Add commandline arguments, implement --config, --version, --help

include/ArgsParser.h

@@ -0,0 +1,49 @@
+#pragma once
+
+#include <initializer_list>
+#include <optional>
+#include <string>
+#include <string_view>
+#include <vector>
+
+/*
+ * Allows syntax:
+ *  --help              : long flags
+ *  --path=/home/lion   : long assignments
+ */
+class ArgsParser {
+public:
+    enum Flags : int {
+        NONE = 0,
+        REQUIRED = 1, // argument is required
+        HAS_VALUE = 2, // argument must have a value
+    };
+
+    ArgsParser() = default;
+
+    void Parse(const std::vector<std::string_view>& ArgList);
+    // prints errors if any errors occurred, in that case also returns false
+    bool Verify();
+    void RegisterArgument(std::vector<std::string>&& ArgumentNames, int Flags);
+    // pass all possible names for this argument (short, long, etc)
+    bool FoundArgument(const std::vector<std::string>& Names);
+    std::optional<std::string> GetValueOfArgument(const std::vector<std::string>& Names);
+
+private:
+    void ConsumeLongAssignment(const std::string& Arg);
+    void ConsumeLongFlag(const std::string& Arg);
+    bool IsRegistered(const std::string& Name);
+
+    struct Argument {
+        std::string Name;
+        std::optional<std::string> Value;
+    };
+
+    struct RegisteredArgument {
+        std::vector<std::string> Names;
+        int Flags;
+    };
+
+    std::vector<RegisteredArgument> mRegisteredArguments;
+    std::vector<Argument> mFoundArgs;
+};