diff --git a/core/src/Trade.cpp b/core/src/Trade.cpp
index ca0c054..9238cc3 100644
--- a/core/src/Trade.cpp
+++ b/core/src/Trade.cpp
@@ -305,3 +305,170 @@ TradeOfferList buildTradeOffers(VillagerProfession profession, uint32_t seed) {
     const OfferSpec* specs = specsForProfession(profession, specCount);
     if (specs == nullptr) return list;
 
+    uint32_t rng = seed ^ (static_cast<uint32_t>(profession) * 0x9e3779b9u);
+    for (int i = 0; i < specCount; ++i) {
+        const OfferSpec& spec = specs[i];
+        TradeOffer offer;
+        offer.tier = static_cast<TradeTier>(spec.tier);
+        offer.inputA = spec.inputA;
+        offer.inputACount = spec.inputACount;
+        offer.inputB = spec.inputB;
+        offer.inputBCount = spec.inputBCount;
+        offer.output = spec.output;
+        offer.outputCount = spec.outputCount;
+        offer.maxUses = spec.maxUses;
+        offer.experienceReward = spec.experience;
+        offer.priceMultiplier = spec.inputA == ItemId::EmeraldGem ? 0.05f : 0.02f;
+
+        uint32_t draw = nextRandom(rng);
+        if (offer.inputACount >= 6) {
+            offer.inputACount += static_cast<int>(draw % 5u) - 2;
+        } else if (offer.outputCount >= 3) {
+            offer.outputCount += static_cast<int>(draw % 3u) - 1;
+        }
+        list.offers.push_back(offer);
+    }
+    return list;
+}
+
+bool restockOffers(TradeOfferList& offers) {
+    bool changed = false;
+    for (TradeOffer& offer : offers.offers) {
+        if (offer.uses > 0) {
+            offer.uses = 0;
+            changed = true;
+        }
+        int faded = offer.demand - tradeDemandDecayPerRestock;
+        if (faded < 0) faded = 0;
+        if (faded != offer.demand) {
+            offer.demand = faded;
+            changed = true;
+        }
+    }
+    return changed;
+}
+
+bool tickVillagerRestock(Villager& villager, TradeOfferList& offers, const TimeOfDay& clock) {
+    long long day = clock.dayCount();
+    if (villager.lastRestockDay != day) {
+        villager.lastRestockDay = day;
+        villager.restocksToday = 0;
+    }
+    if (!villager.alive || villager.restocksToday >= tradeRestocksPerDay) return false;
+    if (villager.activity != VillagerActivity::Work ||
+        villager.state != VillagerState::AtTarget) return false;
+
+    bool anyUsed = false;
+    for (const TradeOffer& offer : offers.offers)
+        if (offer.uses > 0) anyUsed = true;
+    if (!anyUsed) return false;
+
+    restockOffers(offers);
+    ++villager.restocksToday;
+    return true;
+}
+
+const char* tradeResultReasonName(TradeResult::Reason reason) {
+    switch (reason) {
+        case TradeResult::Reason::Ok: return "ok";
+        case TradeResult::Reason::NoSuchOffer: return "noSuchOffer";
+        case TradeResult::Reason::VillagerUnavailable: return "villagerUnavailable";
+        case TradeResult::Reason::LevelLocked: return "levelLocked";
+        case TradeResult::Reason::OfferExhausted: return "offerExhausted";
+        case TradeResult::Reason::MissingInputA: return "missingInputA";
+        case TradeResult::Reason::MissingInputB: return "missingInputB";
+        case TradeResult::Reason::NoRoom: return "noRoom";
+        case TradeResult::Reason::Count: break;
+    }
+    return "unknown";
+}
+
+TradeSession::TradeSession(Villager& villager, TradeOfferList& offers, Container& customerInventory)
+    : villager(villager), offers(offers), inventory(customerInventory) {}
+
+void TradeSession::setPriceModifier(const PriceModifier& newModifier) { modifier = newModifier; }
+
+void TradeSession::refreshPrices(const ReputationView& reputation, int heroLevel) {
+    modifier = priceModifierFor(reputation, heroLevel, villagerHitCount(villager.gossip));
+}
+
+int TradeSession::priceOf(int index) const {
+    if (index < 0 || index >= offers.size()) return 0;
+    return offerPrice(offers.at(index), modifier);
+}
+
+bool TradeSession::available(int index) const {
+    if (index < 0 || index >= offers.size()) return false;
+    if (!villager.alive || !villager.employed()) return false;
+    if (!offers.unlocked(index, villager.level)) return false;
+    return !offers.at(index).exhausted();
+}
+
+bool TradeSession::canAfford(int index) const {
+    if (!available(index)) return false;
+    const TradeOffer& offer = offers.at(index);
+    if (containerCount(inventory, offer.inputA) < priceOf(index)) return false;
+    if (offer.hasSecondaryInput() && containerCount(inventory, offer.inputB) < offer.inputBCount)
+        return false;
+    return true;
+}
+
+TradeResult TradeSession::trade(int index) {
+    TradeResult outcome;
+    if (index < 0 || index >= offers.size()) {
+        outcome.reason = TradeResult::Reason::NoSuchOffer;
+        return outcome;
+    }
+    if (!villager.alive || !villager.employed()) {
+        outcome.reason = TradeResult::Reason::VillagerUnavailable;
+        return outcome;
+    }
+    if (!offers.unlocked(index, villager.level)) {
+        outcome.reason = TradeResult::Reason::LevelLocked;
+        return outcome;
+    }
+
+    TradeOffer& offer = offers.at(index);
+    if (offer.exhausted()) {
+        outcome.reason = TradeResult::Reason::OfferExhausted;
+        return outcome;
+    }
+
+    int price = offerPrice(offer, modifier);
+    if (containerCount(inventory, offer.inputA) < price) {
+        outcome.reason = TradeResult::Reason::MissingInputA;
+        return outcome;
+    }
+    if (offer.hasSecondaryInput() && containerCount(inventory, offer.inputB) < offer.inputBCount) {
+        outcome.reason = TradeResult::Reason::MissingInputB;
+        return outcome;
+    }
+    if (!containerHasRoom(inventory, offer.output, offer.outputCount)) {
+        outcome.reason = TradeResult::Reason::NoRoom;
+        return outcome;
+    }
+
+    inventory.extract(offer.inputA, price);
+    if (offer.hasSecondaryInput()) inventory.extract(offer.inputB, offer.inputBCount);
+    inventory.insert(offer.output, offer.outputCount);
+
+    ++offer.uses;
+    offer.demand = clampInt(offer.demand + tradeDemandPerUse, 0, tradeDemandCap);
+
+    outcome.success = true;
+    outcome.reason = TradeResult::Reason::Ok;
+    outcome.pricePaid = price;
+    outcome.secondaryPaid = offer.hasSecondaryInput() ? offer.inputBCount : 0;
+    outcome.received = offer.output;
+    outcome.receivedCount = offer.outputCount;
+    outcome.experienceGained = offer.experienceReward;
+    outcome.leveledUp = grantVillagerExperience(villager, offer.experienceReward);
+
+    villager.gossip.add(GossipKind::Trading, gossipTradingGain);
+
+    ++completed;
+    if (offer.inputA == ItemId::EmeraldGem) spent += price;
+    return outcome;
+}
+
+} // namespace vf