#pragma once

#include <artichoke/Util/Expected.hpp>
#include <artichoke/Tokenizer/Token.hpp>

namespace arti::lang {
  struct Tokenizer;

  struct [[nodiscard]] TokenizerRange {
    friend struct Tokenizer;
    struct Iterator;
    struct Sentinel;

    using iterator_type = Iterator;
    using sentinel_type = Sentinel;

    TokenizerRange(TokenizerRange &&) noexcept;
    TokenizerRange &operator=(TokenizerRange &&) noexcept;

    TokenizerRange(const TokenizerRange &) noexcept = delete;
    TokenizerRange &operator=(const TokenizerRange &) noexcept = delete;

    Iterator begin();
    Sentinel end() const noexcept;

    struct Iterator {
      friend struct TokenizerRange;
      using iterator_category = std::input_iterator_tag;
      using difference_type = std::ptrdiff_t;

      using ValueType = Expected<Token>;
      using ReferenceType = ValueType &;
      using PointerType = ValueType *;

      using value_type = ValueType;
      using pointer_type = PointerType;

      Iterator(Iterator &&) noexcept;
      Iterator &operator=(Iterator &&) noexcept;

      Iterator(const Iterator &) noexcept = delete;
      Iterator &operator=(const Iterator &) noexcept = delete;

      Iterator &operator++();

      void operator++(int);

      ReferenceType operator*() const noexcept;
      PointerType operator->() const noexcept;

      friend bool operator==(const Iterator &, Sentinel);
      friend bool operator==(Sentinel, const Iterator &);

      friend bool operator!=(const Iterator &, Sentinel);
      friend bool operator!=(Sentinel, const Iterator &);

     private:
      Iterator(Tokenizer *tokenizer) noexcept;

      Tokenizer *tokenizer;
      mutable Expected<Token> cvalue;
    };

    struct Sentinel {};

   private:
    TokenizerRange(Tokenizer *tokenizer);

    Tokenizer *tokenizer;
  };
}