class Bank

# File lib/shilling/bank.rb, line 7
def initialize( address )
  @address = address

  ## note: add address name for now to cache
  ##          allows to start more nodes in same folder / directory
  @cache = Cache.new( "data.#{address.downcase}.json" )
  h = @cache.read
  if h
    ## restore blockchain
    @chain = Blockchain.from_json( h['chain'] )
    ## restore pending (unconfirmed) transactions pool too
    @pending = Pool.from_json( h['transactions'] )
  else
    @chain   = Blockchain.new
    @chain  << [Tx.new( Shilling.config.rand_coinbase,
                        @address,
                        Shilling.config.mining_reward )]    # genesis (big bang!) starter block
    @pending = Pool.new
  end

  ## update ledger (balances) with confirmed transactions
  @ledger = Ledger.new( @chain )
end

# File lib/shilling/bank.rb, line 57
def add_transaction( tx )
  if tx.valid? && transaction_is_new?( tx )
    @pending << tx
    @cache.write as_json
    return true
  else
    return false
  end
end

# File lib/shilling/bank.rb, line 91
def as_json
  { chain:        @chain.as_json,
    transactions: @pending.as_json
  }
end

# File lib/shilling/bank.rb, line 33
def mine_block!
  add_transaction( Tx.new( Shilling.config.rand_coinbase,
                           @address,
                           Shilling.config.mining_reward ))

  ## add mined (w/ computed/calculated hash) block
  @chain << @pending.transactions
  @pending = Pool.new   ## clear out/ empty pool (just create a new one for now)

  ## update ledger (balances) with new confirmed transactions
  @ledger = Ledger.new( @chain )

  @cache.write as_json
end

# File lib/shilling/bank.rb, line 72
def resolve!( chain_new )
  # TODO this does not protect against invalid block shapes (bogus COINBASE transactions for example)

  if !chain_new.empty? && chain_new.last.valid? && chain_new.size > @chain.size
    @chain  = chain_new
    ## update ledger (balances) with new confirmed transactions
    @ledger = Ledger.new( @chain )

    ## document - keep only pending transaction not  yet (confirmed) in (new) blockchain ????
    @pending.update!( @chain.transactions )
    @cache.write as_json
    return true
  else
    return false
  end
end

# File lib/shilling/bank.rb, line 49
def sufficient_funds?( wallet, amount )
  ## (convenience) delegate for ledger
  ##  todo/check: use address instead of wallet - why? why not?
  ##   for now single address wallet (that is, wallet==address)
  @ledger.sufficient?( wallet, amount )
end

# File lib/shilling/bank.rb, line 101
def transaction_is_new?( tx_new )
  ## check if tx exists already in blockchain or pending tx pool

  ## todo: use chain.include?  to check for include
  ##   avoid loop and create new array for check!!!
  (@chain.transactions + @pending.transactions).none? { |tx| tx_new.id == tx.id }
end