From 9228010625f6a83a9e1aa43b1befe74e36508cea Mon Sep 17 00:00:00 2001
From: Georg Hagen <git.georg.hagen@madvoxel.com>
Date: Thu, 10 Oct 2024 14:54:36 +0200
Subject: [PATCH] Add ToValidFileName function

---
 openVulkanoCpp/IO/FsUtils.cpp | 59 +++++++++++++++++++++++++++++++++++
 openVulkanoCpp/IO/FsUtils.hpp |  2 ++
 2 files changed, 61 insertions(+)

diff --git a/openVulkanoCpp/IO/FsUtils.cpp b/openVulkanoCpp/IO/FsUtils.cpp
index 3a3595a..ae38496 100644
--- a/openVulkanoCpp/IO/FsUtils.cpp
+++ b/openVulkanoCpp/IO/FsUtils.cpp
@@ -5,6 +5,8 @@
  */
 
 #include "FsUtils.hpp"
+#include <unordered_map>
+#include <regex>
 
 namespace fs = std::filesystem;
 
@@ -88,4 +90,61 @@ namespace OpenVulkano
 		
 		return size;
 	}
+	
+	std::string FsUtils::ToValidFileName(std::string str)
+	{
+		// Map of characters to replace with similar looking ones
+		static const std::unordered_map<char, std::string> replacements = {
+			{'<', "＜"},  // Use full-width less than
+			{'>', "＞"},  // Use full-width greater than
+			{':', "꞉"},   // Use modifier letter colon
+			{'"', "＂"},  // Use full-width quotation mark
+			{'/', "⁄"},   // Use fraction slash
+			{'\\', "⧹"},  // Use big reverse solidus
+			{'|', "｜"},  // Use full-width vertical line
+			{'?', "？"},  // Use full-width question mark
+			{'*', "∗"},   // Use asterisk operator
+		};
+		
+		// Characters to remove (control characters and others that might cause issues)
+		static const std::regex remove_pattern("[\\x00-\\x1F\\x7F~`!@#$%^&(){}\\[\\]=+,;]");
+		
+		// Maximum length for many filesystems
+		static const size_t MAX_LENGTH = 255;
+		
+		// Replace problematic characters with similar looking ones
+		for (const auto& [key, value] : replacements) {
+			size_t pos = 0;
+			while ((pos = str.find(key, pos)) != std::string::npos) {
+				str.replace(pos, 1, value);
+				pos += value.length();
+			}
+		}
+		
+		// Remove other invalid characters
+		str = std::regex_replace(str, remove_pattern, "");
+		
+		// Trim leading/trailing spaces and periods
+		str = std::regex_replace(str, std::regex("^[\\.\\s]+"), "");
+		str = std::regex_replace(str, std::regex("[\\.\\s]+$"), "");
+		
+		// Replace multiple spaces with a single space
+		str = std::regex_replace(str, std::regex("\\s+"), " ");
+		
+		// Ensure the string isn't empty after sanitization
+		if (str.empty()) {
+			str = "unnamed_file";
+		}
+		
+		// Truncate if too long, being careful not to cut in the middle of a UTF-8 character
+		if (str.length() > MAX_LENGTH) {
+			size_t len = MAX_LENGTH;
+			while (len > 0 && (str[len] & 0xC0) == 0x80) {
+				--len;
+			}
+			str = str.substr(0, len);
+		}
+		
+		return str;
+	}
 }
diff --git a/openVulkanoCpp/IO/FsUtils.hpp b/openVulkanoCpp/IO/FsUtils.hpp
index 4dc397c..e37d2f6 100644
--- a/openVulkanoCpp/IO/FsUtils.hpp
+++ b/openVulkanoCpp/IO/FsUtils.hpp
@@ -20,5 +20,7 @@ namespace OpenVulkano
 		static bool IsTreeEmpty(const std::filesystem::path& dir);
 		
 		static ByteSize GetDirSize(const std::filesystem::path& dir);
+		
+		static std::string ToValidFileName(std::string filename);
 	};
 }