add paginator module

utils/paginator.py

@@ -0,0 +1,140 @@
+import asyncio
+import contextlib
+import typing
+
+import discord
+from discord.ext.commands import Context
+
+
+# Copyright © 2016-2017 Pandentia and contributors
+# https://github.com/Thessia/Liara/blob/75fa11948b8b2ea27842d8815a32e51ef280a999/cogs/utils/paginator.py
+
+
+class Paginator:
+	def __init__(self, ctx: Context, pages: typing.Iterable, *, timeout=300, delete_message=False, predicate=None,
+				 delete_message_on_timeout=False, text_message=None):
+		if predicate is None:
+			def predicate(_, user):
+				return user == ctx.message.author
+
+		self.pages = list(pages)
+		self.predicate = predicate
+		self.timeout = timeout
+		self.target = ctx.channel
+		self.delete_msg = delete_message
+		self.delete_msg_timeout = delete_message_on_timeout
+		self.text_message = text_message
+
+		self._stopped = None  # we use this later
+		self._embed = None
+		self._message = None
+		self._client = ctx.bot
+
+		self.footer = 'Page {} of {}'
+		self.navigation = {
+			'\N{BLACK LEFT-POINTING DOUBLE TRIANGLE WITH VERTICAL BAR}': self.first_page,
+			'\N{BLACK LEFT-POINTING TRIANGLE}': self.previous_page,
+			'\N{BLACK RIGHT-POINTING TRIANGLE}': self.next_page,
+			'\N{BLACK RIGHT-POINTING DOUBLE TRIANGLE WITH VERTICAL BAR}': self.last_page,
+			'\N{BLACK SQUARE FOR STOP}': self.stop
+		}
+
+		self._page = None
+
+	async def begin(self):
+		"""Starts pagination"""
+		self._stopped = False
+		self._embed = discord.Embed()
+		await self.first_page()
+		for button in self.navigation:
+			await self._message.add_reaction(button)
+		while not self._stopped:
+			try:
+				reaction, user = await self._client.wait_for('reaction_add', check=self.predicate, timeout=self.timeout)
+			except asyncio.TimeoutError:
+				await self.stop(delete=self.delete_msg_timeout)
+				continue
+
+			reaction = reaction.emoji
+
+			if reaction not in self.navigation:
+				continue  # not worth our time
+
+			await self.navigation[reaction]()
+
+			await asyncio.sleep(0.2)
+			with contextlib.suppress(discord.HTTPException):
+				await self._message.remove_reaction(reaction, user)
+
+	async def stop(self, *, delete=None):
+		"""Aborts pagination."""
+		if delete is None:
+			delete = self.delete_msg
+
+		if delete:
+			await self._message.delete()
+		else:
+			await self._clear_reactions()
+		self._stopped = True
+
+	async def _clear_reactions(self):
+		try:
+			await self._message.clear_reactions()
+		except discord.Forbidden:
+			for button in self.navigation:
+				await self._message.remove_reaction(button, self._message.author)
+
+	async def format_page(self):
+		self._embed.description = self.pages[self._page]
+		self._embed.set_footer(text=self.footer.format(self._page + 1, len(self.pages)))
+
+		kwargs = {'embed': self._embed}
+		if self.text_message:
+			kwargs['content'] = self.text_message
+
+		if self._message:
+			await self._message.edit(**kwargs)
+		else:
+			self._message = await self.target.send(**kwargs)
+
+	async def first_page(self):
+		self._page = 0
+		await self.format_page()
+
+	async def next_page(self):
+		self._page += 1
+		if self._page == len(self.pages):  # avoid the inevitable IndexError
+			self._page = 0
+		await self.format_page()
+
+	async def previous_page(self):
+		self._page -= 1
+		if self._page < 0:	# ditto
+			self._page = len(self.pages) - 1
+		await self.format_page()
+
+	async def last_page(self):
+		self._page = len(self.pages) - 1
+		await self.format_page()
+
+
+class ListPaginator(Paginator):
+	def __init__(self, ctx, _list: list, per_page=10, **kwargs):
+		pages = []
+		page = ''
+		c = 0
+		l = len(_list)
+		for i in _list:
+			if c > l:
+				break
+			if c % per_page == 0 and page:
+				pages.append(page.strip())
+				page = ''
+			page += '{}. {}\n'.format(c+1, i)
+
+			c += 1
+		pages.append(page.strip())
+		# shut up, IDEA
+		# noinspection PyArgumentList
+		super().__init__(ctx, pages, **kwargs)
+		self.footer += ' ({} entries)'.format(l)