wcコマンドを作成

05.wc/wc.rb

@@ -0,0 +1,77 @@
+# frozen_string_literal: true
+
+require 'optparse'
+
+def main
+  column_names, paths = column_names_and_paths
+  statistics_matrix =
+    if paths.empty?
+      [build_statistics_row($stdin.read)]
+    else
+      build_statistics_matrix(paths)
+    end
+  width = calculate_output_width(statistics_matrix, column_names)
+  statistics_matrix.each do |statistics|
+    render(statistics, column_names, width)
+  end
+end
+
+def column_names_and_paths
+  line = false
+  word = false
+  size = false
+  opt = OptionParser.new
+  opt.on('-l') { |v| line = v }
+  opt.on('-w') { |v| word = v }
+  opt.on('-c') { |v| size = v }
+  paths = opt.parse(ARGV)
+  column_names = [line, word, size].none? ? %i[line_count word_count size] : { line_count: line, word_count: word, size: size }.select { |_, v| v }.keys
+  [column_names, paths]
+end
+
+def build_statistics_row(input, name = nil)
+  {
+    line_count: input.lines.count,
+    word_count: input.split.count,
+    size: input.size,
+    name: name
+  }
+end
+
+def build_statistics_matrix(paths)
+  statistics_matrix = paths.map do |path|
+    build_statistics_row(File.read(path), path)
+  end
+  statistics_matrix << calculate_total(statistics_matrix) if paths.size > 1
+  statistics_matrix
+end
+
+def calculate_total(statistics_matrix)
+  line_count_sum = 0
+  word_count_sum = 0
+  size_sum = 0
+  statistics_matrix.each do |statistics|
+    line_count_sum += statistics[:line_count]
+    word_count_sum += statistics[:word_count]
+    size_sum += statistics[:size]
+  end
+  { line_count: line_count_sum, word_count: word_count_sum, size: size_sum, name: 'total' }
+end
+
+def calculate_output_width(statistics_matrix, column_names)
+  widths = statistics_matrix.map do |statistics|
+    column_names.map do |column_name|
+      statistics[column_name].to_s.length
+    end
+  end
+  widths.flatten.max
+end
+
+def render(statistics, column_names, width)
+  filterd_statistics = column_names.map do |column_name|
+    statistics[column_name].to_s.rjust(width)
+  end
+  puts [*filterd_statistics, statistics[:name]].join(' ')
+end
+
+main