# SPDX-FileCopyrightText: ☭ 2022 Emery Hemingway
# SPDX-License-Identifier: Unlicense

import std/[hashes, tables]
import preserves
import ./actors, ./protocols/dataspace, ./skeletons

from ./protocols/protocol import Handle

template trace(args: varargs[untyped]): untyped = stderr.writeLine(args)

type
  Observe = dataspace.Observe[Ref]
  Turn = actors.Turn

  Dataspace {.final.} = ref object of Entity
    index: Index
    handleMap: Table[Handle, Assertion]

method publish(ds: Dataspace; turn: var Turn; v: Assertion; h: Handle) =
  if add(ds.index, turn, v):
    var obs: Observe
    if obs.fromPreserve v:
      ds.index.add(turn, obs.pattern, unembed obs.observer)
  ds.handleMap[h] = v

method retract(ds: Dataspace; turn: var Turn; h: Handle) =
  try:
    let v = ds.handleMap[h]
    if remove(ds.index, turn, v):
      ds.handleMap.del h
      var obs: Observe
      if obs.fromPreserve v:
        ds.index.remove(turn, obs.pattern, unembed obs.observer)
  except KeyError: discard

method message(ds: Dataspace; turn: var Turn; v: Assertion) =
  ds.index.deliverMessage(turn, v)

type BootProc = proc (ds: Ref; turn: var Turn) {.gcsafe.}

proc bootDataspace*(name: string; bootProc: BootProc): Actor {.discardable.} =
  bootActor(name) do (turn: var Turn):
    discard turn.facet.preventInertCheck()
    let ds = newRef(turn, Dataspace(index: initIndex()))
    bootProc(ds, turn)