class Rsync

# File lib/rsync_wrapper/rsync.rb, line 2
def initialize **opts
  @dirs = {}
  [:src_dir, :dest_dir].each do |k|
    raise ArgumentError, "#{k} is required" unless opts[k]
    @dirs[k] = opts[k]
  end
  @inclusions = opts[:include_extensions] ? opts[:include_extensions].map{|ext| "*.#{ext}"} : []
  @exclusions = opts[:exclusions] || []
  if opts[:subdirs_only]
    @inclusions << '*/' # include subdirectories
    @exclusions << '*'
  end
  @logfile = if opts[:log_dir]
    File.join(opts[:log_dir], "rsync-#{SecureRandom.uuid}.log")
  elsif opts[:logfile]
    opts[:logfile]
  else
    File.join(Dir.pwd, "rsync-#{SecureRandom.uuid}.log")
  end

  @optional_arguments = [
    :bwlimit,
    # TODO: add rsync's other arguments that wouldn't interfere with the design of this gem https://linux.die.net/man/1/rsync
  ].map{|arg| opts[arg] ? [arg, opts[arg]] : nil}.compact.to_h
end

# File lib/rsync_wrapper/rsync.rb, line 28
def sync! &block
  exec_rsync
  parse_logfile &block
end

# File lib/rsync_wrapper/rsync.rb, line 35
def exec_rsync
  rsync_opts = ['-ri', "--log-file '#{@logfile}'", '--size-only', '--prune-empty-dirs']
  rsync_opts += @inclusions.map{|inc| "--include '#{inc}'"}
  rsync_opts += @exclusions.map{|exc| "--exclude '#{exc}'"}

  rsync_opts += @optional_arguments.map{|k,v| "--#{k}=#{v}"}

  cmd = "rsync #{rsync_opts.join(' ')} \"#{@dirs[:src_dir]}\" \"#{@dirs[:dest_dir]}\" > /dev/null 2>&1"
  `#{cmd}`
end

# File lib/rsync_wrapper/rsync.rb, line 46
def parse_logfile
  base_dir = File.basename @dirs[:src_dir]
  File.open(@logfile, 'r') do |f|
    f.each_line do |line|
      line_arr = line.split(/ /)
      next unless line_arr.length > 4
      #http://andreafrancia.it/2010/03/understanding-the-output-of-rsync-itemize-changes.html
      changes = line_arr[3]
      next unless changes.start_with?('>f') # file transfered to local
      file_path = line_arr[4..-1].join(' ').strip
      next unless file_path.start_with?(base_dir)

      if block_given?
        if changes.start_with?('>f+++')
          yield file_path, true
        elsif changes[3] == 's'
          yield file_path, false
        end
      end
    end
  end

  File.delete @logfile
end