#!/usr/bin/ruby -w
#
# $Id: cart,v 1.7 2006/08/06 00:57:26 ianmacd Exp $
#
# This is a more involved example of shopping cart access than rcart. This
# program will take one or more valid ASINs on amazon.com, add them to a
# remote shopping cart, then log into Amazon as the given user and merge the
# remote shopping cart with that user's real shopping cart.

require 'amazon/shoppingcart'
require 'cgi'
require 'uri'

class Hash

  # Take a hash of key/value pairs and turn them into a URL-encoded
  # query string.
  # 
  def url_encode
    str = ''
    each { |k,v| str << CGI::escape(k) << '=' << CGI::escape(v) << '&' }
    str.chomp('&')
  end
end

# Run a block of statements with warnings switched off.
#
def silently(&block)
  warn_level = $VERBOSE
  $VERBOSE = nil
  result = block.call
  $VERBOSE = warn_level
  result
end

# We need to load Net::HTTPS without warnings, as it performs redefinition
# of several methods.
#
silently { require 'net/https' }

if ARGV.size < 2
  $stderr.puts 'Usage: cart <locale> <asin>+'
  exit 1
end

locale = ARGV.shift.dup

sc = Amazon::ShoppingCart.new(nil, Amazon::DEFAULT_ID[locale], locale)

# Add items to remote shopping cart
#
ARGV.each { |asin| sc.add_items(asin, 1) }

# This is the path to which we will POST.
#
path = '/exec/obidos/flex-sign-in-done/'

# Set Content-Type for POSTing a form.
#
headers = { 'Content-Type' => 'application/x-www-form-urlencoded' }

# Connect to the HTTPS port and use SSL.
#
http = Net::HTTP.new(Amazon::SITE[locale], 443)
http.use_ssl = true

# These are the values that Amazon requires to allow a log-in.
#
begin
  line = __LINE__ + 2
  query = {
    'email'       => sc.config['email'],    # replace this with e-mail address
    'password'    => sc.config['password'], # replace this with your password
    'method'      => 'get',
    'opt'	  => 'a',
    'page'        => 'misc/login/flex-sign-in-secure.html',
    'response'    => 'shopping-basket',
    'action'      => 'sign-in'
  }
rescue NoMethodError
  $stderr.puts "Enter your e-mail and password at line #{line} or " +
	       "define them in your \n" +
	       "~/.amazonrc file."
  exit 2
end

# Perform POST.
#
response = silently { http.post(path, query.url_encode, headers) }
headers = {}

# Grab the necessary cookies from the header.
#
cookies = CGI::Cookie::parse(response['set-cookie'])

# Set outgoing cookie to let Amazon know who we are.
#
headers['Cookie'] = 'Cookie: '
cookies.each { |k,v| headers['Cookie'] << "%s=%s;" % [ k, v[0] ] }

# Parse purchase URL from shopping cart object and reassemble, minus the
# scheme (https?://).
#
uri = URI.parse(sc.purchase_url)
url = uri.path << '?' << uri.query

silently do 
  # Getting the purchase URL page gives us an HTTP redirect.
  redirect_location = http.get(url, headers)['location']
  redirect_location.sub!(/MergeCart=False$/, 'MergeCart=True')

  # Now we need to follow the HTTP redirect.
  response = http.get(redirect_location)
end