#ifndef JAVA_TOKENS_HH
#define JAVA_TOKENS_HH

#include "errors.hh"
#include "io.hh"
#include "java_version.hh"  // IWYU pragma: export
#include "location.hh"

#include <expected>
#include <memory>
#include <string_view>

namespace java {

using src::Location;

struct Token {
  enum class Type : uint8_t {
    // str is content of comment, excluding heading or trailing slash and star.
    // int_value is number of stars at head, 0 for single line, 1 for /* and
    // 2 for /** and so on.
    kComment,

    // str is identifier
    kIdentifier,

    // str is keyword
    kReservedKeyword,

    // str is keyword
    kContextualKeyword,

    // str is separator
    kSeparator,

    // str is operator
    kOperator,

    // int_value is literal value
    kLiteralInt,

    // int_value is literal value
    kLiteralLong,

    // str is literal value
    kLiteralString,

    // int_value is literal value as unicode code-point
    kLiteralCharacter,

    kLiteralNull,

    // float_value is literal value
    kLiteralFloatingPoint,

    // float_value is literal value
    kLiteralDoubleFloatingPoint,

    // int_value is literal value, 0 = false, anything else = true
    kLiteralBoolean,

    kError,
  };

  Type type;
  Location loc;
  std::string_view str;
  int64_t int_value{0};
  double float_value{0};
};

struct TokensConfig {
  // Source version of Java file
  Version version = Version::kMax;
};

class Tokens {
 public:
  virtual ~Tokens() = default;
  Tokens(Tokens const&) = delete;
  Tokens& operator=(Tokens const&) = delete;

  virtual std::expected<Token, io::ReadError> read() = 0;

 protected:
  Tokens() = default;
};

[[nodiscard]] std::unique_ptr<Tokens> open(std::unique_ptr<io::Reader> reader,
                                           std::unique_ptr<src::Errors> errors,
                                           TokensConfig config = {});

}  // namespace java

#endif  // JAVA_TOKENS_HH