require 'optparse'
require 'epub/parser'

options = {:format => :line}
opt = OptionParser.new do |opt|
  opt.banner = <<EOB
Show metadata of an EPUB file

Usage: epubinfo [options] EPUBFILE

EOB
  opt.version = EPUB::Parser::VERSION
  formats = [:line, :json, :yaml]
  opt.on '-f', '--format=FORMAT', formats, "format of output(#{formats[0..-2].join(', ')} or #{formats.last}), defaults to line(for console)" do |format|
    options[:format] = format
  end
  opt.on '--words', 'count words of content documents' do
    options[:words] = true
  end
  opt.on '--chars', 'count charactors of content documents' do
    options[:chars] = true
  end
end
opt.parse!(ARGV)

file = ARGV.shift
unless file
  $stdout.puts "error: you must supply an EPUB file name"
  $stdout.puts opt.help
  abort
end

book = EPUB::Parser.parse(file)
data = {'Title' => [book.title]}
data.merge!(book.metadata.to_h)
data['Unique identifier'] = [book.metadata.unique_identifier]
data['EPUB Version'] = [book.package.version]
counts = {:chars => 0, :words => 0}
if options[:words] or options[:chars]
  book.resources.select(&:xhtml?).each do |xhtml|
    begin
      doc = xhtml.content_document.nokogiri
      body = doc.search('body').first
      content = body.content
      if body
        counts[:words] += content.scan(/\S+/).length
        counts[:chars] += content.gsub(/\r|\n/, '').length
      end
    rescue => error
      warn "#{xhtml.href}: #{error}"
    end
  end
end
data['Words'] = [counts[:words]] if options[:words]
data['Characters'] = [counts[:chars]] if options[:chars]
if options[:format] == :line
  key_width = data.keys.map {|k| k.length}.max + 3
  data.each_pair do |k, v|
    puts (k.to_s.capitalize + ':').ljust(key_width) + v.join(', ')
  end
else
  require options[:format].to_s
  puts data.__send__("to_#{options[:format]}")
end