// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

#include "toolchain/check/sem_ir_diagnostic_converter.h"

#include "common/raw_string_ostream.h"
#include "toolchain/sem_ir/absolute_node_id.h"
#include "toolchain/sem_ir/stringify_type.h"

namespace Carbon::Check {

auto SemIRDiagnosticConverter::ConvertLoc(SemIRLoc loc,
                                          ContextFnT context_fn) const
    -> ConvertedDiagnosticLoc {
  auto converted = ConvertLocImpl(loc, context_fn);

  // Use the token when possible, but -1 is the default value.
  auto last_offset = -1;
  if (last_token_.has_value()) {
    last_offset = sem_ir_->parse_tree().tokens().GetByteOffset(last_token_);
  }

  // When the diagnostic is in the same file, we use the last possible offset;
  // otherwise, we ignore the offset because it's probably in that file.
  if (converted.loc.filename == sem_ir_->filename()) {
    converted.last_byte_offset =
        std::max(converted.last_byte_offset, last_offset);
  } else {
    converted.last_byte_offset = last_offset;
  }

  return converted;
}

auto SemIRDiagnosticConverter::ConvertLocImpl(SemIRLoc loc,
                                              ContextFnT context_fn) const
    -> ConvertedDiagnosticLoc {
  llvm::SmallVector<SemIR::AbsoluteNodeId> absolute_node_ids =
      loc.is_inst_id_ ? SemIR::GetAbsoluteNodeId(sem_ir_, loc.inst_id_)
                      : SemIR::GetAbsoluteNodeId(sem_ir_, loc.loc_id_);

  auto final_node_id = absolute_node_ids.pop_back_val();
  for (const auto& absolute_node_id : absolute_node_ids) {
    if (!absolute_node_id.node_id.has_value()) {
      // TODO: Add an "In implicit import of prelude." note for the case where
      // we don't have a location.
      continue;
    }
    // TODO: Include the name of the imported library in the diagnostic.
    auto diag_loc =
        ConvertLocInFile(absolute_node_id, loc.token_only_, context_fn);
    CARBON_DIAGNOSTIC(InImport, LocationInfo, "in import");
    context_fn(diag_loc.loc, InImport);
  }

  return ConvertLocInFile(final_node_id, loc.token_only_, context_fn);
}

auto SemIRDiagnosticConverter::ConvertLocInFile(
    SemIR::AbsoluteNodeId absolute_node_id, bool token_only,
    ContextFnT /*context_fn*/) const -> ConvertedDiagnosticLoc {
  const auto& tree_and_subtrees =
      imported_trees_and_subtrees_[absolute_node_id.check_ir_id.index]();
  return tree_and_subtrees.NodeToDiagnosticLoc(absolute_node_id.node_id,
                                               token_only);
}

auto SemIRDiagnosticConverter::ConvertArg(llvm::Any arg) const -> llvm::Any {
  if (auto* library_name_id = llvm::any_cast<SemIR::LibraryNameId>(&arg)) {
    std::string library_name;
    if (*library_name_id == SemIR::LibraryNameId::Default) {
      library_name = "default library";
    } else if (!library_name_id->has_value()) {
      library_name = "library <none>";
    } else {
      RawStringOstream stream;
      stream << "library \""
             << sem_ir_->string_literal_values().Get(
                    library_name_id->AsStringLiteralValueId())
             << "\"";
      library_name = stream.TakeStr();
    }
    return library_name;
  }
  if (auto* name_id = llvm::any_cast<SemIR::NameId>(&arg)) {
    return sem_ir_->names().GetFormatted(*name_id).str();
  }
  if (auto* type_of_expr = llvm::any_cast<TypeOfInstId>(&arg)) {
    if (!type_of_expr->inst_id.has_value()) {
      return "<none>";
    }
    // TODO: Where possible, produce a better description of the type based on
    // the expression.
    return "`" +
           StringifyTypeExpr(
               *sem_ir_,
               sem_ir_->types().GetInstId(
                   sem_ir_->insts().Get(type_of_expr->inst_id).type_id())) +
           "`";
  }
  if (auto* type_expr = llvm::any_cast<InstIdAsType>(&arg)) {
    return "`" + StringifyTypeExpr(*sem_ir_, type_expr->inst_id) + "`";
  }
  if (auto* type_expr = llvm::any_cast<InstIdAsRawType>(&arg)) {
    return StringifyTypeExpr(*sem_ir_, type_expr->inst_id);
  }
  if (auto* type = llvm::any_cast<TypeIdAsRawType>(&arg)) {
    return StringifyTypeExpr(*sem_ir_,
                             sem_ir_->types().GetInstId(type->type_id));
  }
  if (auto* type_id = llvm::any_cast<SemIR::TypeId>(&arg)) {
    return "`" +
           StringifyTypeExpr(*sem_ir_, sem_ir_->types().GetInstId(*type_id)) +
           "`";
  }
  if (auto* typed_int = llvm::any_cast<TypedInt>(&arg)) {
    return llvm::APSInt(typed_int->value,
                        !sem_ir_->types().IsSignedInt(typed_int->type));
  }
  return DiagnosticConverter<SemIRLoc>::ConvertArg(arg);
}

}  // namespace Carbon::Check