feat(backend) move module scheduler

backend/server/src/scheduler/tasks/basic.rs

@@ -0,0 +1,37 @@
+use crate::scheduler::task_func::TaskFunc;
+use crate::scheduler::tasks::Task;
+use chrono::{DateTime, Utc};
+use cron::Schedule;
+use std::error::Error;
+use std::str::FromStr;
+
+pub struct BasicTask {
+    schedule: Schedule,
+    func: Box<dyn TaskFunc>,
+}
+
+impl BasicTask {
+    pub fn new<F>(func: F, cron_expr: &str) -> Result<Self, Box<dyn Error>>
+    where
+        F: TaskFunc,
+    {
+        Ok(BasicTask {
+            schedule: Schedule::from_str(cron_expr)?,
+            func: Box::new(func),
+        })
+    }
+
+    pub fn to_task(self) -> Box<dyn Task> {
+        Box::new(self)
+    }
+}
+
+impl Task for BasicTask {
+    fn get_next_execution(&self) -> Option<DateTime<Utc>> {
+        self.schedule.upcoming(Utc).next()
+    }
+
+    fn call(&self) {
+        (self.func)()
+    }
+}