// 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-ast-resolve.h"
#include "rust-ast-full.h"
#include "rust-tyty.h"
#include "rust-ast-resolve-toplevel.h"
#include "rust-ast-resolve-item.h"
#include "rust-ast-resolve-expr.h"
#include "rust-ast-resolve-struct-expr-field.h"

extern bool
saw_errors (void);

namespace Rust {
namespace Resolver {

// NameResolution

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

  return instance;
}

NameResolution::NameResolution ()
  : resolver (Resolver::get ()), mappings (Analysis::Mappings::get ())
{
  // these are global
  resolver->get_type_scope ().push (mappings->get_next_node_id ());
  resolver->insert_builtin_types (resolver->get_type_scope ().peek ());
  resolver->push_new_type_rib (resolver->get_type_scope ().peek ());
}

void
NameResolution::Resolve (AST::Crate &crate)
{
  auto resolver = get ();
  resolver->go (crate);
}

void
NameResolution::go (AST::Crate &crate)
{
  // lookup current crate name
  CrateNum cnum = mappings->get_current_crate ();
  std::string crate_name;
  bool ok = mappings->get_crate_name (cnum, crate_name);
  rust_assert (ok);

  // setup the ribs
  NodeId scope_node_id = crate.get_node_id ();
  resolver->get_name_scope ().push (scope_node_id);
  resolver->get_type_scope ().push (scope_node_id);
  resolver->get_label_scope ().push (scope_node_id);
  resolver->push_new_name_rib (resolver->get_name_scope ().peek ());
  resolver->push_new_type_rib (resolver->get_type_scope ().peek ());
  resolver->push_new_label_rib (resolver->get_type_scope ().peek ());

  // get the root segment
  CanonicalPath crate_prefix
    = CanonicalPath::new_seg (scope_node_id, crate_name);
  crate_prefix.set_crate_num (cnum);

  // setup a dummy crate node
  resolver->get_name_scope ().insert (
    CanonicalPath::new_seg (crate.get_node_id (), "__$$crate__"),
    crate.get_node_id (), Location ());

  // setup the root scope
  resolver->push_new_module_scope (scope_node_id);

  // first gather the top-level namespace names then we drill down so this
  // allows for resolving forward declarations since an impl block might have
  // a Self type Foo which is defined after the impl block for example.
  for (auto it = crate.items.begin (); it != crate.items.end (); it++)
    ResolveTopLevel::go (it->get (), CanonicalPath::create_empty (),
			 crate_prefix);

  // FIXME remove this
  if (saw_errors ())
    {
      resolver->pop_module_scope ();
      return;
    }

  // next we can drill down into the items and their scopes
  for (auto it = crate.items.begin (); it != crate.items.end (); it++)
    ResolveItem::go (it->get (), CanonicalPath::create_empty (), crate_prefix);

  // done
  resolver->pop_module_scope ();
}

} // namespace Resolver
} // namespace Rust