Support non-Space Age games (#326)

I checked all of the #320 commits to see if they would a hard dependency
on the Space Age DLC. And I only found the one commit that adds the mods
by default.

As far as I could figure out, there is no need to forcefully add these
mods: when they are enabled in mod-list.json they get loaded. No other
code is depending on these mods, all related code adds support when it
is encountered when loading the mods.

I tested by loading both a Space Age and a non-Space Age project (with
the mods enabled/disabled) without issues.

So in the end the fix for #323 is fairly straightforward 😌

Yafc.Parser/FactorioDataSource.cs

@@ -176,13 +176,14 @@ public static Project Parse(string factorioPath, string modPath, string projectP
             string modListPath = Path.Combine(modPath, "mod-list.json");
             Dictionary<string, Version> versionSpecifiers = [];
 
-            if (File.Exists(modListPath)) {
+            bool hasModList = File.Exists(modListPath);
+            if (hasModList) {
                 var mods = JsonSerializer.Deserialize<ModList>(File.ReadAllText(modListPath)) ?? throw new($"Could not read mod list from {modListPath}");
                 allMods = mods.mods.Where(x => x.enabled).Select(x => x.name).ToDictionary(x => x, x => (ModInfo)null!);
                 versionSpecifiers = mods.mods.Where(x => x.enabled && !string.IsNullOrEmpty(x.version)).ToDictionary(x => x.name, x => Version.Parse(x.version!)); // null-forgiving: null version strings are filtered by the Where.
             }
             else {
-                allMods = new Dictionary<string, ModInfo> { { "base", null! }, { "elevated-rails", null! }, { "quality", null! }, { "space-age", null! } };
+                allMods = new Dictionary<string, ModInfo> { { "base", null! } };
             }
 
             allMods["core"] = null!;
@@ -198,6 +199,18 @@ public static Project Parse(string factorioPath, string modPath, string projectP
                 FindMods(modPath, progress, allFoundMods);
             }
 
+            if (!hasModList) {
+                // Check if the Space Age DLC mods are available, as the game will enable them by default when available.
+                bool foundSpaceAge = allFoundMods.Exists(modInfo => modInfo.name == "space-age");
+                if (foundSpaceAge) {
+                    // Add space-age mod ...
+                    allMods.Add("space-age", null!);
+                    // ... and its dependencies
+                    allMods.Add("quality", null!);
+                    allMods.Add("elevated-rails", null!);
+                }
+            }
+
             Version? factorioVersion = null;
 
             foreach (var mod in allFoundMods) {

changelog.txt

@@ -23,6 +23,7 @@ Date:
     Bugfixes:
         - Recipes no longer have excessive question marks in their names
         - Moved mining and research bonuses have to the Preferences screen.
+        - Support games without the Space Age DLC again.
     Internal changes:
         - Added rudimentary tools for drawing tab controls.
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