We want to build a simplified trade engine for exchanging bitcoins with euros

We have:

  • users which have bitcoins (recorded in btc_balance) and euros (recorded in eur_balance)
  • queued_orders which are created by the users and contain
    • a direction (buy or sell)
    • a btc_amount (which will always be 1 to simplify the algorithm)
    • a price in euros per bitcoins

the aim of the matching engine is to process the queued orders one by one. two orders match when:

  • their direction are different
  • if the price of both exactly match

when two orders match, the engine should execute both orders and update user balances:

  • their state change to executed
  • the seller btc_balance is decreased by the orders btc_amount
  • the seller eur_balance is increased by btc_amount * price
  • the buyer btc_balance is increased by the orders btc_amount
  • the buyer eur_balance is decreased by btc_amount * price

complete the main.rb file to produce the output.js from the data.js