wcコマンドの作成

05.wc/wc.rb

@@ -0,0 +1,127 @@
+#!/usr/bin/env ruby
+
+# frozen_string_literal: true
+
+require 'optparse'
+require 'tempfile'
+
+ENV['POSIXLY_CORRECT'] = '1'
+
+def count_lines(input)
+  input.readlines.size
+end
+
+def count_words(input)
+  input.read.split.size
+end
+
+def count_chars(input)
+  input.each_char.count
+end
+
+OPTION_METHODS_TABLE = {
+  l: method('count_lines'),
+  w: method('count_words'),
+  c: method('count_chars')
+}.freeze
+
+def append_number_of_spaces(text, num)
+  "#{"\s" * num}#{text}"
+end
+
+def get_statuses_from_file(file_name, params)
+  statuses = {}
+
+  File.open(file_name) do |file|
+    params.each_key do |k|
+      statuses[k] = OPTION_METHODS_TABLE[k].call(file)
+      file.rewind
+    end
+  end
+
+  statuses[:file_name] = file_name
+  statuses
+end
+
+def get_statuses_from_stdin(params)
+  statuses = {}
+
+  Tempfile.create('stdin_content') do |file|
+    file.write($stdin.read)
+    file.rewind
+
+    params.each_key do |k|
+      statuses[k] = OPTION_METHODS_TABLE[k].call(file)
+      file.rewind
+    end
+  end
+
+  statuses
+end
+
+def max_content_length(array)
+  array.map(&:to_s).map(&:size).max
+end
+
+options = OptionParser.new do |opts|
+  opts.banner = 'Usage: ./wc.rb [options]'
+
+  opts.on('-l', 'The number of lines in each input file is written to the standard output.')
+  opts.on('-w', 'The number of words in each input file is written to the standard output.')
+  opts.on('-c', ' The number of bytes in each input file is written to the standard output.')
+end
+
+begin
+  params = {}
+  options.parse!(ARGV, into: params)
+rescue OptionParser::ParseError => e
+  puts e.message
+  puts options.help
+  exit
+end
+
+params = { l: true, w: true, c: true } if params.empty?
+file_statuses_array = []
+
+if ARGV.empty?
+  file_statuses_array << get_statuses_from_stdin(params)
+else
+  ARGV.each do |file_name|
+    file_statuses_array << get_statuses_from_file(file_name, params)
+
+  rescue Errno::ENOENT => e
+    file_statuses_array << { error: "wc: #{file_name}: open: No such file or directory" }
+    next
+  end
+
+  if file_statuses_array.length > 1
+    total_statuses = {}
+    params.each_key do |k|
+      total_statuses[k] = file_statuses_array.map { |file_statuses| file_statuses[k] }.reject(&:nil?).sum
+    end
+    total_statuses[:file_name] = 'total'
+    file_statuses_array << total_statuses
+  end
+end
+
+max_content_length_by_column = {}
+params.each_key do |k|
+  file_statuses_by_column = file_statuses_array.map { |file_statuses| file_statuses[k] }
+  max_content_length_by_column[k] = max_content_length(file_statuses_by_column)
+end
+
+file_statuses_array.each do |file_statuses|
+  if file_statuses.include?(:error)
+    puts file_statuses.values_at(:error)
+  else
+    justified_file_statuses = []
+    file_statuses.each do |key, file_status|
+      justified_file_statuses << if key == :file_name
+                                   " #{file_status}"
+                                 else
+                                   "     #{append_number_of_spaces(file_status, max_content_length_by_column[key] - file_status.to_s.length)}"
+                                 end
+    end
+    puts justified_file_statuses.join
+  end
+end