move backend to subfolder

tanks-backend/TanksServer/GameLogic/ShootFromTanks.cs

@@ -0,0 +1,58 @@
+using System.Diagnostics;
+
+namespace TanksServer.GameLogic;
+
+internal sealed class ShootFromTanks(
+    IOptions<GameRules> options,
+    MapEntityManager entityManager
+) : ITickStep
+{
+    private readonly GameRules _config = options.Value;
+
+    public Task TickAsync(TimeSpan _)
+    {
+        foreach (var tank in entityManager.Tanks.Where(t => !t.Moved))
+            Shoot(tank);
+
+        return Task.CompletedTask;
+    }
+
+    private void Shoot(Tank tank)
+    {
+        if (!tank.Owner.Controls.Shoot)
+            return;
+        if (tank.NextShotAfter >= DateTime.Now)
+            return;
+
+        tank.NextShotAfter = DateTime.Now.AddMilliseconds(_config.ShootDelayMs);
+
+        var rotation = tank.Orientation / 16d;
+        var angle = rotation * 2d * Math.PI;
+
+        /* When standing next to a wall, the bullet sometimes misses the first pixel.
+         Spawning the bullet to close to the tank instead means the tank instantly hits itself.
+         Because the tank has a float position, but hit boxes are based on pixels, this problem has been deemed complex
+         enough to do later. These values mostly work. */
+        var distance = (tank.Orientation % 4) switch
+        {
+            0 => 4.4d,
+            1 or 3 => 5.4d,
+            2 => 6d,
+            _ => throw new UnreachableException("this should not be possible")
+        };
+
+        var position = new FloatPosition(
+            tank.Position.X + Math.Sin(angle) * distance,
+            tank.Position.Y - Math.Cos(angle) * distance
+        );
+
+        var explosive = false;
+        if (tank.ExplosiveBullets > 0)
+        {
+            tank.ExplosiveBullets--;
+            explosive = true;
+        }
+
+        entityManager.SpawnBullet(tank.Owner, position, rotation, explosive);
+    }
+}