From eae6d3f7838930578c6d2ac7632e5b6abde8302e Mon Sep 17 00:00:00 2001
From: Factorio Blueprints <factorio.prints@gmail.com>
Date: Tue, 3 Jan 2023 09:19:00 -0500
Subject: [PATCH] Enhance mod loading to respect dependency declarations
 starting with `~` which indicates dependencies that don't affect mod loading
 order. Relates to issues #37 and #42.

---
 .../src/com/demod/factorio/ModInfo.java       | 69 +++++++++++++++----
 .../src/com/demod/factorio/ModLoader.java     |  6 +-
 2 files changed, 60 insertions(+), 15 deletions(-)

diff --git a/FactorioDataWrapper/src/com/demod/factorio/ModInfo.java b/FactorioDataWrapper/src/com/demod/factorio/ModInfo.java
index 8278faf..74b31ad 100644
--- a/FactorioDataWrapper/src/com/demod/factorio/ModInfo.java
+++ b/FactorioDataWrapper/src/com/demod/factorio/ModInfo.java
@@ -2,24 +2,66 @@
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 import org.json.JSONArray;
 import org.json.JSONObject;
 
 public class ModInfo {
+	public static final Pattern DEPENDENCY_REGEX = Pattern.compile(
+			"(^(?:(\\?|\\(\\?\\)|!|~) *)?(.+?)(?: *([<>=]=?) *([0-9.]+))?$)");
+
+	// https://wiki.factorio.com/Tutorial:Mod_structure#dependencies
+	public static enum DependencyType {
+		// ! for incompatibility
+		INCOMPATIBLE,
+		// ? for an optional dependency
+		OPTIONAL,
+		// (?) for a hidden optional dependency
+		HIDDEN_OPTIONAL,
+		// ~ for a dependency that does not affect load order
+		DOES_NOT_AFFECT_LOAD_ORDER,
+		// no prefix for a hard requirement for the other mod.
+		REQUIRED,
+		;
+
+		private static DependencyType fromSymbol(String symbol) {
+			if (symbol == null) {
+				return REQUIRED;
+			}
+			switch (symbol) {
+				case "!":
+					return INCOMPATIBLE;
+				case "?":
+					return OPTIONAL;
+				case "(?)":
+					return HIDDEN_OPTIONAL;
+				case "~":
+					return DOES_NOT_AFFECT_LOAD_ORDER;
+				default:
+					throw new RuntimeException("Invalid dependency symbol: " + symbol);
+			}
+		}
+	}
+
 	public static class Dependency {
-		private final boolean optional;
+		private final DependencyType type;
 		private final String name;
 		private final String conditional;
 		private final String version;
 
-		private Dependency(boolean optional, String name, String conditional, String version) {
-			this.optional = optional;
+		private Dependency(DependencyType type, String name, String conditional, String version) {
+			this.type = type;
 			this.name = name;
 			this.conditional = conditional;
 			this.version = version;
 		}
 
+		public DependencyType getType() {
+			return this.type;
+		}
+
 		public String getConditional() {
 			return conditional;
 		}
@@ -33,7 +75,7 @@ public String getVersion() {
 		}
 
 		public boolean isOptional() {
-			return optional;
+			return this.type == DependencyType.OPTIONAL || this.type == DependencyType.HIDDEN_OPTIONAL;
 		}
 	}
 
@@ -60,15 +102,16 @@ public ModInfo(JSONObject json) {
 		}
 		for (int i = 0; i < dependenciesJson.length(); i++) {
 			String depString = dependenciesJson.getString(i);
-			String[] depSplit = depString.split("\\s");
-			if (depSplit.length == 1) {
-				dependencies.add(new Dependency(false, depSplit[0], null, null));
-			} else if (depSplit.length == 2) {
-				dependencies.add(new Dependency(true, depSplit[1], null, null));
-			} else if (depSplit.length == 3) {
-				dependencies.add(new Dependency(false, depSplit[0], depSplit[1], depSplit[2]));
-			} else if (depSplit.length == 4) {
-				dependencies.add(new Dependency(true, depSplit[1], depSplit[2], depSplit[3]));
+			Matcher matcher = DEPENDENCY_REGEX.matcher(depString);
+			if (matcher.matches()) {
+				String symbol = matcher.group(2);
+				DependencyType type = DependencyType.fromSymbol(symbol);
+				String name = matcher.group(3);
+				String conditional = matcher.group(4);
+				String version = matcher.group(5);
+				dependencies.add(new Dependency(type, name, conditional, version));
+			} else {
+				throw new RuntimeException("Invalid dependency string: " + depString);
 			}
 		}
 	}
diff --git a/FactorioDataWrapper/src/com/demod/factorio/ModLoader.java b/FactorioDataWrapper/src/com/demod/factorio/ModLoader.java
index 9addc7c..1a407b8 100644
--- a/FactorioDataWrapper/src/com/demod/factorio/ModLoader.java
+++ b/FactorioDataWrapper/src/com/demod/factorio/ModLoader.java
@@ -21,6 +21,8 @@
 import org.json.JSONException;
 
 import com.demod.factorio.ModInfo.Dependency;
+import com.demod.factorio.ModInfo.DependencyType;
+
 import com.google.common.io.ByteStreams;
 
 public class ModLoader {
@@ -145,11 +147,11 @@ public List<Mod> getModsInLoadOrder() {
 				for (Dependency dependency : mod.getInfo().getDependencies()) {
 					String depName = dependency.getName();
 					if (getMod(depName).isPresent()) {
-						if (!order.contains(depName)) {
+						if (!order.contains(depName) && dependency.getType() != DependencyType.DOES_NOT_AFFECT_LOAD_ORDER) {
 							missingDep = true;
 							break;
 						}
-					} else if (!dependency.isOptional()) {
+					} else if (!dependency.isOptional() && dependency.getType() != DependencyType.INCOMPATIBLE) {
 						throw new InternalError("MISSING DEPENDENCY FOR " + mod.getInfo().getName() + " : " + depName);
 					}
 				}