// Copyright 2020 The Tint Authors.
//
// 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 SRC_TINT_SEM_TYPE_H_
#define SRC_TINT_SEM_TYPE_H_

#include <functional>
#include <string>

#include "src/tint/sem/node.h"

namespace tint {

// Forward declarations
class ProgramBuilder;
class SymbolTable;

namespace sem {

/// Supported memory layouts for calculating sizes
enum class MemoryLayout { kUniformBuffer, kStorageBuffer };

/// Base class for a type in the system
class Type : public Castable<Type, Node> {
 public:
  /// Move constructor
  Type(Type&&);
  ~Type() override;

  /// @returns a hash of the type.
  virtual size_t Hash() const = 0;

  /// @returns true if the this type is equal to the given type
  virtual bool Equals(const Type&) const = 0;

  /// @param symbols the program's symbol table
  /// @returns the name for this type that closely resembles how it would be
  /// declared in WGSL.
  virtual std::string FriendlyName(const SymbolTable& symbols) const = 0;

  /// @returns the inner most pointee type if this is a pointer, `this`
  /// otherwise
  const Type* UnwrapPtr() const;

  /// @returns the inner type if this is a reference, `this` otherwise
  const Type* UnwrapRef() const;

  /// @returns the size in bytes of the type. This may include tail padding.
  /// @note opaque types will return a size of 0.
  virtual uint32_t Size() const;

  /// @returns the alignment in bytes of the type. This may include tail
  /// padding.
  /// @note opaque types will return a size of 0.
  virtual uint32_t Align() const;

  /// @returns true if constructible as per
  /// https://gpuweb.github.io/gpuweb/wgsl/#constructible-types
  virtual bool IsConstructible() const;

  /// @returns true if this type is a scalar
  bool is_scalar() const;
  /// @returns true if this type is a numeric scalar
  bool is_numeric_scalar() const;
  /// @returns true if this type is a float scalar
  bool is_float_scalar() const;
  /// @returns true if this type is a float matrix
  bool is_float_matrix() const;
  /// @returns true if this type is a square float matrix
  bool is_square_float_matrix() const;
  /// @returns true if this type is a float vector
  bool is_float_vector() const;
  /// @returns true if this type is a float scalar or vector
  bool is_float_scalar_or_vector() const;
  /// @returns true if this type is a float scalar or vector or matrix
  bool is_float_scalar_or_vector_or_matrix() const;
  /// @returns true if this type is an integer scalar
  bool is_integer_scalar() const;
  /// @returns true if this type is a signed integer scalar
  bool is_signed_integer_scalar() const;
  /// @returns true if this type is an unsigned integer scalar
  bool is_unsigned_integer_scalar() const;
  /// @returns true if this type is a signed integer vector
  bool is_signed_integer_vector() const;
  /// @returns true if this type is an unsigned vector
  bool is_unsigned_integer_vector() const;
  /// @returns true if this type is an unsigned scalar or vector
  bool is_unsigned_scalar_or_vector() const;
  /// @returns true if this type is a signed scalar or vector
  bool is_signed_scalar_or_vector() const;
  /// @returns true if this type is an integer scalar or vector
  bool is_integer_scalar_or_vector() const;
  /// @returns true if this type is a boolean vector
  bool is_bool_vector() const;
  /// @returns true if this type is boolean scalar or vector
  bool is_bool_scalar_or_vector() const;
  /// @returns true if this type is a numeric vector
  bool is_numeric_vector() const;
  /// @returns true if this type is a vector of scalar type
  bool is_scalar_vector() const;
  /// @returns true if this type is a numeric scale or vector
  bool is_numeric_scalar_or_vector() const;
  /// @returns true if this type is a handle type
  bool is_handle() const;

 protected:
  Type();
};

}  // namespace sem
}  // namespace tint

namespace std {

/// std::hash specialization for tint::sem::Type
template <>
struct hash<tint::sem::Type> {
  /// @param type the type to obtain a hash from
  /// @returns the hash of the semantic type
  size_t operator()(const tint::sem::Type& type) const { return type.Hash(); }
};

/// std::equal_to specialization for tint::sem::Type
template <>
struct equal_to<tint::sem::Type> {
  /// @param a the first type to compare
  /// @param b the second type to compare
  /// @returns true if the two types are equal
  bool operator()(const tint::sem::Type& a, const tint::sem::Type& b) const {
    return a.Equals(b);
  }
};

}  // namespace std

#endif  // SRC_TINT_SEM_TYPE_H_