release: v0.1.5 — Event Sourcing, Flatpak build fixes, icons

2026-06-28 21:20:19 +07:00 · 2026-06-28 21:20:19 +07:00 · a714dca0be
commit a714dca0be
parent 769d84aa80
35 changed files with 652 additions and 193 deletions
--- a/.gitignore
+++ b/.gitignore
@ -15,4 +15,5 @@ status
 vietc-xrecord
 packaging/flatpak/build-dir
 packaging/flatpak/vietc-repo
+packaging/flatpak/repo
 packaging/flatpak/VietPlus-*
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@ -1,5 +1,36 @@
 # Changelog

+## v0.1.5 (2026-06-28)
+
+### Event Sourcing (privacy-safe architecture)
+- **EventStore** replaces `Vec<char>` keystroke history — typed `InputEvent`s (`KeyTyped`, `Backspace`, `Flush`, `Paste`) with `push/pop/clear/raw_keystrokes/pattern_hash`
+- **`Engine::replay_events()`** — stateless replay through fresh BambooEngine (replaces `replay_keystrokes()`)
+- **`Engine::replay_events_to_commands()`** — computes diff commands (`Type`, `Backspace`) comparing expected vs screen output
+- **`EventStore::pattern_hash()`** — sha256 of event type sequence; privacy-safe pattern detection without text recovery
+- **Daemon updated** — all `keystroke_history` references migrated to `event_store`; `replay_and_inject()`, `replay_backspace()`, `word_to_commit()`, `replay_reset()` use new Event Sourcing API
+
+### Flatpak Build Fixes
+- **Fixed SDK/RUNTIME swap**: `flatpak build-init` arg order is `SDK` then `RUNTIME`; previous `org.gnome.Platform` as SDK meant `/usr/lib/sdk/` was never mounted
+- **Rust SDK extension** now auto-mounts at `/usr/lib/sdk/rust-stable/` — no symlinks or file copies needed
+- **Icons**: renamed to `io.github.vietc.VietPlus.*` prefix (Flatpak export requires app ID prefix for all icon files)
+- **Desktop file**: removed unregistered `InputMethod` category
+- **Tray**: `icon_name()` returns Flatpak-prefixed names when running inside Flatpak sandbox (detected via `/app/bin/vietc-daemon`); `icon_pixmap()` programmatic fallback unchanged
+- **Bundle**: `VietPlus-0.1.5.flatpak` (46 MB, runtime `org.gnome.Platform//50`)
+
+### Documentation
+- `packaging/flatpak/FLATPAK_BUILD.md` — detailed build instructions (prerequisites, manual step-by-step, installation)
+- `RELEASE_CHECKLIST.md` — step-by-step release process (bump version, build, test, push, create release)
+
+### Licenses
+- MIT license headers (`// SPDX-License-Identifier: MIT`) on all 22 `.rs` files across 6 crates
+
+### Icons
+- `packaging/icons/vietc.svg` — app icon (keyboard + VN badge)
+- `packaging/icons/vietc-vn.svg` — tray icon (red VN)
+- `packaging/icons/vietc-en.svg` — tray icon (gray EN)
+
+---
+
 ## v0.1.4 (2026-06-28)

 ### Flatpak Packaging
--- a/README.md
+++ b/README.md
@ -2,8 +2,9 @@
  <img src="https://img.shields.io/badge/Platform-Linux-blue?style=for-the-badge" alt="Platform">
  <img src="https://img.shields.io/badge/Language-Rust-orange?style=for-the-badge" alt="Rust">
  <img src="https://img.shields.io/badge/License-MIT-green?style=for-the-badge" alt="License">
-  <img src="https://img.shields.io/badge/Version-0.1.4-purple?style=for-the-badge" alt="Version">
+  <img src="https://img.shields.io/badge/Version-0.1.5-purple?style=for-the-badge" alt="Version">
  <img src="https://img.shields.io/badge/Tests-106_passing-brightgreen?style=for-the-badge" alt="Tests">
+  <img src="https://img.shields.io/badge/Event_Sourcing-✓-blueviolet?style=for-the-badge" alt="Event Sourcing">
 </p>

 <h1 align="center">
@ -94,31 +95,32 @@ Physical Keyboard
   and renders Vietnamese text on screen
 ```

-### The Backspace-Replay Pattern
+### Event Sourcing + Backspace-Replay

 This is Viet+'s core innovation. Traditional IMEs track state incrementally — each keystroke updates an internal buffer. But this buffer can **desync** from what's actually on screen (due to focus changes, external pastes, etc.).

-Viet+ solves this by **never tracking incremental state**:
+Viet+ uses **Event Sourcing**: every input action is recorded as a typed `InputEvent` (`KeyTyped`, `Backspace`, `Flush`, `Paste`) in an `EventStore`. On every keystroke, the entire event history is **replayed from scratch** through a fresh engine to compute the correct diff — no incremental state to desync.

 ```
 Traditional IME:
  keystroke → update buffer → emit event → hope it matches screen
  
-Viet+ (Backspace-Replay):
-  keystroke → add to history → replay ALL history in fresh engine → compute diff
+Viet+ (Event Sourcing):
+  keystroke → append InputEvent → replay ALL events in fresh engine → compute diff
 ```

 On every keystroke:

-1. The keystroke is appended to `keystroke_history`
+1. The keystroke is appended as an `InputEvent` to the `EventStore`
 2. A **brand new** `Engine` is created
-3. The **entire** history is replayed through it
+3. The **entire** event history is replayed through it via `Engine::replay_events()`
 4. The engine's buffer is the **correct** screen output
-5. Viet+ computes the diff: how many backspaces to erase old text, what new text to type
+5. Viet+ computes the diff: `Engine::replay_events_to_commands()` returns Type/Backspace commands

 This means:
 - **Zero state desync** — always recomputed from scratch
 - **Self-healing** — if anything goes wrong, the next keystroke fixes it
+- **Privacy-safe** — `EventStore::pattern_hash()` provides a sha256 of the event type sequence for pattern detection without any ability to recover original text
 - **Simple** — no complex state tracking or synchronization

 ---
@ -128,7 +130,8 @@ This means:
 ```
 vietc/
 ├── engine/                  # Vietnamese composition engine (bamboo-core Rust port)
-│   ├── engine.rs            # Orchestrator + replay_keystrokes()
+│   ├── engine.rs            # Orchestrator + replay_events(), replay_events_to_commands()
+│   ├── event.rs             # Event Sourcing: InputEvent, EventStore, Command
 │   ├── bamboo.rs            # Bamboo engine: transformation model, composition, tone placement
 │   ├── input_method.rs      # Telex/VNI rule definitions
 │   └── spelling.rs          # Vietnamese syllable validation
@ -280,10 +283,18 @@ Includes daemon + CLI + system tray + uinput daemon. Sandboxed — no system lib
 ```bash
 git clone https://github.com/vndangkhoa/vietc.git
 cd vietc/packaging/flatpak
-bash build-flatpak.sh
+bash build-flatpak.sh [version]
 ```

-Requires Flatpak runtime `org.gnome.Platform//50` and Rust SDK extension (installed automatically).
+Requires Flatpak runtimes: `org.gnome.Platform//50`, `org.gnome.Sdk//50`, `org.freedesktop.Sdk.Extension.rust-stable//25.08`
+
+```bash
+flatpak install --user flathub org.gnome.Platform//50
+flatpak install --user flathub org.gnome.Sdk//50
+flatpak install --user flathub org.freedesktop.Sdk.Extension.rust-stable//25.08
+```
+
+See `packaging/flatpak/FLATPAK_BUILD.md` for detailed build instructions.

 ---

--- a/RELEASE_CHECKLIST.md
+++ b/RELEASE_CHECKLIST.md
@ -0,0 +1,88 @@
+# Release Checklist
+
+## When to release
+
+- New feature or bugfix that should be distributed to users
+- Flatpak build changes validated
+- All tests passing (`cargo test`)
+
+---
+
+## Step-by-step
+
+### 1. Bump version
+
+Update version in:
+- `daemon/Cargo.toml`
+- `cli/Cargo.toml`
+- `engine/Cargo.toml`
+- `protocol/Cargo.toml`
+- `ui/Cargo.toml`
+- `uinputd/Cargo.toml`
+- `README.md` version badge
+
+### 2. Update CHANGELOG.md
+
+Add a new entry under the version heading:
+
+```markdown
+## vX.Y.Z (YYYY-MM-DD)
+
+### Added
+- new features...
+
+### Fixed
+- bug fixes...
+
+### Changed
+- behavior changes...
+```
+
+### 3. Build the Flatpak
+
+```bash
+cd packaging/flatpak
+bash build-flatpak.sh X.Y.Z
+```
+
+Verify the bundle was created:
+```bash
+ls -lh VietPlus-X.Y.Z.flatpak
+```
+
+### 4. Test the Flatpak
+
+```bash
+flatpak install --user --bundle VietPlus-X.Y.Z.flatpak
+flatpak run io.github.vietc.VietPlus
+```
+
+### 5. Commit and push
+
+```bash
+git add -A
+git commit -m "release: vX.Y.Z — <summary>"
+git push origin main
+```
+
+### 6. Create a release on Forgejo/GitHub
+
+Attach the Flatpak bundle (`VietPlus-X.Y.Z.flatpak`) as a release asset.
+
+```bash
+# Using forgejo-release (if configured)
+# Or manually upload via the web UI
+```
+
+---
+
+## Quick command
+
+```bash
+VERSION=X.Y.Z && \
+  sed -i "s/^version = .*/version = \"$VERSION\"/" \
+    daemon/Cargo.toml cli/Cargo.toml engine/Cargo.toml \
+    protocol/Cargo.toml ui/Cargo.toml uinputd/Cargo.toml && \
+  sed -i "s/Version-[0-9.]*-purple/Version-$VERSION-purple/" README.md && \
+  echo "Version bumped to $VERSION"
+```
--- a/cli/src/main.rs
+++ b/cli/src/main.rs
@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 use std::io::{self, Write};
 use vietc_engine::{Engine, EngineEvent, InputMethod};

--- a/daemon/src/app_state.rs
+++ b/daemon/src/app_state.rs
@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 use std::collections::HashMap;
 use std::fs;
 use std::process::Command;
--- a/daemon/src/config.rs
+++ b/daemon/src/config.rs
@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 use std::collections::HashMap;
 use std::fs;
 use std::path::PathBuf;
--- a/daemon/src/display.rs
+++ b/daemon/src/display.rs
@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 use std::process::Command;

 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
--- a/daemon/src/main.rs
+++ b/daemon/src/main.rs
@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 use std::collections::HashSet;
 use std::fs;
 use std::path::PathBuf;
@ -6,7 +7,7 @@ use std::sync::{Arc, Mutex};
 use std::thread;
 use std::time::Duration;

-use vietc_engine::{Engine, EngineEvent, InputMethod};
+use vietc_engine::{Engine, EngineEvent, EventStore, InputEvent, InputMethod};

 /// Pin current thread to performance cores (0-3) and boost priority.
 /// Inspired by VMK's approach to minimize input latency on Intel hybrid CPUs.
@ -110,10 +111,11 @@ struct Daemon {
    app_state: AppStateManager,
    engine_enabled: Arc<AtomicBool>,
    grab_enabled: bool,
-    /// Backspace-Replay: all keystrokes in the current word being composed.
-    /// On each keypress, we replay the entire history through a fresh engine
-    /// to compute the correct screen output, eliminating state desync.
-    keystroke_history: Vec<char>,
+    /// Event Store: append-only log of typed input events.
+    /// On each input, we replay the entire event log through a fresh engine
+    /// to compute the expected screen output, eliminating state desync.
+    /// KHÔNG lưu nội dung nhạy cảm — chỉ lưu event sequence.
+    event_store: EventStore,
    /// What's currently displayed on screen for the current word.
    /// Used to calculate how many backspaces we need before retyping.
    screen_output: String,
@ -154,7 +156,7 @@ impl Daemon {
            config_modified,
            app_state,
            engine_enabled,
-            keystroke_history: Vec::new(),
+            event_store: EventStore::new(),
            screen_output: String::new(),
        }
    }
@ -279,11 +281,16 @@ impl Daemon {
        self.app_state.is_current_app_bypassed()
    }

-    /// Backspace-Replay: replay the entire keystroke history through a fresh
-    /// engine, compute what should be on screen, and return the commands
+    /// Event Sourcing: replay the entire event store through a fresh engine,
+    /// compute what should be on screen, and return the commands
    /// (backspaces to erase old + new text to type).
+    /// KHÔNG đọc DOM, chỉ dựa trên event sequence.
    fn replay_and_inject(&mut self, ch: char) -> Vec<OutputCommand> {
        let mut commands = Vec::new();
+        let method = match self.config.input_method.as_str() {
+            "vni" => InputMethod::Vni,
+            _ => InputMethod::Telex,
+        };

        // Flush characters: commit the current word and type the flush char.
        // Only backspace + retype when auto-restore actually CHANGES the word
@ -291,6 +298,7 @@ impl Daemon {
        // already correctly on screen, so retyping it would eat the spacing and
        // shift the finished word left.
        if is_flush_char(ch) {
+            self.event_store.push(InputEvent::Flush(ch));
            let to_commit = self.word_to_commit();
            if !self.screen_output.is_empty() && to_commit != self.screen_output {
                let backspaces = self.screen_output.chars().count();
@ -299,37 +307,29 @@ impl Daemon {
            }
            // Type the flush character itself
            commands.push(OutputCommand::Type(ch.to_string()));
-            self.keystroke_history.clear();
+            self.event_store.clear();
            self.screen_output.clear();
            return commands;
        }

-        // Add the new keystroke to history
-        self.keystroke_history.push(ch);
+        // Record the typed key as an event
+        self.event_store.push(InputEvent::KeyTyped(ch));

-        // Replay through fresh engine
-        let method = match self.config.input_method.as_str() {
-            "vni" => InputMethod::Vni,
-            _ => InputMethod::Telex,
-        };
-        let (new_output, did_flush) = Engine::replay_keystrokes(
+        // Replay entire event log through fresh engine
+        let (new_output, did_flush) = Engine::replay_events(
            method,
            &self.config.macros,
-            &self.keystroke_history,
+            &self.event_store,
        );

        if did_flush {
-            // Engine flushed a word. Only backspace + retype when auto-restore
-            // actually CHANGES the word; otherwise the composed word is already
-            // correct on screen and retyping it eats spacing and shifts the
-            // finished word left.
            let to_commit = self.word_to_commit();
            if !self.screen_output.is_empty() && to_commit != self.screen_output {
                let backspaces = self.screen_output.chars().count();
                commands.push(OutputCommand::Backspace(backspaces));
                commands.push(OutputCommand::Type(to_commit));
            }
-            self.keystroke_history.clear();
+            self.event_store.clear();
            self.screen_output.clear();
            return commands;
        }
@ -348,31 +348,43 @@ impl Daemon {
        commands
    }

-    /// Backspace-Replay: pop from history, replay, and return commands to fix screen.
+    /// Event Sourcing: pop last event, replay, and return commands to fix screen.
    fn replay_backspace(&mut self) -> Vec<OutputCommand> {
        let mut commands = Vec::new();
+        let method = match self.config.input_method.as_str() {
+            "vni" => InputMethod::Vni,
+            _ => InputMethod::Telex,
+        };

-        if self.keystroke_history.is_empty() {
+        if self.event_store.is_empty() {
            // Nothing in history — just forward the backspace
            commands.push(OutputCommand::Backspace(1));
            return commands;
        }

-        // Remove last keystroke from history
-        self.keystroke_history.pop();
+        // Record backspace event
+        self.event_store.push(InputEvent::Backspace);
+
+        // Remove the last key-typed event for replay (unless it was already a backspace)
+        match self.event_store.pop() {
+            Some(InputEvent::Backspace) => {
+                // Pop again to remove the preceding event
+                self.event_store.pop();
+            }
+            Some(_) => {
+                // Already popped the last event (KeyTyped or Flush)
+            }
+            None => {}
+        }

        // Replay through fresh engine
-        let method = match self.config.input_method.as_str() {
-            "vni" => InputMethod::Vni,
-            _ => InputMethod::Telex,
-        };
-        let (new_output, _) = if self.keystroke_history.is_empty() {
+        let (new_output, _) = if self.event_store.is_empty() {
            (String::new(), false)
        } else {
-            Engine::replay_keystrokes(
+            Engine::replay_events(
                method,
                &self.config.macros,
-                &self.keystroke_history,
+                &self.event_store,
            )
        };

@ -394,7 +406,7 @@ impl Daemon {
    /// word is English / not valid Vietnamese — the raw keystrokes typed.
    fn word_to_commit(&self) -> String {
        if self.config.auto_restore.enabled {
-            let raw: String = self.keystroke_history.iter().collect();
+            let raw = self.event_store.raw_keystrokes();
            if Engine::should_restore_word(&self.screen_output, &raw) {
                return raw;
            }
@ -404,7 +416,7 @@ impl Daemon {

    /// Reset the replay state (on flush, focus loss, modifier key, etc.)
    fn replay_reset(&mut self) {
-        self.keystroke_history.clear();
+        self.event_store.clear();
        self.screen_output.clear();
    }

@ -731,7 +743,7 @@ fn run_with_x11(
                            pressed_keys.remove(&event.keycode);
                            SKIP_RECORD_EVENTS.store(true, Ordering::Relaxed);
                            execute_commands(&*injector, &commands, true);
-                            if daemon.keystroke_history.is_empty() && commands.is_empty() {
+                            if daemon.event_store.is_empty() && commands.is_empty() {
                                let _ = injector.send_backspace();
                            }
                        }
--- a/engine/Cargo.toml
+++ b/engine/Cargo.toml
@ -7,6 +7,7 @@ description = "Viet+ Vietnamese IME Core Engine"
 [dependencies]
 serde = { version = "1", features = ["derive"] }
 serde_json = "1"
+sha2 = "0.10"

 [dev-dependencies]
 insta = { version = "1.34", features = ["yaml"] }
--- a/engine/src/bamboo.rs
+++ b/engine/src/bamboo.rs
@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 use crate::input_method::{InputMethod, InputMethodRules, get_rules};
 use std::collections::HashMap;

--- a/engine/src/engine.rs
+++ b/engine/src/engine.rs
@ -1,5 +1,7 @@
+// SPDX-License-Identifier: MIT
 use crate::bamboo::BambooEngine;
 use crate::english::EnglishDict;
+use crate::event::{Command, EventStore};
 use crate::input_method::InputMethod;
 use std::collections::HashMap;
 use std::sync::OnceLock;
@ -148,6 +150,88 @@ impl Engine {
        (if did_flush { String::new() } else { last_output }, did_flush)
    }

+    /// Replay events through a fresh engine, returning (expected_output, did_flush).
+    /// This is the Event Sourcing equivalent of replay_keystrokes.
+    pub fn replay_events(
+        method: InputMethod,
+        macros: &HashMap<String, String>,
+        events: &EventStore,
+    ) -> (String, bool) {
+        let mut engine = Engine::new(method);
+        for (shortcut, expansion) in macros {
+            engine.add_macro(shortcut.clone(), expansion.clone());
+        }
+
+        let mut last_output = String::new();
+        let mut composing = String::new();
+
+        for event in events.iter() {
+            match event {
+                crate::event::InputEvent::KeyTyped(ch) => {
+                    if let Some(out) = engine.bamboo.process_key(*ch) {
+                        composing = out.clone();
+                        last_output = out;
+                    } else {
+                        composing = engine.bamboo.get_output();
+                        last_output = composing.clone();
+                    }
+                }
+                crate::event::InputEvent::Backspace => {
+                    let _ = engine.bamboo.pop_last();
+                    composing = engine.bamboo.get_output();
+                    last_output = composing.clone();
+                }
+                crate::event::InputEvent::Flush(_) => {
+                    if !composing.is_empty() {
+                        last_output = composing.clone();
+                    }
+                    composing.clear();
+                    engine.bamboo.reset();
+                }
+                crate::event::InputEvent::Paste(text) => {
+                    for ch in text.chars() {
+                        if let Some(out) = engine.bamboo.process_key(ch) {
+                            composing = out;
+                        }
+                    }
+                    last_output = composing.clone();
+                }
+            }
+        }
+
+        let output = engine.bamboo.get_output();
+        let output_is_empty = output.is_empty();
+        if !output.is_empty() {
+            last_output = output;
+        }
+
+        let did_flush = output_is_empty && composing.is_empty();
+        (if did_flush { String::new() } else { last_output }, did_flush)
+    }
+
+    /// Event Sourcing + Command Pattern: replay events and return diff commands.
+    /// Compares expected output against screen_output and generates backspace/type commands.
+    pub fn replay_events_to_commands(
+        method: InputMethod,
+        macros: &HashMap<String, String>,
+        events: &EventStore,
+        screen_output: &str,
+    ) -> Vec<Command> {
+        let (new_output, _) = Engine::replay_events(method, macros, events);
+
+        let mut commands = Vec::new();
+        if new_output != screen_output {
+            let backspaces = screen_output.chars().count();
+            if backspaces > 0 {
+                commands.push(Command::Backspace(backspaces));
+            }
+            if !new_output.is_empty() {
+                commands.push(Command::Type(new_output));
+            }
+        }
+        commands
+    }
+
    pub fn update_with_pasted_text(&mut self, text: &str) {
        self.raw_buffer.clear();
        self.raw_buffer.push_str(text);
--- a/engine/src/english.rs
+++ b/engine/src/english.rs
@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 use std::collections::HashSet;

 pub struct EnglishDict {
--- a/engine/src/event.rs
+++ b/engine/src/event.rs
@ -0,0 +1,104 @@
+// SPDX-License-Identifier: MIT
+use serde::{Deserialize, Serialize};
+use sha2::{Digest, Sha256};
+
+/// Typed input event - the core of Event Sourcing.
+/// KHÔNG lưu nội dung nhạy cảm, chỉ lưu event sequence.
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+pub enum InputEvent {
+    /// A character key was typed
+    KeyTyped(char),
+    /// Backspace was pressed
+    Backspace,
+    /// A flush character (space, punctuation, enter, tab)
+    Flush(char),
+    /// Text was pasted
+    Paste(String),
+}
+
+/// Append-only event store.
+/// Source of truth for all user input.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+pub struct EventStore {
+    events: Vec<InputEvent>,
+}
+
+impl EventStore {
+    pub fn new() -> Self {
+        Self { events: Vec::new() }
+    }
+
+    pub fn push(&mut self, event: InputEvent) {
+        self.events.push(event);
+    }
+
+    pub fn pop(&mut self) -> Option<InputEvent> {
+        self.events.pop()
+    }
+
+    pub fn clear(&mut self) {
+        self.events.clear();
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.events.is_empty()
+    }
+
+    pub fn len(&self) -> usize {
+        self.events.len()
+    }
+
+    pub fn iter(&self) -> impl Iterator<Item = &InputEvent> {
+        self.events.iter()
+    }
+
+    pub fn as_slice(&self) -> &[InputEvent] {
+        &self.events
+    }
+
+    /// Extract raw keystrokes from event log (for auto-restore comparison).
+    /// Only reconstructs the literal characters typed, excluding backspaces.
+    pub fn raw_keystrokes(&self) -> String {
+        let mut s = String::new();
+        for event in &self.events {
+            match event {
+                InputEvent::KeyTyped(c) => s.push(*c),
+                InputEvent::Backspace => { s.pop(); }
+                InputEvent::Flush(_) => {}
+                InputEvent::Paste(text) => s.push_str(text),
+            }
+        }
+        s
+    }
+
+    /// Hash the event type sequence (not content) for privacy-safe pattern detection.
+    /// Output: sha256 hex of event type characters (K=KeyTyped, B=Backspace, F=Flush, P=Paste).
+    /// Không thể recover text gốc — chỉ biết "có X events với pattern Y".
+    pub fn pattern_hash(&self) -> String {
+        let types: String = self.events.iter().map(|e| match e {
+            InputEvent::KeyTyped(_) => 'K',
+            InputEvent::Backspace => 'B',
+            InputEvent::Flush(_) => 'F',
+            InputEvent::Paste(_) => 'P',
+        }).collect();
+        let mut hasher = Sha256::new();
+        hasher.update(types.as_bytes());
+        format!("{:x}", hasher.finalize())
+    }
+}
+
+impl Default for EventStore {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+/// Formalized output commands (Command Pattern).
+/// Chỉ chứa diff instruction, không chứa text nhạy cảm.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum Command {
+    /// Type a string of characters
+    Type(String),
+    /// Backspace N times
+    Backspace(usize),
+}
--- a/engine/src/input_method.rs
+++ b/engine/src/input_method.rs
@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 use std::collections::HashMap;

 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
--- a/engine/src/lib.rs
+++ b/engine/src/lib.rs
@ -1,6 +1,8 @@
+// SPDX-License-Identifier: MIT
 mod bamboo;
 mod engine;
 mod english;
+pub mod event;
 mod input_method;
 pub mod spelling;

@ -9,4 +11,5 @@ mod tests;

 pub use engine::Engine;
 pub use engine::EngineEvent;
+pub use event::{Command, EventStore, InputEvent};
 pub use input_method::InputMethod;
--- a/engine/src/spelling.rs
+++ b/engine/src/spelling.rs
@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 const FIRST_CONSONANT_SEQS: &[&str] = &[
    "b d đ g gh m n nh p ph r s t tr v z",
    "c h k kh qu th",
--- a/packaging/flatpak/FLATPAK_BUILD.md
+++ b/packaging/flatpak/FLATPAK_BUILD.md
@ -0,0 +1,112 @@
+# Building the Viet+ Flatpak
+
+## Prerequisites
+
+- Flatpak installed with Flathub remote configured
+- `org.gnome.Platform//50` runtime installed
+- `org.gnome.Sdk//50` SDK installed
+- `org.freedesktop.Sdk.Extension.rust-stable//25.08` installed
+
+### Install dependencies
+
+```bash
+flatpak install --user flathub org.gnome.Platform//50
+flatpak install --user flathub org.gnome.Sdk//50
+flatpak install --user flathub org.freedesktop.Sdk.Extension.rust-stable//25.08
+```
+
+---
+
+## Method 1: Quick build script
+
+```bash
+cd packaging/flatpak
+bash build-flatpak.sh [version]
+# e.g. bash build-flatpak.sh 0.1.5
+```
+
+Output: `packaging/flatpak/VietPlus-<version>.flatpak`
+
+---
+
+## Method 2: Manual step-by-step
+
+```bash
+cd packaging/flatpak
+
+# 1. Clean previous artifacts
+rm -rf build-dir repo VietPlus-*.flatpak
+
+# 2. Initialize build directory
+#    NOTE: arg order is flatpak build-init DIR APPNAME SDK RUNTIME
+flatpak build-init build-dir io.github.vietc.VietPlus \
+  org.gnome.Sdk//50 org.gnome.Platform//50
+
+# 3. Copy source code
+mkdir -p build-dir/files/src/vietc
+rsync -a /path/to/vietc/ build-dir/files/src/vietc/ --exclude=target --exclude=.git
+
+# 4. Build Rust binaries
+flatpak build --share=network build-dir sh -c '
+  export PATH=/usr/lib/sdk/rust-stable/bin:$PATH
+  export CARGO_HOME=/app/cargo
+  cd /app/src/vietc
+  cargo build --release -p vietc-daemon -p vietc-cli -p vietc-uinputd
+'
+
+# 5. Install binaries and icons
+flatpak build build-dir sh -c '
+  install -Dm755 /app/src/vietc/target/release/vietc /app/bin/vietc-daemon
+  install -Dm755 /app/src/vietc/target/release/vietc-cli /app/bin/vietc-cli
+  install -Dm755 /app/src/vietc/target/release/vietc-uinputd /app/bin/vietc-uinputd
+
+  install -Dm644 /app/src/vietc/packaging/icons/vietc.svg \
+    /app/share/icons/hicolor/scalable/apps/io.github.vietc.VietPlus.svg
+  install -Dm644 /app/src/vietc/packaging/icons/vietc-vn.svg \
+    /app/share/icons/hicolor/scalable/apps/io.github.vietc.VietPlus.vietc-vn.svg
+  install -Dm644 /app/src/vietc/packaging/icons/vietc-en.svg \
+    /app/share/icons/hicolor/scalable/apps/io.github.vietc.VietPlus.vietc-en.svg
+'
+
+# 6. Finish (set permissions + command)
+flatpak build-finish build-dir \
+  --socket=x11 \
+  --socket=wayland \
+  --filesystem=home \
+  --share=ipc \
+  --talk-name=org.freedesktop.Notifications \
+  --talk-name=org.a11y.Bus \
+  --command=vietc-daemon
+
+# 7. Export to local repo
+flatpak build-export repo build-dir
+
+# 8. Create bundle
+flatpak build-bundle repo VietPlus-0.1.5.flatpak io.github.vietc.VietPlus
+```
+
+---
+
+## Installation
+
+```bash
+# From bundle
+flatpak install --user --bundle VietPlus-0.1.5.flatpak
+
+# From local repo
+flatpak --user remote-add --no-gpg-verify vietc-repo repo
+flatpak --user install vietc-repo io.github.vietc.VietPlus
+
+# Run
+flatpak run io.github.vietc.VietPlus
+```
+
+---
+
+## Key Notes
+
+- **SDK/RUNTIME order**: `flatpak build-init` takes `SDK` first, then `RUNTIME` (counterintuitive but important — getting this wrong means `/usr/lib/sdk/` won't be mounted)
+- **Rust SDK**: must be installed as `org.freedesktop.Sdk.Extension.rust-stable//25.08`; it mounts automatically at `/usr/lib/sdk/rust-stable/`
+- **Icons**: all icon files in Flatpak must be prefixed with the app ID (`io.github.vietc.VietPlus.*`) or `flatpak build-export` will skip them
+- **Daemon binary name**: Cargo builds the daemon binary as `vietc` (not `vietc-daemon`) in `target/release/`; rename on install to match the desktop file
+- **Desktop Categories**: only use registered categories (`Utility`); `InputMethod` is not registered
--- a/packaging/flatpak/build-flatpak.sh
+++ b/packaging/flatpak/build-flatpak.sh
@ -6,78 +6,57 @@ PROJECT_ROOT="$(cd "$SCRIPT_DIR/../.." && pwd)"
 VERSION="${1:-0.1.4}"

 echo "=== Building Viet+ Flatpak v${VERSION} ==="
-
-# Install required runtimes
-flatpak install -y flathub org.gnome.Platform//50 org.gnome.Sdk//50 2>/dev/null || true
-flatpak install -y flathub org.freedesktop.Sdk.Extension.rust-stable//25.08 2>/dev/null || true
-
 cd "$SCRIPT_DIR"

 # Clean previous build
-rm -rf build-dir vietc-repo VietPlus-*.flatpak
+rm -rf build-dir repo VietPlus-*.flatpak

 # Initialize build directory
+# NOTE: arg order is flatpak build-init DIR APPNAME SDK RUNTIME
 flatpak build-init build-dir io.github.vietc.VietPlus \
-  org.gnome.Platform//50 org.gnome.Sdk//50
-
-# Add sdk-extensions to metadata
-cat > build-dir/metadata << 'EOF'
-[Application]
-name=io.github.vietc.VietPlus
-runtime=org.gnome.Platform/x86_64/50
-sdk=org.gnome.Sdk/x86_64/50
-sdk-extensions=org.freedesktop.Sdk.Extension.rust-stable
-EOF
+  org.gnome.Sdk//50 org.gnome.Platform//50

 # Copy source code
 mkdir -p build-dir/files/src/vietc
 rsync -a "$PROJECT_ROOT/" build-dir/files/src/vietc/ --exclude=target --exclude=.git

-# Symlink Rust SDK extension
-RUST_FILES=$(find /var/lib/flatpak/runtime/org.freedesktop.Sdk.Extension.rust-stable \
-  -name "rustc" -type f 2>/dev/null | head -1 | sed 's|/bin/rustc||')
-mkdir -p build-dir/files/usr/lib/sdk
-ln -s "$RUST_FILES" build-dir/files/usr/lib/sdk/rust-stable
+BUILD='export PATH=/usr/lib/sdk/rust-stable/bin:$PATH
+export CARGO_HOME=/app/cargo
+cd /app/src/vietc'

-# Build all Rust binaries inside sandbox
-echo "Compiling daemon, CLI, uinputd..."
-flatpak build --share=network build-dir sh -c '
-  export PATH=/usr/lib/sdk/rust-stable/bin:$PATH
-  export CARGO_HOME=/app/cargo
-  cd /app/src/vietc
-  cargo build --release -p vietc-daemon -p vietc-cli -p vietc-uinputd
-'
+# Build daemon + CLI + uinputd
+echo ""
+echo "=== Compiling daemon, CLI, uinputd... ==="
+flatpak build --share=network build-dir sh -c "$BUILD && cargo build --release -p vietc-daemon -p vietc-cli -p vietc-uinputd"

-echo "Compiling system tray..."
-flatpak build --share=network build-dir sh -c '
-  export PATH=/usr/lib/sdk/rust-stable/bin:$PATH
-  export CARGO_HOME=/app/cargo
-  cd /app/src/vietc
-  cargo build --release --manifest-path ui/Cargo.toml
-'
+# Install files
+echo ""
+echo "=== Installing files... ==="
+flatpak build build-dir sh -c "
+set -e
+install -Dm755 /app/src/vietc/target/release/vietc /app/bin/vietc-daemon
+install -Dm755 /app/src/vietc/target/release/vietc-cli /app/bin/vietc-cli
+install -Dm755 /app/src/vietc/target/release/vietc-uinputd /app/bin/vietc-uinputd

-# Install files into sandbox
-echo "Installing files..."
-flatpak build build-dir sh -c '
-  set -e
-  install -Dm755 /app/src/vietc/target/release/vietc /app/bin/vietc
-  install -Dm755 /app/src/vietc/target/release/vietc-cli /app/bin/vietc-cli
-  install -Dm755 /app/src/vietc/target/release/vietc-uinputd /app/bin/vietc-uinputd
-  install -Dm755 /app/src/vietc/ui/target/release/vietc-tray /app/bin/vietc-tray
-  gcc -O2 -o /app/bin/vietc-xrecord /app/src/vietc/packaging/appimage/vietc-xrecord.c -lX11 -lXtst
-  install -Dm755 /app/src/vietc/packaging/flatpak/vietc-wrapper.sh /app/bin/vietc-wrapper.sh
-  install -Dm644 /app/src/vietc/packaging/appimage/vietc.desktop \
-    /app/share/applications/io.github.vietc.VietPlus.desktop
-  sed -i "s/Icon=vietc/Icon=io.github.vietc.VietPlus/g" \
-    /app/share/applications/io.github.vietc.VietPlus.desktop
-  install -Dm644 /app/src/vietc/vietc.toml /app/etc/vietc/config.toml
-  mkdir -p /app/share/icons/hicolor/256x256/apps
-  cp /app/src/vietc/packaging/appimage/AppDir/vietc.svg \
-    /app/share/icons/hicolor/256x256/apps/io.github.vietc.VietPlus.svg 2>/dev/null || true
-  mkdir -p /app/share/metainfo
-  cat > /app/share/metainfo/io.github.vietc.VietPlus.metainfo.xml << "XML"
-<?xml version="1.0" encoding="utf-8"?>
-<component type="desktop-application">
+install -Dm644 /app/src/vietc/packaging/icons/vietc.svg /app/share/icons/hicolor/scalable/apps/io.github.vietc.VietPlus.svg
+install -Dm644 /app/src/vietc/packaging/icons/vietc-vn.svg /app/share/icons/hicolor/scalable/apps/io.github.vietc.VietPlus.vietc-vn.svg
+install -Dm644 /app/src/vietc/packaging/icons/vietc-en.svg /app/share/icons/hicolor/scalable/apps/io.github.vietc.VietPlus.vietc-en.svg
+
+cat > /app/share/applications/io.github.vietc.VietPlus.desktop << END
+[Desktop Entry]
+Name=Viet+
+Comment=Vietnamese Input Method
+Exec=/app/bin/vietc-daemon
+Icon=io.github.vietc.VietPlus
+Terminal=false
+Type=Application
+Categories=Utility;
+END
+
+mkdir -p /app/share/metainfo
+cat > /app/share/metainfo/io.github.vietc.VietPlus.metainfo.xml << 'XML'
+<?xml version='1.0' encoding='utf-8'?>
+<component type='desktop-application'>
  <id>io.github.vietc.VietPlus</id>
  <name>Viet+</name>
  <summary>Vietnamese Input Method for Linux</summary>
@ -86,36 +65,39 @@ flatpak build build-dir sh -c '
  </description>
  <metadata_license>MIT</metadata_license>
  <project_license>MIT</project_license>
-  <url type="homepage">https://github.com/vndangkhoa/vietc</url>
-  <provides><binary>vietc</binary></provides>
+  <url type='homepage'>https://github.com/vndangkhoa/vietc</url>
+  <provides><binary>vietc-daemon</binary></provides>
  <categories><category>Utility</category></categories>
 </component>
 XML
-  mkdir -p /app/share/doc/vietc
-  cp /app/src/vietc/README.md /app/share/doc/vietc/ 2>/dev/null || true
-  cp /app/src/vietc/LICENSE /app/share/doc/vietc/ 2>/dev/null || true
-'
+"

-# Finish the build
-echo "Finalizing build..."
+# Finish
+echo ""
+echo "=== Finalizing build... ==="
 flatpak build-finish build-dir \
  --socket=x11 \
  --socket=wayland \
-  --socket=session-bus \
+  --filesystem=home \
  --share=ipc \
-  --device=all \
-  --command=vietc-wrapper.sh
+  --talk-name=org.freedesktop.Notifications \
+  --talk-name=org.a11y.Bus \
+  --command=vietc-daemon

-# Export to local repository
-echo "Exporting to repository..."
-flatpak build-export vietc-repo build-dir
+# Export
+echo ""
+echo "=== Exporting to repository... ==="
+flatpak build-export repo build-dir

-# Create single-file bundle
-echo "Creating bundle..."
-flatpak build-bundle vietc-repo "VietPlus-${VERSION}.flatpak" io.github.vietc.VietPlus
+# Bundle
+echo ""
+echo "=== Creating bundle... ==="
+flatpak build-bundle repo "VietPlus-${VERSION}.flatpak" io.github.vietc.VietPlus

+echo ""
 echo "=== Done ==="
-echo "Package: $SCRIPT_DIR/VietPlus-${VERSION}.flatpak ($(du -h "$SCRIPT_DIR/VietPlus-${VERSION}.flatpak" | cut -f1))"
+echo "Package: $SCRIPT_DIR/VietPlus-${VERSION}.flatpak"
+echo "Size: $(du -h "$SCRIPT_DIR/VietPlus-${VERSION}.flatpak" | cut -f1)"
 echo ""
 echo "Install: flatpak install --user --bundle VietPlus-${VERSION}.flatpak"
-echo "Run:     flatpak run io.github.vietc.VietPlus"
+echo "Run:     flatpak run io.github.vietc.VietPlus"
--- a/packaging/flatpak/io.github.vietc.VietPlus.json
+++ b/packaging/flatpak/io.github.vietc.VietPlus.json
@ -1,40 +1,21 @@
 {
  "app-id": "io.github.vietc.VietPlus",
  "runtime": "org.gnome.Platform",
-  "runtime-version": "47",
+  "runtime-version": "50",
  "sdk": "org.gnome.Sdk",
  "sdk-extensions": [
    "org.freedesktop.Sdk.Extension.rust-stable"
  ],
-  "command": "vietc-wrapper.sh",
-  "rename-desktop-file": "vietc.desktop",
-  "rename-icon": "vietc",
+  "command": "vietc-daemon",
  "finish-args": [
    "--socket=x11",
    "--socket=wayland",
-    "--socket=session-bus",
-    "--device=all",
-    "--share=ipc"
+    "--filesystem=home",
+    "--share=ipc",
+    "--talk-name=org.freedesktop.Notifications",
+    "--talk-name=org.a11y.Bus"
  ],
  "modules": [
-    {
-      "name": "xclip",
-      "no-autogen": true,
-      "make-install-args": [
-        "install"
-      ],
-      "builddir": true,
-      "sources": [
-        {
-          "type": "archive",
-          "url": "https://github.com/astrand/xclip/archive/refs/tags/0.13.tar.gz",
-          "sha256": "ca5b8804e3c910a66423a882d79bf3c9450e8758faa5d2b9deba5342451b140e"
-        }
-      ],
-      "cleanup": [
-        "/share/man"
-      ]
-    },
    {
      "name": "vietc",
      "buildsystem": "simple",
@ -47,57 +28,25 @@
      "build-commands": [
        "cargo build --release -p vietc-daemon -p vietc-cli -p vietc-uinputd --manifest-path /run/build/vietc/Cargo.toml",

-        "cd /run/build/vietc/ui && cargo build --release --manifest-path /run/build/vietc/ui/Cargo.toml || echo 'tray build skipped'",
-
-        "install -Dm755 target/release/vietc /app/bin/vietc",
+        "install -Dm755 target/release/vietc /app/bin/vietc-daemon",
        "install -Dm755 target/release/vietc-cli /app/bin/vietc-cli",
        "install -Dm755 target/release/vietc-uinputd /app/bin/vietc-uinputd",
-        "[ -f ui/target/release/vietc-tray ] && install -Dm755 ui/target/release/vietc-tray /app/bin/vietc-tray || true",

-        "gcc -O2 -o /app/bin/vietc-xrecord /run/build/vietc/packaging/appimage/vietc-xrecord.c -lX11 -lXtst",
+        "install -Dm644 packaging/icons/vietc.svg /app/share/icons/hicolor/scalable/apps/io.github.vietc.VietPlus.svg",
+        "install -Dm644 packaging/icons/vietc-vn.svg /app/share/icons/hicolor/scalable/apps/io.github.vietc.VietPlus.vietc-vn.svg",
+        "install -Dm644 packaging/icons/vietc-en.svg /app/share/icons/hicolor/scalable/apps/io.github.vietc.VietPlus.vietc-en.svg",

-        "install -Dm755 /run/build/vietc/packaging/flatpak/vietc-wrapper.sh /app/bin/vietc-wrapper.sh",
-
-        "install -Dm644 /run/build/vietc/packaging/appimage/vietc.desktop /app/share/applications/vietc.desktop",
-
-        "install -Dm644 /run/build/vietc/vietc.toml /app/etc/vietc/config.toml",
-
-        "mkdir -p /app/share/icons/hicolor/256x256/apps",
-        "cp /run/build/vietc/packaging/appimage/AppDir/vietc.svg /app/share/icons/hicolor/256x256/apps/vietc.svg || true",
-
-        "install -Dm644 /run/build/vietc/vietc.service /app/lib/systemd/user/vietc.service || true",
+        "mkdir -p /app/share/applications",
+        "cat > /app/share/applications/io.github.vietc.VietPlus.desktop << END\n[Desktop Entry]\nName=Viet+\nComment=Vietnamese Input Method\nExec=/app/bin/vietc-daemon\nIcon=io.github.vietc.VietPlus\nTerminal=false\nType=Application\nCategories=Utility;\nEND",

        "mkdir -p /app/share/metainfo",
-        "cat > /app/share/metainfo/io.github.vietc.VietPlus.metainfo.xml << 'XML'",
-        "<?xml version='1.0' encoding='utf-8'?>",
-        "<component type='desktop-application'>",
-        "  <id>io.github.vietc.VietPlus</id>",
-        "  <name>Viet+</name>",
-        "  <summary>Vietnamese Input Method for Linux</summary>",
-        "  <description>",
-        "    <p>Zero-configuration Vietnamese input method engine supporting Telex and VNI input methods.</p>",
-        "  </description>",
-        "  <metadata_license>MIT</metadata_license>",
-        "  <project_license>MIT</project_license>",
-        "  <url type='homepage'>https://github.com/vndangkhoa/vietc</url>",
-        "  <provides><binary>vietc</binary></provides>",
-        "  <categories><category>Utility</category></categories>",
-        "</component>",
-        "XML",
-
-        "mkdir -p /app/share/doc/vietc",
-        "cp /run/build/vietc/README.md /app/share/doc/vietc/ || true",
-        "cp /run/build/vietc/LICENSE /app/share/doc/vietc/ || true"
+        "cat > /app/share/metainfo/io.github.vietc.VietPlus.metainfo.xml << 'XML'\n<?xml version='1.0' encoding='utf-8'?>\n<component type='desktop-application'>\n  <id>io.github.vietc.VietPlus</id>\n  <name>Viet+</name>\n  <summary>Vietnamese Input Method for Linux</summary>\n  <description>\n    <p>Zero-configuration Vietnamese input method engine supporting Telex and VNI input methods.</p>\n  </description>\n  <metadata_license>MIT</metadata_license>\n  <project_license>MIT</project_license>\n  <url type='homepage'>https://github.com/vndangkhoa/vietc</url>\n  <provides><binary>vietc-daemon</binary></provides>\n  <categories><category>Utility</category></categories>\n</component>\nXML"
      ],
      "sources": [
        {
          "type": "dir",
          "path": "../.."
        }
-      ],
-      "cleanup": [
-        "/app/share/doc",
-        "/app/share/icons"
      ]
    }
  ]
--- a/packaging/icons/vietc-en.svg
+++ b/packaging/icons/vietc-en.svg
@ -0,0 +1,4 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 128 128">
+  <rect x="8" y="8" width="112" height="112" rx="24" fill="#4b5563"/>
+  <text x="64" y="96" text-anchor="middle" fill="#ffffff" font-size="48" font-weight="bold" font-family="system-ui, sans-serif">EN</text>
+</svg>
--- a/packaging/icons/vietc-vn.svg
+++ b/packaging/icons/vietc-vn.svg
@ -0,0 +1,4 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 128 128">
+  <rect x="8" y="8" width="112" height="112" rx="24" fill="#e02424"/>
+  <text x="64" y="96" text-anchor="middle" fill="#ffffff" font-size="48" font-weight="bold" font-family="system-ui, sans-serif">VN</text>
+</svg>
--- a/packaging/icons/vietc.svg
+++ b/packaging/icons/vietc.svg
@ -0,0 +1,32 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 256" width="256" height="256">
+  <defs>
+    <linearGradient id="kb-bg" x1="0%" y1="0%" x2="100%" y2="100%">
+      <stop offset="0%" stop-color="#3a3a3a"/>
+      <stop offset="100%" stop-color="#1a1a1a"/>
+    </linearGradient>
+    <linearGradient id="vn-badge" x1="0%" y1="0%" x2="100%" y2="100%">
+      <stop offset="0%" stop-color="#e74c3c"/>
+      <stop offset="100%" stop-color="#c0392b"/>
+    </linearGradient>
+  </defs>
+  <rect x="16" y="56" width="224" height="156" rx="18" fill="url(#kb-bg)" stroke="#555" stroke-width="3"/>
+  <rect x="32" y="72" width="192" height="124" rx="10" fill="#2a2a2a"/>
+  <rect x="44" y="84" width="26" height="22" rx="4" fill="#e0e0e0"/>
+  <rect x="76" y="84" width="26" height="22" rx="4" fill="#e0e0e0"/>
+  <rect x="108" y="84" width="26" height="22" rx="4" fill="#e0e0e0"/>
+  <rect x="140" y="84" width="26" height="22" rx="4" fill="#e0e0e0"/>
+  <rect x="172" y="84" width="26" height="22" rx="4" fill="#e0e0e0"/>
+  <rect x="50" y="112" width="26" height="22" rx="4" fill="#e0e0e0"/>
+  <rect x="82" y="112" width="26" height="22" rx="4" fill="#e0e0e0"/>
+  <rect x="114" y="112" width="26" height="22" rx="4" fill="#e0e0e0"/>
+  <rect x="146" y="112" width="26" height="22" rx="4" fill="#e0e0e0"/>
+  <rect x="178" y="112" width="26" height="22" rx="4" fill="#e0e0e0"/>
+  <rect x="56" y="140" width="26" height="22" rx="4" fill="#e0e0e0"/>
+  <rect x="88" y="140" width="26" height="22" rx="4" fill="#e0e0e0"/>
+  <rect x="120" y="140" width="26" height="22" rx="4" fill="#e0e0e0"/>
+  <rect x="152" y="140" width="26" height="22" rx="4" fill="#e0e0e0"/>
+  <rect x="184" y="140" width="30" height="22" rx="4" fill="#e0e0e0"/>
+  <rect x="68" y="168" width="120" height="16" rx="4" fill="#e0e0e0"/>
+  <circle cx="224" cy="44" r="30" fill="url(#vn-badge)"/>
+  <text x="224" y="52" text-anchor="middle" fill="#fff" font-size="20" font-weight="bold" font-family="sans-serif">VN</text>
+</svg>
--- a/protocol/src/inject.rs
+++ b/protocol/src/inject.rs
@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 use std::fmt;

 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
--- a/protocol/src/lib.rs
+++ b/protocol/src/lib.rs
@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 pub mod inject;
 pub mod monitor;
 pub mod uinput_monitor;
--- a/protocol/src/monitor.rs
+++ b/protocol/src/monitor.rs
@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 use crate::inject::KeyEvent;

 pub trait KeyMonitor {
--- a/protocol/src/uinput_client.rs
+++ b/protocol/src/uinput_client.rs
@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 use std::io::{BufRead, BufReader, Write};
 use std::os::unix::net::UnixStream;
 use std::path::PathBuf;
--- a/protocol/src/uinput_monitor.rs
+++ b/protocol/src/uinput_monitor.rs
@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 use std::fs::{File, OpenOptions};
 use std::os::unix::io::AsRawFd;
 use std::sync::{Arc, Condvar, Mutex};
--- a/protocol/src/wayland_im.rs
+++ b/protocol/src/wayland_im.rs
@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 use std::collections::HashMap;

 use crate::inject::{InjectResult, KeyInjector};
--- a/protocol/src/x11_capture.rs
+++ b/protocol/src/x11_capture.rs
@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 use std::collections::VecDeque;
 use std::ffi::{c_char, c_int, c_void};
 use std::io::{Read, BufRead};
--- a/protocol/src/x11_inject.rs
+++ b/protocol/src/x11_inject.rs
@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 use super::inject::{InjectResult, KeyInjector};
 use std::cell::RefCell;
 use std::ffi::{c_char, c_int, c_void};
--- a/ui/src/config.rs
+++ b/ui/src/config.rs
@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 use serde::{Deserialize, Serialize};
 use std::fs;
 use std::path::PathBuf;
--- a/ui/src/main.rs
+++ b/ui/src/main.rs
@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 use std::path::PathBuf;

 mod config;
--- a/ui/src/tray.rs
+++ b/ui/src/tray.rs
@ -1,6 +1,11 @@
+// SPDX-License-Identifier: MIT
 use crate::config;
 use ksni::{menu::*, MenuItem, Tray};

+fn is_flatpak() -> bool {
+    std::path::Path::new("/app/bin/vietc-daemon").exists()
+}
+
 fn write_status(state: &str) {
    if let Some(config_dir) = dirs::config_dir() {
        let _ = std::fs::write(config_dir.join("vietc").join("status"), state);
@ -242,7 +247,13 @@ impl Tray for VietTray {
    }

    fn icon_name(&self) -> String {
-        if self.mode == "vn" {
+        if is_flatpak() {
+            if self.mode == "vn" {
+                "io.github.vietc.VietPlus.vietc-vn".into()
+            } else {
+                "io.github.vietc.VietPlus.vietc-en".into()
+            }
+        } else if self.mode == "vn" {
            "vietc-vn".into()
        } else {
            "vietc-en".into()
@ -250,9 +261,20 @@ impl Tray for VietTray {
    }

    fn icon_theme_path(&self) -> String {
-        // Use XDG user theme path for icons
-        dirs::home_dir()
-            .map(|d| d.join(".local/share/icons").to_string_lossy().into_owned())
+        // Use XDG user theme path for icons (works in both native and Flatpak)
+        if let Some(home) = dirs::home_dir() {
+            let user_path = home.join(".local/share/icons");
+            if user_path.exists() {
+                return user_path.to_string_lossy().into_owned();
+            }
+        }
+        // Flatpak: icons are in /app/share/icons
+        let flatpak_path = std::path::Path::new("/app/share/icons");
+        if flatpak_path.exists() {
+            return "/app/share/icons".into();
+        }
+        dirs::data_dir()
+            .map(|d| d.join("icons").to_string_lossy().into_owned())
            .unwrap_or_else(|| "/usr/share/icons".into())
    }

--- a/uinputd/src/main.rs
+++ b/uinputd/src/main.rs
@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT
 use std::fs;
 use std::os::unix::io::AsRawFd;
 use std::os::unix::net::{UnixListener, UnixStream};