class Pry::Command::Hist

def check_for_juxtaposed_replay(replay_sequence)
  if replay_sequence =~ /\Ahist(?:ory)?\b/
    # Create *fresh* instance of Options for parsing of "hist" command.
    slop_instance = slop
    slop_instance.parse(replay_sequence.split(' ')[1..-1])
    if slop_instance.present?(:r)
      replay_sequence = replay_sequence.split("\n").join('; ')
      index = opts[:r]
      index = index.min if index.min == index.max || index.max.nil?
      raise CommandError,
            "Replay index #{index} points out to another replay call: " \
            "`#{replay_sequence}`"
    end
  else
    false
  end
end

def find_history
  h = if opts.present?(:all)
        Pry.history.to_a
      else
        Pry.history.to_a.last(Pry.history.session_line_count)
      end
  Pry::Code(Pry.history.filter(h[0..-2]))
end

def options(opt)
  opt.on :a, :all, "Display all history"
  opt.on :H, :head, "Display the first N items",
         optional_argument: true, as: Integer
  opt.on :T, :tail, "Display the last N items",
         optional_argument: true, as: Integer
  opt.on :s, :show, "Show the given range of lines",
         optional_argument: true, as: Range
  opt.on :G, :grep, "Show lines matching the given pattern",
         argument: true, as: String
  opt.on :c, :clear, "Clear the current session's history"
  opt.on :r, :replay, "Replay a line or range of lines",
         argument: true, as: Range
  opt.on :save, "Save history to a file", argument: true, as: Range
  opt.on :e, :'exclude-pry', "Exclude Pry commands from the history"
  opt.on :n, :'no-numbers',  "Omit line numbers"
end

def process
  @history = find_history
  @history = @history.between(opts[:show]) if opts.present?(:show)
  @history = @history.grep(opts[:grep]) if opts.present?(:grep)
  @history =
    if opts.present?(:head)
      @history.take_lines(1, opts[:head] || 10)
    elsif opts.present?(:tail)
      @history.take_lines(-(opts[:tail] || 10), opts[:tail] || 10)
    else
      @history
    end
  if opts.present?(:'exclude-pry')
    @history = @history.reject do |loc|
      command_set.valid_command?(loc.line)
    end
  end
  if opts.present?(:save)
    process_save
  elsif opts.present?(:clear)
    process_clear
  elsif opts.present?(:replay)
    process_replay
  else
    process_display
  end
end

def process_clear
  Pry.history.clear
  output.puts "History cleared."
end

def process_display
  @history = @history.with_line_numbers unless opts.present?(:'no-numbers')
  pry_instance.pager.open do |pager|
    @history.print_to_output(pager, true)
  end
end

def process_replay
  @history = @history.between(opts[:r])
  replay_sequence = @history.raw
  # If we met follow-up "hist" call, check for the "--replay" option
  # presence. If "hist" command is called with other options, proceed
  # further.
  check_for_juxtaposed_replay(replay_sequence)
  replay_sequence.lines.each do |line|
    pry_instance.eval line, generated: true
  end
end

def process_save
  case opts[:save]
  when Range
    @history = @history.between(opts[:save])
    raise CommandError, "Must provide a file name." unless args.first
    file_name = File.expand_path(args.first)
  when String
    file_name = File.expand_path(opts[:save])
  end
  output.puts "Saving history in #{file_name}..."
  File.open(file_name, 'w') { |f| f.write(@history.raw) }
  output.puts "History saved."
end