Substantial, insufficient work on easiness

* Allow engine arguments to depend on difficulty
* Improve difficulty levels for many engines... but not much
* Stockfish and then Phalanx are now preferred over GNUChess

Unfortunately, all of these engines are too hard for our needs.

Some of these engines seem to be Windows-only; others are proprietary;
and others don't want to compile anymore.  I've left these alone since
there's not much reason to remove them in case you do manage to get one
working. But they won't be getting difficulty levels.

https://bugzilla.gnome.org/show_bug.cgi?id=475535

data/engines.conf

@@ -1,10 +1,31 @@
+[Stockfish]
+protocol=uci
+binary=stockfish
+option-easy-0=name Skill Level value 0
+option-normal-0=name Skill Level value 5
+option-hard-0=name Skill Level value 20
+
+[Phalanx]
+protocol=cecp
+binary=phalanx
+arg-easy-0=-e0
+arg-normal-0=-e40
+option-easy-0=easy
+option-easy-1=depth 2
+option-normal-0=easy
+option-normal-1=depth 3
+option-hard-0=hard
+
 [GNUchess]
 protocol=cecp
 binary=gnuchess
-args=--xboard
+arg-easy-0=--xboard
+arg-normal-0=--xboard
+arg-hard-0=--xboard
 option-easy-0=easy
 option-easy-1=depth 1
-option-normal-0=depth 4
+option-normal-0=easy
+option-normal-1=depth 3
 option-hard-0=hard
 
 [Sjeng]
@@ -12,7 +33,8 @@ protocol=cecp
 binary=sjeng
 option-easy-0=easy
 option-easy-1=depth 1
-option-normal-0=depth 4
+option-normal-0=easy
+option-normal-1=depth 3
 option-hard-0=hard
 
 [Amy]
@@ -20,7 +42,8 @@ protocol=cecp
 binary=Amy
 option-easy-0=easy
 option-easy-1=depth 1
-option-normal-0=depth 4
+option-normal-0=easy
+option-normal-1=depth 3
 option-hard-0=hard
 
 [Crafty]
@@ -28,7 +51,8 @@ protocol=cecp
 binary=crafty
 option-easy-0=easy
 option-easy-1=depth 1
-option-normal-0=depth 4
+option-normal-0=easy
+option-normal-1=depth 3
 option-hard-0=hard
 
 [Faile]
@@ -36,16 +60,8 @@ protocol=cecp
 binary=faile
 option-easy-0=easy
 option-easy-1=depth 1
-option-normal-0=depth 4
-option-hard-0=hard
-
-[Phalanx]
-protocol=cecp
-binary=phalanx
-option-easy-0=easy
-option-easy-1=depth 1
-option-easy-2=level 5
-option-normal-0=depth 4
+option-normal-0=easy
+option-normal-1=depth 3
 option-hard-0=hard
 
 [Glaurung]
@@ -58,70 +74,59 @@ option-normal-1=name Cowardice value 100
 option-hard-0=name Aggressiveness value 200
 option-hard-1=name Cowardice value 50
 
-[Stockfish]
-protocol=uci
-binary=stockfish
-option-easy-0=name Skill Level value 0
-option-easy-1=name Slow Mover value 1000
-option-easy-2=name Minimum Thinking Time value 5000
-option-easy-3=name Threads value 1
-option-normal-0=name Skill Level value 5
-option-normal-1=name Slow Mover value 1000
-option-normal-2=name Minimum Thinking Time value 5000
-option-normal-3=name Threads value 1
-option-hard-0=name Skill Level value 20
-
 [HoiChess]
 protocol=cecp
 binary=hoichess
 option-easy-0=easy
 option-easy-1=depth 1
-option-normal-0=depth 4
+option-normal-0=easy
+option-normal-1=depth 3
 option-hard-0=hard
 
 [Diablo]
 protocol=uci
 binary=diablo
-# FIXME: Add some difficulty levels
 
 [BBChess]
 protocol=uci
 binary=bbchess
-# FIXME: Add some difficulty levels
 
 [Fruit]
 protocol=uci
 binary=fruit
-# FIXME: Add some difficulty levels
 
 [Gambit Fruit]
 protocol=uci
 binary=gfruit
-# FIXME: Add some difficulty levels
 
 [Toga II]
 protocol=uci
 binary=toga2
-# FIXME: Add some difficulty levels
 
 [Amundsen]
 protocol=cecp
 binary=amundsen
 option-easy-0=easy
 option-easy-1=depth 1
-option-normal-0=depth 4
+option-normal-0=easy
+option-normal-1=depth 3
 option-hard-0=hard
 
 [Boo's Chess Engine]
 protocol=cecp
-binary=bce boochess BACE
+binary=bce
+option-easy-0=easy
+option-easy-1=random
+option-normal-0=easy
+option-hard-0=hard
 
 [Fairy-Max]
 protocol=cecp
 binary=fairymax
-# FIXME: Add some difficulty levels
+option-easy-0=easy
+option-normal-0=normal
+option-hard-0=hard
 
 [Shredder]
 protocol=uci
 binary=ShredderClassicLinux
-# FIXME: Add some difficulty levels

src/ai-profile.vala

@@ -14,7 +14,9 @@ public class AIProfile
     public string protocol;
     public string binary;
     public string path;
-    public string args;
+    public string[] easy_args;
+    public string[] normal_args;
+    public string[] hard_args;
     public string[] easy_options;
     public string[] normal_options;
     public string[] hard_options;
@@ -49,13 +51,13 @@ public List<AIProfile> load_ai_profiles (string filename)
            profile.name = name;
            profile.protocol = file.get_value (name, "protocol");
            profile.binary = file.get_value (name, "binary");
-           if (file.has_key (name, "args"))
-               profile.args = file.get_value (name, "args");
-           else
-               profile.args = null; // bgo#696474
-           profile.easy_options = load_options (file, name, "easy");
-           profile.normal_options = load_options (file, name, "normal");
-           profile.hard_options = load_options (file, name, "hard");
+
+           profile.easy_args = load_array (file, name, "arg", "easy");
+           profile.normal_args = load_array (file, name, "arg", "normal");
+           profile.hard_args = load_array (file, name, "arg", "hard");
+           profile.easy_options = load_array (file, name, "option", "easy");
+           profile.normal_options = load_array (file, name, "option", "normal");
+           profile.hard_options = load_array (file, name, "option", "hard");
        }
        catch (KeyFileError e)
        {
@@ -73,15 +75,15 @@ public List<AIProfile> load_ai_profiles (string filename)
    return profiles;
 }
 
-private string[] load_options (KeyFile file, string name, string difficulty) throws KeyFileError
+private string[] load_array (KeyFile file, string name, string type, string difficulty) throws KeyFileError
 {
     int count = 0;
-    while (file.has_key (name, "option-%s-%d".printf (difficulty, count)))
+    while (file.has_key (name, "%s-%s-%d".printf (type, difficulty, count)))
         count++;
 
     string[] options = new string[count];
     for (var i = 0; i < count; i++)
-        options[i] = file.get_value (name, "option-%s-%d".printf (difficulty, i));
+        options[i] = file.get_value (name, "%s-%s-%d".printf (type, difficulty, i));
 
     return options;
 }

src/chess-engine-cecp.vala

@@ -14,7 +14,7 @@ public class ChessEngineCECP : ChessEngine
     private bool moving = false;
     private string[] options;
 
-    public ChessEngineCECP (string binary, string? args, string[] options)
+    public ChessEngineCECP (string binary, string[] args, string[] options)
     {
         base (binary, args);
         this.options = options;

src/chess-engine-uci.vala

@@ -15,7 +15,7 @@ public class ChessEngineUCI : ChessEngine
     private string[] options;
     private bool waiting_for_move;
 
-    public ChessEngineUCI (string binary, string? args, string[] options)
+    public ChessEngineUCI (string binary, string[] args, string[] options)
     {
         base (binary, args);
         this.options = options;

src/chess-engine.vala

@@ -11,7 +11,7 @@
 public abstract class ChessEngine : Object
 {
     private string binary;
-    private string args;
+    private string[] args;
 
     private Pid pid;
     private int stdin_fd;
@@ -41,7 +41,7 @@ public abstract class ChessEngine : Object
         }
     }
 
-    public ChessEngine (string binary, string? args)
+    public ChessEngine (string binary, string[] args)
     {
         this.binary = binary;
         this.args = args;
@@ -49,7 +49,11 @@ public abstract class ChessEngine : Object
 
     public bool start ()
     {
-        string[] argv = { binary, args, null };
+        string[] argv = {binary};
+        foreach (var arg in args)
+            argv += arg;
+        argv += null;
+
         int stdout_fd;
         try
         {

src/gnome-chess.vala

@@ -564,25 +564,28 @@ public class Application : Gtk.Application
             profile = ai_profiles.data;
         }
 
-        string[] options;
+        string[] options, args;
         switch (difficulty)
         {
         case "easy":
             options = profile.easy_options;
+            args = profile.easy_args;
             break;
         default:
         case "normal":
             options = profile.normal_options;
+            args = profile.normal_args;
             break;
         case "hard":
             options = profile.hard_options;
+            args = profile.hard_args;
             break;
         }
 
         if (profile.protocol == "cecp")
-            engine = new ChessEngineCECP (profile.binary, profile.args, options);
+            engine = new ChessEngineCECP (profile.binary, args, options);
         else if (profile.protocol == "uci")
-            engine = new ChessEngineUCI (profile.binary, profile.args, options);
+            engine = new ChessEngineUCI (profile.binary, args, options);
         else
         {
             warning ("Unknown AI protocol %s", profile.protocol);