require "asciidoctor"

require_relative "../database"
require_relative "../citation"
require_relative "../index"
require_relative "../options"

module AsciidoctorBibliography
  module Asciidoctor
    class BibliographerPreprocessor < ::Asciidoctor::Extensions::Preprocessor
      def process(document, reader)
        document.bibliographer.options =
          ::AsciidoctorBibliography::Options.build document, reader

        database_filepath =
          File.expand_path document.bibliographer.options.database,
                           document.base_dir

        document.bibliographer.database =
          ::AsciidoctorBibliography::Database.new database_filepath

        processed_lines = process_lines reader.read_lines, document.bibliographer
        reader.unshift_lines processed_lines
        reader
      end

      private

      def process_lines(lines, bibliographer)
        # First we fetch citations and replace them with uuids,
        lines = fetch_citations lines, bibliographer
        # then we render them
        lines = render_citations lines, bibliographer
        # and finally we render indices.
        render_indices lines, bibliographer
      end

      def fetch_citations(lines, bibliographer)
        lines.join("\n").gsub(Citation::REGEXP) do
          citation = Citation.new(*Regexp.last_match.captures)
          bibliographer.add_citation(citation)
          citation.uuid
        end.lines.map(&:chomp)
      end

      def render_citations(lines, bibliographer)
        processed_lines = lines.join("\n")
        bibliographer.citations.each do |citation|
          processed_lines.sub!(citation.uuid) do
            citation.render bibliographer
          end
        end
        processed_lines.lines.map(&:chomp)
      end

      def render_indices(lines, bibliographer)
        lines.map do |line|
          if line =~ Index::REGEXP
            index = Index.new(*Regexp.last_match.captures)
            index.render bibliographer
          else
            line
          end
        end.flatten
      end
    end
  end
end