Proper naming and help text

The minutes were positive even when the hours were negative. This is obviously undesired, we want the entire time to be negative. That was fixed.

tx

@@ -1,34 +1,83 @@
 #!/usr/bin/env python3
 
-from datetime import datetime, timedelta
+from datetime import date, datetime, timedelta
 import argparse
+import os
 
-# Parse command line arguments
-parser = argparse.ArgumentParser(description="Description")
+def get_current_date():
+    return date.today().strftime("%Y-%m-%d")
 
-# add arguments to the parser
-parser.add_argument("-f", "--file")
-parser.add_argument("mode",
-                    help="display the square of a given number",
-                    nargs='?', default="total",
-                    choices=["total"])
+def get_timefile_line(date, time, desc):
+    return date + " " + time + " " + desc + "\n"
 
-args = parser.parse_args()
-
-if args.file:
-    time_file = open(args.file,'r')
-else:
-    time_file = open('time.txt','r')
-
-if args.mode == "total":
+def get_total(filename):
+    with open(filename, 'r') as time_file:
         total_time = timedelta()
 
         for line in time_file:
             date_time_description = line.split(" ", 2)
             
             hours, minutes = date_time_description[1].split(':', 1)
-        delta = timedelta(hours=int(hours), minutes=int(minutes))
+            
+            # Parse the time to integers
+            hours_int = int(hours)
+            minutes_int = int(minutes)
+            
+            # Make sure that both the hours and the minutes are negative if there's a "-" before the time
+            if hours_int < 0: minutes_int *= -1
+            
+            delta = timedelta(hours=hours_int, minutes=minutes_int)
             
             total_time += delta
 
-    print('Total time: ', total_time)
+        return total_time
+
+# Parse command line arguments
+parser = argparse.ArgumentParser(prog='time.txt', description="simple plain-text time tracking.")
+subparsers = parser.add_subparsers(help='Commands', dest='mode')
+ 
+parser.add_argument("-f", "--file", help="a file in the time.txt format. default: ./time.txt")
+
+# create the parser for the "a" command
+parser_total = subparsers.add_parser('total', help='print the total unbilled time. (default)')
+
+# create the parser for the "b" command
+parser_add = subparsers.add_parser('add', help='add a time entry.')
+parser_add.add_argument("date", nargs='?', default=get_current_date(), help="date in the format 2020-12-30. defaults to the current date.")
+parser_add.add_argument("time", help="time in the format 19:20.")
+parser_add.add_argument("description", help="short description of how the time was spent.")
+
+parser_bill = subparsers.add_parser('bill', help='add a bill entry (a negative time entry).')
+parser_bill.add_argument("date", nargs='?', default=get_current_date(), help="date in the format 2020-12-30. defaults to the current date.")
+parser_bill.add_argument("time", help="time in the format 19:20.")
+parser_bill.add_argument("description", help="short description of how the time was spent.")
+
+parser_create = subparsers.add_parser('create', help='create a new time.txt file.')
+
+args = parser.parse_args()
+
+filename = args.file if args.file else 'time.txt'
+
+if not args.mode or args.mode == "total":
+    print("Total time:", get_total(filename))
+
+elif args.mode == "add":
+    with open(filename, 'a') as time_file:
+        # TODO: Validate date and time
+        time_file.write(get_timefile_line(args.date, args.time, args.description))
+        
+    print("New total:", get_total(filename))
+
+elif args.mode == "bill":
+    with open(filename, 'a') as time_file:
+        # TODO: Validate date and time
+        time_file.write(get_timefile_line(args.date, "-" + args.time, args.description))
+        
+    print("New total:", get_total(filename))
+
+elif args.mode == "create":
+    if (os.path.exists(filename)):
+        print("Error: File", filename, "already exists, can't create a new one!")
+    else:
+        with open(filename, 'w') as time_file:
+            time_file.write(get_timefile_line(get_current_date(), "00:01", "Setup time.txt"))