lib/sibit.rb in sibit-0.0.1 vs lib/sibit.rb in sibit-0.1.0

@@ -23,40 +23,144 @@
 require 'bitcoin'
 require 'typhoeus'
 require 'json'
 
 # Sibit main class.
+#
+# It works through the Blockchain API at the moment:
+# https://www.blockchain.com/api/blockchain_api
+#
 # Author:: Yegor Bugayenko ([e-mail])
 # Copyright:: Copyright (c) 2019 Yegor Bugayenko
 # License:: MIT
 class Sibit
-  # Generate new Bitcon private key.
+  # Constructor.
+  def initialize(log: STDOUT)
+    @log = log
+  end
+
+  # Generate new Bitcon private key and returns in Hash160 format.
   def generate
-    key = Bitcoin::Key.generate
-    key.priv
+    Bitcoin::Key.generate.priv
   end
 
-  # Create Bitcon address using the private key.
+  # Create Bitcon address using the private key in Hash160 format.
   def create(pvt)
-    key = Bitcoin::Key.new
-    key.priv = pvt
-    key.addr
+    key(pvt).addr
   end
 
   # Get the balance of the address, in satoshi.
   def balance(address)
-    request = Typhoeus::Request.new(
-      "https://blockchain.info/rawaddr/#{address}",
-      method: :get,
-      headers: {}
+    get_json("https://blockchain.info/rawaddr/#{address}")['final_balance']
+  end
+
+  # Send a payment and return the transaction hash.
+  #
+  # +pvt+: the private key as a Hash160 string
+  # +amount+: the amount either in satoshis or ending with 'BTC', like '0.7BTC'
+  # +fee+: the miners fee in satoshis (as integer) or S/M/X/XL as a string
+  # +sources+: the array of bitcoin addresses where the coins are now
+  # +target+: the target address to send to
+  # +change+: the address where the change has to be sent to
+  def pay(pvt, amount, fee, sources, target, change)
+    satoshi = satoshi(amount)
+    builder = Bitcoin::Builder::TxBuilder.new
+    unspent = 0
+    size = 100
+    utxos(sources).each do |utxo|
+      unspent += utxo['value']
+      builder.input do |i|
+        i.prev_out(utxo['tx_hash_big_endian'])
+        i.prev_out_index(utxo['tx_output_n'])
+        i.prev_out_script = [utxo['script']].pack('H*')
+        i.signature_key(key(pvt))
+      end
+      size += 180
+      break if unspent > satoshi
+    end
+    raise "Not enough funds to send #{amount}, only #{unspent} left" if unspent < satoshi
+    builder.output(satoshi, target)
+    tx = builder.tx(
+      input_value: unspent,
+      leave_fee: mfee(fee, size),
+      change_address: change
     )
+    post_tx(tx.to_payload.bth)
+    tx.hash
+  end
+
+  private
+
+  # Retrieve all unspent outputs of the given list of
+  # addresses.
+  def utxos(sources)
+    offset = 0
+    txns = []
+    loop do
+      uri = [
+        'https://blockchain.info/unspent?',
+        "active=#{sources.join('|')}",
+        offset.positive? ? "&offset=#{offset}" : ''
+      ].join
+      list = get_json(uri)['unspent_outputs']
+      txns += list
+      break if list.empty?
+      offset += list.count
+    end
+    txns
+  end
+
+  # Convert text to amount.
+  def satoshi(amount)
+    return (amount.gsub(/BTC$/, '').to_f * 100_000_000).to_i if amount.end_with?('BTC')
+    amount.to_i
+  end
+
+  def mfee(fee, size)
+    return fee.to_i if fee.is_a?(Integer) || /^[0-9]+$/.match?(fee)
+    case fee
+    when 'S'
+      return 10 * size
+    when 'M'
+      return 50 * size
+    when 'L'
+      return 100 * size
+    when 'XL'
+      return 250 * size
+    else
+      raise "Can't understand the fee: #{fee.inspect}"
+    end
+  end
+
+  # Make key from private key string in Hash160.
+  def key(hash160)
+    key = Bitcoin::Key.new
+    key.priv = hash160
+    key
+  end
+
+  def post_tx(body)
+    uri = 'https://blockchain.info/pushtx'
+    request = Typhoeus::Request.new(uri, method: :post, body: { tx: body })
     request.run
     response = request.response
-    json = JSON.parse(response.body)
-    json['final_balance']
+    raise "Invalid response at #{uri}: #{response.code}" unless response.code == 200
+    debug("POST #{uri}: #{response.code}")
   end
 
-  # Send a payment.
-  def pay(_pvt, _amount, _fee, _sources, _target)
-    raise 'Not implemented yet'
+  def get_json(uri)
+    request = Typhoeus::Request.new(uri, method: :get, headers: {})
+    request.run
+    response = request.response
+    raise "Invalid response at #{uri}: #{response.code}" unless response.code == 200
+    debug("GET #{uri}: #{response.code}")
+    JSON.parse(response.body)
+  end
+
+  def debug(msg)
+    if @log.respond_to?(:debug)
+      @log.debug(msg)
+    elsif @log.respond_to?(:puts)
+      @log.puts(msg)
+    end
   end
 end