Default to tasks.db in home directory

CMakeLists.txt

@@ -45,6 +45,7 @@ add_executable(lls
   src/Table.cpp
   src/Terminal.cpp
   src/Tokenizer.cpp
+  src/HomeDirectory.cpp
 )
 
 target_include_directories(lls PRIVATE include)

include/HomeDirectory.h

@@ -0,0 +1,13 @@
+#pragma once
+#include <filesystem>
+
+/**
+ * @brief Retrieves the current user's home directory across different operating systems.
+ * 
+ * On Windows, it checks the USERPROFILE environment variable.
+ * On Unix/Linux/macOS, it checks the HOME environment variable, with a fallback
+ * to checking the password database entry (`getpwuid`) if HOME is unset.
+ * 
+ * @return std::filesystem::path Path to the user's home directory, or an empty path if unable to resolve.
+ */
+std::filesystem::path getHomeDirectory();

src/HomeDirectory.cpp

@@ -0,0 +1,29 @@
+#include "HomeDirectory.h"
+#include <cstdlib>
+#include <filesystem>
+
+#if defined(_WIN32)
+    // Windows implementation
+#elif defined(__unix__) || defined(__APPLE__)
+#include <unistd.h>
+#include <sys/types.h>
+#include <pwd.h>
+#endif
+
+std::filesystem::path getHomeDirectory() {
+#if defined(_WIN32)
+    if (const char* env = std::getenv("USERPROFILE")) {
+        return std::filesystem::path(env);
+    }
+#else
+    if (const char* env = std::getenv("HOME")) {
+        return std::filesystem::path(env);
+    }
+    
+    // Fallback for Unix-like systems if HOME environment variable is unset
+    if (struct passwd* pwd = getpwuid(getuid()); pwd && pwd->pw_dir) {
+        return std::filesystem::path(pwd->pw_dir);
+    }
+#endif
+    return {};
+}

src/main.cpp

@@ -2,13 +2,14 @@
 #include <iostream>
 #include <string>
 
+#include "HomeDirectory.h"
 #include "Config.h"
 #include "Database.h"
 #include "Display.h"
 #include "Repl.h"
 
 int main(int argc, char** argv) {
-    const std::string path = (argc > 1) ? argv[1] : "tasks.db";
+    const std::string path = (argc > 1) ? argv[1] : (getHomeDirectory() / "tasks.db");
 
     try {
         Config config;