class Sprockets::SourceMapProcessor

def self.call(input)
  links = Set.new(input[:metadata][:links])
  env = input[:environment]
  uri, _ = env.resolve!(input[:filename], accept: original_content_type(input[:content_type]))
  asset  = env.load(uri)
  map    = asset.metadata[:map]
  # TODO: Because of the default piplene hack we have to apply dependencies
  #       from compiled asset to the source map, otherwise the source map cache
  #       will never detect the changes from directives
  dependencies = Set.new(input[:metadata][:dependencies])
  dependencies.merge(asset.metadata[:dependencies])
  map["file"] = PathUtils.split_subpath(input[:load_path], input[:filename])
  sources = map["sections"] ? map["sections"].map { |s| s["map"]["sources"] }.flatten : map["sources"]
  sources.each do |source|
    source = PathUtils.join(File.dirname(map["file"]), source)
    uri, _ = env.resolve!(source)
    links << uri
  end
  json = JSON.generate(map)
  { data: json, links: links, dependencies: dependencies }
end

def self.original_content_type(source_map_content_type, error_when_not_found: true)
  case source_map_content_type
  when "application/js-sourcemap+json"
    accept = "application/javascript"
  when "application/css-sourcemap+json"
    accept = "text/css"
  else
    fail(source_map_content_type) if error_when_not_found
    source_map_content_type
  end
end