From 6d19374ae866699321d1dda318a0c9d495fc3d72 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@users.noreply.github.com>
Date: Mon, 11 Feb 2019 00:46:13 +0100
Subject: [PATCH] Only replace Strife dialogue content if the default strings
 from zd_extra.pk3 are present.

If not, use the dialogue file's content directly.
---
 src/gamedata/stringtable.cpp | 26 ++++++++++++++++++++++++++
 src/gamedata/stringtable.h   |  1 +
 src/p_conversation.cpp       | 13 +++++++++----
 3 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/src/gamedata/stringtable.cpp b/src/gamedata/stringtable.cpp
index 95c2e754ed..1afc68e439 100644
--- a/src/gamedata/stringtable.cpp
+++ b/src/gamedata/stringtable.cpp
@@ -208,6 +208,32 @@ size_t FStringTable::ProcessEscapes (char *iptr)
 	return optr - sptr;
 }
 
+bool FStringTable::exists(const char *name)
+{
+	// Checks if the given key exists in any one of the default string tables that are valid for all languages.
+	// To replace IWAD content this condition must be true.
+	if (name == nullptr || *name == 0)
+	{
+		return false;
+	}
+	FName nm(name, true);
+	if (nm != NAME_None)
+	{
+		uint32_t defaultStrings[] = { MAKE_ID('*', '*', '*', 0), MAKE_ID('*', 0, 0, 0), MAKE_ID('*', '*', 0, 0) };
+
+		for (auto mapid : defaultStrings)
+		{
+			auto map = allStrings.CheckKey(mapid);
+			if (map)
+			{
+				auto item = map->CheckKey(nm);
+				if (item) return true;
+			}
+		}
+	}
+	return false;
+}
+
 // Finds a string by name and returns its value
 const char *FStringTable::operator[] (const char *name) const
 {
diff --git a/src/gamedata/stringtable.h b/src/gamedata/stringtable.h
index 1c479ba5a5..11416367c1 100644
--- a/src/gamedata/stringtable.h
+++ b/src/gamedata/stringtable.h
@@ -71,6 +71,7 @@ public:
 
 	const char *operator() (const char *name) const;	// Never returns NULL
 	const char *operator[] (const char *name) const;	// Can return NULL
+	bool exists(const char *name);
 
 private:
 
diff --git a/src/p_conversation.cpp b/src/p_conversation.cpp
index d5514c09b6..957f3b0a2f 100644
--- a/src/p_conversation.cpp
+++ b/src/p_conversation.cpp
@@ -352,7 +352,7 @@ static FStrifeDialogueNode *ReadRetailNode (FLevelLocals *Level, const char *nam
 	if (name)
 	{
 		FStringf label("$TXT_DLG_%s_d%d_%s", name, int(pos), TokenFromString(speech.Dialogue).GetChars());
-		node->Dialogue = label;
+		node->Dialogue = GStrings.exists(label)? label : FString(speech.Dialogue);
 	}
 	else
 	{
@@ -376,6 +376,8 @@ static FStrifeDialogueNode *ReadRetailNode (FLevelLocals *Level, const char *nam
 		label.ReplaceChars(' ', '_');
 		label.ReplaceChars('\'', '_');
 		node->SpeakerName.Format("$TXT_SPEAKER_%s", label.GetChars());
+		if (!GStrings.exists(node->SpeakerName)) node->SpeakerName = speech.Name;
+
 	}
 	else
 	{
@@ -446,7 +448,7 @@ static FStrifeDialogueNode *ReadTeaserNode (FLevelLocals *Level, const char *nam
 	if (name)
 	{
 		FStringf label("$TXT_DLG_%s_d%d_%s", name, pos, TokenFromString(speech.Dialogue).GetChars());
-		node->Dialogue = label;
+		node->Dialogue = GStrings.exists(label)? label : FString(speech.Dialogue);
 	}
 	else
 	{
@@ -475,6 +477,7 @@ static FStrifeDialogueNode *ReadTeaserNode (FLevelLocals *Level, const char *nam
 		label.ReplaceChars(' ', '_');
 		label.ReplaceChars('\'', '_');
 		node->SpeakerName.Format("$TXT_SPEAKER_%s", label.GetChars());
+		if (!GStrings.exists(node->SpeakerName)) node->SpeakerName = speech.Name;
 	}
 	else
 	{
@@ -566,6 +569,8 @@ static void ParseReplies (const char *name, int pos, FStrifeDialogueReply **repl
 		if (name)
 		{
 			FStringf label("$TXT_RPLY%d_%s_d%d_%s", j, name, pos, TokenFromString(rsp->Reply).GetChars());
+			reply->Reply = GStrings.exists(label)? label : FString(rsp->Reply);
+
 			reply->Reply = label;
 		}
 		else
@@ -590,7 +595,7 @@ static void ParseReplies (const char *name, int pos, FStrifeDialogueReply **repl
 			if (name)
 			{
 				FStringf label("$TXT_RYES%d_%s_d%d_%s", j, name, pos, TokenFromString(rsp->Yes).GetChars());
-				reply->QuickYes = label;
+				reply->QuickYes = GStrings.exists(label)? label : FString(rsp->Yes);
 			}
 			else
 			{
@@ -600,7 +605,7 @@ static void ParseReplies (const char *name, int pos, FStrifeDialogueReply **repl
 		if (reply->ItemCheck[0].Item != 0)
 		{
 			FStringf label("$TXT_RNO%d_%s_d%d_%s", j, name, pos, TokenFromString(rsp->No).GetChars());
-			reply->QuickNo = label;
+			reply->QuickNo = GStrings.exists(label)? label : FString(rsp->No);
 		}
 		else
 		{