action_items: add reactions

src/extensions/action_items.py

@@ -95,14 +95,20 @@ async def get_action_items(
 
     # send each bullet point separately
     for item in formatted_bullet_points:
-        await action_items.client.rest.create_message(
+        item = await action_items.client.rest.create_message(
             CHANNEL_IDS["action-items"],
             mentions_everyone=False,
             user_mentions=True,
             role_mentions=True,
             content=item,
         )
 
+        await action_items.client.rest.add_reaction(
+            channel=item.channel_id,
+            message=item.id,
+            emoji="✅",
+        )
+
     # respond with success if it executes successfully
     await ctx.respond(
         "✅ Action Items sent successfully!",
@@ -111,6 +117,129 @@ async def get_action_items(
     return
 
 
+async def check_valid_reaction(
+    event: hikari.GuildReactionAddEvent | hikari.GuildReactionDeleteEvent,
+    message: hikari.PartialMessage,
+) -> bool:
+    bot_user = action_items.client.app.get_me()
+    if not bot_user:  # bot_user will always be available after the bot has started
+        return False
+
+    # ignore reactions by the bot, reactions that are not ✅
+    # and reactions not created in the #action-items channel
+    if (
+        event.user_id == bot_user.id
+        or event.emoji_name != "✅"
+        or event.channel_id != CHANNEL_IDS["action-items"]
+    ):
+        return False
+
+    assert message.author  # it will always be available
+
+    # ignore messages not sent by the bot and messages with no content
+    if message.author.id != bot_user.id or not message.content:
+        return False
+
+    return True
+
+
+async def validate_user_reaction(
+    user_id: int, message_content: str, guild_id: int
+) -> bool:
+    # extract user and role mentions from the message content
+    mention_regex = r"<@[!&]?(\d+)>"
+    mentions = re.findall(mention_regex, message_content)
+
+    # make a list of all mentions
+    mentioned_ids = [int(id_) for id_ in mentions]
+
+    if user_id in mentioned_ids:
+        return True
+
+    member = action_items.client.cache.get_member(
+        guild_id, user_id
+    ) or await action_items.client.rest.fetch_member(guild_id, user_id)
+
+    if any(role_id in mentioned_ids for role_id in member.role_ids):
+        return True
+
+    return False
+
+
+@action_items.listen()
+async def reaction_add(event: hikari.GuildReactionAddEvent) -> None:
+    # retrieve the message that was reacted to
+    message = action_items.client.cache.get_message(
+        event.message_id
+    ) or await action_items.client.rest.fetch_message(
+        event.channel_id, event.message_id
+    )
+
+    is_valid_reaction = await check_valid_reaction(event, message)
+    if not is_valid_reaction:
+        return
+
+    assert message.content  # check_valid_reaction verifies the message content exists
+
+    is_valid_reaction = await validate_user_reaction(
+        event.user_id, message.content, event.guild_id
+    )
+    if not is_valid_reaction:
+        return
+
+    # cross out the action item, if it was not crossed out already
+    if not message.content.startswith("- ✅ ~~"):
+        # add strikethrough and checkmark
+        updated_content = f"- ✅ ~~{message.content[2:]}~~"
+        await action_items.client.rest.edit_message(
+            event.channel_id, event.message_id, content=updated_content
+        )
+
+
+@action_items.listen()
+async def reaction_remove(event: hikari.GuildReactionDeleteEvent) -> None:
+    # retrieve the message that was un-reacted to
+    # NOTE: cannot use cached message as the reaction count will be outdated
+    message = await action_items.client.rest.fetch_message(
+        event.channel_id, event.message_id
+    )
+
+    is_valid_reaction = await check_valid_reaction(event, message)
+    if not is_valid_reaction:
+        return
+
+    assert message.content  # check_valid_reaction verifies the message content exists
+
+    checkmark_reactions = await event.app.rest.fetch_reactions_for_emoji(
+        event.channel_id,
+        event.message_id,
+        "✅",
+    )
+
+    reactions = [
+        await validate_user_reaction(user.id, message.content, event.guild_id)
+        for user in checkmark_reactions
+    ]
+    valid_reaction_count = len(
+        list(
+            filter(
+                lambda r: r is True,
+                reactions,
+            )
+        )
+    )
+
+    assert message.content  # check_valid_reaction verifies the message content exists
+    # remove the strikethrough on the item, provided all mentioned users/roles
+    # are not currently reacted to the message
+    if message.content.startswith("- ✅ ~~") and valid_reaction_count == 0:
+        # add strikethrough and checkmark
+        updated_content = f"- {message.content[6:-2]}"
+        await action_items.client.rest.edit_message(
+            event.channel_id, event.message_id, content=updated_content
+        )
+
+
 @arc.loader
 def loader(client: arc.GatewayClient) -> None:
     client.add_plugin(action_items)