class GraphQL::Query::Context::ScopedContext

def [](key)
  each_present_path_ctx do |path_ctx|
    if path_ctx.key?(key)
      return path_ctx[key]
    end
  end
  nil
end

def current_path
  @query_context.current_path || NO_PATH
end

def dig(key, *other_keys)
  each_present_path_ctx do |path_ctx|
    if path_ctx.key?(key)
      found_value = path_ctx[key]
      if other_keys.any?
        return found_value.dig(*other_keys)
      else
        return found_value
      end
    end
  end
  nil
end

def each_present_path_ctx
  ctx = @scoped_contexts
  if ctx.nil?
    # no-op
  else
    current_path.each do |path_part|
      if ctx.key?(path_part)
        ctx = ctx[path_part]
      else
        break
      end
    end
    while ctx
      if (scoped_ctx = ctx[:scoped_context])
        yield(scoped_ctx)
      end
      ctx = ctx[:parent]
    end
  end
end

def initialize(query_context)
  @query_context = query_context
  @scoped_contexts = nil
  @all_keys = nil
end

def key?(key)
  if @all_keys && @all_keys.include?(key)
    each_present_path_ctx do |path_ctx|
      if path_ctx.key?(key)
        return true
      end
    end
  end
  false
end

def merge!(hash)
  @all_keys ||= Set.new
  @all_keys.merge(hash.keys)
  ctx = @scoped_contexts ||= {}
  current_path.each do |path_part|
    ctx = ctx[path_part] ||= { parent: ctx }
  end
  this_scoped_ctx = ctx[:scoped_context] ||= {}
  this_scoped_ctx.merge!(hash)
end

def merged_context
  if @scoped_contexts.nil?
    NO_CONTEXT
  else
    merged_ctx = {}
    each_present_path_ctx do |path_ctx|
      merged_ctx = path_ctx.merge(merged_ctx)
    end
    merged_ctx
  end
end