game: Migrate from GLFW to SDL2 & attempt to rewrite / simplify display and input code (#2397)

Co-authored-by: Hat Kid <6624576+Hat-Kid@users.noreply.github.com>

common/util/string_util.cpp

@@ -1,7 +1,9 @@
 #include "string_util.h"
 
+#include <iomanip>
 #include <random>
 #include <regex>
+#include <sstream>
 
 #include "common/util/diff.h"
 
@@ -141,4 +143,43 @@ std::string repeat(size_t n, const std::string& str) {
   ret.append(ret.c_str(), (n - (m / 2)) * period);
   return ret;
 }
+
+std::string current_local_timestamp() {
+  std::time_t now = std::time(nullptr);
+  std::tm local_time = *std::localtime(&now);
+  const std::string format = "%Y-%m-%dT%H:%M:%S";
+  std::ostringstream oss;
+  oss << std::put_time(&local_time, format.c_str());
+  return oss.str();
+}
+
+std::string current_local_timestamp_no_colons() {
+  std::time_t now = std::time(nullptr);
+  std::tm local_time = *std::localtime(&now);
+  const std::string format = "%Y-%m-%dT%H-%M-%S";
+  std::ostringstream oss;
+  oss << std::put_time(&local_time, format.c_str());
+  return oss.str();
+}
+
+std::string current_isotimestamp() {
+  std::time_t now = std::time(nullptr);
+  std::tm utc_time = *std::gmtime(&now);
+  const std::string format = "%Y-%m-%dT%H:%M:%SZ";
+  std::ostringstream oss;
+  oss << std::put_time(&utc_time, format.c_str());
+  return oss.str();
+}
+
+std::string to_upper(const std::string& str) {
+  std::string new_str(str.size(), ' ');
+  std::transform(str.begin(), str.end(), new_str.begin(), ::toupper);
+  return new_str;
+}
+
+std::string to_lower(const std::string& str) {
+  std::string new_str(str.size(), ' ');
+  std::transform(str.begin(), str.end(), new_str.begin(), ::tolower);
+  return new_str;
+}
 }  // namespace str_util