module Pilbox

# File lib/pilbox.rb, line 8
def self.thumb_uri(base_uri, params = {})
  # Accept a URI, or a string representing what the URI should be. This
  # can simple be used as the base host URI.
  uri = base_uri.is_a?(URI) ? base_uri.dup : URI.parse(base_uri)

  if params.empty?
    return uri
  end

  params = if params.is_a?(Hash)
    params.dup
  else
    # CGI.parse results in key/value pairs where the value is an *array*
    # of values, possibly more than one. We only care about the first, if
    # there is more than one.
    CGI.parse(params.to_s).reduce({}) do |hash, (key, value)|
      hash.merge(key => value.first)
    end
  end

  # Normalize param keys to strings
  params = params.reduce({}) do |hash, (key, value)|
    hash.merge(key.to_s => value)
  end

  # Client Key is supposed to be a secret...don't let it be merged into
  # the URI's query params directly.
  client_key = params.delete("client_key")

  original_params = CGI.parse(uri.query || "")

  uri.query = encode_www_form(original_params.merge(params))

  if client_key
    signature = generate_signature(client_key, uri.query)
    uri.query << "&" << URI.encode_www_form({"sig" => signature})
  end

  return uri
end

# File lib/pilbox.rb, line 54
def self.encode_www_form(enum, except = nil)
  enum.map do |k,v|
    if v.nil?
      URI.encode_www_form_component(k)
    elsif v.respond_to?(:to_ary)
      v.to_ary.map do |w|
        str = URI.encode_www_form_component(k)
        unless w.nil?
          str << '='
          str << URI.encode_www_form_component(w)
        end
      end.join('&')
    else
      str = URI.encode_www_form_component(k)
      str << '='

      if "op" == k
        str << URI.encode_www_form_component(v).gsub("%2C", ",")
      else
        str << URI.encode_www_form_component(v)
      end
    end
  end.join('&')
end

# File lib/pilbox.rb, line 79
def self.generate_signature(client_key, query_string)
  OpenSSL::HMAC.hexdigest(
    OpenSSL::Digest.new("sha1"),
    client_key, query_string
  )
end