// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

#include "toolchain/sem_ir/type.h"

#include <optional>

#include "toolchain/sem_ir/file.h"

namespace Carbon::SemIR {

// Verify that the constant value's type is `TypeType` (or an error).
static void CheckTypeOfConstantIsTypeType(File& file, ConstantId constant_id) {
  CARBON_CHECK(constant_id.is_constant(),
               "Canonicalizing non-constant type: {0}", constant_id);
  auto type_id =
      file.insts().Get(file.constant_values().GetInstId(constant_id)).type_id();
  CARBON_CHECK(
      type_id == TypeType::TypeId || constant_id == ErrorInst::ConstantId,
      "Forming type ID for non-type constant of type {0}",
      file.types().GetAsInst(type_id));
}

auto TypeStore::GetTypeIdForTypeConstantId(ConstantId constant_id) const
    -> TypeId {
  CheckTypeOfConstantIsTypeType(*file_, constant_id);
  return TypeId::ForTypeConstant(constant_id);
}

auto TypeStore::GetTypeIdForTypeInstId(InstId inst_id) const -> TypeId {
  auto constant_id = file_->constant_values().Get(inst_id);
  CheckTypeOfConstantIsTypeType(*file_, constant_id);
  return TypeId::ForTypeConstant(constant_id);
}

auto TypeStore::GetTypeIdForTypeInstId(TypeInstId inst_id) const -> TypeId {
  auto constant_id = file_->constant_values().Get(inst_id);
  return TypeId::ForTypeConstant(constant_id);
}

auto TypeStore::GetAsTypeInstId(InstId inst_id) const -> TypeInstId {
  auto constant_id = file_->constant_values().Get(inst_id);
  CheckTypeOfConstantIsTypeType(*file_, constant_id);
  return TypeInstId::UnsafeMake(inst_id);
}

auto TypeStore::GetInstId(TypeId type_id) const -> TypeInstId {
  // The instruction for a TypeId has a value of that TypeId.
  return TypeInstId::UnsafeMake(
      file_->constant_values().GetInstId(GetConstantId(type_id)));
}

auto TypeStore::GetAsInst(TypeId type_id) const -> Inst {
  return file_->insts().Get(GetInstId(type_id));
}

auto TypeStore::GetObjectRepr(TypeId type_id) const -> TypeId {
  type_id = GetUnqualifiedType(type_id);
  auto class_type = TryGetAs<ClassType>(type_id);
  if (!class_type) {
    return type_id;
  }
  const auto& class_info = file_->classes().Get(class_type->class_id);
  if (!class_info.is_complete()) {
    return TypeId::None;
  }
  return class_info.GetObjectRepr(*file_, class_type->specific_id);
}

auto TypeStore::GetUnqualifiedType(TypeId type_id) const -> TypeId {
  if (auto const_type = TryGetAs<ConstType>(type_id)) {
    return file_->types().GetTypeIdForTypeInstId(const_type->inner_id);
  }
  return type_id;
}

static auto TryGetIntTypeInfo(const File& file, TypeId type_id)
    -> std::optional<TypeStore::IntTypeInfo> {
  auto object_repr_id = file.types().GetObjectRepr(type_id);
  if (!object_repr_id.has_value()) {
    return std::nullopt;
  }
  auto inst_id = file.types().GetInstId(object_repr_id);
  if (inst_id == IntLiteralType::TypeInstId) {
    // `Core.IntLiteral` has an unknown bit-width.
    return TypeStore::IntTypeInfo{.is_signed = true, .bit_width = IntId::None};
  }
  auto int_type = file.insts().TryGetAs<IntType>(inst_id);
  if (!int_type) {
    return std::nullopt;
  }
  auto bit_width_inst = file.insts().TryGetAs<IntValue>(int_type->bit_width_id);
  return TypeStore::IntTypeInfo{
      .is_signed = int_type->int_kind.is_signed(),
      .bit_width = bit_width_inst ? bit_width_inst->int_id : IntId::None};
}

auto TypeStore::IsSignedInt(TypeId int_type_id) const -> bool {
  auto int_info = TryGetIntTypeInfo(*file_, int_type_id);
  return int_info && int_info->is_signed;
}

auto TypeStore::GetIntTypeInfo(TypeId int_type_id) const -> IntTypeInfo {
  auto int_info = TryGetIntTypeInfo(*file_, int_type_id);
  CARBON_CHECK(int_info, "Type {0} is not an integer type", int_type_id);
  return *int_info;
}

}  // namespace Carbon::SemIR