module CouchRestRails
  module Views
    extend self

    # Push views to couchdb
    def push(database, design_doc)
      result = []
      result << "database = #{database} :: design_doc = #{design_doc}"
      db_dir = File.join(RAILS_ROOT, CouchRestRails.setup_path, database)
      return "Database directory '#{database}' does not exist" unless (database == "*" || File.exist?(db_dir))

      Dir[db_dir].each do |db|
        return "Views directory '#{db}/views' does not exist"  unless File.exist?("#{db}/views")

        # CouchDB checks
        db_name = COUCHDB_CONFIG[:db_prefix] + File.basename(db) + COUCHDB_CONFIG[:db_suffix]
        begin
          CouchRest.get("#{COUCHDB_CONFIG[:host_path]}/#{db_name}")
        rescue => err
          return "CouchDB database '#{db_name}' does not exist. Create it first. (#{err})"
        end

        db_con = CouchRest.database("#{COUCHDB_CONFIG[:host_path]}/#{db_name}")
        Dir.glob(File.join(db, "views", design_doc)).each do |doc|
          design_doc_name = File.basename(doc)

          # Load views from filesystem & CouchDB
          views = assemble_views(doc)
          couchdb_design = db_con.get("_design/#{design_doc_name}") rescue nil

          # Update CouchDB's freshly-fetched views, but don't destroy
          # any view not referenced on the FS. Not sure about that part:
          # should we synchronize aggressively?
          views = couchdb_design['views'].merge(views) unless couchdb_design.nil?

          if views.empty?
            result << "No updatable views in #{doc}/#{File.basename(doc)}"
          else

            # Create or update the design, then set its views
            if couchdb_design.nil?
              couchdb_design = { '_id'      => "_design/#{design_doc_name}",
                                 'language' => 'javascript' }
            end
            couchdb_design['views'] = views

            db_con.save_doc(couchdb_design)
            result << "Added views to #{design_doc_name}: #{views.keys.join(', ')}"
          end
        end
        result << "No views were found in '#{File.join(db, "views", design_doc)}'" if result.empty?
      end
      result.join("\n")
    end

    # Assemble views from file-system path design_doc_path
    def assemble_views(design_doc_path)
      views = {}

      Dir.glob(File.join(design_doc_path, '*')).each do |view_folder|
        view = {}
        map_file    = File.join(view_folder, 'map.js')
        reduce_file = File.join(view_folder, 'reduce.js')

        view[:map]    = IO.read(map_file)    if File.exist?(map_file)
        view[:reduce] = IO.read(reduce_file) if File.exist?(reduce_file) && File.size(reduce_file) > 0
        views[File.basename(view_folder)] = view if view[:map]
      end
      views
    end
  end
end