// 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

#ifndef CARBON_TOOLCHAIN_CHECK_TYPE_H_
#define CARBON_TOOLCHAIN_CHECK_TYPE_H_

#include "llvm/ADT/ArrayRef.h"
#include "toolchain/check/context.h"
#include "toolchain/sem_ir/ids.h"

namespace Carbon::Check {

// Enforces that an integer type has a valid bit width.
auto ValidateIntType(Context& context, SemIR::LocId loc_id,
                     SemIR::IntType result) -> bool;

// Enforces that a float type has a valid bit width. If the `float_kind` field
// is `None`, sets it to a suitable kind for the bit width.
auto ValidateFloatTypeAndSetKind(Context& context, SemIR::LocId loc_id,
                                 SemIR::FloatType& result) -> bool;

// Gets the type to use for an unbound associated entity declared in this
// interface. For example, this is the type of `I.T` after
// `interface I { let T:! type; }`. The name of the interface is used for
// diagnostics.
// TODO: Should we use a different type for each such entity, or the same type
// for all associated entities?
auto GetAssociatedEntityType(Context& context, SemIR::InterfaceId interface_id,
                             SemIR::SpecificId interface_specific_id)
    -> SemIR::TypeId;

// Gets a singleton type. The returned type will be complete. Requires that
// `singleton_id` is already validated to be a singleton.
auto GetSingletonType(Context& context, SemIR::TypeInstId singleton_id)
    -> SemIR::TypeId;

// Gets a const-qualified version of a type.
auto GetConstType(Context& context, SemIR::TypeInstId inner_type_id)
    -> SemIR::TypeId;

// Gets a qualified version of a type.
auto GetQualifiedType(Context& context, SemIR::TypeId type_id,
                      SemIR::TypeQualifiers quals) -> SemIR::TypeId;

// Gets a class type.
auto GetClassType(Context& context, SemIR::ClassId class_id,
                  SemIR::SpecificId specific_id) -> SemIR::TypeId;

// Gets a C++ overload set type. The returned type will be complete.
auto GetCppOverloadSetType(Context& context,
                           SemIR::CppOverloadSetId overload_set_id,
                           SemIR::SpecificId specific_id) -> SemIR::TypeId;

// Gets a C++ template name type. The returned type will be complete.
auto GetCppTemplateNameType(Context& context, SemIR::EntityNameId name_id,
                            SemIR::ClangDeclId decl_id) -> SemIR::TypeId;

// Gets a function type. The returned type will be complete.
auto GetFunctionType(Context& context, SemIR::FunctionId fn_id,
                     SemIR::SpecificId specific_id) -> SemIR::TypeId;

auto GetVtableType(Context& context, SemIR::VtableId vtable_id)
    -> SemIR::TypeId;

// Gets the type of an associated function with the `Self` parameter bound to
// a particular value. The returned type will be complete.
auto GetFunctionTypeWithSelfType(Context& context,
                                 SemIR::TypeInstId interface_function_type_id,
                                 SemIR::InstId self_id) -> SemIR::TypeId;

// Gets a generic class type, which is the type of a name of a generic class,
// such as the type of `Vector` given `class Vector(T:! type)`. The returned
// type will be complete.
auto GetGenericClassType(Context& context, SemIR::ClassId class_id,
                         SemIR::SpecificId enclosing_specific_id)
    -> SemIR::TypeId;

// Gets a generic interface type, which is the type of a name of a generic
// interface, such as the type of `AddWith` given
// `interface AddWith(T:! type)`. The returned type will be complete.
auto GetGenericInterfaceType(Context& context, SemIR::InterfaceId interface_id,
                             SemIR::SpecificId enclosing_specific_id)
    -> SemIR::TypeId;

// Gets a generic named constraint type, which is the type of a name of a
// generic named constraint, such as the type of `AddWith` given `constraint
// AddWith(T:! type)`. The returned type will be complete.
auto GetGenericNamedConstraintType(Context& context,
                                   SemIR::NamedConstraintId named_constraint_id,
                                   SemIR::SpecificId enclosing_specific_id)
    -> SemIR::TypeId;

// Gets the facet type corresponding to a particular interface.
auto GetInterfaceType(Context& context, SemIR::InterfaceId interface_id,
                      SemIR::SpecificId specific_id) -> SemIR::TypeId;

// Gets the facet type corresponding to a particular named constraint.
auto GetNamedConstraintType(Context& context,
                            SemIR::NamedConstraintId named_constraint_id,
                            SemIR::SpecificId specific_id) -> SemIR::TypeId;

// Gets the facet type for the given `info`.
auto GetFacetType(Context& context, const SemIR::FacetTypeInfo& info)
    -> SemIR::TypeId;

// Gets the type contained within the given facet value.
auto GetFacetAccessType(Context& context, SemIR::InstId facet_value_inst_id)
    -> SemIR::TypeId;

// Returns a pointer type whose pointee type is `pointee_type_id`. The returned
// type will be complete.
auto GetPointerType(Context& context, SemIR::TypeInstId pointee_type_id)
    -> SemIR::TypeId;

// Returns a struct type with the given fields.
auto GetStructType(Context& context, SemIR::StructTypeFieldsId fields_id)
    -> SemIR::TypeId;

// Returns a tuple type with the given element types.
auto GetTupleType(Context& context, llvm::ArrayRef<SemIR::InstId> type_inst_ids)
    -> SemIR::TypeId;

// Returns a pattern type with the given scrutinee type.
auto GetPatternType(Context& context, SemIR::TypeId scrutinee_type_id)
    -> SemIR::TypeId;

// Returns the type component of the given form value.
auto GetTypeComponent(Context& context, SemIR::InstId form_inst_id)
    -> SemIR::TypeId;

// Returns an unbound element type.
auto GetUnboundElementType(Context& context, SemIR::TypeInstId class_type_id,
                           SemIR::TypeInstId element_type_id) -> SemIR::TypeId;

// Given a facet value or a type value, get the canonical facet value if
// possible, or return the canonical value of the input type expression if it
// has no canonical facet value.
//
// A facet value can be appear in two ways: as a facet value of type
// `FacetType`, or through an `as type` conversion which has type `TypeType` but
// still refers to the original facet value. While both have canonical values of
// their own, in cases that want to work with the facet value when possible,
// this collapses the two cases back together by undoing the `as type`
// conversion.
//
// This extra canonicalization step is important for constant comparison of
// facet values, when the `as type` conversion is not required to compare as a
// different value.
//
// For type expressions other than `<facet value> as type`, the canonical type
// value is returned.
auto GetCanonicalFacetOrTypeValue(Context& context, SemIR::InstId inst_id)
    -> SemIR::InstId;
auto GetCanonicalFacetOrTypeValue(Context& context, SemIR::ConstantId const_id)
    -> SemIR::ConstantId;

// If `inst_id` is a type value which wraps a facet value, return that canonical
// facet value. Otherwise, return None.
//
// In particular, this returns None for non-canonical instructions if no
// transformation was needed to return a facet value, to preserve source
// locations in the caller.
auto TryGetCanonicalFacetValue(Context& context, SemIR::InstId inst_id)
    -> SemIR::InstId;

}  // namespace Carbon::Check

#endif  // CARBON_TOOLCHAIN_CHECK_TYPE_H_
