Simplify Combat (C#) folder structure

28_Combat/csharp/WarState.cs

@@ -0,0 +1,101 @@
+using System;
+
+namespace Game
+{
+    /// <summary>
+    /// Represents the current state of the war.
+    /// </summary>
+    public abstract class WarState
+    {
+        /// <summary>
+        /// Gets the computer's armed forces.
+        /// </summary>
+        public ArmedForces ComputerForces { get; }
+
+        /// <summary>
+        /// Gets the player's armed forces.
+        /// </summary>
+        public ArmedForces PlayerForces { get; }
+
+        /// <summary>
+        /// Gets a flag indicating whether this state represents absolute
+        /// victory for the player.
+        /// </summary>
+        public virtual bool IsAbsoluteVictory => false;
+
+        /// <summary>
+        /// Gets the final outcome of the war.
+        /// </summary>
+        /// <remarks>
+        /// If the war is ongoing, this property will be null.
+        /// </remarks>
+        public virtual WarResult? FinalOutcome => null;
+
+        /// <summary>
+        /// Initializes a new instance of the state class.
+        /// </summary>
+        /// <param name="computerForces">
+        /// The computer's forces.
+        /// </param>
+        /// <param name="playerForces">
+        /// The player's forces.
+        /// </param>
+        public WarState(ArmedForces computerForces, ArmedForces playerForces) =>
+            (ComputerForces, PlayerForces) = (computerForces, playerForces);
+
+        /// <summary>
+        /// Launches an attack.
+        /// </summary>
+        /// <param name="branch">
+        /// The branch of the military to use for the attack.
+        /// </param>
+        /// <param name="attackSize">
+        /// The number of men and women to use for the attack.
+        /// </param>
+        /// <returns>
+        /// The new state of the game resulting from the attack and a message
+        /// describing the result.
+        /// </returns>
+        public (WarState nextState, string message) LaunchAttack(MilitaryBranch branch, int attackSize) =>
+            branch switch
+            {
+                MilitaryBranch.Army     => AttackWithArmy(attackSize),
+                MilitaryBranch.Navy     => AttackWithNavy(attackSize),
+                MilitaryBranch.AirForce => AttackWithAirForce(attackSize),
+                _               => throw new ArgumentException("INVALID BRANCH")
+            };
+
+        /// <summary>
+        /// Conducts an attack with the player's army.
+        /// </summary>
+        /// <param name="attackSize">
+        /// The number of men and women used in the attack.
+        /// </param>
+        /// <returns>
+        /// The new game state and a message describing the result.
+        /// </returns>
+        protected abstract (WarState nextState, string message) AttackWithArmy(int attackSize);
+
+        /// <summary>
+        /// Conducts an attack with the player's navy.
+        /// </summary>
+        /// <param name="attackSize">
+        /// The number of men and women used in the attack.
+        /// </param>
+        /// <returns>
+        /// The new game state and a message describing the result.
+        /// </returns>
+        protected abstract (WarState nextState, string message) AttackWithNavy(int attackSize);
+
+        /// <summary>
+        /// Conducts an attack with the player's air force.
+        /// </summary>
+        /// <param name="attackSize">
+        /// The number of men and women used in the attack.
+        /// </param>
+        /// <returns>
+        /// The new game state and a message describing the result.
+        /// </returns>
+        protected abstract (WarState nextState, string message) AttackWithAirForce(int attackSize);
+    }
+}