Start peers as uninterested and only move to interested if/once they …

…have a piece that we need

lib/torrent.js

@@ -1095,7 +1095,7 @@ Torrent.prototype._onWireWithMetadata = function (wire) {
   })
 
   wire.bitfield(self.bitfield) // always send bitfield (required)
-  wire.interested() // always start out interested
+  wire.uninterested() // always start out uninterested (as per protocol)
 
   // Send PORT message to peers that support DHT
   if (wire.peerExtensions.dht && self.client.dht && self.client.dht.listening) {
@@ -1174,8 +1174,15 @@ Torrent.prototype._updateInterest = function () {
   self._amInterested = !!self._selections.length
 
   self.wires.forEach(function (wire) {
-    // TODO: only call wire.interested if the wire has at least one piece we need
-    if (self._amInterested) wire.interested()
+    var interested = false
+    for (var index = 0; index < self.pieces.length; ++index) {
+      if (self.pieces[index] && wire.peerPieces.get(index)) {
+        interested = true
+        break
+      }
+    }
+
+    if (interested) wire.interested()
     else wire.uninterested()
   })