Error detection and some colours

.gitignore

@@ -1,3 +1,4 @@
 /.vscode
 /0bao01col0.xfbin
-/CC2 Alt Switch.exe
+/CC2 Alt Switch.exe
+3dio01col0.xfbin

src/main.cpp

@@ -2,6 +2,7 @@
 #include <fstream>
 #include <filesystem>
 #include <vector>
+#include <cctype>
 
 namespace fs = std::filesystem;
 
@@ -26,30 +27,67 @@ constexpr bool isAnyOf(const T& cmp, const Cs& ... others) {
     return ((cmp == others) || ...);
 }
 
+void pause(std::string spaces = "") {
+    std::cout << spaces << "> ";
+    system("pause");
+}
+
+void error(std::string message) {
+    std::cerr << "\033[31m" << "> ERROR: " << message << "\033[0m";
+    // TBC: make this red
+}
+
 int main(int argc, char* argv[]) {
+    // Check if file has been drag-&-dropped
+    if (argc < 2) {
+        error("To use this tool, drag&drop the file you want to convert onto this EXE.\n\n");
+        pause(); return 0;
+    }
+
+    // Get dropped file
     fs::path filePath = argv[1];
     std::string fileName = filePath.stem().string();
     std::ifstream file(filePath, std::ios::binary);
     std::vector<char> data;
 
+    // Ask for Tint to switch to
     char tint;
-    std::cout << "> Which tint colour do you want to switch to? (A, B, C, or D)\n";
+    std::cout << "> Which tint colour do you want to switch to? (A - J)\n";
     std::cin >> tint;
-    std::cout << "> Changing \"" + fileName + ".xfbin\" file data to Tint Colour " << tint << "...\n\n";
+    std::cout << "> Changing \"" + fileName + ".xfbin\" file data to Tint Colour " << (char)std::toupper(tint) << "...\n\n";
 
-    int tintNumber = tint - 0x11;
+    // Convert given Tint to the corresponding integer value
+    int tintNumber = (int)tint;
+    if (tintNumber > 0x60 && tintNumber < 0x6B) {
+        tintNumber -= 0x31;
+    } else if (tintNumber > 0x40 && tintNumber < 0x4B) {
+        tintNumber -= 0x11;
+    } else {
+        error("Invalid Tint letter. Must be an English letter between A-J.\n\n");
+        pause(); return 0;
+    }
     std::string outputFileName = stringRange(fileName, 0, 5) + "col" + (char)tintNumber + ".xfbin";
-    std::ofstream output(outputFileName, std::ios::binary);
 
+    // Read through file and store to vector, swapping byte values as needed
     for (int i = 0; file.peek() != EOF; i++) {
         data.push_back(file.get());
         if (isAnyOf(arrayRange(data, i - 4, i - 1), "_s_#", "_d_#")) {
             data[i] = tintNumber;
         }
+    }
+
+    // Check if file is actually unencrypted
+    if (arrayRange(data, 0, 3) != "NUCC") {
+        error("\"NUCC\" could not be found. File is either encrypted or invalid.\n\n");
+        pause(); return 0;
+    }
+
+    // Create output file and send modified data to it
+    std::ofstream output(outputFileName, std::ios::binary);
+    for (int i = 0; i < data.size(); i++) {
         output << data[i];
     }
-    std::cout << "> Conversion successful! File has been output as \"" << outputFileName << "\".\n\n";
+    std::cout << "\033[32m> Conversion successful! File has been output as \"" << outputFileName << "\".\033[0m\n\n";
 
-    std::cout << "> ";
-    system("pause");
+    pause();
 }