{-# Language AllowAmbiguousTypes #-}
module DownloadQ where

import HBS2.Prelude
import HBS2.Clock
import HBS2.Events
import HBS2.Data.Types.Refs
import HBS2.Net.PeerLocator
import HBS2.Peer.Brains
import HBS2.Storage
import HBS2.Storage.Operations.Missed

import PeerTypes
import PeerConfig

import Data.Foldable
import Control.Monad
import Lens.Micro.Platform

downloadQueue :: forall e m . ( MyPeer e
                              , DownloadFromPeerStuff e m
                              , HasPeerLocator e (BlockDownloadM e m)
                              , HasPeerLocator e m
                              , EventListener e (DownloadReq e) m
                              , HasStorage m
                              ) => PeerConfig
                                -> SomeBrains e
                                -> DownloadEnv e -> m ()

downloadQueue _ brains denv = do
  debug "DownloadQ started"

  down <- listDownloads @e brains
  sto <- getStorage

  withDownload denv do
    forM_ down $ \(HashRef h,_)  -> do
      missed <- findMissedBlocks sto (HashRef h)
      for_ missed $ \h -> do
        debug $ "DownloadQ:" <+> pretty h
        addDownload mzero (fromHashRef h)

  -- FIXME: timeout-hardcodes
  let refs = listDownloads @e brains <&> fmap (set _2 30)

  polling (Polling 5 20) refs $ \ref -> do
    missed <- findMissedBlocks sto ref
    trace $ "DownloadQ. check" <+> pretty ref <+> pretty (length missed)

    when (null missed) do
      delDownload @e brains ref