module Idonethis::UseCases
  module Git
    class << self
      def apply(credential, args={})
        log = args[:log] || fail("You need to supply :log adapter")

        log.call args

        opts = args[:opts]
        
        dir = opts.any? ? File.expand_path(opts.first) : File.expand_path(".")

        if opts.any?
          all_dirs = directories_in(dir)
          
          log.call("All directories in <#{dir}>: #{all_dirs}")
          
          dirs_that_have_changed_today = all_dirs.select{|it| modified_today?(it, log) }
        
          puts "Scanning dir <#{dir}>, which has <#{dirs_that_have_changed_today.size}> repositories that have changed today\n\n"

          summarise *dirs_that_have_changed_today
            
          puts ""
        else
          puts "Scanning the current directory <#{dir}>\n\n"
          summarise dir
        end
      end

      def summarise(*dirs)
        dirs.each do |dir|
          summary = commit_summary(dir)
          puts %Q{#{Pathname.new(dir).basename} (#{summary.size}):\n-- #{summary.join("\n-- ")}}
        end
      end

      def directories_in(dir)
        Dir.entries(dir).
          reject{|it| ["..", "."].include?(it) }.
          select{|it| File.directory?(File.join(dir, it))}.
          map{   |it| File.expand_path(File.join(dir, it))}
      end

      def modified_today?(dir, log)
        time = File.ctime(dir)
        now = Time.now
        
        any_file_changed_today?(dir, time, now, log).tap do |result|
          log.call "[#{dir}] Comparing mtime <#{time}> to today <#{now}>. Today? <#{result}>"
        end
      end

      def any_file_changed_today?(dir, time, now, log)
        Dir["#{dir}/**/**"].select do |file|
          mtime = File.ctime(file)
          log.call "File <#{file}> has mtime <#{mtime}>"
          return true if today?(mtime, now)
        end
        return false
      end
      
      def today?(time, now)
        time.year == now.year && time.month == now.month && time.day == now.day
      end

      def commit_summary(dir)
        require 'git'
        git = ::Git.open(dir)
        git.log.since('1am').map{|it| %Q{[#{it.date.strftime("%H:%M")}] #{it.message}}}
      end
    end
  end
end