## Nim-Libp2p
## Copyright (c) 2018 Status Research & Development GmbH
## Licensed under either of
##  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
##  * MIT license ([LICENSE-MIT](LICENSE-MIT))
## at your option.
## This file may not be copied, modified, or distributed except according to
## those terms.

{.used.}

import unittest, sequtils, options, tables, sets
import chronos
import chronicles
import utils, ../../libp2p/[errors,
                            peer,
                            peerinfo,
                            connection,
                            crypto/crypto,
                            stream/bufferstream,
                            protocols/pubsub/pubsub,
                            protocols/pubsub/gossipsub,
                            protocols/pubsub/rpc/messages]

import ../helpers

proc waitSub(sender, receiver: auto; key: string) {.async, gcsafe.} =
  if sender == receiver:
    return
  # turn things deterministic
  # this is for testing purposes only
  # peers can be inside `mesh` and `fanout`, not just `gossipsub`
  var ceil = 15
  let fsub = GossipSub(sender.pubSub.get())
  while (not fsub.gossipsub.hasKey(key) or
         not fsub.gossipsub[key].contains(receiver.peerInfo.id)) and
        (not fsub.mesh.hasKey(key) or
         not fsub.mesh[key].contains(receiver.peerInfo.id)) and
        (not fsub.fanout.hasKey(key) or
         not fsub.fanout[key].contains(receiver.peerInfo.id)):
    trace "waitSub sleeping...", peers=fsub.gossipsub[key]
    await sleepAsync(100.millis)
    dec ceil
    doAssert(ceil > 0, "waitSub timeout!")

suite "GossipSub":
  teardown:
    for tracker in testTrackers():
      check tracker.isLeaked() == false

  test "GossipSub validation should succeed":
    proc runTests(): Future[bool] {.async.} =
      var handlerFut = newFuture[bool]()
      proc handler(topic: string, data: seq[byte]) {.async, gcsafe.} =
        check topic == "foobar"
        handlerFut.complete(true)

      var nodes = generateNodes(2, true)
      var awaiters: seq[Future[void]]
      awaiters.add((await nodes[0].start()))
      awaiters.add((await nodes[1].start()))

      await subscribeNodes(nodes)

      await nodes[0].subscribe("foobar", handler)
      await waitSub(nodes[1], nodes[0], "foobar")
      await nodes[1].subscribe("foobar", handler)
      await waitSub(nodes[0], nodes[1], "foobar")

      var validatorFut = newFuture[bool]()
      proc validator(topic: string,
                     message: Message):
                     Future[bool] {.async.} =
        check topic == "foobar"
        validatorFut.complete(true)
        result = true

      nodes[1].addValidator("foobar", validator)
      await nodes[0].publish("foobar", cast[seq[byte]]("Hello!"))

      result = (await validatorFut) and (await handlerFut)
      await allFuturesThrowing(nodes[0].stop(), nodes[1].stop())
      await allFuturesThrowing(awaiters)

    check:
      waitFor(runTests()) == true

  test "GossipSub validation should fail":
    proc runTests(): Future[bool] {.async.} =
      proc handler(topic: string, data: seq[byte]) {.async, gcsafe.} =
        check false # if we get here, it should fail

      var nodes = generateNodes(2, true)
      var awaiters: seq[Future[void]]
      awaiters.add((await nodes[0].start()))
      awaiters.add((await nodes[1].start()))

      await subscribeNodes(nodes)

      await nodes[1].subscribe("foobar", handler)
      await waitSub(nodes[0], nodes[1], "foobar")

      var validatorFut = newFuture[bool]()
      proc validator(topic: string,
                     message: Message):
                     Future[bool] {.async.} =
        validatorFut.complete(true)
        result = false

      nodes[1].addValidator("foobar", validator)
      await nodes[0].publish("foobar", cast[seq[byte]]("Hello!"))

      result = await validatorFut
      await allFuturesThrowing(nodes[0].stop(), nodes[1].stop())
      await allFuturesThrowing(awaiters)

    check:
      waitFor(runTests()) == true

  test "GossipSub validation one fails and one succeeds":
    proc runTests(): Future[bool] {.async.} =
      var handlerFut = newFuture[bool]()
      proc handler(topic: string, data: seq[byte]) {.async, gcsafe.} =
        check topic == "foo"
        handlerFut.complete(true)

      var nodes = generateNodes(2, true)
      var awaiters: seq[Future[void]]
      awaiters.add((await nodes[0].start()))
      awaiters.add((await nodes[1].start()))

      await subscribeNodes(nodes)
      await nodes[1].subscribe("foo", handler)
      await waitSub(nodes[0], nodes[1], "foo")
      await nodes[1].subscribe("bar", handler)
      await waitSub(nodes[0], nodes[1], "bar")

      var passed, failed: Future[bool] = newFuture[bool]()
      proc validator(topic: string,
                     message: Message):
                     Future[bool] {.async.} =
        result = if topic == "foo":
          passed.complete(true)
          true
        else:
          failed.complete(true)
          false

      nodes[1].addValidator("foo", "bar", validator)
      await nodes[0].publish("foo", cast[seq[byte]]("Hello!"))
      await nodes[0].publish("bar", cast[seq[byte]]("Hello!"))

      result = ((await passed) and (await failed) and (await handlerFut))
      await allFuturesThrowing(nodes[0].stop(), nodes[1].stop())
      await allFuturesThrowing(awaiters)
      result = true
    check:
      waitFor(runTests()) == true

  test "e2e - GossipSub should add remote peer topic subscriptions":
    proc testBasicGossipSub(): Future[bool] {.async.} =
      proc handler(topic: string, data: seq[byte]) {.async, gcsafe.} =
        discard

      var nodes: seq[Switch] = newSeq[Switch]()
      for i in 0..<2:
        nodes.add newStandardSwitch(gossip = true)

      var awaitters: seq[Future[void]]
      for node in nodes:
        awaitters.add(await node.start())

      await subscribeNodes(nodes)
      await nodes[1].subscribe("foobar", handler)
      await sleepAsync(1.seconds)

      let gossip1 = GossipSub(nodes[0].pubSub.get())
      let gossip2 = GossipSub(nodes[1].pubSub.get())

      check:
        "foobar" in gossip2.topics
        "foobar" in gossip1.gossipsub
        gossip2.peerInfo.id in gossip1.gossipsub["foobar"]

      await allFuturesThrowing(nodes.mapIt(it.stop()))
      await allFuturesThrowing(awaitters)

      result = true

    check:
      waitFor(testBasicGossipSub()) == true

  test "e2e - GossipSub should add remote peer topic subscriptions if both peers are subscribed":
    proc testBasicGossipSub(): Future[bool] {.async.} =
      proc handler(topic: string, data: seq[byte]) {.async, gcsafe.} =
        discard

      var nodes: seq[Switch] = newSeq[Switch]()
      for i in 0..<2:
        nodes.add newStandardSwitch(gossip = true)

      var awaitters: seq[Future[void]]
      for node in nodes:
        awaitters.add(await node.start())

      await subscribeNodes(nodes)

      await nodes[0].subscribe("foobar", handler)
      await nodes[1].subscribe("foobar", handler)

      var subs: seq[Future[void]]
      subs &= waitSub(nodes[1], nodes[0], "foobar")
      subs &= waitSub(nodes[0], nodes[1], "foobar")
      await allFuturesThrowing(subs)

      let
        gossip1 = GossipSub(nodes[0].pubSub.get())
        gossip2 = GossipSub(nodes[1].pubSub.get())

      check:
        "foobar" in gossip1.topics
        "foobar" in gossip2.topics

        "foobar" in gossip1.gossipsub
        "foobar" in gossip2.gossipsub

        gossip2.peerInfo.id in gossip1.gossipsub["foobar"] or
        gossip2.peerInfo.id in gossip1.mesh["foobar"]

        gossip1.peerInfo.id in gossip2.gossipsub["foobar"] or
        gossip1.peerInfo.id in gossip2.mesh["foobar"]

      await allFuturesThrowing(nodes.mapIt(it.stop()))
      await allFuturesThrowing(awaitters)

      result = true

    check:
      waitFor(testBasicGossipSub()) == true

  test "e2e - GossipSub send over fanout A -> B":
    proc runTests(): Future[bool] {.async.} =
      var passed = newFuture[void]()
      proc handler(topic: string, data: seq[byte]) {.async, gcsafe.} =
        check topic == "foobar"
        passed.complete()

      var nodes = generateNodes(2, true)
      var wait = newSeq[Future[void]]()
      wait.add(await nodes[0].start())
      wait.add(await nodes[1].start())

      await subscribeNodes(nodes)

      await nodes[1].subscribe("foobar", handler)
      await waitSub(nodes[0], nodes[1], "foobar")

      var observed = 0
      let
        obs1 = PubSubObserver(onRecv: proc(peer: PubSubPeer; msgs: var RPCMsg) =
          inc observed
        )
        obs2 = PubSubObserver(onSend: proc(peer: PubSubPeer; msgs: var RPCMsg) =
          inc observed
        )
      nodes[1].pubsub.get().addObserver(obs1)
      nodes[0].pubsub.get().addObserver(obs2)

      await nodes[0].publish("foobar", cast[seq[byte]]("Hello!"))

      var gossipSub1: GossipSub = GossipSub(nodes[0].pubSub.get())

      check:
        "foobar" in gossipSub1.gossipsub

      await passed.wait(1.seconds)

      trace "test done, stopping..."

      await nodes[0].stop()
      await nodes[1].stop()
      await allFuturesThrowing(wait)

      result = observed == 2

    check:
      waitFor(runTests()) == true

  test "e2e - GossipSub send over mesh A -> B":
    proc runTests(): Future[bool] {.async.} =
      var passed: Future[bool] = newFuture[bool]()
      proc handler(topic: string, data: seq[byte]) {.async, gcsafe.} =
        check topic == "foobar"
        passed.complete(true)

      var nodes = generateNodes(2, true)
      var wait: seq[Future[void]]
      wait.add(await nodes[0].start())
      wait.add(await nodes[1].start())

      await subscribeNodes(nodes)

      await nodes[1].subscribe("foobar", handler)
      await waitSub(nodes[0], nodes[1], "foobar")

      await nodes[0].publish("foobar", cast[seq[byte]]("Hello!"))

      result = await passed

      await nodes[0].stop()
      await nodes[1].stop()
      await allFuturesThrowing(wait)

    check:
      waitFor(runTests()) == true

  test "e2e - GossipSub with multiple peers":
    proc runTests(): Future[bool] {.async.} =
      var nodes: seq[Switch] = newSeq[Switch]()
      var awaitters: seq[Future[void]]

      for i in 0..<11:
        nodes.add newStandardSwitch(triggerSelf = true, gossip = true)
        awaitters.add((await nodes[i].start()))

      await subscribeNodes(nodes)

      var seen: Table[string, int]
      var subs: seq[Future[void]]
      var seenFut = newFuture[void]()
      for dialer in nodes:
        var handler: TopicHandler
        closureScope:
          var dialerNode = dialer
          handler = proc(topic: string, data: seq[byte]) {.async, gcsafe, closure.} =
            if dialerNode.peerInfo.id notin seen:
              seen[dialerNode.peerInfo.id] = 0
            seen[dialerNode.peerInfo.id].inc
            check topic == "foobar"
            if not seenFut.finished() and seen.len == 10:
              seenFut.complete()

        subs.add(allFutures(dialer.subscribe("foobar", handler), waitSub(nodes[0], dialer, "foobar")))

      await allFuturesThrowing(subs)

      await wait(nodes[0].publish("foobar",
                                  cast[seq[byte]]("from node " &
                                  nodes[1].peerInfo.id)),
                                  1.minutes)

      await wait(seenFut, 2.minutes)
      check: seen.len >= 10
      for k, v in seen.pairs:
        check: v == 1

      await allFuturesThrowing(nodes.mapIt(it.stop()))
      await allFuturesThrowing(awaitters)
      result = true

    check:
      waitFor(runTests()) == true