Add a reminder plugin

bot/plugins/Reminder/reminder.plug

+[Core]
+name = Reminder
+module = reminder
+
+[Documentation]
+description = Allow people to add reminders
+
+[Python]
+version = 3

bot/plugins/Reminder/reminder.py

+# Copyright © 2018 Bruce Cowan <bruce@bcowan.eu>
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from datetime import datetime
+from threading import Timer
+
+from dateparser import parse
+from errbot import BotPlugin, botcmd
+
+class ReminderType:
+    def __init__(self, message, time, text):
+        self.message = message
+        self.time = time
+        self.text = text
+
+class Reminder(BotPlugin):
+    """Allows reminder functionality"""
+
+    def activate(self):
+        super().activate()
+        self.reminders = []
+
+    @staticmethod
+    def _separate_args(args):
+        i = args.index(':')
+
+        time_str = ' '.join(args[:i])
+        time = parse(time_str, settings={'DATE_ORDER': 'DMY'})
+        msg = ' '.join(args[i+1:])
+
+        return time, msg
+
+    def _timer_func(self, message, reminder):
+        self.send(message.to, reminder.text, message)
+        del self.reminders[self.reminders.index(reminder)]
+
+    @staticmethod
+    def _get_delta(time):
+        now = datetime.now()
+        if time < now:
+            return "**Error**: Bot cannot time travel (yet)"
+
+        return (time - now).seconds + 1
+
+    @botcmd(split_args_with=None)
+    def reminder_add(self, message, args):
+        """ Add a reminder"""
+        if len(args) < 2 or ':' not in args:
+            return "**Usage**: !reminder add <time> : <message>"
+
+        time, text = self._separate_args(args)
+        if time is None:
+            return "**Error**: Could not parse time"
+
+        delta = self._get_delta(time)
+
+        reminder = ReminderType(message, time, text)
+        reminder.timer = Timer(delta, self._timer_func, [message, reminder])
+        reminder.timer.start()
+
+        self.reminders.append(reminder)
+
+        return "Set timer for {}".format(time.strftime('%x %X'))
+
+    @botcmd
+    def reminder_list(self, message, args):
+        """ List reminders"""
+        reminders = list(enumerate(self.reminders))
+        reminders = [(e[0], e[1].time.strftime('%x %X')) for e in reminders]
+        for e in reminders:
+            yield "{}: {}".format(e[0], e[1])
+
+    @botcmd(split_args_with=None)
+    def reminder_edit(self, message, args):
+        """ Edit the message and time of a timer"""
+        if len(args) < 3 or ':' not in args:
+            return "**Usage**: !reminder edit <id> <time> : <message>"
+
+        try:
+            idx = int(args[0])
+            edit = self.reminders[idx]
+        except IndexError:
+            return "**Error**: reminder '{}' not in database".format(args)
+        else:
+            time, text = self._separate_args(args[1:])
+            if time is None:
+                return "**Error**: Could not parse time"
+
+            edit.message = text
+
+            delta = self._get_delta(time)
+            edit.timer.cancel()
+            edit.timer = Timer(delta, self._timer_func, [message, edit])
+            edit.timer.start()
+            edit.time = time
+
+            return "Edited reminder '{}'".format(args[0])
+
+    @botcmd
+    def reminder_remove(self, message, args):
+        """ Remove the timer """
+        if not args:
+            return "**Usage**: !reminder remove <id>"
+
+        try:
+            idx = int(args)
+            self.reminders[idx].timer.cancel()
+            del self.reminders[idx]
+            return "Deleted reminder '{}'".format(args)
+        except IndexError:
+            return "**Error**: reminder '{}' not in database".format(args)