nim-datastore/datastore/threads/threadbackend.nim

import pkg/chronos
import pkg/chronos/threadsync
import pkg/questionable
import pkg/questionable/results
import stew/results
import pkg/upraises
import pkg/taskpools
import pkg/threading/smartptrs

import ../key
import ../query
import ./datastore
import ./databuffer
import ./threadresults

# import pretty

export key, query, smartptrs, databuffer
export threadresults

push: {.upraises: [].}

type
  ThreadDatastore* = object
    tp*: Taskpool
    ds*: Datastore

  ThreadDatastorePtr* = SharedPtr[ThreadDatastore]

  QueryIterStore* = object
    it*: QueryIter
  QueryIterPtr* = SharedPtr[QueryIterStore]

proc hasTask*(
  ret: TResult[bool],
  tds: ThreadDatastorePtr,
  kb: KeyBuffer,
) =
  without key =? kb.toKey(), err:
    ret.failure(err)

  try:
    let res = waitFor tds[].ds.has(key)
    if res.isErr:
      ret.failure(res.error())
    else:
      ret.success(res.get())
    discard ret[].signal.fireSync()
  except CatchableError as err:
    ret.failure(err)

proc has*(
  ret: TResult[bool],
  tds: ThreadDatastorePtr,
  key: Key,
) =
  let bkey = StringBuffer.new(key.id())
  tds[].tp.spawn hasTask(ret, tds, bkey)

proc getTask*(
  ret: TResult[DataBuffer],
  tds: ThreadDatastorePtr,
  kb: KeyBuffer,
) =
  without key =? kb.toKey(), err:
    ret.failure(err)
  try:
    let res = waitFor tds[].ds.get(key)
    if res.isErr:
      ret.failure(res.error())
    else:
      let db = DataBuffer.new res.get()
      ret.success(db)

    discard ret[].signal.fireSync()
  except CatchableError as err:
    ret.failure(err)

proc get*(
  ret: TResult[DataBuffer],
  tds: ThreadDatastorePtr,
  key: Key,
) =
  let bkey = StringBuffer.new(key.id())
  tds[].tp.spawn getTask(ret, tds, bkey)


proc putTask*(
  ret: TResult[void],
  tds: ThreadDatastorePtr,
  kb: KeyBuffer,
  db: DataBuffer,
) =

  without key =? kb.toKey(), err:
    ret.failure(err)

  let data = db.toSeq(byte)
  let res = (waitFor tds[].ds.put(key, data)).catch
  # print "thrbackend: putTask: fire", ret[].signal.fireSync().get()
  if res.isErr:
    ret.failure(res.error())
  else:
    ret.success()

  discard ret[].signal.fireSync()

proc put*(
  ret: TResult[void],
  tds: ThreadDatastorePtr,
  key: Key,
  data: seq[byte]
) =
  let bkey = StringBuffer.new(key.id())
  let bval = DataBuffer.new(data)

  tds[].tp.spawn putTask(ret, tds, bkey, bval)


proc deleteTask*(
  ret: TResult[void],
  tds: ThreadDatastorePtr,
  kb: KeyBuffer,
) =

  without key =? kb.toKey(), err:
    ret.failure(err)

  let res = (waitFor tds[].ds.delete(key)).catch
  # print "thrbackend: putTask: fire", ret[].signal.fireSync().get()
  if res.isErr:
    ret.failure(res.error())
  else:
    ret.success()

  discard ret[].signal.fireSync()

# import pretty

proc delete*(
  ret: TResult[void],
  tds: ThreadDatastorePtr,
  key: Key,
) =
  let bkey = StringBuffer.new(key.id())
  tds[].tp.spawn deleteTask(ret, tds, bkey)

# import os

proc queryTask*(
  ret: TResult[QueryResponseBuffer],
  tds: ThreadDatastorePtr,
  qiter: QueryIterPtr,
) =

  try:
    # os.sleep(100)
    without res =? waitFor(qiter[].it.next()), err:
      ret.failure(err)

    let qrb = res.toBuffer()
    # print "queryTask: ", " res: ", res

    ret.success(qrb)
    # print "queryTask: ", " qrb:key: ", ret[].results.get().key.toString()
    # print "queryTask: ", " qrb:data: ", ret[].results.get().data.toString()

  except Exception as exc:
    ret.failure(exc)

  discard ret[].signal.fireSync()

proc query*(
  ret: TResult[QueryResponseBuffer],
  tds: ThreadDatastorePtr,
  qiter: QueryIterPtr,
) =
  tds[].tp.spawn queryTask(ret, tds, qiter)