New feature! Added Elo rating system!

README.md

@@ -1,6 +1,7 @@
 # Mastodon Chess
 Play with other fediverse users a Chess game! Mastodon Chess control games, players and boards and even it post, graphically, every move to both players!  
 Mastodon Chess (mastochess) uses [python-chess](https://python-chess.readthedocs.io/en/latest/) library.  
+Mastodon Chess uses Elo rating system to calculate the relative skill levels of fediverse players!
 
 ### How to play:  
 
@@ -100,3 +101,4 @@ Within Python Virtual Environment:
 05.12.2020 - New feature! Add panel stats.  
 19.12.2020 - New feature! Now you can configure bot's language!  
 19.12.2020 - New feature! Added french language!  
+21.12.2020 - New feature! Added Elo rating system!

app/locales/ca.txt

@@ -71,3 +71,4 @@ post_my_panel_str: panell (publica les estadístiques)
 locale_change_successfully: llengua canviada amb èxit a
 locale_not_changed: encara no és suportada :-(
 change_lang_str: conf ca (per a configurar el bot en català)
+panel_elo_rating_str: Elo 

app/locales/en.txt

@@ -71,3 +71,4 @@ post_my_panel_str: panel (post player stats)
 locale_change_successfully: language sucessfully changed to
 locale_not_changed: is not supported yet :-(
 change_lang_str: conf en (to configure the bot in english)
+panel_elo_rating_str: Elo 

app/locales/es.txt

@@ -71,3 +71,4 @@ post_my_panel_str: panel (publica el panel de datos)
 locale_change_successfully: idioma cambiado con éxito a
 locale_not_changed: no es soportado aún :-(
 change_lang_str: conf es (para configurar el bot en castellano)
+panel_elo_rating_str: Elo 

app/locales/fr.txt

@@ -71,3 +71,4 @@ post_my_panel_str: panneau (publie les statistiques)
 locale_change_successfully: langue modifiée avec succès en
 locale_not_changed: n'est pas encore pris en charge :-(
 change_lang_str: conf fr (pour configurer le bot en français)
+panel_elo_rating_str: Elo 

db-setup.py

@@ -169,7 +169,7 @@ if __name__ == '__main__':
     create_table(db, db_user, table, sql)
 
     table = "players"
-    sql = "create table "+table+" (player_id bigint PRIMARY KEY, player_name varchar(40), lang varchar(2))"
+    sql = "create table "+table+" (player_id bigint PRIMARY KEY, player_name varchar(40), lang varchar(2), elo_rating float)"
     create_table(db, db_user, table, sql)
 
     ############################################################

mastochess.py

@@ -20,7 +20,7 @@ import chess.svg
 from cairosvg import svg2png
 import chess.pgn
 from PIL import Image, ImageFont, ImageDraw
-import lichess.api
+import math
 
 def cleanhtml(raw_html):
     cleanr = re.compile('<.*?>')
@@ -31,7 +31,48 @@ def unescape(s):
     s = s.replace("&apos;", "'")
     return s
 
-def create_panel(username, played_games, wins):
+# Function to calculate the Probability 
+def Probability(rating1, rating2):
+
+    return 1.0 * 1.0 / (1 + 1.0 * math.pow(10, 1.0 * (rating1 - rating2) / 400))
+
+# Function to calculate Elo rating 
+# K is a constant. 
+# d determines whether 
+# Player A wins or Player B.  
+def EloRating(Ra, Rb, K, d):
+
+    # To calculate the Winning 
+    # Probability of Player B 
+    Pb = Probability(Ra, Rb)
+
+    # To calculate the Winning 
+    # Probability of Player A 
+    Pa = Probability(Rb, Ra)
+
+    # Case -1 When Player A wins 
+    # Updating the Elo Ratings 
+    if (d == 1) :
+        Ra = Ra + K * (1 - Pa)
+        Rb = Rb + K * (0 - Pb)
+
+    # Case -2 When Player B wins 
+    # Updating the Elo Ratings 
+    else :
+        Ra = Ra + K * (0 - Pa)
+        Rb = Rb + K * (1 - Pb)
+
+    Ra = round(Ra, 6)
+    Rb = round(Rb, 6)
+    print("Updated Ratings:-")
+    print("Ra =", Ra," Rb =", Rb)
+
+    return(Ra, Rb)
+
+    # This code is contributed by 
+    # Smitha Dinesh Semwal
+
+def create_panel(username, rating, played_games, wins):
 
     if played_games > 0 and wins > 0:
 
@@ -77,10 +118,12 @@ def create_panel(username, played_games, wins):
     panel_games_str = get_locale("panel_games_str", player_lang)
     panel_wins_str = get_locale("panel_wins_str", player_lang)
     panel_ratio_str = get_locale("panel_ratio_str", player_lang)
+    panel_elo_rating_str = get_locale("panel_elo_rating_str", player_lang)
 
-    draw.text((y+70,x+120), panel_games_str + ': ' + str(played_games), font=fnt, fill=(255,255,255,220)) #fill=(255,255,255,255)) ## full opacity
+    draw.text((y+70,x+80), panel_games_str + ': ' + str(played_games), font=fnt, fill=(255,255,255,220)) #fill=(255,255,255,255)) ## full opacity
-    draw.text((y+70,x+170), panel_wins_str + ': ' + str(wins), font=fnt, fill=(255,255,255,220)) #fill=(255,255,255,255)) ## full opacity
+    draw.text((y+70,x+130), panel_wins_str + ': ' + str(wins), font=fnt, fill=(255,255,255,220)) #fill=(255,255,255,255)) ## full opacity
-    draw.text((y+70,x+220), panel_ratio_str + ': ' + str(ratio) + '%', font=fnt, fill=(255,255,255,220))
+    draw.text((y+70,x+180), panel_ratio_str + ': ' + str(ratio) + '%', font=fnt, fill=(255,255,255,220))
+    draw.text((y+70,x+230), panel_elo_rating_str + ': ' + str(round(rating)), font=fnt, fill=(255,255,255,220))
 
     fnt = ImageFont.truetype('app/fonts/DroidSans.ttf', 15, layout_engine=ImageFont.LAYOUT_BASIC)
 
@@ -978,6 +1021,8 @@ def claim_draw(username):
 
 def close_game(username, checkmate):
 
+    d = 0
+
     try:
 
         conn = None
@@ -996,6 +1041,30 @@ def close_game(username, checkmate):
 
             black_player = row[1]
 
+        cur.execute("select elo_rating from players where player_name = (%s)", (white_player,))
+
+        row = cur.fetchone()
+
+        if row[0] != None:
+
+            white_rating = row[0]
+
+        else:
+
+            white_rating = 1500
+
+        cur.execute("select elo_rating from players where player_name = (%s)", (black_player,))
+
+        row = cur.fetchone()
+
+        if row[0] != None:
+
+            black_rating = row[0]
+
+        else:
+
+            black_rating = 1500
+
         cur.close()
 
     except (Exception, psycopg2.DatabaseError) as error:
@@ -1028,16 +1097,28 @@ def close_game(username, checkmate):
 
         winner = username
 
+        if winner == white_player:
+
+            d = 1
+
     else:
 
         if query_word == search_end and username == white_user and stalemate == False:
 
             winner = black_user
 
+            d = 2
+
         elif query_word == search_end and username == black_user and stalemate == False:
 
             winner = white_user
 
+            d = 1
+
+    K = 30
+
+    new_white_rating, new_black_rating = EloRating(white_rating, black_rating, K, d)
+
     try:
 
         conn = None
@@ -1050,6 +1131,10 @@ def close_game(username, checkmate):
 
         cur.execute("update stats set winner=(%s), finished=(%s), updated_at=(%s) where game_id=(%s)", (winner, finished, now, game_id))
 
+        cur.execute("update players set elo_rating=(%s) where player_name=(%s)", (new_white_rating, white_user))
+
+        cur.execute("update players set elo_rating=(%s) where player_name=(%s)", (new_black_rating, black_user))
+
         conn.commit()
 
         cur.close()
@@ -1094,9 +1179,21 @@ def get_stats(player):
 
           wins = row[0]
 
+        cur.execute("select elo_rating from players where player_name = (%s)", (player,))
+
+        row = cur.fetchone()
+
+        if row[0] != None:
+
+            rating = row[0]
+
+        else:
+
+            rating = 1500
+
         cur.close()
 
-        return (played_games, wins)
+        return (rating, played_games, wins)
 
     except (Exception, psycopg2.DatabaseError) as error:
 
@@ -1745,9 +1842,9 @@ if __name__ == '__main__':
 
                     elif query_word == search_panel:
 
-                        played_games, wins = get_stats(username)
+                        rating, played_games, wins = get_stats(username)
 
-                        create_panel(username, played_games, wins)
+                        create_panel(username, rating, played_games, wins)
 
                         toot_text = '@'+username
 
@@ -1969,11 +2066,11 @@ if __name__ == '__main__':
 
                                     toot_text += '\n' + winned_games + "\n"
 
-                                    played_games, wins = get_stats(username)
+                                    rating, played_games, wins = get_stats(username)
 
                                     wins_of_many = get_locale("wins_of_many", player_lang1)
 
-                                    toot_text += username + ': ' + str(wins) + ' ' + wins_of_many + ' ' + str(played_games) + "\n"
+                                    toot_text += username + ': ' + str(wins) + ' ' + wins_of_many + ' ' + str(played_games) + ' (Elo: ' + str(round(rating)) + ')' + '\n'
 
                                     player_lang2 = get_lang(playing_user)
 
@@ -1981,7 +2078,7 @@ if __name__ == '__main__':
 
                                     toot_text += "\n@"+playing_user + ': ' + well_done + "\n"
 
-                                    played_games, wins = get_stats(playing_user)
+                                    rating, played_games, wins = get_stats(playing_user)
 
                                     winned_games = get_locale("winned_games", player_lang2)
 
@@ -1989,7 +2086,7 @@ if __name__ == '__main__':
 
                                     toot_text += '\n\n' + winned_games + "\n"
 
-                                    toot_text += playing_user + ': ' + str(wins) + ' ' + wins_of_many + ' ' + str(played_games) + "\n"
+                                    toot_text += playing_user + ': ' + str(wins) + ' ' + wins_of_many + ' ' + str(played_games) + ' (Elo: ' + str(round(rating)) + ')' + '\n'
 
                                 elif check == False and stalemate == True:
 
@@ -1999,11 +2096,11 @@ if __name__ == '__main__':
 
                                     toot_text += '\n' + winned_games + "\n"
 
-                                    played_games, wins = get_stats(username)
+                                    rating, played_games, wins = get_stats(username)
 
                                     toot_text += username + ': ' + str(wins) + ' ' + wins_of_many + ' ' + str(played_games) + "\n"
 
-                                    played_games, wins = get_stats(playing_user)
+                                    rating, played_games, wins = get_stats(playing_user)
 
                                     toot_text += playing_user + ': ' + str(wins) + ' ' + wins_of_many + ' ' + str(played_games) + "\n"
 
@@ -2258,7 +2355,7 @@ if __name__ == '__main__':
 
                             toot_text += '\n' + winned_games + "\n"
 
-                            played_games, wins = get_stats(white_player)
+                            rating, played_games, wins = get_stats(white_player)
 
                             toot_text += white_player + ': ' + str(wins) + ' ' + wins_of_many + ' ' + str(played_games) + "\n"
 
@@ -2274,7 +2371,7 @@ if __name__ == '__main__':
 
                                 toot_text += '\n' + winned_games + "\n"
 
-                            played_games, wins = get_stats(black_player)
+                            rating, played_games, wins = get_stats(black_player)
 
                             toot_text += black_player + ': ' + str(wins) + ' ' + wins_of_many + ' ' + str(played_games) + "\n"
 
@@ -2288,9 +2385,9 @@ if __name__ == '__main__':
 
                     elif query_word == search_panel:
 
-                        played_games, wins = get_stats(username)
+                        rating, played_games, wins = get_stats(username)
 
-                        create_panel(username, played_games, wins)
+                        create_panel(username, rating, played_games, wins)
 
                         toot_text = '@'+username