Add optional difficulty level descriptions for AIs

* support the following keys in JSON files for AIs, by difficulty level:
  * Easy: "easy_tip"
  * Medium: "medium_tip"
  * Hard: "hard_tip"
  * Insane: "insane_tip"

* keys should contain messages explaining differences between levels and
  any cheats an AI might use (e.g. power bonuses or skipping research)

* append non-empty key values to AI difficulty tooltips in an extra line

* make key values translatable

* fill out key values for all AIs installed by default

Fixes Warzone2100#419

data/mp/multiplay/skirmish/nb_generic.json

@@ -2,6 +2,8 @@
     "AI": {
         "js": "nb_generic.js",
         "name": "NullBot",
-        "tip": "Adaptive AI with multiple personalities"
+        "tip": "Adaptive AI with multiple personalities",
+        "easy_tip": "Gets ~ 25% less power from each oil derrick\nResearch is not focused on a specific weapon branch",
+        "insane_tip": "Gets ~ 100% more power from each oil derrick\nStarts with defensive structures and oil derricks"
     }
 }

data/mp/multiplay/skirmish/nb_hover.json

@@ -2,6 +2,8 @@
     "AI": {
         "js": "nb_hover.js",
         "name": "Hover AI",
-        "tip": "Sea map AI, based on NullBot"
+        "tip": "Sea map AI, based on NullBot",
+        "easy_tip": "Gets ~ 25% less power from each oil derrick",
+        "insane_tip": "Gets ~ 100% more power from each oil derrick\nStarts with defensive structures and oil derricks"
     }
 }

data/mp/multiplay/skirmish/nb_turtle.json

@@ -2,6 +2,8 @@
     "AI": {
         "js": "nb_turtle.js",
         "name": "Turtle AI",
-        "tip": "Tower wars AI, based on NullBot"
+        "tip": "Tower wars AI, based on NullBot",
+        "easy_tip": "Gets ~ 25% less power from each oil derrick\nResearch is not focused on a specific weapon branch",
+        "insane_tip": "Gets ~ 100% more power from each oil derrick\nStarts with defensive structures and oil derricks"
     }
 }

data/mp/multiplay/skirmish/nexus.json

@@ -1,8 +1,12 @@
 {
     "AI": {
-        "name": "Nexus",
         "slo": "nexus.slo",
+        "vlo": "nexus.vlo",
+        "name": "Nexus",
         "tip": "Initial AI, now supplanted by NullBot",
-        "vlo": "nexus.vlo"
+        "easy_tip": "Gets ~ 25% less power from each oil derrick",
+        "medium_tip": "Research speed +40% (per minute)",
+        "hard_tip": "Research speed +60% (per minute)",
+        "insane_tip": "Gets ~ 100% more power from each oil derrick\nResearch speed +80% (per minute)\nStarts with defensive structures and oil derricks"
     }
 }

data/mp/multiplay/skirmish/semperfi-js.json

@@ -2,6 +2,8 @@
     "AI": {
         "js": "semperfi.js",
         "name": "SemperFi JavaScript",
-        "tip": "Prototypical JavaScript AI focusing on rockets/missiles"
+        "tip": "Prototypical JavaScript AI focusing on rockets/missiles",
+        "easy_tip": "Gets ~ 25% less power from each oil derrick",
+        "insane_tip": "Gets ~ 100% more power from each oil derrick\nStarts with defensive structures and oil derricks"
     }
 }

data/mp/multiplay/skirmish/semperfi.json

@@ -1,8 +1,11 @@
 {
     "AI": {
-        "name": "SemperFi",
         "slo": "semperfi.slo",
+        "vlo": "semperfi.vlo",
+        "name": "SemperFi",
         "tip": "Enhanced Nexus AI",
-        "vlo": "semperfi.vlo"
+        "easy_tip": "Gets ~ 25% less power from each oil derrick\nDoes not build defenses next to enemy oil derricks\nNever tries a truck rush",
+        "medium_tip": "Never tries a truck rush",
+        "insane_tip": "Gets ~ 100% more power from each oil derrick\nStarts with defensive structures and oil derricks"
     }
 }

po/custom/fromJson.txt

@@ -509,6 +509,11 @@ _("Gauss Cannon Hardpoint")
 _("Gauss Cannon Python Tracks")
 _("Gauss Cannon Wyvern Tracks")
 _("Generates and concentrates bursts of laser energy")
+_("Gets ~ 100% more power from each oil derrick\nResearch speed +80% (per minute)\nStarts with defensive structures and oil derricks")
+_("Gets ~ 100% more power from each oil derrick\nStarts with defensive structures and oil derricks")
+_("Gets ~ 25% less power from each oil derrick")
+_("Gets ~ 25% less power from each oil derrick\nDoes not build defenses next to enemy oil derricks\nNever tries a truck rush")
+_("Gets ~ 25% less power from each oil derrick\nResearch is not focused on a specific weapon branch")
 _("Gives Cyborg limited flight abilities")
 _("Good main battle tank and heavy artillery platform")
 _("Good medium tank and support vehicle")
@@ -937,6 +942,7 @@ _("Needle Gun Vengeance Tracks")
 _("Neural Synapse Research Brain")
 _("Neural Synapse Research Brain Mk2")
 _("Neural Synapse Research Brain Mk3")
+_("Never tries a truck rush")
 _("New AA Turret Available")
 _("New Advanced Weapon Available")
 _("New armored construction")
@@ -1138,6 +1144,8 @@ _("Research Module")
 _("Research Module Available")
 _("Research module expands research facilities")
 _("Research speed +30%")
+_("Research speed +40% (per minute)")
+_("Research speed +60% (per minute)")
 _("Research speed +85%")
 _("Retaliation")
 _("Retribution")

po/parseJson.py

@@ -8,7 +8,7 @@ def parse(obj):
 	if isinstance(obj, dict):
 		for k, v in obj.items():
 			parse(v)
-			if k in ['name', 'tip'] and isinstance(v, str):
+			if k in ['name', 'tip', 'easy_tip', 'medium_tip', 'hard_tip', 'insane_tip'] and isinstance(v, str):
 				printString(v, '_(', '\n')
 			elif k in ['text', 'ranks'] and isinstance(v, list):
 				for s in v:

src/multiint.cpp

@@ -276,6 +276,7 @@ struct AIDATA
 	char vlo[MAX_LEN_AI_NAME];
 	char js[MAX_LEN_AI_NAME];
 	char tip[255];
+	char difficultyTips[4][255]; // optional difficulty level info
 	int assigned;	///< How many AIs have we assigned of this type
 };
 static std::vector<AIDATA> aidata;
@@ -787,6 +788,20 @@ void readAIs()
 		sstrcpy(ai.vlo, aiconf.value("vlo", "").toWzString().toUtf8().c_str());
 		sstrcpy(ai.js, aiconf.value("js", "").toWzString().toUtf8().c_str());
 
+		const char *difficultyKeys[] = { "easy_tip", "medium_tip", "hard_tip", "insane_tip" };
+		for (int i = 0; i < ARRAY_SIZE(difficultyKeys); i++)
+		{
+			if (aiconf.contains(difficultyKeys[i]))
+			{
+				sstrcpy(ai.difficultyTips[i], _(aiconf.value(difficultyKeys[i], "").toWzString().toUtf8().c_str()));
+			}
+			else
+			{
+				// note that the empty string "" must never be translated
+				sstrcpy(ai.difficultyTips[i], "");
+			}
+		}
+
 		if (aiconf.contains("tip"))
 		{
 			sstrcpy(ai.tip, _(aiconf.value("tip", "").toWzString().toUtf8().c_str()));
@@ -1932,6 +1947,12 @@ static void addDifficultyChooser(int player)
 		case 2: sButInit.pTip = _("No holds barred"); break;
 		case 3: sButInit.pTip = _("Starts with advantages"); break;
 		}
+		const char *difficultyTip = aidata[NetPlay.players[player].ai].difficultyTips[i];
+		if (strcmp(difficultyTip, "") != 0)
+		{
+			sButInit.pTip += "\n";
+			sButInit.pTip += difficultyTip;
+		}
 		sButInit.pDisplay = displayDifficulty;
 		sButInit.UserData = i;
 		sButInit.pUserData = new DisplayDifficultyCache();
@@ -2519,8 +2540,17 @@ static void drawReadyButton(UDWORD player)
 	if (!NetPlay.players[player].allocated && NetPlay.players[player].ai >= 0)
 	{
 		int icon = difficultyIcon(NetPlay.players[player].difficulty);
+		int playerDifficulty = NetPlay.players[player].difficulty;
+		char tooltip[128 + 255];
+		sstrcpy(tooltip, _(difficultyList[playerDifficulty]));
+		const char *difficultyTip = aidata[NetPlay.players[player].ai].difficultyTips[playerDifficulty];
+		if (strcmp(difficultyTip, "") != 0)
+		{
+			sstrcat(tooltip, "\n");
+			sstrcat(tooltip, difficultyTip);
+		}
 		addMultiBut(psWScreen, MULTIOP_READY_FORM_ID + player, MULTIOP_DIFFICULTY_INIT_START + player, 6, 4, MULTIOP_READY_WIDTH, MULTIOP_READY_HEIGHT,
-		            (NetPlay.isHost && !locked.difficulty) ? _("Click to change difficulty") : _(difficultyList[NetPlay.players[player].difficulty]), icon, icon, icon);
+		            (NetPlay.isHost && !locked.difficulty) ? _("Click to change difficulty") : tooltip, icon, icon, icon);
 		return;
 	}
 	else if (!NetPlay.players[player].allocated)