class Jekyll::Excerpt

def data
  @data ||= doc.data.dup
  @data.delete("layout")
  @data.delete("excerpt")
  @data
end

def endtag_regex_stash(tag_name)
  @endtag_regex_stash ||= {}
  @endtag_regex_stash[tag_name] ||= %r!{%-?\s*end#{tag_name}.*?\s*-?%}!m
end

def extract_excerpt(doc_content)
  head, _, tail = doc_content.to_s.partition(doc.excerpt_separator)
  return head if tail.empty?
  head = sanctify_liquid_tags(head) if head.include?("{%")
  definitions = extract_markdown_link_reference_definitions(head, tail)
  return head if definitions.empty?
  head << "\n\n" << definitions.join("\n")
end

def extract_markdown_link_reference_definitions(head, tail)
  [].tap do |definitions|
    tail.scan(MKDWN_LINK_REF_REGEX).each do |segments|
      definitions << segments.join if head.include?(segments[0])
    end
  end
end

def id
  "#{doc.id}#excerpt"
end

def include?(something)
  output&.include?(something) || content.include?(something)
end

def initialize(doc)
  self.doc = doc
  self.content = extract_excerpt(doc.content)
end

def inspect
  "<#{self.class} id=#{id}>"
end

def liquid_block?(tag_name)
  return false unless tag_name.is_a?(String)
  return false unless Liquid::Template.tags[tag_name]
  Liquid::Template.tags[tag_name].ancestors.include?(Liquid::Block)
rescue NoMethodError
  Jekyll.logger.error "Error:",
                      "A Liquid tag in the excerpt of #{doc.relative_path} couldn't be parsed."
  raise
end

def output
  @output ||= Renderer.new(doc.site, self, site.site_payload).run
end

def path
  File.join(doc.path, "#excerpt")
end

def place_in_layout?
  false
end

def print_build_warning
  Jekyll.logger.warn "Warning:", "Excerpt modified in #{doc.relative_path}!"
  Jekyll.logger.warn "", "Found a Liquid block containing the excerpt separator " \
                         "#{doc.excerpt_separator.inspect}."
  Jekyll.logger.warn "", "The block has been modified with the appropriate closing tag."
  Jekyll.logger.warn "", "Feel free to define a custom excerpt or excerpt_separator in the"
  Jekyll.logger.warn "", "document's Front Matter if the generated excerpt is unsatisfactory."
end

def relative_path
  @relative_path ||= File.join(doc.relative_path, "#excerpt")
end

def render_with_liquid?
  return false if data["render_with_liquid"] == false
  !(coffeescript_file? || yaml_file? || !Utils.has_liquid_construct?(content))
end

def sanctify_liquid_tags(head)
  modified  = false
  tag_names = head.scan(LIQUID_TAG_REGEX)
  tag_names.flatten!
  tag_names.reverse_each do |tag_name|
    next unless liquid_block?(tag_name)
    next if endtag_regex_stash(tag_name).match?(head)
    modified = true
    head << "\n{% end#{tag_name} %}"
  end
  print_build_warning if modified
  head
end

def to_liquid
  Jekyll::Drops::ExcerptDrop.new(self)
end

def to_s
  output || content
end

def trigger_hooks(*); end