feat: 前端添加下载状态卡片 (#385)

crates/bili_sync/src/utils/task_notifier.rs

@@ -0,0 +1,79 @@
+use std::sync::{Arc, LazyLock};
+
+use serde::Serialize;
+use tokio::sync::MutexGuard;
+
+use crate::config::VersionedConfig;
+
+pub static TASK_STATUS_NOTIFIER: LazyLock<TaskStatusNotifier> = LazyLock::new(TaskStatusNotifier::new);
+
+#[derive(Serialize)]
+pub struct TaskStatus {
+    is_running: bool,
+    last_run: Option<chrono::DateTime<chrono::Local>>,
+    last_finish: Option<chrono::DateTime<chrono::Local>>,
+    next_run: Option<chrono::DateTime<chrono::Local>>,
+}
+
+pub struct TaskStatusNotifier {
+    mutex: tokio::sync::Mutex<()>,
+    tx: tokio::sync::watch::Sender<Arc<TaskStatus>>,
+    rx: tokio::sync::watch::Receiver<Arc<TaskStatus>>,
+}
+
+impl Default for TaskStatus {
+    fn default() -> Self {
+        Self {
+            is_running: false,
+            last_run: None,
+            last_finish: None,
+            next_run: None,
+        }
+    }
+}
+
+impl TaskStatusNotifier {
+    pub fn new() -> Self {
+        let (tx, rx) = tokio::sync::watch::channel(Arc::new(TaskStatus::default()));
+        Self {
+            mutex: tokio::sync::Mutex::const_new(()),
+            tx,
+            rx,
+        }
+    }
+
+    pub async fn start_running(&self) -> MutexGuard<()> {
+        let lock = self.mutex.lock().await;
+        let _ = self.tx.send(Arc::new(TaskStatus {
+            is_running: true,
+            last_run: Some(chrono::Local::now()),
+            last_finish: None,
+            next_run: None,
+        }));
+        lock
+    }
+
+    pub fn finish_running(&self, _lock: MutexGuard<()>) {
+        let last_status = self.tx.borrow();
+        let last_run = last_status.last_run.clone();
+        drop(last_status);
+        let config = VersionedConfig::get().load();
+        let now = chrono::Local::now();
+
+        let _ = self.tx.send(Arc::new(TaskStatus {
+            is_running: false,
+            last_run,
+            last_finish: Some(now),
+            next_run: now.checked_add_signed(chrono::Duration::seconds(config.interval as i64)),
+        }));
+    }
+
+    /// 精确探测任务执行状态，保证如果读取到“未运行”，那么在锁释放之前任务不会被执行
+    pub fn detect_running(&self) -> Option<MutexGuard<'_, ()>> {
+        self.mutex.try_lock().ok()
+    }
+
+    pub fn subscribe(&self) -> tokio::sync::watch::Receiver<Arc<TaskStatus>> {
+        self.rx.clone()
+    }
+}