# beacon_chain
# Copyright (c) 2018-2020 Status Research & Development GmbH
# Licensed and distributed under either of
#   * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
#   * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
# at your option. This file may not be copied, modified, or distributed except according to those terms.

{.used.}

import
  std/unittest,
  chronicles, chronos,
  stew/byteutils,
  ./testutil, ./testblockutil,
  ../beacon_chain/spec/[crypto, datatypes, digest, validator, state_transition,
                        helpers, beaconstate, presets, network],
  ../beacon_chain/[
    beacon_node_types, attestation_pool, attestation_aggregation, extras, time],
  ../beacon_chain/fork_choice/[fork_choice_types, fork_choice],
  ../beacon_chain/block_pools/[chain_dag, clearance]

func combine(tgt: var Attestation, src: Attestation, flags: UpdateFlags) =
  ## Combine the signature and participation bitfield, with the assumption that
  ## the same data is being signed - if the signatures overlap, they are not
  ## combined.

  doAssert tgt.data == src.data

  # In a BLS aggregate signature, one needs to count how many times a
  # particular public key has been added - since we use a single bit per key, we
  # can only it once, thus we can never combine signatures that overlap already!
  if not tgt.aggregation_bits.overlaps(src.aggregation_bits):
    tgt.aggregation_bits.combine(src.aggregation_bits)

    if skipBlsValidation notin flags:
      var agg {.noInit.}: AggregateSignature
      agg.init(tgt.signature)
      agg.aggregate(src.signature)
      tgt.signature = agg.finish()

template wrappedTimedTest(name: string, body: untyped) =
  # `check` macro takes a copy of whatever it's checking, on the stack!
  # This leads to stack overflow
  # We can mitigate that by wrapping checks in proc
  block: # Symbol namespacing
    proc wrappedTest() =
      timedTest name:
        body
    wrappedTest()

suiteReport "Attestation pool processing" & preset():
  ## For now just test that we can compile and execute block processing with
  ## mock data.

  setup:
    # Genesis state that results in 3 members per committee
    var
      chainDag = init(ChainDAGRef, defaultRuntimePreset, makeTestDB(SLOTS_PER_EPOCH * 3))
      quarantine = QuarantineRef()
      pool = newClone(AttestationPool.init(chainDag, quarantine))
      state = newClone(chainDag.headState)
      cache = StateCache()
    # Slot 0 is a finalized slot - won't be making attestations for it..
    check:
      process_slots(state.data, state.data.data.slot + 1, cache)

  wrappedTimedTest "Can add and retrieve simple attestation" & preset():
    let
      # Create an attestation for slot 1!
      beacon_committee = get_beacon_committee(
        state.data.data, state.data.data.slot, 0.CommitteeIndex, cache)
      attestation = makeAttestation(
        state.data.data, state.blck.root, beacon_committee[0], cache)

    pool[].addAttestation(
      attestation, [beacon_committee[0]].toHashSet(), attestation.data.slot)

    check:
      process_slots(state.data, MIN_ATTESTATION_INCLUSION_DELAY.Slot + 1, cache)

    let attestations = pool[].getAttestationsForBlock(state.data.data, cache)

    check:
      attestations.len == 1

  wrappedTimedTest "Attestations may arrive in any order" & preset():
    var cache = StateCache()
    let
      # Create an attestation for slot 1!
      bc0 = get_beacon_committee(
        state.data.data, state.data.data.slot, 0.CommitteeIndex, cache)
      attestation0 = makeAttestation(
        state.data.data, state.blck.root, bc0[0], cache)

    check:
      process_slots(state.data, state.data.data.slot + 1, cache)

    let
      bc1 = get_beacon_committee(state.data.data,
        state.data.data.slot, 0.CommitteeIndex, cache)
      attestation1 = makeAttestation(
        state.data.data, state.blck.root, bc1[0], cache)

    # test reverse order
    pool[].addAttestation(
      attestation1, [bc1[0]].toHashSet, attestation1.data.slot)
    pool[].addAttestation(
      attestation0, [bc0[0]].toHashSet, attestation1.data.slot)

    discard process_slots(
      state.data, MIN_ATTESTATION_INCLUSION_DELAY.Slot + 1, cache)

    let attestations = pool[].getAttestationsForBlock(state.data.data, cache)

    check:
      attestations.len == 1

  wrappedTimedTest "Attestations should be combined" & preset():
    var cache = StateCache()
    let
      # Create an attestation for slot 1!
      bc0 = get_beacon_committee(
        state.data.data, state.data.data.slot, 0.CommitteeIndex, cache)
      attestation0 = makeAttestation(
        state.data.data, state.blck.root, bc0[0], cache)
      attestation1 = makeAttestation(
        state.data.data, state.blck.root, bc0[1], cache)

    pool[].addAttestation(
      attestation0, [bc0[0]].toHashSet, attestation0.data.slot)
    pool[].addAttestation(
      attestation1, [bc0[1]].toHashSet, attestation1.data.slot)

    check:
      process_slots(state.data, MIN_ATTESTATION_INCLUSION_DELAY.Slot + 1, cache)

    let attestations = pool[].getAttestationsForBlock(state.data.data, cache)

    check:
      attestations.len == 1

  wrappedTimedTest "Attestations may overlap, bigger first" & preset():
    var cache = StateCache()

    var
      # Create an attestation for slot 1!
      bc0 = get_beacon_committee(
        state.data.data, state.data.data.slot, 0.CommitteeIndex, cache)
      attestation0 = makeAttestation(
        state.data.data, state.blck.root, bc0[0], cache)
      attestation1 = makeAttestation(
        state.data.data, state.blck.root, bc0[1], cache)

    attestation0.combine(attestation1, {})

    pool[].addAttestation(
      attestation0, [bc0[0]].toHashSet, attestation0.data.slot)
    pool[].addAttestation(
      attestation1, [bc0[1]].toHashSet, attestation1.data.slot)

    check:
      process_slots(state.data, MIN_ATTESTATION_INCLUSION_DELAY.Slot + 1, cache)

    let attestations = pool[].getAttestationsForBlock(state.data.data, cache)

    check:
      attestations.len == 1

  wrappedTimedTest "Attestations may overlap, smaller first" & preset():
    var cache = StateCache()
    var
      # Create an attestation for slot 1!
      bc0 = get_beacon_committee(state.data.data,
        state.data.data.slot, 0.CommitteeIndex, cache)
      attestation0 = makeAttestation(
        state.data.data, state.blck.root, bc0[0], cache)
      attestation1 = makeAttestation(
        state.data.data, state.blck.root, bc0[1], cache)

    attestation0.combine(attestation1, {})

    pool[].addAttestation(
      attestation1, [bc0[1]].toHashSet, attestation1.data.slot)
    pool[].addAttestation(
      attestation0, [bc0[0]].toHashSet, attestation0.data.slot)

    check:
      process_slots(state.data, MIN_ATTESTATION_INCLUSION_DELAY.Slot + 1, cache)

    let attestations = pool[].getAttestationsForBlock(state.data.data, cache)

    check:
      attestations.len == 1

  wrappedTimedTest "Fork choice returns latest block with no attestations":
    var cache = StateCache()
    let
      b1 = addTestBlock(state.data, chainDag.tail.root, cache)
      b1Add = chainDag.addRawBlock(quarantine, b1) do (
          blckRef: BlockRef, signedBlock: SignedBeaconBlock,
          epochRef: EpochRef, state: HashedBeaconState):
        # Callback add to fork choice if valid
        pool[].addForkChoice(epochRef, blckRef, signedBlock.message, blckRef.slot)

    let head = pool[].selectHead(b1Add[].slot)

    check:
      head == b1Add[]

    let
      b2 = addTestBlock(state.data, b1.root, cache)
      b2Add = chainDag.addRawBlock(quarantine, b2) do (
          blckRef: BlockRef, signedBlock: SignedBeaconBlock,
          epochRef: EpochRef, state: HashedBeaconState):
        # Callback add to fork choice if valid
        pool[].addForkChoice(epochRef, blckRef, signedBlock.message, blckRef.slot)

    let head2 = pool[].selectHead(b2Add[].slot)

    check:
      head2 == b2Add[]

  wrappedTimedTest "Fork choice returns block with attestation":
    var cache = StateCache()
    let
      b10 = makeTestBlock(state.data, chainDag.tail.root, cache)
      b10Add = chainDag.addRawBlock(quarantine, b10) do (
          blckRef: BlockRef, signedBlock: SignedBeaconBlock,
          epochRef: EpochRef, state: HashedBeaconState):
        # Callback add to fork choice if valid
        pool[].addForkChoice(epochRef, blckRef, signedBlock.message, blckRef.slot)

    let head = pool[].selectHead(b10Add[].slot)

    check:
      head == b10Add[]

    let
      b11 = makeTestBlock(state.data, chainDag.tail.root, cache,
        graffiti = GraffitiBytes [1'u8, 0, 0, 0 ,0 ,0 ,0 ,0 ,0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
      )
      b11Add = chainDag.addRawBlock(quarantine, b11) do (
          blckRef: BlockRef, signedBlock: SignedBeaconBlock,
          epochRef: EpochRef, state: HashedBeaconState):
        # Callback add to fork choice if valid
        pool[].addForkChoice(epochRef, blckRef, signedBlock.message, blckRef.slot)

      bc1 = get_beacon_committee(
        state.data.data, state.data.data.slot - 1, 1.CommitteeIndex, cache)
      attestation0 = makeAttestation(state.data.data, b10.root, bc1[0], cache)

    pool[].addAttestation(
      attestation0, [bc1[0]].toHashSet, attestation0.data.slot)

    let head2 = pool[].selectHead(b10Add[].slot)

    check:
      # Single vote for b10 and no votes for b11
      head2 == b10Add[]

    let
      attestation1 = makeAttestation(state.data.data, b11.root, bc1[1], cache)
      attestation2 = makeAttestation(state.data.data, b11.root, bc1[2], cache)
    pool[].addAttestation(
      attestation1, [bc1[1]].toHashSet, attestation1.data.slot)

    let head3 = pool[].selectHead(b10Add[].slot)
    let bigger = if b11.root.data < b10.root.data: b10Add else: b11Add

    check:
      # Ties broken lexicographically in spec -> ?
      head3 == bigger[]

    pool[].addAttestation(
      attestation2, [bc1[2]].toHashSet, attestation2.data.slot)

    let head4 = pool[].selectHead(b11Add[].slot)

    check:
      # Two votes for b11
      head4 == b11Add[]

  wrappedTimedTest "Trying to add a block twice tags the second as an error":
    var cache = StateCache()
    let
      b10 = makeTestBlock(state.data, chainDag.tail.root, cache)
      b10Add = chainDag.addRawBlock(quarantine, b10) do (
          blckRef: BlockRef, signedBlock: SignedBeaconBlock,
          epochRef: EpochRef, state: HashedBeaconState):
        # Callback add to fork choice if valid
        pool[].addForkChoice(epochRef, blckRef, signedBlock.message, blckRef.slot)

    let head = pool[].selectHead(b10Add[].slot)

    check:
      head == b10Add[]

    # -------------------------------------------------------------
    # Add back the old block to ensure we have a duplicate error
    let b10_clone = b10 # Assumes deep copy
    let b10Add_clone = chainDag.addRawBlock(quarantine, b10_clone) do (
          blckRef: BlockRef, signedBlock: SignedBeaconBlock,
          epochRef: EpochRef, state: HashedBeaconState):
        # Callback add to fork choice if valid
        pool[].addForkChoice(epochRef, blckRef, signedBlock.message, blckRef.slot)

    doAssert: b10Add_clone.error == (ValidationResult.Ignore, Duplicate)

  wrappedTimedTest "Trying to add a duplicate block from an old pruned epoch is tagged as an error":
    # Note: very sensitive to stack usage

    chainDag.updateFlags.incl {skipBLSValidation}
    var cache = StateCache()
    let
      b10 = addTestBlock(state.data, chainDag.tail.root, cache)
      b10Add = chainDag.addRawBlock(quarantine, b10) do (
          blckRef: BlockRef, signedBlock: SignedBeaconBlock,
          epochRef: EpochRef, state: HashedBeaconState):
        # Callback add to fork choice if valid
        pool[].addForkChoice(epochRef, blckRef, signedBlock.message, blckRef.slot)

    let head = pool[].selectHead(b10Add[].slot)

    doAssert: head == b10Add[]

    # -------------------------------------------------------------
    let b10_clone = b10 # Assumes deep copy

    # -------------------------------------------------------------
    # Pass an epoch
    var block_root = b10.root

    var attestations: seq[Attestation]

    for epoch in 0 ..< 5:
      let start_slot = compute_start_slot_at_epoch(Epoch epoch)
      let committees_per_slot =
        get_committee_count_per_slot(state.data.data, Epoch epoch, cache)
      for slot in start_slot ..< start_slot + SLOTS_PER_EPOCH:
        let new_block = addTestBlock(
          state.data, block_root, cache, attestations = attestations)

        block_root = new_block.root
        let blockRef = chainDag.addRawBlock(quarantine, new_block) do (
            blckRef: BlockRef, signedBlock: SignedBeaconBlock,
            epochRef: EpochRef, state: HashedBeaconState):
          # Callback add to fork choice if valid
          pool[].addForkChoice(epochRef, blckRef, signedBlock.message, blckRef.slot)

        let head = pool[].selectHead(blockRef[].slot)
        doassert: head == blockRef[]
        chainDag.updateHead(head, quarantine)

        attestations.setlen(0)
        for index in 0'u64 ..< committees_per_slot:
          let committee = get_beacon_committee(
              state.data.data, state.data.data.slot, index.CommitteeIndex, cache)

          # Create a bitfield filled with the given count per attestation,
          # exactly on the right-most part of the committee field.
          var aggregation_bits = init(CommitteeValidatorsBits, committee.len)
          for v in 0 ..< committee.len * 2 div 3 + 1:
            aggregation_bits[v] = true

          attestations.add Attestation(
            aggregation_bits: aggregation_bits,
            data: makeAttestationData(
              state.data.data, state.data.data.slot,
              index.CommitteeIndex, blockroot)
            # signature: ValidatorSig()
          )

      cache = StateCache()

    # -------------------------------------------------------------
    # Prune

    doAssert: chainDag.finalizedHead.slot != 0

    pool[].prune()
    doAssert: b10.root notin pool.forkChoice.backend

    # Add back the old block to ensure we have a duplicate error
    let b10Add_clone = chainDag.addRawBlock(quarantine, b10_clone) do (
          blckRef: BlockRef, signedBlock: SignedBeaconBlock,
          epochRef: EpochRef, state: HashedBeaconState):
        # Callback add to fork choice if valid
        pool[].addForkChoice(epochRef, blckRef, signedBlock.message, blckRef.slot)

    doAssert: b10Add_clone.error == (ValidationResult.Ignore, Duplicate)


suiteReport "Attestation validation " & preset():
  setup:
    # Genesis state that results in 3 members per committee
    var
      chainDag = init(ChainDAGRef, defaultRuntimePreset, makeTestDB(SLOTS_PER_EPOCH * 3))
      quarantine = QuarantineRef()
      pool = newClone(AttestationPool.init(chainDag, quarantine))
      state = newClone(chainDag.headState)
      cache = StateCache()
    # Slot 0 is a finalized slot - won't be making attestations for it..
    check:
      process_slots(state.data, state.data.data.slot + 1, cache)

  wrappedTimedTest "Validation sanity":
    chainDag.updateFlags.incl {skipBLSValidation}

    var
      cache: StateCache
    for blck in makeTestBlocks(
        chainDag.headState.data, chainDag.head.root, cache,
        int(SLOTS_PER_EPOCH * 5), false):
      let added = chainDag.addRawBlock(quarantine, blck) do (
          blckRef: BlockRef, signedBlock: SignedBeaconBlock,
          epochRef: EpochRef, state: HashedBeaconState):
        # Callback add to fork choice if valid
        pool[].addForkChoice(epochRef, blckRef, signedBlock.message, blckRef.slot)

      check: added.isOk()
      chainDag.updateHead(added[], quarantine)

    var
      # Create an attestation for slot 1!
      beacon_committee = get_beacon_committee(
        chainDag.headState.data.data, chainDag.head.slot, 0.CommitteeIndex, cache)
      attestation = makeAttestation(
        chainDag.headState.data.data, chainDag.head.root, beacon_committee[0], cache)

      committees_per_slot =
        get_committee_count_per_slot(chainDag.headState.data.data,
        attestation.data.slot.epoch, cache)

      subnet = compute_subnet_for_attestation(
        committees_per_slot,
        attestation.data.slot, attestation.data.index.CommitteeIndex)

      beaconTime = attestation.data.slot.toBeaconTime()

    check:
      validateAttestation(pool[], attestation, beaconTime, subnet).isOk

      # Same validator again
      validateAttestation(pool[], attestation, beaconTime, subnet).error()[0] ==
        ValidationResult.Ignore

    pool[].nextAttestationEpoch.setLen(0) # reset for test
    check:
      # Wrong subnet
      validateAttestation(pool[], attestation, beaconTime, subnet + 1).isErr

    pool[].nextAttestationEpoch.setLen(0) # reset for test
    check:
      # Too far in the future
      validateAttestation(
        pool[], attestation, beaconTime - 1.seconds, subnet + 1).isErr

    pool[].nextAttestationEpoch.setLen(0) # reset for test
    check:
      # Too far in the past
      validateAttestation(
        pool[], attestation,
        beaconTime - (SECONDS_PER_SLOT * SLOTS_PER_EPOCH - 1).int.seconds,
        subnet + 1).isErr