# Nimbus
# Copyright (c) 2023-2024 Status Research & Development GmbH
# Licensed under either of
#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
#    http://www.apache.org/licenses/LICENSE-2.0)
#  * MIT license ([LICENSE-MIT](LICENSE-MIT) or
#    http://opensource.org/licenses/MIT)
# at your option. This file may not be copied, modified, or
# distributed except according to those terms.

## Aristo (aka Patricia) DB records transaction based merge test

import
  std/[algorithm, bitops, sequtils, sets, tables],
  eth/common,
  results,
  unittest2,
  stew/endians2,
  ../../nimbus/db/opts,
  ../../nimbus/db/core_db/backend/aristo_rocksdb,
  ../../nimbus/db/aristo/[
    aristo_check,
    aristo_debug,
    aristo_delete,
    aristo_desc,
    aristo_get,
    aristo_hike,
    aristo_init/persistent,
    aristo_nearby,
    aristo_part,
    aristo_part/part_debug,
    aristo_tx],
  ../replay/xcheck,
  ./test_helpers

type
  PrngDesc = object
    prng: uint32                       ## random state

  KnownHasherFailure* = seq[(string,(int,AristoError))]
    ## (<sample-name> & "#" <instance>, (<vertex-id>,<error-symbol>))

const
  testRootVid = VertexID(2)
    ## Need to reconfigure for the test, root ID 1 cannot be deleted as a trie

# ------------------------------------------------------------------------------
# Private helpers
# ------------------------------------------------------------------------------

proc posixPrngRand(state: var uint32): byte =
  ## POSIX.1-2001 example of a rand() implementation, see manual page rand(3).
  state = state * 1103515245 + 12345;
  let val = (state shr 16) and 32767    # mod 2^31
  (val shr 8).byte                      # Extract second byte

proc rand[W: SomeInteger|VertexID](ap: var PrngDesc; T: type W): T =
  var a: array[sizeof T,byte]
  for n in 0 ..< sizeof T:
    a[n] = ap.prng.posixPrngRand().byte
  when sizeof(T) == 1:
    let w = uint8.fromBytesBE(a).T
  when sizeof(T) == 2:
    let w = uint16.fromBytesBE(a).T
  when sizeof(T) == 4:
    let w = uint32.fromBytesBE(a).T
  else:
    let w = uint64.fromBytesBE(a).T
  when T is SomeUnsignedInt:
    # That way, `fromBytesBE()` can be applied to `uint`
    result = w
  else:
    # That way the result is independent of endianness
    (addr result).copyMem(unsafeAddr w, sizeof w)

proc init(T: type PrngDesc; seed: int): PrngDesc =
  result.prng = (seed and 0x7fffffff).uint32

proc rand(td: var PrngDesc; top: int): int =
  if 0 < top:
    let mask = (1 shl (8 * sizeof(int) - top.countLeadingZeroBits)) - 1
    for _ in 0 ..< 100:
      let w = mask and td.rand(typeof(result))
      if w < top:
        return w
    raiseAssert "Not here (!)"

# -----------------------

proc randomisedLeafs(
    db: AristoDbRef;
    ltys: HashSet[LeafTie];
    td: var PrngDesc;
       ): Result[seq[(LeafTie,RootedVertexID)],(VertexID,AristoError)] =
  var lvp: seq[(LeafTie,RootedVertexID)]
  for lty in ltys:
    var hike: Hike
    ?lty.hikeUp(db, Opt.none(VertexRef), hike)
    lvp.add (lty,(hike.root, hike.legs[^1].wp.vid))

  var lvp2 = lvp.sorted(
    cmp = proc(a,b: (LeafTie,RootedVertexID)): int = cmp(a[0],b[0]))
  if 2 < lvp2.len:
    for n in 0 ..< lvp2.len-1:
      let r = n + td.rand(lvp2.len - n)
      lvp2[n].swap lvp2[r]
  ok lvp2

proc innerCleanUp(db: var AristoDbRef): bool {.discardable.}  =
  ## Defer action
  if not db.isNil:
    let rx = db.txTop()
    if rx.isOk:
      let rc = rx.value.collapse(commit=false)
      xCheckRc rc.error == 0
    db.finish(eradicate=true)
    db = AristoDbRef(nil)
  true

# --------------------------------

proc saveToBackend(
    tx: var AristoTxRef;
    relax: bool;
    noisy: bool;
    debugID: int;
      ): bool =
  var db = tx.to(AristoDbRef)

  # Verify context: nesting level must be 2 (i.e. two transactions)
  xCheck tx.level == 2

  block:
    let rc = db.checkTop()
    xCheckRc rc.error == (0,0)

  # Commit and hashify the current layer
  block:
    let rc = tx.commit()
    xCheckRc rc.error == 0

  block:
    let rc = db.txTop()
    xCheckRc rc.error == 0
    tx = rc.value

  # Verify context: nesting level must be 1 (i.e. one transaction)
  xCheck tx.level == 1

  block:
    let rc = db.checkBE()
    xCheckRc rc.error == (0,0)

  # Commit and save to backend
  block:
    let rc = tx.commit()
    xCheckRc rc.error == 0

  block:
    let rc = db.txTop()
    xCheckErr rc.value.level < 0 # force error

  block:
    let rc = db.schedStow()
    xCheckRc rc.error == 0

  block:
    let rc = db.checkBE()
    xCheckRc rc.error == (0,0):
      noisy.say "***", "saveToBackend (8)", " debugID=", debugID

  # Update layers to original level
  tx = db.txBegin().value.to(AristoDbRef).txBegin().value

  true


proc fwdWalkVerify(
    db: AristoDbRef;
    root: VertexID;
    leftOver: HashSet[LeafTie];
    noisy: bool;
    debugID: int;
      ): bool =
  let
    nLeafs = leftOver.len
  var
    leftOver = leftOver
    last = LeafTie()
    n = 0
  for (key,_) in db.rightPairs low(LeafTie,root):
    xCheck key in leftOver:
      noisy.say "*** fwdWalkVerify", "id=", n + (nLeafs + 1) * debugID
    leftOver.excl key
    last = key
    n.inc

  # Verify stop condition
  if last.root == VertexID(0):
    last = low(LeafTie,root)
  elif last != high(LeafTie,root):
    last = last.next
  let rc = last.right db
  xCheck rc.isErr
  xCheck rc.error[1] == NearbyBeyondRange
  xCheck n == nLeafs

  true

proc revWalkVerify(
    db: AristoDbRef;
    root: VertexID;
    leftOver: HashSet[LeafTie];
    noisy: bool;
    debugID: int;
      ): bool =
  let
    nLeafs = leftOver.len
  var
    leftOver = leftOver
    last = LeafTie()
    n = 0
  for (key,_) in db.leftPairs high(LeafTie,root):
    xCheck key in leftOver:
      noisy.say "*** revWalkVerify", " id=", n + (nLeafs + 1) * debugID
    leftOver.excl key
    last = key
    n.inc

  # Verify stop condition
  if last.root == VertexID(0):
    last = high(LeafTie,root)
  elif last != low(LeafTie,root):
    last = last.prev
  let rc = last.left db
  xCheck rc.isErr
  xCheck rc.error[1] == NearbyBeyondRange
  xCheck n == nLeafs

  true

# ------------------------------------------------------------------------------
# Public test function
# ------------------------------------------------------------------------------

proc testTxMergeAndDeleteOneByOne*(
    noisy: bool;
    list: openArray[ProofTrieData];
    rdbPath: string;                          # Rocks DB storage directory
       ): bool {.deprecated: "rewrite to use non-generic data".} =
  # var
  #   prng = PrngDesc.init 42
  #   db = AristoDbRef(nil)
  #   fwdRevVfyToggle = true
  # defer:
  #   if not db.isNil:
  #     db.finish(eradicate=true)

  # for n,w in list:
  #   # Start with brand new persistent database.
  #   db = block:
  #     if 0 < rdbPath.len:
  #       let (dbOpts, cfOpts) = DbOptions.init().toRocksDb()
  #       let rc = AristoDbRef.init(RdbBackendRef, rdbPath, DbOptions.init(), dbOpts, cfOpts, [])
  #       xCheckRc rc.error == 0
  #       rc.value()[0]
  #     else:
  #       AristoDbRef.init(MemBackendRef)

  #   # Start transaction (double frame for testing)
  #   xCheck db.txTop.isErr
  #   var tx = db.txBegin().value.to(AristoDbRef).txBegin().value
  #   xCheck tx.isTop()
  #   xCheck tx.level == 2

  #   # Reset database so that the next round has a clean setup
  #   defer: db.innerCleanUp

  #   # Merge leaf data into main trie
  #   let kvpLeafs = block:
  #     var lst = w.kvpLst.mapRootVid testRootVid
  #     # The list might be reduced for isolation of particular properties,
  #     # e.g. lst.setLen(min(5,lst.len))
  #     lst
  #   for i,leaf in kvpLeafs:
  #     let rc = db.mergeGenericData leaf
  #     xCheckRc rc.error == 0

  #   # List of all leaf entries that should be on the database
  #   var leafsLeft = kvpLeafs.mapIt(it.leafTie).toHashSet

  #   # Provide a (reproducible) peudo-random copy of the leafs list
  #   let leafVidPairs = block:
  #     let rc = db.randomisedLeafs(leafsLeft, prng)
  #     xCheckRc rc.error == (0,0)
  #     rc.value

  #   # Trigger subsequent saving tasks in loop below
  #   let (saveMod, saveRest, relax) = block:
  #     if leafVidPairs.len < 17:    (7, 3, false)
  #     elif leafVidPairs.len < 31: (11, 7, false)
  #     else:   (leafVidPairs.len div 5, 11, true)

  #   # === Loop over leafs ===
  #   for u,lvp in leafVidPairs:
  #     let
  #       runID = n + list.len * u
  #       tailWalkVerify = 7 # + 999
  #       doSaveBeOk = ((u mod saveMod) == saveRest)
  #       (leaf, lid) = lvp

  #     if doSaveBeOk:
  #       let saveBeOk = tx.saveToBackend(relax=relax, noisy=noisy, runID)
  #       xCheck saveBeOk:
  #         noisy.say "***", "del1by1(2)",
  #           " u=", u,
  #           " n=", n, "/", list.len,
  #           "\n    db\n    ", db.pp(backendOk=true),
  #           ""

  #     # Delete leaf
  #     block:
  #       let rc = db.deleteGenericData(leaf.root, @(leaf.path))
  #       xCheckRc rc.error == 0

  #     # Update list of remaininf leafs
  #     leafsLeft.excl leaf

  #     let deletedVtx = tx.db.getVtx lid
  #     xCheck deletedVtx.isValid == false:
  #       noisy.say "***", "del1by1(8)"

  #     # Walking the database is too slow for large tables. So the hope is that
  #     # potential errors will not go away and rather pop up later, as well.
  #     if leafsLeft.len <= tailWalkVerify:
  #       if u < leafVidPairs.len-1:
  #         if fwdRevVfyToggle:
  #           fwdRevVfyToggle = false
  #           if not db.fwdWalkVerify(leaf.root, leafsLeft, noisy, runID):
  #             return
  #         else:
  #           fwdRevVfyToggle = true
  #           if not db.revWalkVerify(leaf.root, leafsLeft, noisy, runID):
  #             return

  #   when true and false:
  #     noisy.say "***", "del1by1(9)",
  #       " n=", n, "/", list.len,
  #       " nLeafs=", kvpLeafs.len

  true


proc testTxMergeAndDeleteSubTree*(
    noisy: bool;
    list: openArray[ProofTrieData];
    rdbPath: string;                          # Rocks DB storage directory
       ): bool {.deprecated: "rewrite to use non-generic data".} =
  # var
  #   prng = PrngDesc.init 42
  #   db = AristoDbRef(nil)
  # defer:
  #   if not db.isNil:
  #     db.finish(eradicate=true)

  # for n,w in list:
  #   # Start with brand new persistent database.
  #   db = block:
  #     if 0 < rdbPath.len:
  #       let (dbOpts, cfOpts) = DbOptions.init().toRocksDb()
  #       let rc = AristoDbRef.init(RdbBackendRef, rdbPath, DbOptions.init(), dbOpts, cfOpts, [])
  #       xCheckRc rc.error == 0
  #       rc.value()[0]
  #     else:
  #       AristoDbRef.init(MemBackendRef)

  #   # Start transaction (double frame for testing)
  #   xCheck db.txTop.isErr
  #   var tx = db.txBegin().value.to(AristoDbRef).txBegin().value
  #   xCheck tx.isTop()
  #   xCheck tx.level == 2

  #   # Reset database so that the next round has a clean setup
  #   defer: db.innerCleanUp

  #   # Merge leaf data into main trie (w/vertex ID 2)
  #   let kvpLeafs = block:
  #     var lst = w.kvpLst.mapRootVid testRootVid
  #     # The list might be reduced for isolation of particular properties,
  #     # e.g. lst.setLen(min(5,lst.len))
  #     lst
  #   for i,leaf in kvpLeafs:
  #     let rc = db.mergeGenericData leaf
  #     xCheckRc rc.error == 0

  #   # List of all leaf entries that should be on the database
  #   var leafsLeft = kvpLeafs.mapIt(it.leafTie).toHashSet

  #   # Provide a (reproducible) peudo-random copy of the leafs list
  #   let leafVidPairs = block:
  #     let rc = db.randomisedLeafs(leafsLeft, prng)
  #     xCheckRc rc.error == (0,0)
  #     rc.value
  #   discard leafVidPairs

  #   # === delete sub-tree ===
  #   block:
  #     let saveBeOk = tx.saveToBackend(relax=false, noisy=noisy, 1+list.len*n)
  #     xCheck saveBeOk:
  #       noisy.say "***", "del(1)",
  #         " n=", n, "/", list.len,
  #         "\n    db\n    ", db.pp(backendOk=true),
  #         ""
  #   # Delete sub-tree
  #   block:
  #     let rc = db.deleteGenericTree testRootVid
  #     xCheckRc rc.error == 0:
  #       noisy.say "***", "del(2)",
  #         " n=", n, "/", list.len,
  #         "\n    db\n    ", db.pp(backendOk=true),
  #         ""
  #   block:
  #     let saveBeOk = tx.saveToBackend(relax=false, noisy=noisy, 2+list.len*n)
  #     xCheck saveBeOk:
  #       noisy.say "***", "del(3)",
  #         " n=", n, "/", list.len,
  #         "\n    db\n    ", db.pp(backendOk=true),
  #         ""
  #   when true and false:
  #     noisy.say "***", "del(9) n=", n, "/", list.len, " nLeafs=", kvpLeafs.len

  true

# ------------------------------------------------------------------------------
# End
# ------------------------------------------------------------------------------