Add some comments and add the fetch sub command

src/main.rs

@@ -42,7 +42,7 @@ struct TableSummary {
     tag_ids: Vec<u64>,
 }
 
-use chrono::TimeDelta;
+use chrono::{NaiveDate, TimeDelta};
 use clap::{Parser, Subcommand};
 use std::net::IpAddr;
 
@@ -64,6 +64,7 @@ struct Cli {
 
 #[derive(Subcommand)]
 enum Commands {
+    /// Start the built-in HTTP server
     Server {
         #[arg(long, env = "IP", default_value = "127.0.0.1")]
         ip: IpAddr,
@@ -72,9 +73,17 @@ enum Commands {
         port: u16,
     },
 
+    /// Migrate the database without performing any other actions
     Migrate,
 
+    /// Sync changes since the database was last updated, with a default look-back of 30 days
     Sync,
+
+    /// Fetch time entries within a date range
+    Fetch {
+        since: NaiveDate,
+        until: NaiveDate,
+    },
 }
 
 #[tokio::main]
@@ -102,14 +111,26 @@ async fn main() {
 
     let worker = Worker { db, toggl_api };
 
-    if let Commands::Server { ip, port } = cli.command {
-        server::serve(worker, ip, port)
-            .await
-            .expect("Failed to start server");
-    } else {
-        worker
-            .update(TimeDelta::days(30))
-            .await
-            .expect("Failed to update worker");
+    match cli.command {
+        Commands::Server { ip, port } => {
+            server::serve(worker, ip, port)
+                .await
+                .expect("Failed to start server");
+        }
+        Commands::Sync => {
+            worker
+                .update(TimeDelta::days(30))
+                .await
+                .expect("Failed to update worker");
+        }
+
+        Commands::Fetch { since, until } => {
+            worker
+                .fetch_within(since, until)
+                .await
+                .expect("Failed to fetch worker");
+        }
+
+        Commands::Migrate => unreachable!("Migrate should have returned early"),
     }
 }