extract IRandomGen interface from RandomGen

src/api/ApiUtils.cs

@@ -118,14 +118,14 @@ private static bool EmptyJson(string requestBody)
     public static GameSession NewGameSession(GameState? initialGameState = null)
     {
         List<GameSessionTurn>? turnList = initialGameState != null ? [new GameSessionTurn(startState: initialGameState)] : null;
-        var gameSession = new GameSession(new RandomGen(new Random()), turnList);
+        var gameSession = new GameSession(new RandomGen(), turnList);
         return gameSession;
     }
 
     public static GameSession NewGameSessionFromTurn(GameSessionTurn? initialTurn = null)
     {
         List<GameSessionTurn>? turnList = initialTurn != null ? [initialTurn] : null;
-        var gameSession = new GameSession(new RandomGen(new Random()), turnList);
+        var gameSession = new GameSession(new RandomGen(), turnList);
         return gameSession;
     }
 

src/api/WebApplicationRoutes.cs

@@ -33,7 +33,7 @@ public void Register(WebApplication app)
 
     private static string HelloCoinFlip()
     {
-        var randomGen = new RandomGen(new Random());
+        var randomGen = new RandomGen();
         return $"Hello World! Coin flip: {randomGen.FlipCoin()}";
     }
 }

src/game-cli/Program.cs

@@ -13,7 +13,7 @@ private static void Main(string[] args)
     {
         var config = new Configuration(new FileSystem());
         using var log = new Log(config);
-        var randomGen = new RandomGen(new Random());
+        var randomGen = new RandomGen();
 
         var controller = new GameSessionController(config, log, new GameSession(randomGen));
 

src/game-lib-tests/AIPlayerTests.cs

@@ -10,7 +10,7 @@ public class AIPlayerTests
 {
     private Configuration _config = null!;
     private ILog _log = null!;
-    private readonly RandomGen _randomGen = new RandomGen(new Random());
+    private readonly IRandomGen _randomGen = new RandomGen();
 
     [SetUp]
     public void Setup()
@@ -43,7 +43,7 @@ public void ExampleGameSessionForApi()
     {
         var config = new Configuration(new SimulatedFileSystem());
         var log = new Log(config);
-        var randomGen = new RandomGen(new Random());
+        var randomGen = new RandomGen();
         var intellect = AIPlayer.Intellect.Basic;
         var controller = new GameSessionController(config, log, new GameSession(randomGen));
         var aiPlayer = new AIPlayer(log, intellect);

src/game-lib-tests/FactionFixtures.cs

@@ -5,7 +5,7 @@ namespace UfoGameLib.Tests;
 
 public static class FactionFixtures
 {
-    public static Factions SingleFaction(RandomGen randomGen) => new(
+    public static Factions SingleFaction(IRandomGen randomGen) => new(
     [
         // Note: need to ensure here that IDs are consecutive, and from zero.
         Faction.Init(randomGen, id: 0, "Black Lotus cult", power: 200, powerIncrease: 5),

src/game-lib-tests/GameSessionControllerTests.cs

@@ -11,7 +11,7 @@ public class GameSessionControllerTests
 {
     private Configuration _config = null!;
     private ILog _log = null!;
-    private readonly RandomGen _randomGen = new RandomGen(new Random());
+    private readonly IRandomGen _randomGen = new RandomGen();
 
     [SetUp]
     public void Setup()

src/game-lib-tests/GameSessionTests.cs

@@ -12,15 +12,15 @@ public class GameSessionTests
     // Using null! as these fields will be initialized in Setup() method.
     private Configuration _config = null!;
     private ILog _log = null!;
-    private RandomGen _randomGen = null!;
+    private IRandomGen _randomGen = null!;
     private Factions _factions = null!;
 
     [SetUp]
     public void Setup()
     {
         _config = new Configuration(new FileSystem());
         _log = new Log(_config);
-        _randomGen = new RandomGen(new Random());
+        _randomGen = new RandomGen();
         _factions = FactionFixtures.SingleFaction(_randomGen);
     }
 
@@ -88,7 +88,6 @@ public void BasicHappyPathGameSessionWorks()
         //
         // This way for testing I can say "the countdown is always 3"
         //
-        // 2. Allow to pass factions when initing game session
         MissionSite site = controller.CurrentGameStatePlayerView.MissionSites.First();
         turnController.LaunchMission(site, agentCount: 3);
         controller.AdvanceTime();

src/game-lib/Controller/CheatingGameSessionController.cs

@@ -10,7 +10,7 @@ namespace UfoGameLib.Controller;
 /// </summary>
 public class CheatingGameSessionController : GameSessionController
 {
-    public CheatingGameSessionController(Configuration config, ILog log, RandomGen randomGen, GameSession gameSession)
+    public CheatingGameSessionController(Configuration config, ILog log, IRandomGen randomGen, GameSession gameSession)
         : base(
             config,
             log,

src/game-lib/Controller/GameTurnController.cs

@@ -9,7 +9,7 @@ namespace UfoGameLib.Controller;
 public class GameTurnController
 {
     private readonly ILog _log;
-    public RandomGen RandomGen { get; }
+    public IRandomGen RandomGen { get; }
     private readonly EventIdGen _eventIdGen;
     private readonly AgentIdGen _agentIdGen;
     private readonly MissionIdGen _missionIdGen;
@@ -19,7 +19,7 @@ public class GameTurnController
 
     public GameTurnController(
         ILog log,
-        RandomGen randomGen,
+        IRandomGen randomGen,
         EventIdGen eventIdGen,
         AgentIdGen agentIdGen,
         MissionIdGen missionIdGen,

src/game-lib/Controller/TimeAdvancementController.cs

@@ -9,14 +9,14 @@ namespace UfoGameLib.Controller;
 public class TimeAdvancementController
 {
     private readonly ILog _log;
-    private readonly RandomGen _randomGen;
+    private readonly IRandomGen _randomGen;
     private readonly List<WorldEvent> _worldEvents;
     private readonly EventIdGen _eventIdGen;
     private readonly MissionSiteIdGen _missionSiteIdGen;
 
     public TimeAdvancementController(
         ILog log,
-        RandomGen randomGen,
+        IRandomGen randomGen,
         EventIdGen eventIdGen,
         MissionSiteIdGen missionSiteIdGen)
     {

src/game-lib/Lib/IRandomGen.cs

@@ -0,0 +1,13 @@
+namespace UfoGameLib.Lib;
+
+public interface IRandomGen
+{
+    int Roll1To(int n);
+    int Roll0To(int n);
+    int Roll(int min, int max);
+    int Roll(Range range);
+    T Pick<T>(List<T> items);
+    List<T> Pick<T>(List<T> items, int count);
+    TValue Pick<TKey, TValue>(IDictionary<TKey, TValue> dict);
+    bool FlipCoin();
+}

src/game-lib/Lib/RandomGen.cs

@@ -5,13 +5,14 @@ namespace UfoGameLib.Lib;
 
 // Note: currently upon save/load the random gets re-randomized.
 // To fix that, the Save file should include a seed used to recreate upon load.
-public class RandomGen
+
+public class RandomGen : IRandomGen
 {
     private readonly Random _random;
 
-    public RandomGen(Random random)
+    public RandomGen(Random? random = null)
     {
-        _random = random;
+        _random = random ?? new Random();
     }
 
     public int Roll1To(int n)

src/game-lib/Model/AgentSurvivalRoll.cs

@@ -17,7 +17,7 @@ public class AgentSurvivalRoll
 
     public const int MaxRecoversIn = 30;
 
-    public AgentSurvivalRoll(ILog log, RandomGen randomGen, Agent agent, Mission mission)
+    public AgentSurvivalRoll(ILog log, IRandomGen randomGen, Agent agent, Mission mission)
     {
         SurvivalChance = ComputeSurvivalChance(agent, mission.Site.Difficulty);
         Roll = randomGen.Roll(RollRange);

src/game-lib/Model/Faction.cs

@@ -37,7 +37,7 @@ public Faction(
     }
 
     public static Faction Init(
-        RandomGen randomGen,
+        IRandomGen randomGen,
         int id,
         string name,
         int power,
@@ -57,7 +57,7 @@ public Faction DeepClone()
 
     public List<MissionSite> CreateMissionSites(
         ILog log,
-        RandomGen randomGen,
+        IRandomGen randomGen,
         MissionSiteIdGen missionSiteIdGen,
         GameState state)
     {
@@ -98,6 +98,6 @@ public List<MissionSite> CreateMissionSites(
         return sites;
     }
 
-    private static int RandomizeMissionSiteCountdown(RandomGen randomGen)
+    private static int RandomizeMissionSiteCountdown(IRandomGen randomGen)
         => randomGen.Roll(Ruleset.FactionMissionSiteCountdown);
 }

src/game-lib/Model/Factions.cs

@@ -19,7 +19,7 @@ public Factions DeepClone()
 
     public List<MissionSite> CreateMissionSites(
         ILog log,
-        RandomGen randomGen,
+        IRandomGen randomGen,
         MissionSiteIdGen missionSiteIdGen,
         GameState state)
         => this.SelectMany(faction => faction.CreateMissionSites(log, randomGen, missionSiteIdGen, state)).ToList();

src/game-lib/Model/Ruleset.cs

@@ -14,7 +14,7 @@ public static class Ruleset
 
     // For more example factions data, see:
     // https://github.com/konrad-jamrozik/game/blob/eccb44a1d5f074e95b07aebca2c6bc5bbfdfdda8/src/ufo-game/Model/Data/FactionsData.cs#L34
-    public static Factions InitialFactions(RandomGen randomGen) => new(
+    public static Factions InitialFactions(IRandomGen randomGen) => new(
     [
         // Note: need to ensure here that IDs are consecutive, and from zero.
         Faction.Init(randomGen, id: 0, "Black Lotus cult", power: 200, powerIncrease: 5),
@@ -36,7 +36,7 @@ public static class Ruleset
 
     public static (bool survived, int? recoversIn) RollForAgentSurvival(
         ILog log,
-        RandomGen randomGen,
+        IRandomGen randomGen,
         Agent agent,
         Mission mission)
     {
@@ -73,7 +73,7 @@ private static int SkillFromMissions(Agent agent)
     // based on faction data and possibly other factors. And faction will have power correlating with turn.
     public static (int difficulty, int difficultyFromTurn, int roll) RollMissionSiteDifficulty(
             int currentTurn,
-            RandomGen randomGen)
+            IRandomGen randomGen)
     {
         // Note that currently the only ways of increasing agents survivability of difficulty is:
         // - by surviving missions

src/game-lib/State/GameSession.cs

@@ -16,7 +16,7 @@ namespace UfoGameLib.State;
 /// </summary>
 public class GameSession
 {
-    public readonly RandomGen RandomGen;
+    public readonly IRandomGen RandomGen;
 
     public readonly List<GameSessionTurn> Turns;
 
@@ -34,7 +34,7 @@ public class GameSession
 
     public readonly MissionSiteIdGen MissionSiteIdGen;
 
-    public GameSession(RandomGen randomGen, List<GameSessionTurn>? turns = null, Factions? factions = null)
+    public GameSession(IRandomGen randomGen, List<GameSessionTurn>? turns = null, Factions? factions = null)
     {
         RandomGen = randomGen;
         Turns = turns ?? [new GameSessionTurn(startState: GameState.NewInitialGameState(randomGen, factions))];

src/game-lib/State/GameState.cs

@@ -40,9 +40,9 @@ public GameState(
         Factions = factions;
     }
 
-    public static GameState NewInitialGameState(RandomGen? randomGen = null, Factions? factions = null)
+    public static GameState NewInitialGameState(IRandomGen? randomGen = null, Factions? factions = null)
     {
-        randomGen ??= new RandomGen(new Random());
+        randomGen ??= new RandomGen();
         return new GameState(
             updateCount: 0,
             new Timeline(currentTurn: Timeline.InitialTurn),