class Sass::Embedded::Host::ImporterRegistry

def canonicalize(canonicalize_request)
  importer = @importers_by_id[canonicalize_request.importer_id]
  url = importer.canonicalize(canonicalize_request.url, from_import: canonicalize_request.from_import)&.to_s
  EmbeddedProtocol::InboundMessage::CanonicalizeResponse.new(
    id: canonicalize_request.id,
    url: url
  )
rescue StandardError => e
  EmbeddedProtocol::InboundMessage::CanonicalizeResponse.new(
    id: canonicalize_request.id,
    error: e.full_message(highlight: @highlight, order: :top)
  )
end

def file_import(file_import_request)
  importer = @importers_by_id[file_import_request.importer_id]
  file_url = importer.find_file_url(file_import_request.url, from_import: file_import_request.from_import)&.to_s
  if !file_url.nil? && !file_url.start_with?('file:')
    raise "file_url must be a file: URL, was #{file_url.inspect}"
  end
  EmbeddedProtocol::InboundMessage::FileImportResponse.new(
    id: file_import_request.id,
    file_url: file_url
  )
rescue StandardError => e
  EmbeddedProtocol::InboundMessage::FileImportResponse.new(
    id: file_import_request.id,
    error: e.full_message(highlight: @highlight, order: :top)
  )
end

def import(import_request)
  importer = @importers_by_id[import_request.importer_id]
  importer_result = Structifier.to_struct importer.load(import_request.url)
  EmbeddedProtocol::InboundMessage::ImportResponse.new(
    id: import_request.id,
    success: EmbeddedProtocol::InboundMessage::ImportResponse::ImportSuccess.new(
      contents: importer_result.contents,
      syntax: Protofier.to_proto_syntax(importer_result.syntax),
      source_map_url: (importer_result.source_map_url&.to_s if importer_result.respond_to?(:source_map_url))
    )
  )
rescue StandardError => e
  EmbeddedProtocol::InboundMessage::ImportResponse.new(
    id: import_request.id,
    error: e.full_message(highlight: @highlight, order: :top)
  )
end

def initialize(importers, load_paths, alert_color:)
  @id = 0
  @importers_by_id = {}
  @importers = importers
               .map { |importer| register(importer) }
               .concat(
                 load_paths.map do |load_path|
                   EmbeddedProtocol::InboundMessage::CompileRequest::Importer.new(
                     path: File.absolute_path(load_path)
                   )
                 end
               )
  @highlight = alert_color
end

def register(importer)
  importer = Structifier.to_struct(importer)
  is_importer = importer.respond_to?(:canonicalize) && importer.respond_to?(:load)
  is_file_importer = importer.respond_to?(:find_file_url)
  raise ArgumentError, 'importer must be an Importer or a FileImporter' if is_importer == is_file_importer
  id = @id
  @id = id.next
  @importers_by_id[id] = importer
  if is_importer
    EmbeddedProtocol::InboundMessage::CompileRequest::Importer.new(
      importer_id: id
    )
  else
    EmbeddedProtocol::InboundMessage::CompileRequest::Importer.new(
      file_importer_id: id
    )
  end
end