require 'jbuilder'
require 'action_view'
require 'action_view/dependency_tracker'

class Jbuilder
  class DependencyTracker < ::ActionView::DependencyTracker::ERBTracker
    # Matches:
    #   json.partial! "messages/message"
    #   json.partial!('messages/message')
    #
    DIRECT_RENDERS = /
      \w+\.partial!     # json.partial!
      \(?\s*            # optional parenthesis
      (['"])([^""]+)\1  # quoted value
    /x

    # Matches:
    #   json.partial! partial: "comments/comment"
    #   json.comments @post.comments, partial: "comments/comment", as: :comment
    #   json.array! @posts, partial: "posts/post", as: :post
    #   = render partial: "account"
    #
    INDIRECT_RENDERS = /
      (?::partial\s*=>|partial:)  # partial: or :partial =>
      \s*                         # optional whitespace
      (['"])([^'"]+)\1            # quoted value
    /x

    def dependencies
      direct_dependencies + indirect_dependencies + explicit_dependencies
    end

    private

    def direct_dependencies
      source.scan(DIRECT_RENDERS).map(&:second)
    end

    def indirect_dependencies
      source.scan(INDIRECT_RENDERS).map(&:second)
    end
  end
end


ActiveSupport.on_load :action_view do
  ActiveSupport.on_load :after_initialize do
    ActionView::DependencyTracker.register_tracker :jbuilder, Jbuilder::DependencyTracker
  end
end