class Filewatcher

# File lib/filewatcher.rb, line 20
def initialize(unexpanded_filenames, options = {})
  @unexpanded_filenames = unexpanded_filenames
  @unexpanded_excluded_filenames = options[:exclude]
  @keep_watching = false
  @pausing = false
  @immediate = options[:immediate]
  @show_spinner = options[:spinner]
  @interval = options.fetch(:interval, 0.5)
  @every = options[:every]
end

# File lib/filewatcher.rb, line 75
def finalize(&on_update)
  on_update = @on_update unless block_given?
  while filesystem_updated?(@end_snapshot || mtime_snapshot)
    update_spinner('Finalizing')
    trigger_changes(on_update)
  end
  @end_snapshot = nil
end

# File lib/filewatcher.rb, line 84
def last_found_filenames
  last_snapshot.keys
end

# File lib/filewatcher.rb, line 48
def pause
  @pausing = true
  update_spinner('Initiating pause')
  # Ensure we wait long enough to enter pause loop in #watch
  sleep @interval
end

# File lib/filewatcher.rb, line 55
def resume
  if !@keep_watching || !@pausing
    raise "Can't resume unless #watch and #pause were first called"
  end
  @last_snapshot = mtime_snapshot # resume with fresh snapshot
  @pausing = false
  update_spinner('Resuming')
  sleep @interval # Wait long enough to exit pause loop in #watch
end

# File lib/filewatcher.rb, line 67
def stop
  @keep_watching = false
  update_spinner('Stopping')
  nil
end

# File lib/filewatcher.rb, line 14
def update_spinner(label)
  return unless @show_spinner
  @spinner ||= %w[\\ | / -]
  print "#{' ' * 30}\r#{label}  #{@spinner.rotate!.first}\r"
end

# File lib/filewatcher.rb, line 31
def watch(&on_update)
  ## The set of available signals depends on the OS
  ## Windows doesn't support `HUP` signal, for example
  (%w[HUP INT TERM] & Signal.list.keys).each do |signal|
    trap(signal) { exit }
  end

  @on_update = on_update
  @keep_watching = true
  yield('', '') if @immediate

  main_cycle

  @end_snapshot = mtime_snapshot
  finalize(&on_update)
end

# File lib/filewatcher.rb, line 125
def expand_directories(patterns)
  patterns = Array(patterns) unless patterns.is_a? Array
  expanded_patterns = patterns.map do |pattern|
    pattern = File.expand_path(pattern)
    Dir[
      File.directory?(pattern) ? File.join(pattern, '**', '*') : pattern
    ]
  end
  expanded_patterns.flatten!
  expanded_patterns.uniq!
  expanded_patterns
end

# File lib/filewatcher.rb, line 110
def filesystem_updated?(snapshot = mtime_snapshot)
  @changes = {}

  (snapshot.to_a - last_snapshot.to_a).each do |file, _mtime|
    @changes[file] = last_snapshot[file] ? :updated : :created
  end

  (last_snapshot.keys - snapshot.keys).each do |file|
    @changes[file] = :deleted
  end

  @last_snapshot = snapshot
  @changes.any?
end

# File lib/filewatcher.rb, line 90
def last_snapshot
  @last_snapshot ||= mtime_snapshot
end

# File lib/filewatcher.rb, line 96
def mtime_snapshot
  snapshot = {}
  filenames = expand_directories(@unexpanded_filenames)

  # Remove files in the exclude filenames list
  filenames -= expand_directories(@unexpanded_excluded_filenames)

  filenames.each do |filename|
    mtime = File.exist?(filename) ? File.mtime(filename) : Time.new(0)
    snapshot[filename] = mtime
  end
  snapshot
end