diff --git a/rank_progress.py b/rank_progress.py
--- a/rank_progress.py
+++ b/rank_progress.py
@@ -3,13 +3,6 @@ from itertools import groupby
 from datetime import datetime
 import argparse
 
-parser = argparse.ArgumentParser()
-parser.add_argument("since", help="a date in YYYYMMDD format")
-parser.add_argument("to", nargs="?", help="a date in YYYYMMDD format")
-parser.add_argument("-c", "--country-code", default="CZ", help="a two letter country code, default=CZ")
-
-args = parser.parse_args()
-
 
 class Record:
 	def __init__(self, tokens, source):
@@ -41,6 +34,33 @@ class Record:
 		return s
 
 
+class RankTracker:
+	def __init__(self, rating):
+		self._rounded_rating = round_rating(rating)
+
+	@property
+	def rank(self):
+		return rating_to_rank(self._rounded_rating)
+
+	def update(self, rating):
+		rounded_rating = round_rating(rating)
+
+		if rounded_rating == self._rounded_rating:
+			return False
+		elif rounded_rating > self._rounded_rating:  # promotion
+			self._rounded_rating = rounded_rating
+			return self.rank
+		else:  # demotion
+			if rounded_rating >= 1500 and self._rounded_rating - rating > 100:
+				self._rounded_rating = rounded_rating
+				return self.rank
+			elif self._rounded_rating - rating > 150:
+				self._rounded_rating = rounded_rating+100
+				return self.rank
+			else:
+				return False
+
+
 def parse_record(record):
 	types = [int, str, str, str, str, str, int, int, int, int]
 	columns = [f(token) for (f, token) in zip(types, record)] + [datetime.strptime(record[5][1:7], "%y%m%d")]
@@ -57,38 +77,46 @@ def rating_to_rank(rating):
 	return rank_list[min(key+9, 36)]
 
 
-since = datetime.strptime(args.since, "%Y%m%d")
-to = datetime.strptime(args.to, "%Y%m%d") if args.to else datetime.now()
-
-with open("/tmp/all.hst") as f:
-	s = f.read()
+if __name__ == "__main__":
+	parser = argparse.ArgumentParser()
+	parser.add_argument("since", help="a date in YYYYMMDD format")
+	parser.add_argument("to", nargs="?", help="a date in YYYYMMDD format")
+	parser.add_argument("-c", "--country-code", default="CZ", help="a two letter country code, default=CZ")
 
-records = [Record.parse(line) for line in s.splitlines()]
-records = filter(lambda rec: rec is not None, records)
-national_records = filter(lambda rec: rec.country_code == args.country_code, records)
-player_records = groupby(national_records, lambda rec: rec.pin)
+	args = parser.parse_args()
+	
+	since = datetime.strptime(args.since, "%Y%m%d")
+	to = datetime.strptime(args.to, "%Y%m%d") if args.to else datetime.now()
 
-for (pin, recs) in player_records:
-	tourneys = list(recs)
-	rounded_rating = tourneys[0].rounded_before
+	with open("/tmp/all.hst") as f:
+		s = f.read()
 
-	steps = []
+	records = [Record.parse(line) for line in s.splitlines()]
+	records = filter(lambda rec: rec is not None, records)
+	national_records = filter(lambda rec: rec.country_code == args.country_code, records)
+	player_records = groupby(national_records, lambda rec: rec.pin)
 
-	for r in tourneys:
-		# omit reset ratings
-		if rounded_rating != r.rounded_before:
-			rounded_rating = r.rounded_before
+	for (pin, recs) in player_records:
+		tourneys = list(recs)
+		rounded_rating = tourneys[0].rounded_before
+
+		steps = []
+
+		for r in tourneys:
+			# omit reset ratings
+			if rounded_rating != r.rounded_before:
+				rounded_rating = r.rounded_before
 
-		if r.rating_after-rounded_rating >= 50 or \
-				(rounded_rating-r.rating_after > 100 and rounded_rating >= 1600):
-			steps.append(r)
-			rounded_rating = r.rounded_after
-		elif rounded_rating-r.rating_after > 150:
+			if r.rating_after-rounded_rating >= 50 or \
+					(rounded_rating-r.rating_after > 100 and rounded_rating >= 1600):
+				steps.append(r)
+				rounded_rating = r.rounded_after
+			elif rounded_rating-r.rating_after > 150:
 
-			steps.append(r)
-			rounded_rating = r.rounded_after + 100
+				steps.append(r)
+				rounded_rating = r.rounded_after + 100
 
-	steps = [r for r in steps if since <= r.date <= to]
-	if steps:
-		print("\n".join(map(str, steps)))
-		print()
+		steps = [r for r in steps if since <= r.date <= to]
+		if steps:
+			print("\n".join(map(str, steps)))
+			print()