module Eco
  module API
    class MicroCases
      # Helper to load `People` that works in different phases:
      #   1. first tries to get the newest cached file that follows `filename` pattern
      #     - if not the newest, it tries to find the specific filename
      #   2. if it succeeds to identif a cached file, it loads it
      #     - if it fails, it tries to get people from the server
      # @note
      #  - `filename` will be relative to the working directory (the one of the session `enviro` set by the user).
      # @param filename [String] the name of the file where the cached data is to be found.
      # @param modifier [Array<Symbol>] modifiers to specify how this function should proceed:
      #   - `:newest` if it should try to find the newest file (pattern alike).
      #   - `:api` if it should try to get people from the server in case there's no cache.
      #   - `:file` if it is supposed to load people from a file.
      #   - `:save` if it is supposed to cache/save the data locally once obtained people from the server (`:api`)
      # @return [Eco::API::Organization::People] the `People` object with the data.
      def people_load(filename = enviro.config.people.cache, modifier: [:newest, :api])
        modifier  = [modifier].flatten
        load_file = [:file, :newest].any? {|flag| modifier.include?(flag)}
        case
        when filename && load_file
          if file = people_load_filename(filename, newest: modifier.include?(:newest))
            file_manager.load_json(file).tap do |people|
              logger.info("#{people&.length} people loaded from file #{file}") if people.is_a?(Array)
            end
          else
            logger.error("could not find the file #{file_manager.dir.file(filename)}")
            exit unless modifier.include?(:api)
            people_load(modifier: modifier - [:newest, :file])
          end
        when modifier.include?(:api)
          logger.info("Going to get all the people via API (load)")

          start = Time.now
          session.batch.get_people.tap do |people|
            secs    = (Time.now - start).round(3)
            cnt     = people.count
            per_sec = (cnt.to_f / secs).round(2)
            logger.info("Loaded #{cnt} people in #{secs} seconds (#{per_sec} people/sec)")

            if modifier.include?(:save) && people && people.length > 0
              file = file_manager.save_json(people, filename, :timestamp)
              logger.info("#{people.length } people saved to file #{file}.")
            end
          end
        end.yield_self do |people|
          Eco::API::Organization::People.new(people)
        end
      end

      private

      def people_load_filename(filename, newest: false)
        if newest
          # search input file based on pattern (in case the name has a timestamp)
          file_manager.dir.newest_file(file: filename).tap do |file|
            logger.info("previous file found: #{file}") if file
          end
        else
          file_manager.dir.file(filename, should_exist: true)
        end
      end

    end
  end
end