feat: sketch out a trade_in behavior

packages/cli/lib/behavior/trade_in.dart

@@ -0,0 +1,63 @@
+import 'package:cli/behavior/job.dart';
+import 'package:cli/caches.dart';
+import 'package:cli/central_command.dart';
+import 'package:cli/nav/exploring.dart';
+import 'package:cli/net/actions.dart';
+import 'package:cli/net/queries.dart';
+import 'package:cli/plan/ships.dart';
+import 'package:db/db.dart';
+import 'package:types/types.dart';
+
+/// Upcycle the ship.
+Future<JobResult> doTradeInJob(
+  BehaviorState state,
+  Api api,
+  Database db,
+  CentralCommand centralCommand,
+  Caches caches,
+  Ship ship, {
+  DateTime Function() getNow = defaultGetNow,
+}) async {
+  // Will also dock the ship.
+  await visitLocalShipyard(
+    db,
+    api,
+    caches.waypoints,
+    caches.static,
+    caches.agent,
+    ship,
+  );
+  // Get the purchase price of a new ship of this type.
+  final shipType = assertNotNull(
+    guessShipType(caches.static.shipyardShips, ship),
+    'No ship type found.',
+    const Duration(minutes: 5),
+  );
+
+  final price = assertNotNull(
+    await db.shipyardPriceAt(ship.waypointSymbol, shipType),
+    'No price found.',
+    const Duration(minutes: 5),
+  );
+
+  final scrapTransaction = assertNotNull(
+    await getScrapValue(api, ship.symbol),
+    'No scrap value found',
+    const Duration(minutes: 5),
+  );
+  final scrapValue = scrapTransaction.totalPrice;
+  jobAssert(
+    scrapValue > price.purchasePrice,
+    'Scrap value is too low.',
+    const Duration(minutes: 5),
+  );
+  // New ships are cheaper than the scrap value, trade in!
+  await purchaseShip(db, api, caches.agent, ship.waypointSymbol, shipType);
+  await scrapShipAndLog(api, db, caches.agent, ship);
+  return JobResult.complete();
+}
+
+/// Advance the trade in.
+final advanceTradeIn = const MultiJob('Trade In', [
+  doTradeInJob,
+]).run;

packages/cli/lib/net/queries.dart

@@ -104,6 +104,13 @@ Future<Market> getMarket(Api api, WaypointSymbol waypointSymbol) async {
   return response!.data;
 }
 
+/// Fetches Scrap value for a given Ship.
+/// Ship must be docked at a shipyard.
+Future<ScrapTransaction?> getScrapValue(Api api, ShipSymbol symbol) async {
+  final response = await api.fleet.getScrapShip(symbol.symbol);
+  return response?.data.transaction;
+}
+
 /// Fetches Construction for a given Waypoint.
 Future<Construction> getConstruction(
   Api api,

packages/db/lib/db.dart

@@ -481,6 +481,15 @@ class Database {
     return queryMany(allShipyardPricesQuery(), shipyardPriceFromColumnMap);
   }
 
+  /// Get the shipyard price for the given waypoint and ship type.
+  Future<ShipyardPrice?> shipyardPriceAt(
+    WaypointSymbol waypointSymbol,
+    ShipType shipType,
+  ) async {
+    final query = shipyardPriceQuery(waypointSymbol, shipType);
+    return queryOne(query, shipyardPriceFromColumnMap);
+  }
+
   /// Add a shipyard price to the database.
   Future<void> upsertShipyardPrice(ShipyardPrice price) async {
     await execute(upsertShipyardPriceQuery(price));

packages/db/lib/src/shipyard_price.dart

@@ -16,6 +16,17 @@ Query upsertShipyardPriceQuery(ShipyardPrice price) => Query(
       parameters: shipyardPriceToColumnMap(price),
     );
 
+/// Query to get the shipyard price for a given waypoint and ship type.
+/// Returns null if no price is found.
+Query shipyardPriceQuery(WaypointSymbol symbol, ShipType shipType) => Query(
+      'SELECT * FROM shipyard_price_ '
+      'WHERE waypoint_symbol = @symbol AND ship_type = @ship_type',
+      parameters: {
+        'symbol': symbol.toJson(),
+        'ship_type': shipType.toJson(),
+      },
+    );
+
 /// Query to get the timestamp of the most recent shipyard price for a waypoint.
 Query timestampOfMostRecentShipyardPriceQuery(WaypointSymbol symbol) => Query(
       'SELECT MAX(timestamp) FROM shipyard_price_ '