Add currency selection with live exchange rate fetching

Currency dropdown now uses 30 currencies from ExchangeRateService.
Defaults to base currency from settings. Selecting a different
currency fetches the exchange rate asynchronously and displays it.
Rate is stored with the transaction on save.

outlay-gtk/src/log_view.rs

@@ -1,8 +1,9 @@
 use adw::prelude::*;
 use gtk::glib;
 use outlay_core::db::Database;
+use outlay_core::exchange::ExchangeRateService;
 use outlay_core::models::{NewTransaction, TransactionType};
-use std::cell::RefCell;
+use std::cell::{Cell, RefCell};
 use std::rc::Rc;
 
 pub struct LogView {
@@ -24,8 +25,25 @@ impl LogView {
 
         let inner = gtk::Box::new(gtk::Orientation::Vertical, 24);
 
-        // Category IDs tracked alongside the model
         let category_ids: Rc<RefCell<Vec<i64>>> = Rc::new(RefCell::new(Vec::new()));
+        let exchange_rate: Rc<Cell<f64>> = Rc::new(Cell::new(1.0));
+
+        // Get base currency from settings
+        let base_currency = db
+            .get_setting("base_currency")
+            .ok()
+            .flatten()
+            .unwrap_or_else(|| "USD".to_string());
+
+        // Currency codes list
+        let currencies = ExchangeRateService::supported_currencies();
+        let currency_codes: Vec<&str> = currencies.iter().map(|(code, _)| *code).collect();
+
+        // Find index of base currency
+        let base_idx = currency_codes
+            .iter()
+            .position(|c| c.eq_ignore_ascii_case(&base_currency))
+            .unwrap_or(0);
 
         // -- Transaction type toggle --
         let type_box = gtk::Box::new(gtk::Orientation::Horizontal, 0);
@@ -56,15 +74,27 @@ impl LogView {
         form_group.add(&amount_row);
 
         // Currency
-        let currency_model = gtk::StringList::new(&[
+        let currency_labels: Vec<String> = currencies
-            "USD", "EUR", "GBP", "JPY", "CAD", "AUD", "CHF", "CNY", "INR", "BRL",
+            .iter()
-        ]);
+            .map(|(code, name)| format!("{} - {}", code, name))
+            .collect();
+        let currency_label_refs: Vec<&str> = currency_labels.iter().map(|s| s.as_str()).collect();
+        let currency_model = gtk::StringList::new(&currency_label_refs);
         let currency_row = adw::ComboRow::builder()
             .title("Currency")
             .model(&currency_model)
+            .selected(base_idx as u32)
             .build();
         form_group.add(&currency_row);
 
+        // Exchange rate info label
+        let rate_label = gtk::Label::new(None);
+        rate_label.add_css_class("dim-label");
+        rate_label.add_css_class("caption");
+        rate_label.set_halign(gtk::Align::Start);
+        rate_label.set_margin_start(16);
+        rate_label.set_visible(false);
+
         // Category
         let category_model = gtk::StringList::new(&[]);
         let category_row = adw::ComboRow::builder()
@@ -72,7 +102,6 @@ impl LogView {
             .model(&category_model)
             .build();
 
-        // Populate from database
         Self::populate_categories_from_db(&db, &category_model, &category_ids, TransactionType::Expense);
 
         form_group.add(&category_row);
@@ -128,6 +157,50 @@ impl LogView {
         save_button.set_halign(gtk::Align::Center);
         save_button.set_margin_top(8);
 
+        // -- Wire currency change to fetch exchange rate --
+        {
+            let db_ref = db.clone();
+            let rate_ref = exchange_rate.clone();
+            let rate_label_ref = rate_label.clone();
+            let base_currency_clone = base_currency.clone();
+            let currency_codes_clone: Vec<String> = currency_codes.iter().map(|s| s.to_string()).collect();
+            currency_row.connect_selected_notify(move |row| {
+                let idx = row.selected() as usize;
+                if idx >= currency_codes_clone.len() {
+                    return;
+                }
+                let selected = &currency_codes_clone[idx];
+                if selected.eq_ignore_ascii_case(&base_currency_clone) {
+                    rate_ref.set(1.0);
+                    rate_label_ref.set_visible(false);
+                } else {
+                    // Fetch rate asynchronously
+                    let db_async = db_ref.clone();
+                    let base = base_currency_clone.clone();
+                    let target = selected.clone();
+                    let rate_async = rate_ref.clone();
+                    let label_async = rate_label_ref.clone();
+                    glib::spawn_future_local(async move {
+                        let service = ExchangeRateService::new(&db_async);
+                        match service.get_rate(&base, &target).await {
+                            Ok(rate) => {
+                                rate_async.set(rate);
+                                label_async.set_label(&format!(
+                                    "1 {} = {:.4} {}", base, rate, target
+                                ));
+                                label_async.set_visible(true);
+                            }
+                            Err(_) => {
+                                rate_async.set(1.0);
+                                label_async.set_label("Could not fetch exchange rate");
+                                label_async.set_visible(true);
+                            }
+                        }
+                    });
+                }
+            });
+        }
+
         // -- Wire type toggle to filter categories from DB --
         {
             let db_ref = db.clone();
@@ -167,13 +240,14 @@ impl LogView {
             let expense_btn_ref = expense_btn.clone();
             let amount_row_ref = amount_row.clone();
             let currency_row_ref = currency_row.clone();
-            let currency_model_ref = currency_model.clone();
             let category_row_ref = category_row.clone();
             let ids_ref = category_ids.clone();
             let date_label_ref = date_label.clone();
             let note_row_ref = note_row.clone();
             let recent_group_ref = recent_group.clone();
             let toast_overlay_ref = toast_overlay.clone();
+            let rate_ref = exchange_rate.clone();
+            let currency_codes_save: Vec<String> = currency_codes.iter().map(|s| s.to_string()).collect();
 
             save_button.connect_clicked(move |_| {
                 let amount_text = amount_row_ref.text();
@@ -203,10 +277,10 @@ impl LogView {
                     }
                 };
 
-                let currency_idx = currency_row_ref.selected();
+                let currency_idx = currency_row_ref.selected() as usize;
-                let currency_item = currency_model_ref
+                let currency = currency_codes_save
-                    .string(currency_idx)
+                    .get(currency_idx)
-                    .map(|s| s.to_string())
+                    .cloned()
                     .unwrap_or_else(|| "USD".to_string());
 
                 let date_text = date_label_ref.label();
@@ -224,8 +298,8 @@ impl LogView {
                     amount,
                     transaction_type: txn_type,
                     category_id,
-                    currency: currency_item,
+                    currency,
-                    exchange_rate: 1.0,
+                    exchange_rate: rate_ref.get(),
                     note,
                     date,
                     recurring_id: None,
@@ -240,11 +314,9 @@ impl LogView {
                         let toast = adw::Toast::new(msg);
                         toast_overlay_ref.add_toast(toast);
 
-                        // Clear form
                         amount_row_ref.set_text("");
                         note_row_ref.set_text("");
 
-                        // Refresh recent
                         Self::refresh_recent(&db_ref, &recent_group_ref);
                     }
                     Err(e) => {
@@ -258,6 +330,7 @@ impl LogView {
         // -- Assemble --
         inner.append(&type_box);
         inner.append(&form_group);
+        inner.append(&rate_label);
         inner.append(&save_button);
         inner.append(&recent_group);
 
@@ -296,16 +369,10 @@ impl LogView {
     }
 
     fn refresh_recent(db: &Database, group: &adw::PreferencesGroup) {
-        // Remove all existing children by rebuilding
-        // PreferencesGroup doesn't have a clear method, so we remove then re-add
-        // We track children via a helper: iterate and remove
         while let Some(child) = group.first_child() {
-            // The group has an internal listbox; we need to find ActionRows
-            // Actually, PreferencesGroup.remove() takes a widget ref
             if let Some(row) = child.downcast_ref::<adw::ActionRow>() {
                 group.remove(row);
             } else if let Some(row) = child.downcast_ref::<gtk::ListBoxRow>() {
-                // Try generic removal via parent
                 if let Some(parent) = row.parent() {
                     if let Some(listbox) = parent.downcast_ref::<gtk::ListBox>() {
                         listbox.remove(row);
@@ -321,11 +388,9 @@ impl LogView {
                 for txn in &txns {
                     let cat_name = db
                         .get_category(txn.category_id)
-                        .map(|c| {
+                        .map(|c| match &c.icon {
-                            match &c.icon {
                             Some(icon) => format!("{} {}", icon, c.name),
                             None => c.name,
-                            }
                         })
                         .unwrap_or_else(|_| "Unknown".to_string());