From 64b682c4ea49e014e87221a42d02730e38601212 Mon Sep 17 00:00:00 2001
From: etenie <etenium@proton.me>
Date: Mon, 25 Nov 2024 02:51:30 +0100
Subject: [PATCH] argparser: refactor the entire argparser

---
 src/ArgParser.hpp | 145 ++++++++++++++++++++++++++--------------------
 src/main.cpp      |   6 +-
 2 files changed, 85 insertions(+), 66 deletions(-)

diff --git a/src/ArgParser.hpp b/src/ArgParser.hpp
index 3f96b6b..f3dd58a 100644
--- a/src/ArgParser.hpp
+++ b/src/ArgParser.hpp
@@ -1,63 +1,117 @@
 #pragma once
 
+#include <format>
 #include <optional>
 #include <print>
 #include <stdexcept>
-#include <string>
+#include <string_view>
 #include <unordered_map>
 #include <vector>
 
 class ArgParser {
 public:
-  void add(const std::string& shortOpt, const std::string& longOpt, const std::string& description, bool requiresValue = true) {
-    Argument arg{shortOpt, longOpt, description, std::nullopt, requiresValue, false};
-    m_arguments.push_back(arg);
-    if (!shortOpt.empty())
-      m_optMap[shortOpt] = &m_arguments.back();
-    if (!longOpt.empty())
-      m_optMap[longOpt] = &m_arguments.back();
+  void add(std::string_view shortOpt, std::string_view longOpt, const std::string_view desc, const bool hasValue = true, const bool isRequired = false,
+           std::string_view defaultValue = "") {
+    const Argument arg{shortOpt, longOpt, desc, defaultValue, hasValue, isRequired};
+    m_arguments.emplace_back(arg);
+
+    m_opts.emplace(shortOpt, std::ref(m_arguments.back()));
+    m_opts.emplace(longOpt, std::ref(m_arguments.back()));
   }
 
-  bool parse(int argc, char* argv[]) {
+  [[nodiscard]] bool parse(const int argc, const char* argv[]) const {
     if (argc == 1) {
       printHelp();
       return false;
     }
 
     for (int i = 1; i < argc; ++i) {
-      std::string arg = argv[i];
+      std::string_view arg = argv[i];
 
       if (arg == "-h" || arg == "--help") {
         printHelp();
         return false;
       }
 
-      if (auto* argument = findArgument(arg); argument) {
-        argument->exists = true;
-        if (argument->requiresValue) {
-          if (i + 1 >= argc)
-            throw std::invalid_argument("Missing value for " + arg);
-          argument->value = argv[++i];
+      if (auto argument = findArgument(arg); argument.has_value()) {
+        auto& argRef     = argument->get();
+        argRef.isPresent = true;
+
+        if (argRef.requiresValue) {
+          if (i + 1 >= argc) {
+            throw std::invalid_argument(std::format("Missing value for: {}", arg));
+          }
+          argRef.value = argv[++i];
         }
       } else {
-        throw std::invalid_argument("Unknown option: " + arg);
+        throw std::invalid_argument(std::format("Unknown option: {}", arg));
+      }
+    }
+    for (const auto& arg : m_opts) {
+      const auto& argRef = arg.second.get();
+      if (argRef.isRequired && !argRef.isPresent) {
+        throw std::invalid_argument(std::format("Required argument: [{}, {}] not provided", argRef.shortOpt, argRef.longOpt));
       }
     }
     return true;
   }
 
   template <typename T>
-  T get(const std::string& arg) const {
-    const Argument* argument = findArgument(arg);
-    if (!argument || !argument->value)
-      throw std::runtime_error(arg + " has no value");
-
-    return convertToType<T>(*argument->value);
+  T get(const std::string_view arg) const {
+    if (const auto argument = findArgument(arg); argument.has_value()) {
+      return convertToType<T>(argument->get().value.value());
+    } else {
+      throw std::runtime_error(std::format("{} has no value", arg));
+    }
   }
 
-  bool has(const std::string& arg) const {
-    const Argument* argument = findArgument(arg);
-    return argument && argument->exists;
+  bool has(std::string_view arg) const {
+    if (const auto argument = findArgument(arg); argument.has_value()) {
+      return argument->get().isPresent;
+    }
+    return false;
+  }
+
+private:
+  struct Argument {
+    std::string_view                shortOpt;
+    std::string_view                longOpt;
+    std::string_view                description;
+    std::optional<std::string_view> value;
+    bool                            requiresValue;
+    bool                            isRequired = false;
+    bool                            isPresent  = false;
+  };
+
+  template <typename T>
+  T convertToType(const std::string_view value) const {
+    if constexpr (std::is_same_v<T, bool>) {
+      if (value == "true")
+        return true;
+      if (value == "false")
+        return false;
+      throw std::runtime_error("Invalid boolean string");
+    } else if constexpr (std::is_arithmetic_v<T>) {
+      T result{};
+      auto [ptr, ec] = std::from_chars(value.data(), value.data() + value.size(), result);
+      if (ec != std::errc()) {
+        throw std::runtime_error(std::format("Failed to convert the value: {}", value));
+      }
+      return result;
+    } else if constexpr (std::is_same_v<T, std::string>) {
+      return std::string(value);
+    } else if constexpr (std::is_same_v<T, std::string_view>) {
+      return value;
+    } else {
+      throw std::runtime_error("Unsupported type for conversion");
+    }
+  }
+
+  std::optional<std::reference_wrapper<Argument>> findArgument(const std::string_view opt) const {
+    if (const auto it = m_opts.find(opt); it != m_opts.end()) {
+      return it->second;
+    }
+    return std::nullopt;
   }
 
   void printHelp() const {
@@ -67,41 +121,6 @@ public:
     }
   }
 
-private:
-  struct Argument {
-    std::string                shortOpt;
-    std::string                longOpt;
-    std::string                description;
-    std::optional<std::string> value;
-    bool                       requiresValue;
-    bool                       exists = false;
-  };
-
-  Argument* findArgument(const std::string& opt) {
-    if (auto it = m_optMap.find(opt); it != m_optMap.end())
-      return it->second;
-    return nullptr;
-  }
-
-  const Argument* findArgument(const std::string& opt) const {
-    if (auto it = m_optMap.find(opt); it != m_optMap.end())
-      return it->second;
-    return nullptr;
-  }
-
-  template <typename T>
-  T convertToType(const std::string& value) const {
-    if constexpr (std::is_same_v<T, std::string>) {
-      return value;
-    } else if constexpr (std::is_same_v<T, int>) {
-      return std::stoi(value);
-    } else if constexpr (std::is_same_v<T, double>) {
-      return std::stod(value);
-    } else {
-      throw std::runtime_error("Unsupported type for argument conversion");
-    }
-  }
-
-  std::vector<Argument>                      m_arguments;
-  std::unordered_map<std::string, Argument*> m_optMap;
+  std::vector<Argument>                                                  m_arguments;
+  std::unordered_map<std::string_view, std::reference_wrapper<Argument>> m_opts;
 };
diff --git a/src/main.cpp b/src/main.cpp
index 2f8f998..457d22d 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -2,12 +2,12 @@
 #include "Helpers/WolframAlpha.hpp"
 #include <print>
 
-int main(const int argc, char* argv[]) {
+int main(const int argc, const char* argv[]) {
   try {
     ArgParser args;
     args.add("-h", "--help", "Print help", false);
-    args.add("-f", "--food", "Specify the food item");
-    args.add("-a", "--amount", "Specify the amount (in grams)");
+    args.add("-f", "--food", "Specify the food item", true, true);
+    args.add("-a", "--amount", "Specify the amount (in grams)", true, false, "100");
 
     if (!args.parse(argc, argv)) {
       return 0;