module S3DirectRails
  module UploaderHelper

    def s3_uploader(options = {})
      options[:uploader_path] ||= File.join(S3DirectRails.s3_uploader_folder,'uploader.html')
      options[:uploaded_files_path] ||= "uploads/#{controller_name}/:uuid"
      options[:create_resource_url] ||= url_for(only_path: false)
      options[:resource_name] ||= controller_name.singularize

      upload_params = { key: s3_key(options[:uploaded_files_path]),
                        AWSAccessKeyId: S3DirectRails.s3_access_key_id,
                        bucket: s3_bucket_url,
                        _policy: s3_policy(path: options[:uploaded_files_path]),
                        _signature: s3_signature(path: options[:uploaded_files_path]) }.to_query

      content_tag :iframe, '',
                  src: "#{s3_bucket_url}/#{options[:uploader_path]}?#{upload_params}",
                  frameborder: 0,
                  height: options[:iframe_height] || 40,
                  width: options[:iframe_width] || 350,
                  data: { create_resource_url: options[:create_resource_url] }
    end

    def s3_bucket_url
      "http://#{S3DirectRails.s3_uploader_bucket}.s3.amazonaws.com"
    end

    def s3_key(path)
      "#{path}/${filename}"
    end

    def s3_policy(options = {})
      options[:content_type] ||= ''
      options[:acl] ||= 'public-read'
      options[:max_file_size] ||= 5.gigabytes
      options[:path] ||= ''

      Base64.encode64(
        "{'expiration': '#{10.hours.from_now.utc.strftime('%Y-%m-%dT%H:%M:%S.000Z')}',
          'conditions': [
            {'bucket': '#{S3DirectRails.s3_uploader_bucket}'},
            ['starts-with', '$key', ''],
            {'acl': '#{options[:acl]}'},
            {'success_action_status': '201'},
            ['content-length-range', 0, #{options[:max_file_size]}],
            ['starts-with','$Content-Type','']
          ]
      }").gsub(/\n|\r/, '')
    end

    def s3_signature options = {}
      Base64.encode64(
        OpenSSL::HMAC.digest(
        OpenSSL::Digest::Digest.new('sha1'),
        S3DirectRails.s3_secret_access_key, s3_policy(options))).gsub("\n","")
    end
  end
end