import std/times import pkg/stint import pkg/chronos import pkg/questionable import pkg/nimcrypto import ./market export questionable export market type Purchasing* = ref object market: Market proofProbability*: UInt256 requestExpiryInterval*: UInt256 offerExpiryMargin*: UInt256 Purchase* = ref object future: Future[void] market: Market offerExpiryMargin: UInt256 request*: StorageRequest offers*: seq[StorageOffer] selected*: ?StorageOffer const DefaultProofProbability = 100.u256 const DefaultRequestExpiryInterval = (10 * 60).u256 const DefaultOfferExpiryMargin = (8 * 60).u256 proc start(purchase: Purchase) {.gcsafe.} proc new*(_: type Purchasing, market: Market): Purchasing = Purchasing( market: market, proofProbability: DefaultProofProbability, requestExpiryInterval: DefaultRequestExpiryInterval, offerExpiryMargin: DefaultOfferExpiryMargin ) proc populate*(purchasing: Purchasing, request: StorageRequest): StorageRequest = result = request if result.proofProbability == 0.u256: result.proofProbability = purchasing.proofProbability if result.expiry == 0.u256: result.expiry = (getTime().toUnix().u256 + purchasing.requestExpiryInterval) if result.nonce == array[32, byte].default: doAssert randomBytes(result.nonce) == 32 proc purchase*(purchasing: Purchasing, request: StorageRequest): Purchase = let request = purchasing.populate(request) let purchase = Purchase( request: request, market: purchasing.market, offerExpiryMargin: purchasing.offerExpiryMargin ) purchase.start() purchase proc selectOffer(purchase: Purchase) {.async.} = var cheapest: ?StorageOffer for offer in purchase.offers: without getTime().toUnix().u256 < offer.expiry - purchase.offerExpiryMargin: continue without current =? cheapest: cheapest = some offer continue if current.price > offer.price: cheapest = some offer if cheapest =? cheapest: await purchase.market.selectOffer(cheapest.id) proc run(purchase: Purchase) {.async.} = proc onOffer(offer: StorageOffer) = purchase.offers.add(offer) let market = purchase.market purchase.request = await market.requestStorage(purchase.request) let subscription = await market.subscribeOffers(purchase.request.id, onOffer) await market.waitUntil(purchase.request.expiry) await purchase.selectOffer() await subscription.unsubscribe() proc start(purchase: Purchase) = purchase.future = purchase.run() asyncSpawn purchase.future proc wait*(purchase: Purchase) {.async.} = await purchase.future