Preparing for Multi-signature Transactions

lib/src/payments/p2ms.dart

@@ -0,0 +1,205 @@
+import '../utils/constants/op.dart';
+import 'package:meta/meta.dart';
+import '../utils/script.dart' as bscript;
+import '../models/networks.dart';
+import 'dart:typed_data';
+import 'package:bip32/src/utils/ecurve.dart' show isPoint;
+
+class P2MS {
+  P2MSData data;
+  NetworkType network;
+  List<dynamic> _chunks;
+  bool _isDecoded;
+
+  P2MS({@required data}) {
+    this.data = data;
+    this.network = network ?? bitcoin;
+    this._isDecoded = false;
+    _init();
+  }
+  void _init() {
+    _enoughInformation(data);
+    _extraValidation(data.options);
+    _setNetwork(this.network);
+    _extendedValidation();
+  }
+
+  void _enoughInformation(data) {
+    if (data.input == null &&
+        data.output == null &&
+        !((data.pubkeys  != null) && (data.m != null)) &&
+        data.signatures == null) {
+      throw new ArgumentError('Not enough data');
+    }
+  }
+  void _setNetwork(network){
+      this.network == network;
+  }
+  void _extraValidation(options) {
+    if(data.options == null){data.options = {};}
+    data.options['validate'] = true;
+  }
+
+  void _extendedValidation(){
+    if(data.options['validate']==true){
+      _check();
+    }
+  }
+   void _decode(output){
+
+    if(_isDecoded) {return;}
+    else{
+      _isDecoded = true;
+      _chunks = bscript.decompile(output);
+      data.m = _chunks[0] - OPS['OP_RESERVED'];
+      data.n = _chunks[_chunks.length - 2] - OPS['OP_RESERVED'];
+      data.pubkeys = _chunks.sublist(1,_chunks.length-2);
+    }
+  }
+  void _setOutput(){
+    if (data.m == null){ return;}
+    if (data.n == null) {return;}
+    if (data.pubkeys == null) {return;}
+    List<dynamic> list = [OPS['OP_RESERVED']+data.m];
+    data.pubkeys.forEach((pubkey) => list.add(pubkey));
+    list.add(OPS['OP_RESERVED'] + data.n);
+    list.add(OPS['OP_CHECKMULTISIG']);
+    data.output = bscript.compile(list);
+  }
+  void _setSigs(){
+    if (data.input == null) {return;}
+    var list = bscript.decompile(data.input);
+    list.removeAt(0);
+    List<Uint8List> _chunks = [];
+
+    for (var i = 0; i < list.length; i++) {
+      dynamic temp = list[i];
+      if(list[i] is int ){
+        List<int> temp1 = [];
+        temp1.add(list[i]);
+        temp = Uint8List.fromList(temp1);
+      }
+      _chunks.add(temp);
+    }
+
+    data.signatures = _chunks;
+  }
+  void _setInput(){
+    if (data.signatures == null) {return;}
+    String tempString = 'OP_0 ';
+    List<Uint8List> tempsignatures = [];
+    for (var i = 0; i < data.signatures.length; i++) {
+      if(data.signatures[i].toString()=='[0]'){
+        tempString = tempString + 'OP_0 ';
+      }else{
+        tempsignatures.add(data.signatures[i]);
+      }
+    }
+    tempString = tempString+(bscript.toASM(tempsignatures));
+    Uint8List tempList = bscript.fromASM(tempString);
+    data.input = bscript.compile(tempList);  
+  }
+  void _setWitness(){
+    if (data.input == null && data.input == null) {return;}
+    List <Uint8List> temp = [];
+    data.witness = temp;
+  }
+
+  void _setM(){
+    if (data.output == null) {return;}
+    _decode(data.output);
+  }
+    void _setN(){
+    _setPubkeys();
+    if (data.pubkeys == null) {return;}
+    data.n= data.pubkeys.length;
+  }
+    void _setPubkeys(){
+    if (data.output == null) {return;}
+    _decode(data.output);
+  }
+    bool _stacksEqual(a, b) {
+    if (a.length != b.length) {return false;}
+    for (int i = 0; i <= a.length-1; i++) {
+      if (a[i] != b[i]) {
+        return false;
+      }
+    }
+    return true;
+  }
+    bool _isAcceptableSignature(signature, options) {
+    return (bscript.isCanonicalScriptSignature(signature) ||
+        ((options['allowIncomplete'] == true) && (signature[0] == 0)));
+  }
+  void _check(){
+    if (data.output != null){
+      final tempChunks = bscript.decompile(data.output);
+      if (tempChunks[0] == null) {throw new ArgumentError('Output is invalid');}
+      if (tempChunks.length < 2 ) {throw new ArgumentError('Output is invalid');}
+      if (tempChunks[tempChunks.length - 1] != OPS['OP_CHECKMULTISIG']) {throw new ArgumentError('Output is invalid');}
+      _decode(data.output);
+    if(data.m <= 0 ||
+        data.n > 16 ||
+        data.m > data.n ||
+        data.n != _chunks.length - 3) {throw new ArgumentError('Output is invalid');}
+    if (!data.pubkeys.every((x) => isPoint(x))) {throw new ArgumentError('Output is invalid');}
+    if (data.m != null && data.m != data.m) {throw new ArgumentError('m mismatch');}
+    if (data.n != null && data.n != data.n) {throw new ArgumentError('n mismatch');}
+    if (data.pubkeys != null && !_stacksEqual(data.pubkeys, data.pubkeys)) {throw new ArgumentError('Pubkeys mismatch');}
+  }
+  if (data.pubkeys != null){
+    if (data.n != null && data.n != data.pubkeys.length) {throw new ArgumentError('Pubkey count mismatch');}
+    data.n = data.pubkeys.length;
+    _setOutput();
+    _setM();
+    _setN();
+    if (data.n < data.m) {throw new ArgumentError('Pubkey count cannot be less than m');}
+  }
+  if (data.signatures != null) {
+    _setSigs();
+    _setInput();
+    if (data.signatures.length < data.m) {throw new ArgumentError('Not enough signatures provided');}
+    if (data.signatures.length > data.m) {throw new ArgumentError('Too many signatures provided');}
+    }
+
+
+  if (data.input != null) {
+      if (data.input[0] != OPS['OP_0']) {throw new ArgumentError('Input is invalid');}
+      _setSigs();
+      if (data.signatures.length == 0 || !data.signatures.every((x) => _isAcceptableSignature(x,data.options)))
+      {throw new ArgumentError('Input has invalid signature(s)');}
+      if (data.signatures != null&& !_stacksEqual(data.signatures,data.signatures)) {throw new ArgumentError('Signature mismatch');}
+      if (data.m != null && data.m != data.signatures.length) {throw new ArgumentError('Signature count mismatch');}
+    }
+  _setInput();
+  _setWitness();
+  }
+
+
+}
+
+
+class P2MSData {
+  int m;
+  int n;
+  Uint8List output;
+  Uint8List input;
+  List<dynamic> pubkeys;
+  List<Uint8List> signatures;
+  List<Uint8List> witness;
+  Map options;
+
+  P2MSData(
+      {this.m,
+      this.n,
+      this.output,
+      this.input,
+      this.pubkeys,
+      this.signatures,
+      this.witness,
+      this.options});
+  @override
+  String toString() {
+    return 'P2MSData{m: $m, n: $n, output: $output, input: $input, pubkeys: $pubkeys, sigs: $signatures, options: $signatures, witness: $witness}';
+  }
+}