[Commands] Cleanup #untraindisc Command. (#1996)

- Cleanup messages and logic.

zone/gm_commands/untraindisc.cpp

@@ -1,17 +1,68 @@
 #include "../client.h"
+#include "../../common/data_verification.h"
 
 void command_untraindisc(Client *c, const Seperator *sep)
 {
-	Client *t = c;
-	if (c->GetTarget() && c->GetTarget()->IsClient() && c->GetGM()) {
-		t = c->GetTarget()->CastToClient();
+	int arguments = sep->argnum;
+	if (!arguments || !sep->IsNumber(1)) {
+		c->Message(Chat::White, "Usage: #untraindisc [Spell ID] - Untrain your or your target's discipline by Spell ID");
+		return;
 	}
 
-	for (int i = 0; i < MAX_PP_DISCIPLINES; i++) {
-		if (t->GetPP().disciplines.values[i] == atoi(sep->arg[1])) {
-			t->UntrainDisc(i, 1);
-			return;
-		}
+	auto target = c;
+	if (c->GetTarget() && c->GetTarget()->IsClient() && c->GetGM()) {
+		target = c->GetTarget()->CastToClient();
+	}
+
+	uint16 spell_id = EQ::Clamp(std::stoi(sep->arg[1]), 0, 65535);
+
+	if (!IsValidSpell(spell_id)) {
+		c->Message(
+			Chat::White,
+			fmt::format(
+				"Spell ID {} could not be found.",
+				spell_id
+			).c_str()
+		);
+		return;
+	}
+
+	auto spell_name = GetSpellName(spell_id);
+
+	if (target->HasDisciplineLearned(spell_id)) {
+		target->UntrainDiscBySpellID(spell_id);
+
+		c->Message(
+			Chat::White,
+			fmt::format(
+				"Untraining {} ({}) for {}.",
+				spell_name,
+				spell_id,
+				c == target ?
+				"yourself" :
+				fmt::format(
+					"{} ({})",
+					target->GetCleanName(),
+					target->GetID()
+				)
+			).c_str()
+		);
+	} else {
+		c->Message(
+			Chat::White,
+			fmt::format(
+				"{} not have {} ({}) trained.",
+				c == target ?
+				"You do" :
+				fmt::format(
+					"{} ({}) does",
+					target->GetCleanName(),
+					target->GetID()
+				),
+				spell_name,
+				spell_id
+			).c_str()
+		);
 	}
 }