// Copyright (C) 2020-2022 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-compile-stmt.h"
#include "rust-compile-expr.h"

namespace Rust {
namespace Compile {

CompileStmt::CompileStmt (Context *ctx)
  : HIRCompileBase (ctx), translated (nullptr)
{}

tree
CompileStmt::Compile (HIR::Stmt *stmt, Context *ctx)
{
  CompileStmt compiler (ctx);
  stmt->accept_vis (compiler);
  return compiler.translated;
}

void
CompileStmt::visit (HIR::ExprStmtWithBlock &stmt)
{
  translated = CompileExpr::Compile (stmt.get_expr (), ctx);
}

void
CompileStmt::visit (HIR::ExprStmtWithoutBlock &stmt)
{
  translated = CompileExpr::Compile (stmt.get_expr (), ctx);
}

void
CompileStmt::visit (HIR::LetStmt &stmt)
{
  // nothing to do
  if (!stmt.has_init_expr ())
    return;

  const HIR::Pattern &stmt_pattern = *stmt.get_pattern ();
  HirId stmt_id = stmt_pattern.get_pattern_mappings ().get_hirid ();

  TyTy::BaseType *ty = nullptr;
  if (!ctx->get_tyctx ()->lookup_type (stmt_id, &ty))
    {
      // FIXME this should be an assertion instead
      rust_fatal_error (stmt.get_locus (),
			"failed to lookup variable declaration type");
      return;
    }

  Bvariable *var = nullptr;
  if (!ctx->lookup_var_decl (stmt_id, &var))
    {
      // FIXME this should be an assertion instead and use error mark node
      rust_fatal_error (stmt.get_locus (),
			"failed to lookup compiled variable declaration");
      return;
    }

  tree init = CompileExpr::Compile (stmt.get_init_expr (), ctx);
  // FIXME use error_mark_node, check that CompileExpr returns error_mark_node
  // on failure and make this an assertion
  if (init == nullptr)
    return;

  TyTy::BaseType *actual = nullptr;
  bool ok = ctx->get_tyctx ()->lookup_type (
    stmt.get_init_expr ()->get_mappings ().get_hirid (), &actual);
  rust_assert (ok);
  tree stmt_type = TyTyResolveCompile::compile (ctx, ty);

  Location lvalue_locus = stmt.get_pattern ()->get_locus ();
  Location rvalue_locus = stmt.get_init_expr ()->get_locus ();
  TyTy::BaseType *expected = ty;
  init = coercion_site (stmt.get_mappings ().get_hirid (), init, actual,
			expected, lvalue_locus, rvalue_locus);

  auto fnctx = ctx->peek_fn ();
  if (ty->is_unit ())
    {
      ctx->add_statement (init);

      auto unit_type_init_expr
	= ctx->get_backend ()->constructor_expression (stmt_type, false, {}, -1,
						       rvalue_locus);
      auto s = ctx->get_backend ()->init_statement (fnctx.fndecl, var,
						    unit_type_init_expr);
      ctx->add_statement (s);
    }
  else
    {
      auto s = ctx->get_backend ()->init_statement (fnctx.fndecl, var, init);
      ctx->add_statement (s);
    }
}

} // namespace Compile
} // namespace Rust