import
  std/[options, tables, strutils, sequtils],
  chronos, chronicles, stew/shims/net as stewNet,
  # TODO: Why do we need eth keys?
  eth/keys,
  libp2p/multiaddress,
  libp2p/crypto/crypto,
  libp2p/protocols/protocol,
  # NOTE For TopicHandler, solve with exports?
  libp2p/protocols/pubsub/pubsub,
  libp2p/peerinfo,
  libp2p/standard_setup,
  ../protocol/[waku_relay, waku_filter, message_notifier],
  ../protocol/waku_store/waku_store,
  ../protocol/waku_swap/waku_swap,
  ../waku_types,
  ./message_store,
  ./sqlite

export waku_types

logScope:
  topics = "wakunode"

# Default clientId
const clientId* = "Nimbus Waku v2 node"

# key and crypto modules different
type
  KeyPair* = crypto.KeyPair
  PublicKey* = crypto.PublicKey
  PrivateKey* = crypto.PrivateKey

  # TODO Get rid of this and use waku_types one
  Topic* = waku_types.Topic
  Message* = seq[byte]

  # NOTE based on Eth2Node in NBC eth2_network.nim
  WakuNode* = ref object of RootObj
    switch*: Switch
    wakuRelay*: WakuRelay
    wakuStore*: WakuStore
    wakuFilter*: WakuFilter
    wakuSwap*: WakuSwap
    peerInfo*: PeerInfo
    libp2pTransportLoops*: seq[Future[void]]
  # TODO Revist messages field indexing as well as if this should be Message or WakuMessage
    messages*: seq[(Topic, WakuMessage)]
    filters*: Filters
    subscriptions*: MessageNotificationSubscriptions
    rng*: ref BrHmacDrbgContext

# NOTE Any difference here in Waku vs Eth2?
# E.g. Devp2p/Libp2p support, etc.
#func asLibp2pKey*(key: keys.PublicKey): PublicKey =
#  PublicKey(scheme: Secp256k1, skkey: secp.SkPublicKey(key))

func asEthKey*(key: PrivateKey): keys.PrivateKey =
  keys.PrivateKey(key.skkey)

proc initAddress(T: type MultiAddress, str: string): T =
  let address = MultiAddress.init(str).tryGet()
  if IPFS.match(address) and matchPartial(multiaddress.TCP, address):
    result = address
  else:
    raise newException(ValueError,
                       "Invalid bootstrap node multi-address")

proc removeContentFilters(filters: var Filters, contentFilters: seq[ContentFilter]) {.gcsafe.} =
  # Flatten all unsubscribe topics into single seq
  var unsubscribeTopics: seq[ContentTopic]
  for cf in contentFilters:
    unsubscribeTopics = unsubscribeTopics.concat(cf.topics)
  
  debug "unsubscribing", unsubscribeTopics=unsubscribeTopics

  var rIdToRemove: seq[string] = @[]
  for rId, f in filters.mpairs:
    # Iterate filter entries to remove matching content topics
    for cf in f.contentFilters.mitems:
      # Iterate content filters in filter entry
      cf.topics.keepIf(proc (t: auto): bool = t notin unsubscribeTopics)
    # make sure we delete the content filter
    # if no more topics are left
    f.contentFilters.keepIf(proc (cf: auto): bool = cf.topics.len > 0)

    if f.contentFilters.len == 0:
      rIdToRemove.add(rId)

  # make sure we delete the filter entry
  # if no more content filters left
  for rId in rIdToRemove:
    filters.del(rId)
  
  debug "filters modified", filters=filters

template tcpEndPoint(address, port): auto =
  MultiAddress.init(address, tcpProtocol, port)

## Public API
##

proc init*(T: type WakuNode, nodeKey: crypto.PrivateKey,
    bindIp: ValidIpAddress, bindPort: Port,
    extIp = none[ValidIpAddress](), extPort = none[Port]()): T =
  ## Creates a Waku Node.
  ##
  ## Status: Implemented.
  ##
  let
    rng = crypto.newRng()
    hostAddress = tcpEndPoint(bindIp, bindPort)
    announcedAddresses = if extIp.isNone() or extPort.isNone(): @[]
                         else: @[tcpEndPoint(extIp.get(), extPort.get())]
    peerInfo = PeerInfo.init(nodekey)
  info "Initializing networking", hostAddress,
                                  announcedAddresses
  # XXX: Add this when we create node or start it?
  peerInfo.addrs.add(hostAddress)

  var switch = newStandardSwitch(some(nodekey), hostAddress,
    transportFlags = {ServerFlags.ReuseAddr}, rng = rng)
  # TODO Untested - verify behavior after switch interface change
  # More like this:
  # let pubsub = GossipSub.init(
  #    switch = switch,
  #    msgIdProvider = msgIdProvider,
  #    triggerSelf = true, sign = false,
  #    verifySignature = false).PubSub
  result = WakuNode(
    switch: switch,
    rng: rng,
    peerInfo: peerInfo,
    subscriptions: newTable[string, MessageNotificationSubscription](),
    filters: initTable[string, Filter]()
  )

proc start*(node: WakuNode) {.async.} =
  ## Starts a created Waku Node.
  ##
  ## Status: Implemented.
  ##
  node.libp2pTransportLoops = await node.switch.start()
  
  # TODO Get this from WakuNode obj
  let peerInfo = node.peerInfo
  info "PeerInfo", peerId = peerInfo.peerId, addrs = peerInfo.addrs
  let listenStr = $peerInfo.addrs[0] & "/p2p/" & $peerInfo.peerId
  ## XXX: this should be /ip4..., / stripped?
  info "Listening on", full = listenStr

proc stop*(node: WakuNode) {.async.} =
  if not node.wakuRelay.isNil:
    await node.wakuRelay.stop()

  await node.switch.stop()

proc subscribe*(node: WakuNode, topic: Topic, handler: TopicHandler) {.async.} =
  ## Subscribes to a PubSub topic. Triggers handler when receiving messages on
  ## this topic. TopicHandler is a method that takes a topic and some data.
  ##
  ## NOTE The data field SHOULD be decoded as a WakuMessage.
  ## Status: Implemented.
  info "subscribe", topic=topic

  let wakuRelay = node.wakuRelay
  await wakuRelay.subscribe(topic, handler)

proc subscribe*(node: WakuNode, request: FilterRequest, handler: ContentFilterHandler) {.async, gcsafe.} =
  ## Registers for messages that match a specific filter. Triggers the handler whenever a message is received.
  ## FilterHandler is a method that takes a MessagePush.
  ##
  ## Status: Implemented.
  
  # Sanity check for well-formed subscribe FilterRequest
  doAssert(request.subscribe, "invalid subscribe request")
  
  info "subscribe content", filter=request

  var id = generateRequestId(node.rng)
  if node.wakuFilter.isNil == false:
    # @TODO: ERROR HANDLING
    id = await node.wakuFilter.subscribe(request)
  node.filters[id] = Filter(contentFilters: request.contentFilters, handler: handler)

proc unsubscribe*(node: WakuNode, topic: Topic, handler: TopicHandler) {.async.} =
  ## Unsubscribes a handler from a PubSub topic.
  ##
  ## Status: Implemented.
  info "unsubscribe", topic=topic

  let wakuRelay = node.wakuRelay
  await wakuRelay.unsubscribe(@[(topic, handler)])

proc unsubscribeAll*(node: WakuNode, topic: Topic) {.async.} =
  ## Unsubscribes all handlers registered on a specific PubSub topic.
  ##
  ## Status: Implemented.
  info "unsubscribeAll", topic=topic

  let wakuRelay = node.wakuRelay
  await wakuRelay.unsubscribeAll(topic)
  

proc unsubscribe*(node: WakuNode, request: FilterRequest) {.async, gcsafe.} =
  ## Unsubscribe from a content filter.
  ##
  ## Status: Implemented.
  
  # Sanity check for well-formed unsubscribe FilterRequest
  doAssert(request.subscribe == false, "invalid unsubscribe request")
  
  info "unsubscribe content", filter=request
  
  await node.wakuFilter.unsubscribe(request)
  node.filters.removeContentFilters(request.contentFilters)


proc publish*(node: WakuNode, topic: Topic, message: WakuMessage) {.async, gcsafe.} =
  ## Publish a `WakuMessage` to a PubSub topic. `WakuMessage` should contain a
  ## `contentTopic` field for light node functionality. This field may be also
  ## be omitted.
  ##
  ## Status: Implemented.
  ##

  let wakuRelay = node.wakuRelay

  debug "publish", topic=topic, contentTopic=message.contentTopic
  let data = message.encode().buffer

  discard await wakuRelay.publish(topic, data)

proc query*(node: WakuNode, query: HistoryQuery, handler: QueryHandlerFunc) {.async, gcsafe.} =
  ## Queries known nodes for historical messages. Triggers the handler whenever a response is received.
  ## QueryHandlerFunc is a method that takes a HistoryResponse.
  ##
  ## Status: Implemented.

  # TODO Once waku swap is less experimental, this can simplified
  if node.wakuSwap.isNil:
    debug "Using default query"
    await node.wakuStore.query(query, handler)
  else:
    debug "Using SWAPAccounting query"
    # TODO wakuSwap now part of wakuStore object
    await node.wakuStore.queryWithAccounting(query, handler)

# TODO Extend with more relevant info: topics, peers, memory usage, online time, etc
proc info*(node: WakuNode): WakuInfo =
  ## Returns information about the Node, such as what multiaddress it can be reached at.
  ##
  ## Status: Implemented.
  ##

  # TODO Generalize this for other type of multiaddresses
  let peerInfo = node.peerInfo
  let listenStr = $peerInfo.addrs[0] & "/p2p/" & $peerInfo.peerId
  let wakuInfo = WakuInfo(listenStr: listenStr)
  return wakuInfo

proc mountFilter*(node: WakuNode) =
  info "mounting filter"
  proc filterHandler(requestId: string, msg: MessagePush) {.gcsafe.} =
    info "push received"
    for message in msg.messages:
      node.filters.notify(message, requestId)

  node.wakuFilter = WakuFilter.init(node.switch, node.rng, filterHandler)
  node.switch.mount(node.wakuFilter)
  node.subscriptions.subscribe(WakuFilterCodec, node.wakuFilter.subscription())

# NOTE: If using the swap protocol, it must be mounted before store. This is
# because store is using a reference to the swap protocol.
proc mountSwap*(node: WakuNode) =
  info "mounting swap"
  node.wakuSwap = WakuSwap.init(node.switch, node.rng)
  node.switch.mount(node.wakuSwap)
  # NYI - Do we need this?
  #node.subscriptions.subscribe(WakuSwapCodec, node.wakuSwap.subscription())

proc mountStore*(node: WakuNode, store: MessageStore = nil) =
  info "mounting store"

  if node.wakuSwap.isNil:
    debug "mounting store without swap"
    node.wakuStore = WakuStore.init(node.switch, node.rng, store)
  else:
    debug "mounting store with swap"
    node.wakuStore = WakuStore.init(node.switch, node.rng, store, node.wakuSwap)

  node.switch.mount(node.wakuStore)
  node.subscriptions.subscribe(WakuStoreCodec, node.wakuStore.subscription())

proc mountRelay*(node: WakuNode, topics: seq[string] = newSeq[string]()) {.async, gcsafe.} =
  let wakuRelay = WakuRelay.init(
    switch = node.switch,
    # Use default
    #msgIdProvider = msgIdProvider,
    triggerSelf = true,
    sign = false,
    verifySignature = false
  )

  node.wakuRelay = wakuRelay
  node.switch.mount(wakuRelay)

  info "mounting relay"
  proc relayHandler(topic: string, data: seq[byte]) {.async, gcsafe.} =
    let msg = WakuMessage.init(data)
    if msg.isOk():
      node.filters.notify(msg.value(), "")
      await node.subscriptions.notify(topic, msg.value())

  await node.wakuRelay.subscribe("/waku/2/default-waku/proto", relayHandler)

  for topic in topics:
    proc handler(topic: string, data: seq[byte]) {.async, gcsafe.} =
      debug "Hit handler", topic=topic, data=data

    # XXX: Is using discard here fine? Not sure if we want init to be async?
    # Can also move this to the start proc, possibly wiser?
    discard node.subscribe(topic, handler)

## Helpers
proc parsePeerInfo(address: string): PeerInfo =
  let multiAddr = MultiAddress.initAddress(address)
  let parts = address.split("/")
  return PeerInfo.init(parts[^1], [multiAddr])

proc dialPeer*(n: WakuNode, address: string) {.async.} =
  info "dialPeer", address = address
  # XXX: This turns ipfs into p2p, not quite sure why
  let remotePeer = parsePeerInfo(address)

  info "Dialing peer", ma = remotePeer.addrs[0]
  # NOTE This is dialing on WakuRelay protocol specifically
  # TODO Keep track of conn and connected state somewhere (WakuRelay?)
  #p.conn = await p.switch.dial(remotePeer, WakuRelayCodec)
  #p.connected = true
  discard await n.switch.dial(remotePeer.peerId, remotePeer.addrs, WakuRelayCodec)
  info "Post switch dial"

proc setStorePeer*(n: WakuNode, address: string) =
  info "dialPeer", address = address

  let remotePeer = parsePeerInfo(address)

  n.wakuStore.setPeer(remotePeer)

proc setFilterPeer*(n: WakuNode, address: string) =
  info "dialPeer", address = address

  let remotePeer = parsePeerInfo(address)

  n.wakuFilter.setPeer(remotePeer)

proc connectToNodes*(n: WakuNode, nodes: seq[string]) {.async.} =
  for nodeId in nodes:
    info "connectToNodes", node = nodeId
    # XXX: This seems...brittle
    await dialPeer(n, nodeId)

  # The issue seems to be around peers not being fully connected when
  # trying to subscribe. So what we do is sleep to guarantee nodes are
  # fully connected.
  #
  # This issue was known to Dmitiry on nim-libp2p and may be resolvable
  # later.
  await sleepAsync(5.seconds)

proc connectToNodes*(n: WakuNode, nodes: seq[PeerInfo]) {.async.} =
  for peerInfo in nodes:
    info "connectToNodes", peer = peerInfo
    discard await n.switch.dial(peerInfo.peerId, peerInfo.addrs, WakuRelayCodec)

  # The issue seems to be around peers not being fully connected when
  # trying to subscribe. So what we do is sleep to guarantee nodes are
  # fully connected.
  #
  # This issue was known to Dmitiry on nim-libp2p and may be resolvable
  # later.
  await sleepAsync(5.seconds)

when isMainModule:
  import
    confutils, json_rpc/rpcserver, metrics,
    ./config, ./rpc/wakurpc,
    ../../common/utils/nat

  proc startRpc(node: WakuNode, rpcIp: ValidIpAddress, rpcPort: Port) =
    let
      ta = initTAddress(rpcIp, rpcPort)
      rpcServer = newRpcHttpServer([ta])
    setupWakuRPC(node, rpcServer)
    rpcServer.start()
    info "RPC Server started", ta

  proc startMetricsServer(serverIp: ValidIpAddress, serverPort: Port) =
      info "Starting metrics HTTP server", serverIp, serverPort
      metrics.startHttpServer($serverIp, serverPort)

  proc startMetricsLog() =
    proc logMetrics(udata: pointer) {.closure, gcsafe.} =
      {.gcsafe.}:
        # TODO: libp2p_pubsub_peers is not public, so we need to make this either
        # public in libp2p or do our own peer counting after all.
        let
          totalMessages = total_messages.value

      info "Node metrics", totalMessages
      discard setTimer(Moment.fromNow(2.seconds), logMetrics)
    discard setTimer(Moment.fromNow(2.seconds), logMetrics)

  let
    conf = WakuNodeConf.load()
    (extIp, extTcpPort, extUdpPort) = setupNat(conf.nat, clientId,
      Port(uint16(conf.tcpPort) + conf.portsShift),
      Port(uint16(conf.udpPort) + conf.portsShift))
    node = WakuNode.init(conf.nodeKey, conf.listenAddress,
      Port(uint16(conf.tcpPort) + conf.portsShift), extIp, extTcpPort)

  waitFor node.start()

  if conf.swap:
    mountSwap(node)

  # TODO Set swap peer, for now should be same as store peer

  if conf.store:
    var store: MessageStore

    if conf.dbpath != "":
      let dbRes = SqliteDatabase.init(conf.dbpath)
      if dbRes.isErr:
        warn "failed to init database", err = dbRes.error

      let res = MessageStore.init(dbRes.value)
      if res.isErr:
        warn "failed to init MessageStore", err = res.error
      else:
        store = res.value

    mountStore(node, store)

  if conf.filter:
    mountFilter(node)

  if conf.relay:
    waitFor mountRelay(node, conf.topics.split(" "))

  if conf.staticnodes.len > 0:
    waitFor connectToNodes(node, conf.staticnodes)

  if conf.storenode != "":
    setStorePeer(node, conf.storenode)

  if conf.filternode != "":
    setFilterPeer(node, conf.filternode)

  if conf.rpc:
    startRpc(node, conf.rpcAddress, Port(conf.rpcPort + conf.portsShift))

  if conf.logMetrics:
    startMetricsLog()

  when defined(insecure):
    if conf.metricsServer:
      startMetricsServer(conf.metricsServerAddress,
        Port(conf.metricsServerPort + conf.portsShift))

  runForever()