wallet: use locateBirthdayBlock within birthdaySanityCheck

We use the recently introduced locateBirthdayBlock function within
birthdaySanityCheck as it serves as a more optimized alternative that
achieves the same purpose.

wallet/chainntfns.go

@@ -464,140 +464,16 @@ func birthdaySanityCheck(chainConn chainConn,
 		return &birthdayBlock, nil
 	}
 
-	log.Debugf("Starting sanity check for the wallet's birthday block "+
-		"from: height=%d, hash=%v", birthdayBlock.Height,
-		birthdayBlock.Hash)
-
-	// Now, we'll need to determine if our block correctly reflects our
-	// timestamp. To do so, we'll fetch the block header and check its
-	// timestamp in the event that the birthday block's timestamp was not
-	// set (this is possible if it was set through the migration, since we
-	// do not store block timestamps).
-	candidate := birthdayBlock
-	header, err := chainConn.GetBlockHeader(&candidate.Hash)
-	if err != nil {
-		return nil, fmt.Errorf("unable to get header for block hash "+
-			"%v: %v", candidate.Hash, err)
-	}
-	candidate.Timestamp = header.Timestamp
-
-	// We'll go back a day worth of blocks in the chain until we find a
-	// block whose timestamp is below our birthday timestamp.
-	heightDelta := int32(144)
-	for birthdayTimestamp.Before(candidate.Timestamp) {
-		// If the birthday block has reached genesis, then we can exit
-		// our search as there exists no data before this point.
-		if candidate.Height == 0 {
-			break
-		}
-
-		// To prevent requesting blocks out of range, we'll use a lower
-		// bound of the first block in the chain.
-		newCandidateHeight := int64(candidate.Height - heightDelta)
-		if newCandidateHeight < 0 {
-			newCandidateHeight = 0
-		}
-
-		// Then, we'll fetch the current candidate's hash and header to
-		// determine if it is valid.
-		hash, err := chainConn.GetBlockHash(newCandidateHeight)
-		if err != nil {
-			return nil, fmt.Errorf("unable to get block hash for "+
-				"height %d: %v", candidate.Height, err)
-		}
-		header, err := chainConn.GetBlockHeader(hash)
-		if err != nil {
-			return nil, fmt.Errorf("unable to get header for "+
-				"block hash %v: %v", candidate.Hash, err)
-		}
-
-		candidate.Hash = *hash
-		candidate.Height = int32(newCandidateHeight)
-		candidate.Timestamp = header.Timestamp
-
-		log.Debugf("Checking next birthday block candidate: "+
-			"height=%d, hash=%v, timestamp=%v",
-			candidate.Height, candidate.Hash,
-			candidate.Timestamp)
-	}
-
-	// To ensure we have a reasonable birthday block, we'll make sure it
-	// respects our birthday timestamp and it is within a reasonable delta.
-	// The birthday has already been adjusted to two days in the past of the
-	// actual birthday, so we'll make our expected delta to be within two
-	// hours of it to account for the network-adjusted time and prevent
-	// fetching more unnecessary blocks.
-	_, bestHeight, err := chainConn.GetBestBlock()
+	// Otherwise, we'll attempt to locate a better one now that we have
+	// access to the chain.
+	newBirthdayBlock, err := locateBirthdayBlock(chainConn, birthdayTimestamp)
 	if err != nil {
 		return nil, err
 	}
-	timestampDelta := birthdayTimestamp.Sub(candidate.Timestamp)
-	for timestampDelta > birthdayBlockDelta {
-		// We'll determine the height for our next candidate and make
-		// sure it is not out of range. If it is, we'll lower our height
-		// delta until finding a height within range.
-		newHeight := candidate.Height + heightDelta
-		if newHeight > bestHeight {
-			heightDelta /= 2
 
-			// If we've exhausted all of our possible options at a
-			// later height, then we can assume the current birthday
-			// block is our best estimate.
-			if heightDelta == 0 {
-				break
-			}
-
-			continue
-		}
-
-		// We'll fetch the header for the next candidate and compare its
-		// timestamp.
-		hash, err := chainConn.GetBlockHash(int64(newHeight))
-		if err != nil {
-			return nil, fmt.Errorf("unable to get block hash for "+
-				"height %d: %v", candidate.Height, err)
-		}
-		header, err := chainConn.GetBlockHeader(hash)
-		if err != nil {
-			return nil, fmt.Errorf("unable to get header for "+
-				"block hash %v: %v", hash, err)
-		}
-
-		log.Debugf("Checking next birthday block candidate: "+
-			"height=%d, hash=%v, timestamp=%v", newHeight, hash,
-			header.Timestamp)
-
-		// If this block has exceeded our birthday timestamp, we'll look
-		// for the next candidate with a lower height delta.
-		if birthdayTimestamp.Before(header.Timestamp) {
-			heightDelta /= 2
-
-			// If we've exhausted all of our possible options at a
-			// later height, then we can assume the current birthday
-			// block is our best estimate.
-			if heightDelta == 0 {
-				break
-			}
-
-			continue
-		}
-
-		// Otherwise, this is a valid candidate, so we'll check to see
-		// if it meets our expected timestamp delta.
-		candidate.Hash = *hash
-		candidate.Height = newHeight
-		candidate.Timestamp = header.Timestamp
-		timestampDelta = birthdayTimestamp.Sub(header.Timestamp)
-	}
-
-	// At this point, we've found a new, better candidate, so we'll write it
-	// to disk.
-	log.Debugf("Found a new valid wallet birthday block: height=%d, hash=%v",
-		candidate.Height, candidate.Hash)
-
-	if err := birthdayStore.SetBirthdayBlock(candidate); err != nil {
+	if err := birthdayStore.SetBirthdayBlock(*newBirthdayBlock); err != nil {
 		return nil, err
 	}
 
-	return &candidate, nil
+	return newBirthdayBlock, nil
 }