// SPDX-License-Identifier: Apache-2.0

// SPDX-FileCopyrightText: Copyright The WasmEdge Authors

#include "loader/loader.h"

namespace WasmEdge {

namespace Loader {

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

  auto ReportError = [this](auto E) {

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

  };

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

  // core:aliastarget ::= 0x01 ct:<u32> idx:<u32>            => outer ct idx

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

  EXPECTED_TRY(uint8_t Flag, FMgr.readByte().map_error(ReportError));

  if (Flag != 0x01) {

    return logLoadError(ErrCode::Value::MalformedAliasTarget,

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

  }

  EXPECTED_TRY(uint32_t Ct, FMgr.readU32().map_error(ReportError));

  EXPECTED_TRY(uint32_t Idx, FMgr.readU32().map_error(ReportError));

  Alias.setComponentJump(Ct);

  Alias.setIndex(Idx);

  return {};

}

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))

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

  EXPECTED_TRY(uint8_t Flag, FMgr.readByte().map_error(ReportError));

  switch (Flag) {

  case 0x00:

  case 0x01: {

    EXPECTED_TRY(uint32_t Idx, FMgr.readU32().map_error(ReportError));

    EXPECTED_TRY(std::string Name, FMgr.readName().map_error(ReportError));

    Alias.setExport(Idx, Name);

    break;

  }

  case 0x02: {

    EXPECTED_TRY(uint32_t Ct, FMgr.readU32().map_error(ReportError));

    EXPECTED_TRY(uint32_t Idx, FMgr.readU32().map_error(ReportError));

    Alias.setOuter(Ct, Idx);

    break;

  }

  default:

    return logLoadError(ErrCode::Value::MalformedAliasTarget,

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

  }

  Alias.setTargetType(static_cast<AST::Component::Alias::TargetType>(Flag));

  return {};

}

} // namespace Loader

} // namespace WasmEdge