").expect("failed to bind");
    let server_addr = listener.local_addr().expect("failed to get local address");

    // Server thread: accept on pre-bound listener and send snapshot
    let server_handle = thread::spawn(move || {
        let bridge = TcpBridge::accept_on(listener).expect("failed to accept");

        let snapshot = ObserverSnapshot {
            version: 4,
            tick: 42,
            game_time: GameTime {
                day: 0,
                time_of_day: 0,
                day_phase: DayPhase::Morning,
                tick_rate: TickRate::Full,
            },
            player_facing: FacingDirection::North,
            entities: vec![VisibleEntity {
                entity_id: 100,
                x: 10.5,
                y: 20.3,
                z: 0,
                kind: EntityKind::Npc,
                visibility: VisibilitySector::Forward,
                relationship: RelationshipState::Unknown,
                observation: EntityVisibility::Visible,
            }],
            visible_tiles: vec![],
            nearby_interactions: vec![],
        };

        bridge
            .send_snapshot(&snapshot)
            .expect("failed to send snapshot");
    });

    // Client: connect and receive snapshot (no sleep needed — listener already bound)
    let stream = TcpStream::connect(server_addr).expect("failed to connect");
    let mut reader = std::io::BufReader::new(stream);

    let payload = read_framed(&mut reader)
        .expect("failed to read frame")
        .expect("unexpected EOF");

    let snapshot: ObserverSnapshot =
        rmp_serde::from_slice(&payload).expect("failed to deserialize");

    assert_eq!(snapshot.tick, 42);
    assert_eq!(snapshot.entities.len(), 1);
    assert_eq!(snapshot.entities[0].entity_id, 100);
    assert_eq!(snapshot.entities[0].x, 10.5);
    assert_eq!(snapshot.entities[0].y, 20.3);

    server_handle.join().expect("server thread panicked");
}

#[test]
fn input_roundtrip_over_tcp() {
    let listener = TcpListener::bind("127.0.0.1:0").expect("failed to bind");
    let server_addr = listener.local_addr().expect("failed to get local address");

    let server_handle = thread::spawn(move || {
        let bridge = TcpBridge::accept_on(listener).expect("failed to accept");

        let inputs = bridge.receive_inputs().expect("failed to receive inputs");

        assert_eq!(inputs.len(), 2);
        assert_eq!(inputs[0].tick, 10);
        assert_eq!(inputs[1].tick, 11);

        inputs
    });

    // Client: connect and send inputs
    let stream = TcpStream::connect(server_addr).expect("failed to connect");
    let mut writer = std::io::BufWriter::new(stream);

    let inputs = vec![
        PlayerInput {
            tick: 10,
            action: PlayerAction::MoveNorth,
        },
        PlayerInput {
            tick: 11,
            action: PlayerAction::Interact,
        },
    ];

    let payload = rmp_serde::to_vec_named(&inputs).expect("failed to serialize");
    write_framed(&mut writer, &payload).expect("failed to write frame");

    // Drop writer to close connection and signal EOF to server
    drop(writer);

    let received_inputs = server_handle.join().expect("server thread panicked");

    match &received_inputs[0].action {
        PlayerAction::MoveNorth => {}
        _ => panic!("expected MoveNorth action"),
    }
    match &received_inputs[1].action {
        PlayerAction::Interact => {}
        _ => panic!("expected Interact action"),
    }
}

#[test]
fn tcp_bridge_eof_returns_error() {
    let listener = TcpListener::bind("127.0.0.1:0").expect("failed to bind");
    let server_addr = listener.local_addr().expect("failed to get local address");

    let server_handle = thread::spawn(move || {
        let bridge = TcpBridge::accept_on(listener).expect("failed to accept");

        let result = bridge.receive_inputs();

        assert!(result.is_err(), "expected error on EOF");
        assert!(
            matches!(
                result,
                Err(settled_reach_server::bridge::BridgeError::Disconnected)
            ),
            "expected Disconnected error"
        );
    });

    // Client: connect and immediately disconnect without sending data
    let stream = TcpStream::connect(server_addr).expect("failed to connect");
    drop(stream);

    server_handle.join().expect("server thread panicked");
}