feat: implement model management commands and overlays for enhanced user interaction

src/app/state/misc.rs

@@ -62,6 +62,7 @@ pub struct InputState {
     pub autocomplete_prefix: String,
     pub autocomplete_candidates: Vec<String>,
     pub autocomplete_idx: usize,
+    pub autocomplete_visible: bool,
 }
 
 const COMMANDS: &[&str] = &[
@@ -87,6 +88,9 @@ const COMMANDS: &[&str] = &[
     "/login openai",
     "/edit",
     "/mcp add",
+    "/model",
+    "/model ls",
+    "/model add",
 ];
 
 impl InputState {
@@ -99,36 +103,63 @@ impl InputState {
             autocomplete_prefix: String::new(),
             autocomplete_candidates: Vec::new(),
             autocomplete_idx: 0,
+            autocomplete_visible: false,
         }
     }
 
-    pub fn tab_complete(&mut self) {
-        let trimmed = self.buffer.trim().to_string();
-        if trimmed.is_empty() {
-            return;
-        }
+    pub fn close_autocomplete(&mut self) {
+        self.autocomplete_visible = false;
+        self.autocomplete_candidates.clear();
+        self.autocomplete_prefix.clear();
+        self.autocomplete_idx = 0;
+    }
 
-        if !trimmed.starts_with('/') {
+    pub fn open_autocomplete(&mut self) {
+        let trimmed = self.buffer.trim().to_string();
+        if trimmed.is_empty() || !trimmed.starts_with('/') {
+            self.close_autocomplete();
             return;
         }
 
         let prefix = trimmed.to_lowercase();
+        self.autocomplete_candidates = COMMANDS
+            .iter()
+            .filter(|c| c.starts_with(&prefix))
+            .map(|c| c.to_string())
+            .collect();
+        self.autocomplete_prefix = prefix;
+        self.autocomplete_idx = 0;
+        self.autocomplete_visible = !self.autocomplete_candidates.is_empty();
+    }
 
-        if prefix != self.autocomplete_prefix || self.autocomplete_candidates.is_empty() {
-            self.autocomplete_candidates = COMMANDS
-                .iter()
-                .filter(|c| c.starts_with(&prefix))
-                .map(|c| c.to_string())
-                .collect();
-            self.autocomplete_prefix = prefix;
-            self.autocomplete_idx = 0;
+    pub fn cycle_autocomplete(&mut self, forward: bool) {
+        let n = self.autocomplete_candidates.len();
+        if n == 0 { return; }
+        if forward {
+            self.autocomplete_idx = (self.autocomplete_idx + 1) % n;
         } else {
-            self.autocomplete_idx = (self.autocomplete_idx + 1) % self.autocomplete_candidates.len();
+            self.autocomplete_idx = if self.autocomplete_idx == 0 { n - 1 } else { self.autocomplete_idx - 1 };
         }
+    }
 
+    pub fn select_autocomplete(&mut self) -> bool {
         if let Some(candidate) = self.autocomplete_candidates.get(self.autocomplete_idx) {
             self.buffer = candidate.clone();
             self.cursor = self.buffer.len();
+            self.close_autocomplete();
+            true
+        } else {
+            false
+        }
+    }
+
+    pub fn tab_complete(&mut self) {
+        // Legacy inline tab-complete — used as a fallback when the dropdown
+        // isn't visible yet. Opens the dropdown on the first Tab press.
+        if !self.autocomplete_visible {
+            self.open_autocomplete();
+        } else {
+            self.cycle_autocomplete(true);
         }
     }