From e5ea38b4425dbb8e5a7c7c9414f705856c85d81f Mon Sep 17 00:00:00 2001
From: Natsu Kagami <natsukagami@gmail.com>
Date: Thu, 16 Jan 2020 03:56:19 -0500
Subject: [PATCH] Implement announcer

---
 youmubot/src/commands/announcer.rs | 51 ++++++++++++++++++++++++++++++
 youmubot/src/commands/mod.rs       |  1 +
 2 files changed, 52 insertions(+)
 create mode 100644 youmubot/src/commands/announcer.rs

diff --git a/youmubot/src/commands/announcer.rs b/youmubot/src/commands/announcer.rs
new file mode 100644
index 0000000..4e98114
--- /dev/null
+++ b/youmubot/src/commands/announcer.rs
@@ -0,0 +1,51 @@
+use serenity::{
+    builder::CreateMessage,
+    framework::standard::{CommandError as Error, CommandResult},
+    http::{CacheHttp, Http},
+    model::id::{ChannelId, GuildId, UserId},
+};
+use std::{
+    collections::HashSet,
+    thread::{spawn, JoinHandle},
+};
+
+pub trait Announcer {
+    type MessageSender: for<'a, 'r> Fn(&'r mut CreateMessage<'a>) -> &'r mut CreateMessage<'a>;
+
+    fn get_guilds(c: impl AsRef<Http>) -> Result<Vec<(GuildId, ChannelId)>, Error>;
+    fn fetch_messages(c: impl AsRef<Http>) -> Result<Vec<(UserId, Self::MessageSender)>, Error>;
+
+    fn announce(c: impl AsRef<Http>) -> CommandResult {
+        let guilds: Vec<_> = Self::get_guilds(c.as_ref())?;
+        let member_sets = {
+            let mut v = Vec::with_capacity(guilds.len());
+            for (guild, channel) in guilds.into_iter() {
+                let mut s = HashSet::new();
+                for user in guild.members_iter(c.as_ref()) {
+                    s.insert(user?.user_id());
+                }
+                v.push((s, channel))
+            }
+            v
+        };
+        for (user_id, f) in Self::fetch_messages(c.as_ref())?.into_iter() {
+            for (members, channel) in member_sets.iter() {
+                if members.contains(&user_id) {
+                    if let Err(e) = channel.send_message(c.as_ref(), &f) {
+                        dbg!((user_id, channel, e));
+                    }
+                }
+            }
+        }
+        Ok(())
+    }
+
+    fn scan(c: impl CacheHttp + 'static + Send, cooldown: std::time::Duration) -> JoinHandle<()> {
+        spawn(move || loop {
+            if let Err(e) = Self::announce(c.http()) {
+                dbg!(e);
+            }
+            std::thread::sleep(cooldown);
+        })
+    }
+}
diff --git a/youmubot/src/commands/mod.rs b/youmubot/src/commands/mod.rs
index b323cbb..00925ac 100644
--- a/youmubot/src/commands/mod.rs
+++ b/youmubot/src/commands/mod.rs
@@ -7,6 +7,7 @@ use serenity::{
 };
 use std::collections::HashSet;
 
+mod announcer;
 mod args;
 
 pub mod admin;