feat: add fee multiplier caching and use it across all UI screens

src/backend_task/platform_info.rs

@@ -367,7 +367,16 @@ impl AppContext {
             PlatformInfoTaskRequestType::CurrentEpochInfo => {
                 match ExtendedEpochInfo::fetch_current(&sdk).await {
                     Ok(epoch_info) => {
-                        let formatted = format_extended_epoch_info(epoch_info, self.network, true);
+                        // Cache the fee multiplier for UI fee estimation
+                        let fee_multiplier = epoch_info.fee_multiplier_permille();
+                        self.set_fee_multiplier_permille(fee_multiplier);
+
+                        let mut formatted =
+                            format_extended_epoch_info(epoch_info, self.network, true);
+                        formatted.push_str(&format!(
+                            "\n\n(Fee multiplier cache updated: {}x)",
+                            fee_multiplier as f64 / 1000.0
+                        ));
                         Ok(BackendTaskSuccessResult::PlatformInfo(
                             PlatformInfoTaskResult::TextResult(formatted),
                         ))

src/context.rs

@@ -6,6 +6,7 @@ use crate::context_provider::Provider as RpcProvider;
 use crate::context_provider_spv::SpvProvider;
 use crate::database::Database;
 use crate::model::contested_name::ContestedName;
+use crate::model::fee_estimation::PlatformFeeEstimator;
 use crate::model::password_info::PasswordInfo;
 use crate::model::qualified_contract::QualifiedContract;
 use crate::model::qualified_identity::{DPNSNameInfo, QualifiedIdentity};
@@ -49,7 +50,7 @@ use dash_sdk::query_types::IndexMap;
 use egui::Context;
 use rusqlite::Result;
 use std::collections::{BTreeMap, HashMap};
-use std::sync::atomic::{AtomicBool, AtomicU8, Ordering};
+use std::sync::atomic::{AtomicBool, AtomicU8, AtomicU64, Ordering};
 use std::sync::{Arc, Mutex, RwLock, RwLockWriteGuard};
 
 const ANIMATION_REFRESH_TIME: std::time::Duration = std::time::Duration::from_millis(100);
@@ -106,6 +107,9 @@ pub struct AppContext {
     pub(crate) selected_wallet_hash: Mutex<Option<WalletSeedHash>>,
     /// Currently selected single key wallet (persisted across screen navigation)
     pub(crate) selected_single_key_hash: Mutex<Option<SingleKeyHash>>,
+    /// Cached fee multiplier permille from current epoch (1000 = 1x, 2000 = 2x)
+    /// Updated when epoch info is fetched from Platform
+    fee_multiplier_permille: AtomicU64,
 }
 
 impl AppContext {
@@ -275,6 +279,9 @@ impl AppContext {
             pending_wallet_selection: Mutex::new(None),
             selected_wallet_hash: Mutex::new(selected_wallet_hash),
             selected_single_key_hash: Mutex::new(selected_single_key_hash),
+            fee_multiplier_permille: AtomicU64::new(
+                PlatformFeeEstimator::DEFAULT_FEE_MULTIPLIER_PERMILLE,
+            ),
         };
 
         let app_context = Arc::new(app_context);
@@ -395,6 +402,24 @@ impl AppContext {
         }
     }
 
+    /// Get the cached fee multiplier permille (1000 = 1x, 2000 = 2x)
+    pub fn fee_multiplier_permille(&self) -> u64 {
+        self.fee_multiplier_permille.load(Ordering::Relaxed)
+    }
+
+    /// Update the cached fee multiplier from epoch info
+    pub fn set_fee_multiplier_permille(&self, multiplier: u64) {
+        self.fee_multiplier_permille
+            .store(multiplier, Ordering::Relaxed);
+    }
+
+    /// Get a fee estimator configured with the cached fee multiplier.
+    /// Use this instead of `PlatformFeeEstimator::new()` to get accurate fee estimates
+    /// that reflect the current network fee multiplier.
+    pub fn fee_estimator(&self) -> PlatformFeeEstimator {
+        PlatformFeeEstimator::with_fee_multiplier(self.fee_multiplier_permille())
+    }
+
     pub fn spv_manager(&self) -> &Arc<SpvManager> {
         &self.spv_manager
     }