addition to MCUpdater's PathWalker, to create a path/filename given the mod id and original filename

part-of-PathWalker.java

	private static Map<String, String> modPaths = new HashMap<>();
	private static List<String> badVersionStrings = new ArrayList<>();
	static {
		// key is mod id
		// value is mod filename (no `mods/`)
		modPaths.put("betterbuilderswands", "BetterBuildersWands.jar");
		modPaths.put("bibliocraft", "BiblioCraft.jar");
		modPaths.put("biomesoplenty", "BiomesOPlenty.jar");
		modPaths.put("ChunkPregeneratorV", "Chunk Pregenerator.jar");
		modPaths.put("craftstudioapi", "CraftStudio.jar");
		modPaths.put("environmentaltech", "environmentaltech.jar");
		modPaths.put("extracells", "ExtraCells.jar");
		modPaths.put("immersiveengineeringcore", "ImmersiveEngineering-core.jar");
		modPaths.put("industrialforegoing", "industrialforegoing.jar");
		modPaths.put("InvTweaks", "InventoryTweaks.jar");
		modPaths.put("jeresources", "JustEnoughResources.jar");
		modPaths.put("magipsi", "MagicalPsi.jar");
		modPaths.put("mcjtylib_ng", "mcjtylib.jar");
		modPaths.put("harvestcraft", "PamsHarvestcraft.jar");
		modPaths.put("scalinghealth", "ScalingHealth.jar");
		modPaths.put("signals", "Signals.jar");
		modPaths.put("SilentLib", "SilentLib.jar");
		modPaths.put("tinkertoolleveling", "TinkerToolLeveling.jar");
		modPaths.put("waila", "Hwyla.jar"); // This one seems iffy
		modPaths.put("wailaharvestability", "WailaHarvestability.jar");

		badVersionStrings.add("@VERSION@");
		badVersionStrings.add("${version}");
	}

	private String generateModPath(String modId, Path file, MCModInfo info) {
		String knownPath = modPaths.get(modId);
		if (knownPath != null) {
			return "mods/" + knownPath;
		}

		String name = file.getFileName().toString();

		// fix a few common jar mistakes or similarities
		name = name.replace("-universal.jar", ".jar");
		name = name.replace("--", "-");

		// Catch the various minecraft versions
		List<String> minecraftVersions = new ArrayList<>();
		// 1.12.2
		minecraftVersions.add(minecraftVersion);
		// 1.12
		String shorterMcVersion = minecraftVersion.substring(0, minecraftVersion.lastIndexOf("."));
		minecraftVersions.add(shorterMcVersion);
		// 1.12.1, 1.12.0
		int lastDigit = Integer.parseInt(minecraftVersion.substring(minecraftVersion.lastIndexOf(".") + 1));
		for (int i = lastDigit - 1; i >= 0; i--) {
			minecraftVersions.add(shorterMcVersion + "." + Integer.toString(i));
		}

		String mcVersionRegex = "(?:" + Joiner.on("|").join(
				minecraftVersions.stream().map(Pattern::quote).collect(Collectors.toSet()))
				+ ")";

		boolean modVersionIsSubstringOfMcVersion = false;
		if (info != null && info.version != null && !info.version.isEmpty()) {
			for (String mcVersion : minecraftVersions) {
				if (mcVersion.contains(info.version)) {
					modVersionIsSubstringOfMcVersion = true;
					break;
				}
			}
		}

		if (info != null && info.version != null && !info.version.isEmpty()) {
			// Remove the mod version from the name, except if the mod version is a substring of the minecraft version
			if (!modVersionIsSubstringOfMcVersion) {
				name = name.replaceAll("[-_ ]?" + Pattern.quote(info.version), "");
			}

			// Sometimes the mod version has 1.12.2 in it; remove that from the mod version, then again remove the mod
			// version from the name.
			// [-_] after mc version:
			String versionWithoutMc = info.version.replaceAll(mcVersionRegex + "[-_]?", "");
			// [-_] before mc version:
			versionWithoutMc = versionWithoutMc.replaceAll("[-_]?" + mcVersionRegex, "");
			if (!modVersionIsSubstringOfMcVersion) {
				name = name.replaceAll("[-_ ]?" + Pattern.quote(versionWithoutMc), "");
			}
		}

		// Remove 1.12.2 from the name
		name = name.replaceAll("[-_]?(?:mc|MC)?" + mcVersionRegex, "");

		// Now go back, if the mod version was inside the minecraft version, and remove the mod version.
		if (modVersionIsSubstringOfMcVersion) {
			name = name.replaceAll("[-_ ]?" + Pattern.quote(info.version), "");
		}

		// If the mod didn't have a parseable info, then the filename likely has a version number still in it. Try to
		// parse that out.
		if (info == null || info.version == null || info.version.isEmpty() || badVersionStrings.contains(info.version)) {
			// replace like -12.34 or -12.34.56
			name = name.replaceAll("[-_ ][0-9]+(?:\\.[0-9]+)+", "");
		}

		return "mods/" + name;
	}