refactor: remove sync_usage option, enhance SSH connection error messages

src/app/settings.rs

@@ -13,7 +13,6 @@ pub enum SettingsField {
     S3Bucket,
     S3AccessKey,
     S3SecretKey,
-    SyncUsage,
 }
 
 impl SettingsField {
@@ -37,7 +36,6 @@ impl SettingsField {
                 ]);
             }
         }
-        fields.push(SettingsField::SyncUsage);
         fields
     }
 
@@ -53,12 +51,11 @@ impl SettingsField {
             Self::S3Bucket => "Bucket",
             Self::S3AccessKey => "Access Key",
             Self::S3SecretKey => "Secret Key",
-            Self::SyncUsage => "Sync Usage",
-        }
+            }
     }
 
     pub fn is_toggle(self) -> bool {
-        matches!(self, Self::Backend | Self::SyncUsage)
+        matches!(self, Self::Backend)
     }
 
     pub fn is_text(self) -> bool {
@@ -78,7 +75,6 @@ pub struct SettingsState {
     pub s3_bucket: String,
     pub s3_access_key: String,
     pub s3_secret_key: String,
-    pub sync_usage: bool,
     pub active: SettingsField,
     pub cursor: usize,
 }
@@ -148,7 +144,6 @@ impl Default for SettingsState {
             s3_bucket: String::new(),
             s3_access_key: String::new(),
             s3_secret_key: String::new(),
-            sync_usage: false,
             active: SettingsField::SyncPassword,
             cursor: 0,
         }
@@ -225,7 +220,6 @@ impl App {
             self.config.settings.s3_access_key.clone().unwrap_or_default();
         self.session.settings.s3_secret_key =
             self.config.settings.s3_secret_key.clone().unwrap_or_default();
-        self.session.settings.sync_usage = self.config.settings.sync_usage_count;
         self.session.settings.active = SettingsField::SyncPassword;
         self.session.settings.cursor = char_len(self.session.settings.active_text());
         self.session.mode = Mode::Settings;
@@ -259,7 +253,6 @@ impl App {
         } else {
             Some(s3_sk)
         };
-        self.config.settings.sync_usage_count = self.session.settings.sync_usage;
         self.config.save()?;
         self.session.mode = Mode::Home;
         Ok(())

src/config.rs

@@ -64,8 +64,6 @@ pub struct Settings {
     pub s3_bucket: Option<String>,
     pub s3_access_key: Option<String>,
     pub s3_secret_key: Option<String>,
-    #[serde(default)]
-    pub sync_usage_count: bool,
     pub sync_password: Option<String>,
 }
 

src/connection.rs

@@ -1,9 +1,38 @@
-use crate::config::{ConnectionType, CredentialEntry, SshellConfig};
+use crate::config::{ConnectionType, CredentialEntry, SshellConfig, find_binary};
 use anyhow::{Context, Result, bail};
 use std::io::Write;
 use std::process::Command;
 use tempfile::NamedTempFile;
 
+fn require_binary(name: &str) -> Result<()> {
+    if find_binary(name).is_some() {
+        return Ok(());
+    }
+    let hint = match name {
+        "ssh" => "\n\
+            sshell requires `ssh` to connect via SSH.\n\
+            \n\
+            Install it with:\n\
+              macOS:    pre-installed (or: xcode-select --install)\n\
+              Debian:   sudo apt install openssh-client\n\
+              Arch:     sudo pacman -S openssh\n\
+              Fedora:   sudo dnf install openssh-clients\n\
+              Windows:  Settings → Apps → Optional Features → OpenSSH Client"
+            ,
+        "sshpass" => "\n\
+            Password-based SSH login requires `sshpass`.\n\
+            Consider switching to private-key auth instead, or install it:\n\
+              macOS:    brew install hudochenkov/sshpass/sshpass\n\
+              Debian:   sudo apt install sshpass\n\
+              Arch:     sudo pacman -S sshpass\n\
+              Fedora:   sudo dnf install sshpass\n\
+              Windows:  not available — use private-key auth"
+            ,
+        _ => "",
+    };
+    bail!("command not found: `{name}`{hint}");
+}
+
 pub fn connect(name: &str, cfg: &SshellConfig) -> Result<()> {
     let profile = cfg
         .connections
@@ -41,8 +70,10 @@ fn connect_ssh(
     if auth_ref.is_empty() {
         bail!("this connection has no credential; edit it and set password or private key");
     }
+    require_binary("ssh")?;
     match cfg.credential(auth_ref) {
         Some(CredentialEntry::Password { value, .. }) => {
+            require_binary("sshpass")?;
             let args = vec![
                 "ssh".to_string(),
                 "-o".to_string(),
@@ -87,7 +118,7 @@ fn run_sshpass(args: &[String], password: &str) -> Result<()> {
         .args(args)
         .env("SSHPASS", password)
         .status()
-        .context("failed to run sshpass — is it installed?")?;
+        .context("failed to run sshpass")?;
     std::process::exit(status.code().unwrap_or(1));
 }
 

src/sync.rs

@@ -60,9 +60,6 @@ pub(crate) fn build_sync_payload(
     sync_password: Option<&str>,
 ) -> Result<toml::Value> {
     let mut payload = cfg.clone();
-    payload.settings.sync_password = None;
-    payload.settings.webdav_password = None;
-    payload.settings.s3_secret_key = None;
 
     let synced_refs: Vec<String> = payload
         .connections
@@ -90,14 +87,10 @@ pub(crate) fn build_sync_payload(
         "version".to_string(),
         toml::Value::Integer(payload.version as i64),
     );
-    table.insert("settings".to_string(), to_toml_value(&payload.settings)?);
-
     let mut conns = toml::map::Map::new();
     for (name, profile) in &mut payload.connections {
         profile.local_tags.clear();
-        if !payload.settings.sync_usage_count {
-            profile.usage_count = 0;
-        }
+        profile.usage_count = 0;
         match &mut profile.kind {
             ConnectionType::Shell {
                 auth_ref,

src/ui/view/settings.rs

@@ -1,7 +1,7 @@
 use crate::app::{App, FormAction, Mode, SettingsField, SettingsState, char_len};
 use crate::config::SyncBackend;
 use crate::ui::component::{FormRow, badge_span};
-use crate::ui::{ACCENT, GREEN, ORANGE, PURPLE, RED};
+use crate::ui::{ACCENT, ORANGE, PURPLE};
 
 use super::{View, handle_form_nav};
 
@@ -31,7 +31,7 @@ impl View for SettingsView {
             let active = settings.active == field;
             let label = field.label().to_string();
 
-            if i == 2 || matches!(field, SettingsField::SyncUsage) {
+            if i == 2 {
                 rows.push(FormRow::Separator);
             }
 
@@ -42,13 +42,6 @@ impl View for SettingsView {
                         SyncBackend::Webdav => badge_span("WebDAV", ORANGE),
                         SyncBackend::S3 => badge_span("S3", PURPLE),
                     },
-                    SettingsField::SyncUsage => {
-                        if settings.sync_usage {
-                            badge_span("Yes", GREEN)
-                        } else {
-                            badge_span("No", RED)
-                        }
-                    }
                     _ => unreachable!(),
                 };
                 rows.push(FormRow::Toggle {
@@ -131,9 +124,6 @@ fn settings_toggle(settings: &mut SettingsState) {
             };
             settings.ensure_active_visible();
         }
-        SettingsField::SyncUsage => {
-            settings.sync_usage = !settings.sync_usage;
-        }
         _ => {}
     }
 }