// Copyright (C) 2020-2023 Free Software Foundation, Inc.

// This file is part of GCC.

// GCC is free software; you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 3, or (at your option) any later
// version.

// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
// for more details.

// You should have received a copy of the GNU General Public License
// along with GCC; see the file COPYING3.  If not see
// <http://www.gnu.org/licenses/>.

#include "rust-hir-type-check.h"

namespace Rust {
namespace Resolver {

TypeCheckContext *
TypeCheckContext::get ()
{
  static TypeCheckContext *instance;
  if (instance == nullptr)
    instance = new TypeCheckContext ();

  return instance;
}

TypeCheckContext::TypeCheckContext () {}

TypeCheckContext::~TypeCheckContext () {}

bool
TypeCheckContext::lookup_builtin (NodeId id, TyTy::BaseType **type)
{
  auto ref_it = node_id_refs.find (id);
  if (ref_it == node_id_refs.end ())
    return false;

  auto it = resolved.find (ref_it->second);
  if (it == resolved.end ())
    return false;

  *type = it->second;
  return true;
}

bool
TypeCheckContext::lookup_builtin (std::string name, TyTy::BaseType **type)
{
  for (auto &builtin : builtins)
    {
      if (name.compare (builtin->as_string ()) == 0)
	{
	  *type = builtin.get ();
	  return true;
	}
    }
  return false;
}

void
TypeCheckContext::insert_builtin (HirId id, NodeId ref, TyTy::BaseType *type)
{
  node_id_refs[ref] = id;
  resolved[id] = type;
  builtins.push_back (std::unique_ptr<TyTy::BaseType> (type));
}

void
TypeCheckContext::insert_type (const Analysis::NodeMapping &mappings,
			       TyTy::BaseType *type)
{
  rust_assert (type != nullptr);
  NodeId ref = mappings.get_nodeid ();
  HirId id = mappings.get_hirid ();
  node_id_refs[ref] = id;
  resolved[id] = type;
}

void
TypeCheckContext::insert_implicit_type (TyTy::BaseType *type)
{
  rust_assert (type != nullptr);
  resolved[type->get_ref ()] = type;
}

void
TypeCheckContext::insert_implicit_type (HirId id, TyTy::BaseType *type)
{
  rust_assert (type != nullptr);
  resolved[id] = type;
}

bool
TypeCheckContext::lookup_type (HirId id, TyTy::BaseType **type) const
{
  auto it = resolved.find (id);
  if (it == resolved.end ())
    return false;

  *type = it->second;
  return true;
}

void
TypeCheckContext::insert_type_by_node_id (NodeId ref, HirId id)
{
  rust_assert (node_id_refs.find (ref) == node_id_refs.end ());
  node_id_refs[ref] = id;
}

bool
TypeCheckContext::lookup_type_by_node_id (NodeId ref, HirId *id)
{
  auto it = node_id_refs.find (ref);
  if (it == node_id_refs.end ())
    return false;

  *id = it->second;
  return true;
}

TyTy::BaseType *
TypeCheckContext::peek_return_type ()
{
  rust_assert (!return_type_stack.empty ());
  return return_type_stack.back ().second;
}

void
TypeCheckContext::push_return_type (TypeCheckContextItem item,
				    TyTy::BaseType *return_type)
{
  return_type_stack.push_back ({std::move (item), return_type});
}

void
TypeCheckContext::pop_return_type ()
{
  rust_assert (!return_type_stack.empty ());
  return_type_stack.pop_back ();
}

TypeCheckContextItem &
TypeCheckContext::peek_context ()
{
  rust_assert (!return_type_stack.empty ());
  return return_type_stack.back ().first;
}

void
TypeCheckContext::iterate (std::function<bool (HirId, TyTy::BaseType *)> cb)
{
  for (auto it = resolved.begin (); it != resolved.end (); it++)
    {
      if (!cb (it->first, it->second))
	return;
    }
}

bool
TypeCheckContext::have_loop_context () const
{
  return !loop_type_stack.empty ();
}

void
TypeCheckContext::push_new_loop_context (HirId id, Location locus)
{
  TyTy::BaseType *infer_var
    = new TyTy::InferType (id, TyTy::InferType::InferTypeKind::GENERAL, locus);
  loop_type_stack.push_back (infer_var);
}

void
TypeCheckContext::push_new_while_loop_context (HirId id)
{
  TyTy::BaseType *infer_var = new TyTy::ErrorType (id);
  loop_type_stack.push_back (infer_var);
}

TyTy::BaseType *
TypeCheckContext::peek_loop_context ()
{
  return loop_type_stack.back ();
}

TyTy::BaseType *
TypeCheckContext::pop_loop_context ()
{
  auto back = peek_loop_context ();
  loop_type_stack.pop_back ();
  return back;
}

void
TypeCheckContext::swap_head_loop_context (TyTy::BaseType *val)
{
  loop_type_stack.pop_back ();
  loop_type_stack.push_back (val);
}

void
TypeCheckContext::insert_trait_reference (DefId id, TraitReference &&ref)
{
  rust_assert (trait_context.find (id) == trait_context.end ());
  trait_context.emplace (id, std::move (ref));
}

bool
TypeCheckContext::lookup_trait_reference (DefId id, TraitReference **ref)
{
  auto it = trait_context.find (id);
  if (it == trait_context.end ())
    return false;

  *ref = &it->second;
  return true;
}

void
TypeCheckContext::insert_receiver (HirId id, TyTy::BaseType *t)
{
  receiver_context[id] = t;
}

bool
TypeCheckContext::lookup_receiver (HirId id, TyTy::BaseType **ref)
{
  auto it = receiver_context.find (id);
  if (it == receiver_context.end ())
    return false;

  *ref = it->second;
  return true;
}

void
TypeCheckContext::insert_associated_trait_impl (
  HirId id, AssociatedImplTrait &&associated)
{
  rust_assert (associated_impl_traits.find (id)
	       == associated_impl_traits.end ());
  associated_impl_traits.emplace (id, std::move (associated));
}

bool
TypeCheckContext::lookup_associated_trait_impl (
  HirId id, AssociatedImplTrait **associated)
{
  auto it = associated_impl_traits.find (id);
  if (it == associated_impl_traits.end ())
    return false;

  *associated = &it->second;
  return true;
}

void
TypeCheckContext::insert_associated_type_mapping (HirId id, HirId mapping)
{
  associated_type_mappings[id] = mapping;
}

void
TypeCheckContext::clear_associated_type_mapping (HirId id)
{
  auto it = associated_type_mappings.find (id);
  if (it != associated_type_mappings.end ())
    associated_type_mappings.erase (it);
}

// lookup any associated type mappings, the out parameter of mapping is
// allowed to be nullptr which allows this interface to do a simple does exist
// check
bool
TypeCheckContext::lookup_associated_type_mapping (HirId id, HirId *mapping)
{
  auto it = associated_type_mappings.find (id);
  if (it == associated_type_mappings.end ())
    return false;

  if (mapping != nullptr)
    *mapping = it->second;

  return true;
}

void
TypeCheckContext::insert_associated_impl_mapping (
  HirId trait_id, const TyTy::BaseType *impl_type, HirId impl_id)
{
  auto it = associated_traits_to_impls.find (trait_id);
  if (it == associated_traits_to_impls.end ())
    {
      associated_traits_to_impls[trait_id] = {};
    }

  associated_traits_to_impls[trait_id].push_back ({impl_type, impl_id});
}

bool
TypeCheckContext::lookup_associated_impl_mapping_for_self (
  HirId trait_id, const TyTy::BaseType *self, HirId *mapping)
{
  auto it = associated_traits_to_impls.find (trait_id);
  if (it == associated_traits_to_impls.end ())
    return false;

  for (auto &item : it->second)
    {
      if (item.first->can_eq (self, false))
	{
	  *mapping = item.second;
	  return true;
	}
    }
  return false;
}

void
TypeCheckContext::insert_autoderef_mappings (
  HirId id, std::vector<Adjustment> &&adjustments)
{
  rust_assert (autoderef_mappings.find (id) == autoderef_mappings.end ());
  autoderef_mappings.emplace (id, std::move (adjustments));
}

bool
TypeCheckContext::lookup_autoderef_mappings (
  HirId id, std::vector<Adjustment> **adjustments)
{
  auto it = autoderef_mappings.find (id);
  if (it == autoderef_mappings.end ())
    return false;

  *adjustments = &it->second;
  return true;
}

void
TypeCheckContext::insert_cast_autoderef_mappings (
  HirId id, std::vector<Adjustment> &&adjustments)
{
  rust_assert (cast_autoderef_mappings.find (id)
	       == cast_autoderef_mappings.end ());
  cast_autoderef_mappings.emplace (id, std::move (adjustments));
}

bool
TypeCheckContext::lookup_cast_autoderef_mappings (
  HirId id, std::vector<Adjustment> **adjustments)
{
  auto it = cast_autoderef_mappings.find (id);
  if (it == cast_autoderef_mappings.end ())
    return false;

  *adjustments = &it->second;
  return true;
}

void
TypeCheckContext::insert_variant_definition (HirId id, HirId variant)
{
  auto it = variants.find (id);
  rust_assert (it == variants.end ());

  variants[id] = variant;
}

bool
TypeCheckContext::lookup_variant_definition (HirId id, HirId *variant)
{
  auto it = variants.find (id);
  if (it == variants.end ())
    return false;

  *variant = it->second;
  return true;
}

void
TypeCheckContext::insert_operator_overload (HirId id, TyTy::FnType *call_site)
{
  auto it = operator_overloads.find (id);
  rust_assert (it == operator_overloads.end ());

  operator_overloads[id] = call_site;
}

bool
TypeCheckContext::lookup_operator_overload (HirId id, TyTy::FnType **call)
{
  auto it = operator_overloads.find (id);
  if (it == operator_overloads.end ())
    return false;

  *call = it->second;
  return true;
}

void
TypeCheckContext::insert_unconstrained_check_marker (HirId id, bool status)
{
  unconstrained[id] = status;
}

bool
TypeCheckContext::have_checked_for_unconstrained (HirId id, bool *result)
{
  auto it = unconstrained.find (id);
  bool found = it != unconstrained.end ();
  if (!found)
    return false;

  *result = it->second;
  return true;
}

void
TypeCheckContext::insert_resolved_predicate (HirId id,
					     TyTy::TypeBoundPredicate predicate)
{
  auto it = predicates.find (id);
  rust_assert (it == predicates.end ());

  predicates.insert ({id, predicate});
}

bool
TypeCheckContext::lookup_predicate (HirId id, TyTy::TypeBoundPredicate *result)
{
  auto it = predicates.find (id);
  bool found = it != predicates.end ();
  if (!found)
    return false;

  *result = it->second;
  return true;
}

void
TypeCheckContext::insert_query (HirId id)
{
  querys_in_progress.insert (id);
}

void
TypeCheckContext::query_completed (HirId id)
{
  querys_in_progress.erase (id);
}

bool
TypeCheckContext::query_in_progress (HirId id) const
{
  return querys_in_progress.find (id) != querys_in_progress.end ();
}

void
TypeCheckContext::insert_trait_query (DefId id)
{
  trait_queries_in_progress.insert (id);
}

void
TypeCheckContext::trait_query_completed (DefId id)
{
  trait_queries_in_progress.erase (id);
}

bool
TypeCheckContext::trait_query_in_progress (DefId id) const
{
  return trait_queries_in_progress.find (id)
	 != trait_queries_in_progress.end ();
}

// TypeCheckContextItem

TypeCheckContextItem::Item::Item (HIR::Function *item) : item (item) {}

TypeCheckContextItem::Item::Item (HIR::ImplBlock *impl_block,
				  HIR::Function *item)
  : impl_item ({impl_block, item})
{}

TypeCheckContextItem::Item::Item (HIR::TraitItemFunc *trait_item)
  : trait_item (trait_item)
{}

TypeCheckContextItem::TypeCheckContextItem (HIR::Function *item)
  : type (ItemType::ITEM), item (item)
{}

TypeCheckContextItem::TypeCheckContextItem (HIR::ImplBlock *impl_block,
					    HIR::Function *item)
  : type (ItemType::IMPL_ITEM), item (impl_block, item)
{}

TypeCheckContextItem::TypeCheckContextItem (HIR::TraitItemFunc *trait_item)
  : type (ItemType::TRAIT_ITEM), item (trait_item)
{}

HIR::Function *
TypeCheckContextItem::get_item ()
{
  rust_assert (get_type () == ItemType::ITEM);
  return item.item;
}

std::pair<HIR::ImplBlock *, HIR::Function *> &
TypeCheckContextItem::get_impl_item ()
{
  rust_assert (get_type () == ItemType::IMPL_ITEM);
  return item.impl_item;
}

HIR::TraitItemFunc *
TypeCheckContextItem::get_trait_item ()
{
  rust_assert (get_type () == ItemType::TRAIT_ITEM);
  return item.trait_item;
}

TypeCheckContextItem::ItemType
TypeCheckContextItem::get_type () const
{
  return type;
}

TyTy::FnType *
TypeCheckContextItem::get_context_type ()
{
  auto &context = *TypeCheckContext::get ();

  HirId reference = UNKNOWN_HIRID;
  switch (get_type ())
    {
    case ITEM:
      reference = get_item ()->get_mappings ().get_hirid ();
      break;

    case IMPL_ITEM:
      reference = get_impl_item ().second->get_mappings ().get_hirid ();
      break;

    case TRAIT_ITEM:
      reference = get_trait_item ()->get_mappings ().get_hirid ();
      break;
    }

  rust_assert (reference != UNKNOWN_HIRID);

  TyTy::BaseType *lookup = nullptr;
  bool ok = context.lookup_type (reference, &lookup);
  rust_assert (ok);
  rust_assert (lookup->get_kind () == TyTy::TypeKind::FNDEF);
  return static_cast<TyTy::FnType *> (lookup);
}

} // namespace Resolver
} // namespace Rust