feat(cmd): improve error message

The error message displayed in case of a missing Core Lightning configuration file has been enhanced to provide users with more friendly and actionable information.

Now, when coffee fails to find the configuration file at the specified path, it advises users to resolve the issue by running the coffee setup <cln_path> command, helping them quickly address the problem and proceed smoothly.

Signed-off-by: Tarek <tareknaser360@gmail.com>

coffee_core/src/coffee.rs

@@ -2,6 +2,7 @@
 
 use std::collections::HashMap;
 use std::fmt::Debug;
+use std::path::Path;
 use std::vec::Vec;
 use tokio::fs;
 
@@ -195,10 +196,24 @@ impl CoffeeManager {
         if self.config.cln_config_path.is_none() {
             return Ok(());
         }
-        let root = self.config.cln_root.clone().unwrap();
+        let root = self
+            .config
+            .cln_root
+            .clone()
+            .ok_or_else(|| error!("cln root path not found, please run `coffee setup`"))?;
         let rpc = Client::new(format!("{root}/{}/lightning-rpc", self.config.network));
         self.rpc = Some(rpc);
-        let path = self.config.cln_config_path.clone().unwrap();
+        let path = self
+            .config
+            .cln_config_path
+            .clone()
+            .ok_or_else(|| error!("cln config path not found, please run `coffee setup`"))?;
+        // Ensure that the file exists
+        if !Path::new(&path).exists() {
+            return Err(error!(
+                "cln config path not found, please run `coffee setup`"
+            ));
+        }
         let mut file = CLNConf::new(path.clone(), true);
         log::info!("looking for the cln config: {path}");
         file.parse()
@@ -217,7 +232,10 @@ impl CoffeeManager {
         self.config.cln_config_path = Some(path_with_network);
         self.config.cln_root = Some(cln_dir.to_owned());
         self.load_cln_conf().await?;
-        let mut conf = self.cln_config.clone().unwrap();
+        let mut conf = self
+            .cln_config
+            .clone()
+            .ok_or_else(|| error!("cln config path not found, please run `coffee setup`"))?;
         conf.add_subconf(self.coffee_cln_config.clone())
             .map_err(|err| error!("{}", &err.cause))?;
         conf.flush()?;