[suggestion] i wanted an option to specify a date

[luffah]

A little suggestion to specify a start date (instead of now).
Too, in python, code is clear enough not to comment every lines.

ヽ(´ー｀)┌

--- trainline_cli.py	2021-02-17 18:40:51.312990416 +0100
+++ trainline_cli.py	2021-02-17 19:17:46.396430200 +0100
@@ -4,9 +4,16 @@
 """CLI tool for trainline."""
 import click
 import trainline
+import re
 from datetime import datetime, timedelta
 
 # Usage : trainline_cli.py --help
+DATE_FORMAT="%d/%m/%Y %H:%M"
+KNOWN_DATE_FORMATS=list(set([
+    DATE_FORMAT,
+    "%d/%m/%Y", "%d/%m/%Y %H:%M",
+    '%Y-%m-%d', '%Y-%m-%d %H:%M'
+]))
 
 
 @click.command()
@@ -24,9 +31,16 @@
     required=True,
 )
 @click.option(
+    '--start', '-s',
+    type=click.DateTime(formats=KNOWN_DATE_FORMATS),
+    help='start date',
+    default=datetime.now().strftime(DATE_FORMAT),
+    show_default=True,
+)
+@click.option(
     '--next', '-n',
     type=str,
-    help='period of search from now \
+    help='period of search from start date \
 (example : 1day, 2days, 3d, 1hour, 2hours, 3h)',
     default='3hours',
     show_default=True,
@@ -43,21 +57,16 @@
     is_flag=True,
     help='verbose mode',
 )
-def main(departure, arrival, next, transport, verbose):
+def main(departure, arrival, start, next, transport, verbose):
     """ Search trips with Trainline and returns it in csv """
 
-    # Get current datetime > from_date
-    from_date_obj = datetime.now()
-
-    # Decode duration (ex : 1day => timedelta(days=1))
+    from_date = start
     delta = _decode_next_param(next)
-
-    # Calculate the end date > to_date
-    to_date_obj = from_date_obj + delta
+    to_date = from_date + delta
 
     # Convert the datetime objects to strings
-    from_date = from_date_obj.strftime("%d/%m/%Y %H:%M")
-    to_date = to_date_obj.strftime("%d/%m/%Y %H:%M")
+    from_date = from_date.strftime(DATE_FORMAT)
+    to_date = to_date.strftime(DATE_FORMAT)
 
     if transport == "any":
         transport = None