#pragma once

#include <deque>
#include <vector>

#include <artichoke/Util/Expected.hpp>
#include <artichoke/Coroutine/Generator.hpp>

#include <artichoke/Tokenizer/Token.hpp>

namespace arti::lang {

  struct [[nodiscard]] Tokenizer {
    Tokenizer() noexcept = delete;

    Tokenizer(std::string source) noexcept;

    ~Tokenizer() noexcept = default;

    Tokenizer(Tokenizer &&rhs) noexcept;
    Tokenizer &operator=(Tokenizer &&rhs) noexcept;

    Tokenizer(const Tokenizer &rhs) = delete;
    Tokenizer &operator=(const Tokenizer &rhs) = delete;

    Expected<void> consume(std::size_t n = 1) noexcept;
    Expected<Token> peek(std::size_t n = 0) noexcept;

    bool finished() const noexcept;

    void swap(Tokenizer &other) noexcept;

   private:
    Generator<Expected<Token>> tokenize();

    void skip_whitespace();
    Expected<void> skip_comment();

    Expected<Token> readNumber();
    Expected<Token> readString();
    Expected<Token> readCharacter();
    Expected<Token> readIdentifier();
    Expected<Token> readOperator();

    size_t line;
    size_t column;
    std::string::iterator iter;

    Generator<Expected<Token>> tokensGenerator;

    std::deque<Token> tokensBuffer;

    std::string source;
  };

} // namespace arti::lang