// 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/>.

#ifndef RUST_COMPILE_STMT
#define RUST_COMPILE_STMT

#include "rust-compile-base.h"
#include "rust-compile-expr.h"

namespace Rust {
namespace Compile {

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

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

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

  void visit (HIR::LetStmt &stmt) override
  {
    // 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 (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);
      }
  }

  // Empty visit for unused Stmt HIR nodes.
  void visit (HIR::TupleStruct &) override {}
  void visit (HIR::EnumItem &) override {}
  void visit (HIR::EnumItemTuple &) override {}
  void visit (HIR::EnumItemStruct &) override {}
  void visit (HIR::EnumItemDiscriminant &) override {}
  void visit (HIR::TypePathSegmentFunction &) override {}
  void visit (HIR::TypePath &) override {}
  void visit (HIR::QualifiedPathInType &) override {}
  void visit (HIR::Module &) override {}
  void visit (HIR::ExternCrate &) override {}
  void visit (HIR::UseDeclaration &) override {}
  void visit (HIR::Function &) override {}
  void visit (HIR::TypeAlias &) override {}
  void visit (HIR::StructStruct &) override {}
  void visit (HIR::Enum &) override {}
  void visit (HIR::Union &) override {}
  void visit (HIR::ConstantItem &) override {}
  void visit (HIR::StaticItem &) override {}
  void visit (HIR::Trait &) override {}
  void visit (HIR::ImplBlock &) override {}
  void visit (HIR::ExternBlock &) override {}
  void visit (HIR::EmptyStmt &) override {}

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

  tree translated;
};

} // namespace Compile
} // namespace Rust

#endif // RUST_COMPILE_STMT