#!/usr/bin/env ruby
# coding: utf-8

# Get the access token and the access token secret

require 'oauth'

class AccessTokenGetter
  USAGE = 'Usage: ./get_access_token <consumer key> <consumer secret>'
  SITE_URI = 'https://www.hatena.com'
  REQUEST_TOKEN_URI = '/oauth/initiate?scope=read_public%2Cread_private%2Cwrite_public%2Cwrite_private'
  ACCESS_TOKEN_URI = '/oauth/token'
  AUTHORIZE_URI = 'https://www.hatena.ne.jp/oauth/authorize'

  def initialize(consumer_key, consumer_secret)
    @consumer_key    = consumer_key
    @consumer_secret = consumer_secret
    @consumer = OAuth::Consumer.new(@consumer_key,
                                    @consumer_secret,
                                    oauth_callback: 'oob',
                                    site: SITE_URI,
                                    request_token_url: REQUEST_TOKEN_URI,
                                    access_token_url: ACCESS_TOKEN_URI,
                                    authorize_url: AUTHORIZE_URI)
  end

  def get_request_token
    @consumer.get_request_token
  end

  def get_access_token(request_token, oauth_verifier)
    # Maybe Hatena returns "parameter_rejected"
    # if "oauth_callback" is in the request header.
    # So oauth_callback is deleted from the header.
    @consumer.options.delete(:oauth_callback)

    begin
      access_token = request_token.get_access_token(oauth_verifier: oauth_verifier)
    rescue => problem
      raise "Fail to get the access token:\n" + problem.request.body
    end
    access_token
  end

  def self.get_access_token
    if ARGV.size != 2
      warn USAGE
      exit
    end

    getter = AccessTokenGetter.new(ARGV[0], ARGV[1])
    request_token = getter.get_request_token
    puts "Visit this website and get the PIN: #{request_token.authorize_url}"
    print 'Enter the PIN:'
    pin = (STDIN.readline).chomp
    access_token = getter.get_access_token(request_token, pin)
    puts "Access token: #{access_token.token}"
    puts "Access token secret: #{access_token.secret}"
  end
end

AccessTokenGetter.get_access_token