Error Handling with Result and Option (page 34)

src/main.rs

@@ -109,18 +109,32 @@ impl TodoList {
 
 fn main() {
     let cli = Cli::parse();
-    match cli.command {
-        Commands::Add { task } => {
-            println!("Adding task: {}", task);
-        }
-        Commands::List => {
-            println!("Listing tasks");
-        }
-        Commands::Complete { id } => {
-            println!("Completing task with id: {}", id);
-        }
-        Commands::Remove { id } => {
-            println!("Removing task with id: {}", id);
-        }
+
+    if let Err(e) = run_command(cli) {
+        eprintln!("Error: {}", e);
+        std::process::exit(1);
     }
 }
+
+fn run_command(cli: Cli) -> Result<(), TodoError> {
+    let mut todo_list =
+        TodoList::load_from_file("tasks.json").map_err(|e| TodoError::FileError(e.to_string()))?;
+
+    match cli.command {
+        Commands::Add { task } => {
+            todo_list.add_task(task)?;
+            println!("Task added successfully");
+        }
+        Commands::Complete { id } => {
+            todo_list.complete_task(id)?;
+            println!("Task {} marked as complete", id);
+        }
+        _ => {} // Handle other commands
+    }
+
+    todo_list
+        .save_to_file("todo.json")
+        .map_err(|e| TodoError::FileError(e.to_string()))?;
+
+    Ok(())
+}