mod common;
use common::*;

use std::sync::atomic::{AtomicUsize, Ordering};
use std::sync::Arc;

// ── Identity Hasher Correctness ────────────────────────────────────────────

/// Given: 200 actors each expecting a unique numbered message
/// When:  Each actor receives its number and replies with (self_addr, number)
/// Then:  All 200 replies match -- no message was misrouted by the identity hasher
#[test]
fn many_actors_all_receive_correct_messages() {
    #[derive(Clone)]
    struct NumberedMsg {
        n: usize,
        reply_to: ActorAddress,
    }

    #[derive(Clone, Debug, PartialEq)]
    struct NumberedReply {
        from: ActorAddress,
        n: usize,
    }

    struct NumberedActor;

    impl ActorInterface for NumberedActor {
        type Incoming = NumberedMsg;
        type Response = ();
        fn handle(&mut self, ctx: &Ctx, msg: NumberedMsg) {
            let _ = ctx.send(
                msg.reply_to,
                NumberedReply {
                    from: ctx.self_addr(),
                    n: msg.n,
                },
            );
        }
    }

    let rt = std_runtime(RuntimeConfig {
        max_actors: 300,
        channel_buffer_size: 1024,
        num_threads: 1,
        ..Default::default()
    });

    let inbox = rt.new_inbox::<NumberedReply>().unwrap();
    let inbox_addr = *inbox.addr();

    // Spawn 200 actors
    let mut addrs = Vec::new();
    for _ in 0..200 {
        addrs.push(rt.spawn(NumberedActor).unwrap());
    }
    rt.tick(); // on_start

    // Send unique numbered message to each
    for (i, addr) in addrs.iter().enumerate() {
        rt.send_to(
            *addr,
            NumberedMsg {
                n: i,
                reply_to: inbox_addr,
            },
        )
        .unwrap();
    }
    rt.tick(); // process + reply
    rt.tick(); // deliver replies

    // Verify all 200 replies
    let mut replies: Vec<NumberedReply> = Vec::new();
    while let Some(reply) = inbox.try_recv() {
        replies.push(reply);
    }

    assert_eq!(replies.len(), 200, "should receive exactly 200 replies");

    // Verify each reply came from the correct actor with the correct number
    for (i, addr) in addrs.iter().enumerate() {
        let reply = replies.iter().find(|r| r.n == i);
        assert!(
            reply.is_some(),
            "missing reply for actor #{i}"
        );
        assert_eq!(
            reply.unwrap().from, *addr,
            "reply #{i} came from wrong actor"
        );
    }
}

/// Given: A 100-actor ring where each actor forwards to the next
/// When:  A message enters the ring and traverses all 100 hops
/// Then:  The message completes the full circuit (address_map lookups all correct)
#[test]
fn ring_routing_unchanged_after_hasher_optimization() {
    #[derive(Clone)]
    struct RingHop {
        hops_remaining: usize,
        final_dest: ActorAddress,
    }

    #[derive(Clone, Debug, PartialEq)]
    struct RingDone(usize); // total hops completed

    struct RingNode {
        next: ActorAddress,
    }

    impl ActorInterface for RingNode {
        type Incoming = RingHop;
        type Response = ();
        fn handle(&mut self, ctx: &Ctx, msg: RingHop) {
            if msg.hops_remaining == 0 {
                let _ = ctx.send(msg.final_dest, RingDone(100));
            } else {
                let _ = ctx.send(
                    self.next,
                    RingHop {
                        hops_remaining: msg.hops_remaining - 1,
                        final_dest: msg.final_dest,
                    },
                );
            }
        }
    }

    let rt = std_runtime(RuntimeConfig {
        max_actors: 200,
        channel_buffer_size: 1024,
        num_threads: 1,
        ..Default::default()
    });

    let inbox = rt.new_inbox::<RingDone>().unwrap();
    let inbox_addr = *inbox.addr();

    // Build chain backwards: last node sends to inbox, first node receives
    let mut addrs = Vec::new();
    let mut next = inbox_addr;
    for _ in (0..100).rev() {
        let node = RingNode { next };
        let addr = rt.spawn(node).unwrap();
        addrs.push(addr);
        next = addr;
    }
    addrs.reverse(); // addrs[0] is start of chain

    rt.tick(); // on_start

    // Inject message at the start
    rt.send_to(
        addrs[0],
        RingHop {
            hops_remaining: 99,
            final_dest: inbox_addr,
        },
    )
    .unwrap();

    // Tick enough times for the message to traverse all 100 actors
    for _ in 0..110 {
        rt.tick();
    }

    let result = inbox.try_recv();
    assert!(result.is_some(), "ring message should complete all 100 hops");
    assert_eq!(result.unwrap(), RingDone(100));
}

/// Given: An actor that calls ctx.stop_self() upon receiving a trigger message
/// When:  The trigger is sent, then 5 more messages are sent, then ticked
/// Then:  The actor is removed, only messages before stop are processed
#[test]
fn stop_self_with_pending_messages_still_works() {
    let processed = Arc::new(AtomicUsize::new(0));

    #[derive(Clone)]
    struct Msg(bool); // true = trigger stop

    struct StopOnTrigger(Arc<AtomicUsize>);

    impl ActorInterface for StopOnTrigger {
        type Incoming = Msg;
        type Response = ();
        fn handle(&mut self, ctx: &Ctx, msg: Msg) {
            self.0.fetch_add(1, Ordering::Relaxed);
            if msg.0 {
                ctx.stop_self();
            }
        }
    }

    let rt = std_runtime(RuntimeConfig::default());
    let p = processed.clone();
    let addr = rt.spawn(StopOnTrigger(p)).unwrap();
    rt.tick(); // on_start

    // Send: 2 normal, 1 trigger, 5 more normal
    rt.send_to(addr, Msg(false)).unwrap();
    rt.send_to(addr, Msg(false)).unwrap();
    rt.send_to(addr, Msg(true)).unwrap(); // stop trigger
    rt.send_to(addr, Msg(false)).unwrap();
    rt.send_to(addr, Msg(false)).unwrap();
    rt.send_to(addr, Msg(false)).unwrap();
    rt.send_to(addr, Msg(false)).unwrap();
    rt.send_to(addr, Msg(false)).unwrap();

    rt.tick(); // process messages -- stops after trigger
    rt.tick(); // cleanup

    // Only 3 messages should be processed (2 normal + 1 trigger)
    assert_eq!(
        processed.load(Ordering::Relaxed),
        3,
        "should process exactly the messages up to and including the stop trigger"
    );

    // Subsequent sends should fail
    assert!(rt.send_to(addr, Msg(false)).is_err());
}