require 'rubygems'
require 'bundler'
require 'sinatra'
require 'digest/sha1'

# For this example we assume that you have another file with the methods necessary to credit the reward to your users.
require File.join(File.dirname(__FILE__), 'reward_processing.rb')

# Your security token should only be present on your server and Fyber's
$SECURITY_TOKEN = '<YOUR SECURITY TOKEN>'

#### ENDPOINT ####
# Your endpoint for the reward callback should be configured in the Fyber dashboard
get '/reward' do
  begin
    #### PARAMETERS ####
    # Gather the parameters that will be used when calculated the sid and for crediting the reward
    user_id = params['uid']
    amount = params['amount']
    # For this example we assume that you have activated the transaction id in the Fyber dashboard
    # If you have not, you can remove the following line
    trans_id = params['_trans_id_']
    # For this example we assume you are passing custom parameters to assist in rewarding
    # If you are not, you can remove the following two lines
    pub0 = params['pub0']
    pub1 = params['pub1']
  
    # Gather the additional parameters not used for the sid but still used rewarding
    currency_name = params['currency_name']
    currency_id = params['currency_id']
  
    #### SID ####
    # Calculate the sid from the callback parameters
    sid_string = ''
    sid_string += $SECURITY_TOKEN
    sid_string += user_id
    sid_string += amount
    # For this example we assume you have the trasaction id, pub0 and pub1 parameters
    # If you do not, you can remove the following three lines
    sid_string += trans_id
    sid_string += pub0
    sid_string += pub1
    sid = Digest::SHA1.hexdigest sid_string
  
    #### PROCESSING ####
    # Make sure the sid parameter matches what's in the callback
    if (sid == params['sid'])
      
      # Make sure you have not already processed the transaction
      # For this example we assume that get_transactions returns an array of credited transactions
      if !(get_transactions(uid).include? trans_id)
        
        # Reward the user
        # For this example we assume that reward_user credits the user with the reward amount
        reward_user(uid, amount, pub0, pub1, currency_name)
        
        # Set the status to 200 so that Fyber knows the callback was processed
        status 200
        body 'Callback Successful.'
        
      else
        # If the transaction was already rewarded, you can safely ignore the callback
        # Set the status to 200 so that Fyber knows the callback was processed
        status 200
        body 'Duplicate transaction id. Callback rejected.'
      end
      
    else
      # If the sid is incorrect, you can safely ignore the callback
      # Set the status to 200 so that Fyber knows the callback was processed
      status 200
      body 'Bad sid. Callback rejected.'
    end
    
  rescue Exception => e
    # If you ran into any error while processing the callback, you will want Fyber to try again
    # Set the status to something other than 200 so that Fyber knows the reward was not processed
    status 500
    body 'Callback failed. Error: ' + e.message
  end
end