/*
 * Copyright 2017 WebAssembly Community Group participants
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef WABT_TOKEN_H_
#define WABT_TOKEN_H_

#include <string>

#include "src/literal.h"
#include "src/opcode.h"

namespace wabt {

struct Literal {
  Literal() = default;
  Literal(LiteralType type, const std::string& text) : type(type), text(text) {}

  LiteralType type;
  std::string text;
};

enum class TokenType {
  // Tokens with no additional data (i.e. bare).
  Invalid,
  Anyfunc,
  AssertExhaustion,
  AssertInvalid,
  AssertMalformed,
  AssertReturn,
  AssertReturnArithmeticNan,
  AssertReturnCanonicalNan,
  AssertTrap,
  AssertUnlinkable,
  Bin,
  Data,
  Elem,
  Eof,
  Except,
  Export,
  Func,
  Get,
  Global,
  Import,
  Invoke,
  Local,
  Lpar,
  Memory,
  Module,
  Mut,
  Offset,
  Param,
  Quote,
  Register,
  Result,
  Rpar,
  Shared,
  Start,
  Table,
  Then,
  Type,
  First_Bare = Invalid,
  Last_Bare = Type,

  // Tokens with Literal data.
  Float,
  Int,
  Nat,
  First_Literal = Float,
  Last_Literal = Nat,

  // Tokens with Opcode data.
  AtomicLoad,
  AtomicRmw,
  AtomicRmwCmpxchg,
  AtomicStore,
  Binary,
  Block,
  Br,
  BrIf,
  BrTable,
  Call,
  CallIndirect,
  Catch,
  CatchAll,
  Compare,
  Const,
  Convert,
  CurrentMemory,
  Drop,
  Else,
  End,
  GetGlobal,
  GetLocal,
  GrowMemory,
  If,
  Load,
  Loop,
  Nop,
  Rethrow,
  Return,
  Select,
  SetGlobal,
  SetLocal,
  Store,
  TeeLocal,
  Throw,
  Try,
  Unary,
  Unreachable,
  Wait,
  Wake,
  First_Opcode = AtomicLoad,
  Last_Opcode = Wake,

  // Tokens with string data.
  AlignEqNat,
  OffsetEqNat,
  Reserved,
  Text,
  Var,
  First_String = AlignEqNat,
  Last_String = Var,

  // Tokens with Type data.
  ValueType,
  First_Type = ValueType,
  Last_Type = ValueType,

  First = First_Bare,
  Last = Last_Type,
};

const char* GetTokenTypeName(TokenType);

inline bool IsTokenTypeBare(TokenType token_type) {
  return token_type >= TokenType::First_Bare &&
         token_type <= TokenType::Last_Bare;
}

inline bool IsTokenTypeString(TokenType token_type) {
  return token_type >= TokenType::First_String &&
         token_type <= TokenType::Last_String;
}

inline bool IsTokenTypeType(TokenType token_type) {
  return token_type == TokenType::ValueType;
}

inline bool IsTokenTypeOpcode(TokenType token_type) {
  return token_type >= TokenType::First_Opcode &&
         token_type <= TokenType::Last_Opcode;
}

inline bool IsTokenTypeLiteral(TokenType token_type) {
  return token_type >= TokenType::First_Literal &&
         token_type <= TokenType::Last_Literal;
}

struct Token {
  Token() : token_type_(TokenType::Invalid) {}
  Token(Location, TokenType);
  Token(Location, TokenType, Type);
  Token(Location, TokenType, const std::string&);
  Token(Location, TokenType, Opcode);
  Token(Location, TokenType, const Literal&);
  Token(const Token&);
  Token(Token&&);
  Token& operator=(const Token&);
  Token& operator=(Token&&);
  ~Token();

  Location loc;

  TokenType token_type() const { return token_type_; }

  bool HasText() const { return IsTokenTypeString(token_type_); }
  bool HasType() const { return IsTokenTypeType(token_type_); }
  bool HasOpcode() const { return IsTokenTypeOpcode(token_type_); }
  bool HasLiteral() const { return IsTokenTypeLiteral(token_type_); }

  const std::string& text() const {
    assert(HasText());
    return text_;
  }

  Type type() const { assert(HasType()); return type_; }

  Opcode opcode() const { assert(HasOpcode()); return opcode_; }

  const Literal& literal() const {
    assert(HasLiteral());
    return literal_;
  }

  std::string to_string() const;
  std::string to_string_clamp(size_t max_length) const;

 private:
  void Destroy();

  TokenType token_type_;

  union {
    std::string text_;
    Type type_;
    Opcode opcode_;
    Literal literal_;
  };
};

}  // namespace wabt

#endif // WABT_TOKEN_H_