Add notification module

src/lib.rs

@@ -9,6 +9,7 @@ use time::Duration;
 pub mod config;
 
 pub mod account;
+pub mod notification;
 pub mod post;
 
 pub mod resource;

src/main.rs

@@ -3,7 +3,7 @@ use std::sync::Arc;
 use dmds::{IoHandle, World};
 use lettre::AsyncSmtpTransport;
 use sms4_backend::{account::Account, config::Config, resource, Error};
-use tokio::sync::{Mutex, RwLock};
+use tokio::sync::Mutex;
 
 macro_rules! ipc {
     ($c:literal) => {

src/notification.rs

@@ -0,0 +1,102 @@
+use std::{
+    hash::{Hash, Hasher},
+    time::SystemTime,
+};
+
+use serde::{Deserialize, Serialize};
+use time::OffsetDateTime;
+
+/// Notification sent by admins, and displayed
+/// by the screens.
+///
+/// # dmds Dimensions
+///
+/// ```txt
+/// 0 -> id
+/// 1 -> start date day of the year
+/// ```
+#[derive(Serialize, Deserialize, Debug, Clone)]
+pub struct Notification {
+    /// Id of the notification.
+    #[serde(skip)]
+    id: u64,
+
+    /// Title of the notification.
+    ///
+    /// # Examples
+    ///
+    /// ```txt
+    /// 教务通知
+    /// ```
+    ///
+    /// ```txt
+    /// 教务公告
+    /// ```
+    pub title: String,
+    /// Body of the notification.
+    pub body: String,
+
+    /// Start time of the notification.
+    time: OffsetDateTime,
+    /// Sender's account id of the notification.
+    sender: u64,
+}
+
+impl Notification {
+    /// Creates a new notification.
+    ///
+    /// The **id** of the notification is generated
+    /// from the body, time and current time.
+    pub fn new(title: String, body: String, time: OffsetDateTime, sender: u64) -> Self {
+        let mut hasher = siphasher::sip::SipHasher24::new();
+        body.hash(&mut hasher);
+        time.hash(&mut hasher);
+        SystemTime::now().hash(&mut hasher);
+
+        Self {
+            id: hasher.finish(),
+            title,
+            body,
+            time,
+            sender,
+        }
+    }
+
+    /// Returns the id of the notification.
+    #[inline]
+    pub fn id(&self) -> u64 {
+        self.id
+    }
+}
+
+impl dmds::Data for Notification {
+    const DIMS: usize = 2;
+    const VERSION: u32 = 1;
+
+    #[inline]
+    fn dim(&self, dim: usize) -> u64 {
+        match dim {
+            0 => self.id,
+            1 => self.time.date().ordinal() as u64,
+            _ => unreachable!(),
+        }
+    }
+
+    fn decode<B: bytes::Buf>(version: u32, dims: &[u64], buf: B) -> std::io::Result<Self> {
+        match version {
+            1 => bincode::deserialize_from(buf.reader())
+                .map(|mut n: Self| {
+                    n.id = dims[0];
+                    n
+                })
+                .map_err(|err| std::io::Error::new(std::io::ErrorKind::Other, err)),
+            _ => unreachable!("unsupported data version {version}"),
+        }
+    }
+
+    #[inline]
+    fn encode<B: bytes::BufMut>(&self, buf: B) -> std::io::Result<()> {
+        bincode::serialize_into(buf.writer(), self)
+            .map_err(|err| std::io::Error::new(std::io::ErrorKind::Other, err))
+    }
+}

src/tests/mod.rs

@@ -3,7 +3,7 @@ use std::{path::PathBuf, sync::Arc};
 use axum::Router;
 use dmds::{mem_io_handle::MemStorage, world};
 use sms4_backend::config::Config;
-use tokio::sync::{Mutex, RwLock};
+use tokio::sync::Mutex;
 
 use crate::Global;