// SPDX-License-Identifier: Apache-2.0

// SPDX-FileCopyrightText: 2019-2024 Second State INC

#include "loader/loader.h"

namespace WasmEdge {

namespace Loader {

Expect<void> Loader::loadAlias(AST::Component::Alias &Alias) {

  auto ReportError = [this](auto E) {

    return logLoadError(E, FMgr.getLastOffset(), ASTNodeAttr::Comp_Alias);

  };

  // alias ::= s:<sort> t:<aliastarget> => (alias t (s))

  EXPECTED_TRY(loadSort(Alias.getSort()).map_error(ReportError));

  EXPECTED_TRY(loadAliasTarget(Alias.getTarget()).map_error(ReportError));

  return {};

}

Expect<void> Loader::loadAliasTarget(AST::Component::AliasTarget &AliasTarget) {

  auto ReportError = [this](auto E) {

    return logLoadError(E, FMgr.getLastOffset(), ASTNodeAttr::Comp_AliasTarget);

  };

  // aliastarget ::= 0x00 i:<instanceidx> n:<string>         => export i n

  //               | 0x01 i:<core:instanceidx> n:<core:name> => core export i n

  //               | 0x02 ct:<u32> idx:<u32>                 => outer ct idx

  EXPECTED_TRY(auto Flag, FMgr.readByte().map_error(ReportError));

  switch (Flag) {

  case 0x00:

  case 0x01: {

    auto &Ex = AliasTarget.emplace<AST::Component::AliasTargetExport>();

    EXPECTED_TRY(Ex.getInstanceIdx(), FMgr.readU32().map_error(ReportError));

    EXPECTED_TRY(Ex.getName(), FMgr.readName().map_error(ReportError));

    return {};

  }

  case 0x02: {

    auto &Out = AliasTarget.emplace<AST::Component::AliasTargetOuter>();

    EXPECTED_TRY(Out.getComponent(), FMgr.readU32().map_error(ReportError));

    EXPECTED_TRY(Out.getIndex(), FMgr.readU32().map_error(ReportError));

    return {};

  }

  default:

    return logLoadError(ErrCode::Value::MalformedAliasTarget,

                        FMgr.getLastOffset(), ASTNodeAttr::Comp_AliasTarget);

  }

}

} // namespace Loader

} // namespace WasmEdge