Fix issues with opening files in desktop app (#4876)

# Description of Changes
Locking to just having one instance of the app running unifies the
experience across all OSs. Opening new files in Stirling will cause the
files to be opened in the existing window rather than spawning a new
instance of the app with just that file in the new instance.

There's much more to explore here to allow multiple windows open at
once, but that can be done all from one instance of the app, and will
likely make it easier to allow movement of files etc. across different
windows.

Also fixes extra newlines in the logs and directly builds to `.app` on
Mac because it's frustrating during development to have to repeatedly
mount & unmount the `.dmg`.

frontend/src-tauri/Cargo.lock

@@ -81,6 +81,137 @@ version = "0.7.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7c02d123df017efcdfbd739ef81735b36c5ba83ec3c59c80a9d7ecc718f92e50"
 
+[[package]]
+name = "async-broadcast"
+version = "0.7.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "435a87a52755b8f27fcf321ac4f04b2802e337c8c4872923137471ec39c37532"
+dependencies = [
+ "event-listener",
+ "event-listener-strategy",
+ "futures-core",
+ "pin-project-lite",
+]
+
+[[package]]
+name = "async-channel"
+version = "2.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "924ed96dd52d1b75e9c1a3e6275715fd320f5f9439fb5a4a11fa51f4221158d2"
+dependencies = [
+ "concurrent-queue",
+ "event-listener-strategy",
+ "futures-core",
+ "pin-project-lite",
+]
+
+[[package]]
+name = "async-executor"
+version = "1.13.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "497c00e0fd83a72a79a39fcbd8e3e2f055d6f6c7e025f3b3d91f4f8e76527fb8"
+dependencies = [
+ "async-task",
+ "concurrent-queue",
+ "fastrand",
+ "futures-lite",
+ "pin-project-lite",
+ "slab",
+]
+
+[[package]]
+name = "async-io"
+version = "2.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "456b8a8feb6f42d237746d4b3e9a178494627745c3c56c6ea55d92ba50d026fc"
+dependencies = [
+ "autocfg",
+ "cfg-if",
+ "concurrent-queue",
+ "futures-io",
+ "futures-lite",
+ "parking",
+ "polling",
+ "rustix",
+ "slab",
+ "windows-sys 0.61.2",
+]
+
+[[package]]
+name = "async-lock"
+version = "3.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5fd03604047cee9b6ce9de9f70c6cd540a0520c813cbd49bae61f33ab80ed1dc"
+dependencies = [
+ "event-listener",
+ "event-listener-strategy",
+ "pin-project-lite",
+]
+
+[[package]]
+name = "async-process"
+version = "2.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fc50921ec0055cdd8a16de48773bfeec5c972598674347252c0399676be7da75"
+dependencies = [
+ "async-channel",
+ "async-io",
+ "async-lock",
+ "async-signal",
+ "async-task",
+ "blocking",
+ "cfg-if",
+ "event-listener",
+ "futures-lite",
+ "rustix",
+]
+
+[[package]]
+name = "async-recursion"
+version = "1.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3b43422f69d8ff38f95f1b2bb76517c91589a924d1559a0e935d7c8ce0274c11"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.108",
+]
+
+[[package]]
+name = "async-signal"
+version = "0.2.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "43c070bbf59cd3570b6b2dd54cd772527c7c3620fce8be898406dd3ed6adc64c"
+dependencies = [
+ "async-io",
+ "async-lock",
+ "atomic-waker",
+ "cfg-if",
+ "futures-core",
+ "futures-io",
+ "rustix",
+ "signal-hook-registry",
+ "slab",
+ "windows-sys 0.61.2",
+]
+
+[[package]]
+name = "async-task"
+version = "4.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8b75356056920673b02621b35afd0f7dda9306d03c79a30f5c56c44cf256e3de"
+
+[[package]]
+name = "async-trait"
+version = "0.1.89"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9035ad2d096bed7955a320ee7e2230574d28fd3c3a0f186cbea1ff3c7eed5dbb"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.108",
+]
+
 [[package]]
 name = "atk"
 version = "0.18.2"
@@ -182,6 +313,19 @@ dependencies = [
  "objc2 0.6.3",
 ]
 
+[[package]]
+name = "blocking"
+version = "1.6.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e83f8d02be6967315521be875afa792a316e28d57b5a2d401897e2a7921b7f21"
+dependencies = [
+ "async-channel",
+ "async-task",
+ "futures-io",
+ "futures-lite",
+ "piper",
+]
+
 [[package]]
 name = "borsh"
 version = "1.5.7"
@@ -424,6 +568,15 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "concurrent-queue"
+version = "2.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4ca0197aee26d1ae37445ee532fefce43251d24cc7c166799f4d46817f1d3973"
+dependencies = [
+ "crossbeam-utils",
+]
+
 [[package]]
 name = "convert_case"
 version = "0.4.0"
@@ -774,6 +927,33 @@ dependencies = [
  "cfg-if",
 ]
 
+[[package]]
+name = "endi"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a3d8a32ae18130a3c84dd492d4215c3d913c3b07c6b63c2eb3eb7ff1101ab7bf"
+
+[[package]]
+name = "enumflags2"
+version = "0.7.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1027f7680c853e056ebcec683615fb6fbbc07dbaa13b4d5d9442b146ded4ecef"
+dependencies = [
+ "enumflags2_derive",
+ "serde",
+]
+
+[[package]]
+name = "enumflags2_derive"
+version = "0.7.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "67c78a4d8fdf9953a5c9d458f9efe940fd97a0cab0941c075a813ac594733827"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.108",
+]
+
 [[package]]
 name = "env_filter"
 version = "0.1.4"
@@ -811,6 +991,27 @@ dependencies = [
  "windows-sys 0.61.2",
 ]
 
+[[package]]
+name = "event-listener"
+version = "5.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e13b66accf52311f30a0db42147dadea9850cb48cd070028831ae5f5d4b856ab"
+dependencies = [
+ "concurrent-queue",
+ "parking",
+ "pin-project-lite",
+]
+
+[[package]]
+name = "event-listener-strategy"
+version = "0.5.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "8be9f3dfaaffdae2972880079a491a1a8bb7cbed0b8dd7a347f668b4150a3b93"
+dependencies = [
+ "event-listener",
+ "pin-project-lite",
+]
+
 [[package]]
 name = "fastrand"
 version = "2.3.0"
@@ -966,6 +1167,19 @@ version = "0.3.31"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9e5c1b78ca4aae1ac06c48a526a655760685149f0d465d21f37abfe57ce075c6"
 
+[[package]]
+name = "futures-lite"
+version = "2.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f78e10609fe0e0b3f4157ffab1876319b5b0db102a2c60dc4626306dc46b44ad"
+dependencies = [
+ "fastrand",
+ "futures-core",
+ "futures-io",
+ "parking",
+ "pin-project-lite",
+]
+
 [[package]]
 name = "futures-macro"
 version = "0.3.31"
@@ -1352,6 +1566,12 @@ version = "0.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2304e00983f87ffb38b55b444b5e3b60a884b5d30c0fca7d82fe33449bbe55ea"
 
+[[package]]
+name = "hermit-abi"
+version = "0.5.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fc0fef456e4baa96da950455cd02c081ca953b141298e41db3fc7e36b1da849c"
+
 [[package]]
 name = "hex"
 version = "0.4.3"
@@ -2079,6 +2299,19 @@ version = "1.0.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "650eef8c711430f1a879fdd01d4745a7deea475becfb90269c06775983bbf086"
 
+[[package]]
+name = "nix"
+version = "0.30.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "74523f3a35e05aba87a1d978330aef40f67b0304ac79c1c00b294c9830543db6"
+dependencies = [
+ "bitflags 2.10.0",
+ "cfg-if",
+ "cfg_aliases",
+ "libc",
+ "memoffset",
+]
+
 [[package]]
 name = "nodrop"
 version = "0.1.14"
@@ -2463,6 +2696,16 @@ version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "04744f49eae99ab78e0d5c0b603ab218f515ea8cfe5a456d7629ad883a3b6e7d"
 
+[[package]]
+name = "ordered-stream"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9aa2b01e1d916879f73a53d01d1d6cee68adbb31d6d9177a8cfce093cced1d50"
+dependencies = [
+ "futures-core",
+ "pin-project-lite",
+]
+
 [[package]]
 name = "os_pipe"
 version = "1.2.3"
@@ -2498,6 +2741,12 @@ dependencies = [
  "system-deps",
 ]
 
+[[package]]
+name = "parking"
+version = "2.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f38d5652c16fde515bb1ecef450ab0f6a219d619a7274976324d5e377f7dceba"
+
 [[package]]
 name = "parking_lot"
 version = "0.12.5"
@@ -2679,6 +2928,17 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8b870d8c151b6f2fb93e84a13146138f05d02ed11c7e7c54f8826aaaf7c9f184"
 
+[[package]]
+name = "piper"
+version = "0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "96c8c490f422ef9a4efd2cb5b42b76c8613d7e7dfc1caf667b8a3350a5acc066"
+dependencies = [
+ "atomic-waker",
+ "fastrand",
+ "futures-io",
+]
+
 [[package]]
 name = "pkg-config"
 version = "0.3.32"
@@ -2711,6 +2971,20 @@ dependencies = [
  "miniz_oxide",
 ]
 
+[[package]]
+name = "polling"
+version = "3.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5d0e4f59085d47d8241c88ead0f274e8a0cb551f3625263c05eb8dd897c34218"
+dependencies = [
+ "cfg-if",
+ "concurrent-queue",
+ "hermit-abi",
+ "pin-project-lite",
+ "rustix",
+ "windows-sys 0.61.2",
+]
+
 [[package]]
 name = "potential_utf"
 version = "0.1.3"
@@ -3657,6 +3931,12 @@ version = "1.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6ce2be8dc25455e1f91df71bfa12ad37d7af1092ae736f3a6cd0e37bc7810596"
 
+[[package]]
+name = "static_assertions"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a2eb9349b6444b326872e140eb1cf5e7c522154d69e7a0ffb0fb81c06b37543f"
+
 [[package]]
 name = "stirling-pdf"
 version = "0.1.0"
@@ -3670,6 +3950,7 @@ dependencies = [
  "tauri-plugin-fs",
  "tauri-plugin-log",
  "tauri-plugin-shell",
+ "tauri-plugin-single-instance",
  "tokio",
 ]
 
@@ -4056,6 +4337,21 @@ dependencies = [
  "tokio",
 ]
 
+[[package]]
+name = "tauri-plugin-single-instance"
+version = "2.3.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dd707f8c86b4e3004e2c141fa24351f1909ba40ce1b8437e30d5ed5277dd3710"
+dependencies = [
+ "serde",
+ "serde_json",
+ "tauri",
+ "thiserror 2.0.17",
+ "tracing",
+ "windows-sys 0.60.2",
+ "zbus",
+]
+
 [[package]]
 name = "tauri-runtime"
 version = "2.9.1"
@@ -4463,9 +4759,21 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "784e0ac535deb450455cbfa28a6f0df145ea1bb7ae51b821cf5e7927fdcfbdd0"
 dependencies = [
  "pin-project-lite",
+ "tracing-attributes",
  "tracing-core",
 ]
 
+[[package]]
+name = "tracing-attributes"
+version = "0.1.30"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "81383ab64e72a7a8b8e13130c49e3dab29def6d0c7d76a03087b3cf71c5c6903"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.108",
+]
+
 [[package]]
 name = "tracing-core"
 version = "0.1.34"
@@ -4515,6 +4823,17 @@ version = "1.19.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "562d481066bde0658276a35467c4af00bdc6ee726305698a55b86e61d7ad82bb"
 
+[[package]]
+name = "uds_windows"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "89daebc3e6fd160ac4aa9fc8b3bf71e1f74fbf92367ae71fb83a037e8bf164b9"
+dependencies = [
+ "memoffset",
+ "tempfile",
+ "winapi",
+]
+
 [[package]]
 name = "unic-char-property"
 version = "0.9.0"
@@ -5530,6 +5849,67 @@ dependencies = [
  "synstructure",
 ]
 
+[[package]]
+name = "zbus"
+version = "5.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b622b18155f7a93d1cd2dc8c01d2d6a44e08fb9ebb7b3f9e6ed101488bad6c91"
+dependencies = [
+ "async-broadcast",
+ "async-executor",
+ "async-io",
+ "async-lock",
+ "async-process",
+ "async-recursion",
+ "async-task",
+ "async-trait",
+ "blocking",
+ "enumflags2",
+ "event-listener",
+ "futures-core",
+ "futures-lite",
+ "hex",
+ "nix",
+ "ordered-stream",
+ "serde",
+ "serde_repr",
+ "tracing",
+ "uds_windows",
+ "uuid",
+ "windows-sys 0.61.2",
+ "winnow 0.7.13",
+ "zbus_macros",
+ "zbus_names",
+ "zvariant",
+]
+
+[[package]]
+name = "zbus_macros"
+version = "5.12.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1cdb94821ca8a87ca9c298b5d1cbd80e2a8b67115d99f6e4551ac49e42b6a314"
+dependencies = [
+ "proc-macro-crate 3.4.0",
+ "proc-macro2",
+ "quote",
+ "syn 2.0.108",
+ "zbus_names",
+ "zvariant",
+ "zvariant_utils",
+]
+
+[[package]]
+name = "zbus_names"
+version = "4.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7be68e64bf6ce8db94f63e72f0c7eb9a60d733f7e0499e628dfab0f84d6bcb97"
+dependencies = [
+ "serde",
+ "static_assertions",
+ "winnow 0.7.13",
+ "zvariant",
+]
+
 [[package]]
 name = "zerocopy"
 version = "0.8.27"
@@ -5603,3 +5983,43 @@ dependencies = [
  "quote",
  "syn 2.0.108",
 ]
+
+[[package]]
+name = "zvariant"
+version = "5.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2be61892e4f2b1772727be11630a62664a1826b62efa43a6fe7449521cb8744c"
+dependencies = [
+ "endi",
+ "enumflags2",
+ "serde",
+ "winnow 0.7.13",
+ "zvariant_derive",
+ "zvariant_utils",
+]
+
+[[package]]
+name = "zvariant_derive"
+version = "5.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "da58575a1b2b20766513b1ec59d8e2e68db2745379f961f86650655e862d2006"
+dependencies = [
+ "proc-macro-crate 3.4.0",
+ "proc-macro2",
+ "quote",
+ "syn 2.0.108",
+ "zvariant_utils",
+]
+
+[[package]]
+name = "zvariant_utils"
+version = "3.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c6949d142f89f6916deca2232cf26a8afacf2b9fdc35ce766105e104478be599"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "serde",
+ "syn 2.0.108",
+ "winnow 0.7.13",
+]

frontend/src-tauri/Cargo.toml

@@ -28,5 +28,6 @@ tauri = { version = "2.9.0", features = [ "devtools"] }
 tauri-plugin-log = "2.0.0-rc"
 tauri-plugin-shell = "2.1.0"
 tauri-plugin-fs = "2.4.4"
+tauri-plugin-single-instance = "2.0.1"
 tokio = { version = "1.0", features = ["time"] }
 reqwest = { version = "0.11", features = ["json"] }

frontend/src-tauri/src/commands/backend.rs

@@ -234,6 +234,8 @@ fn monitor_backend_output(mut rx: tauri::async_runtime::Receiver<tauri_plugin_sh
             match event {
                 tauri_plugin_shell::process::CommandEvent::Stdout(output) => {
                     let output_str = String::from_utf8_lossy(&output);
+                    // Strip exactly one trailing newline to avoid double newlines
+                    let output_str = output_str.strip_suffix('\n').unwrap_or(&output_str);
                     add_log(format!("📤 Backend: {}", output_str));
                     
                     // Look for startup indicators
@@ -250,6 +252,8 @@ fn monitor_backend_output(mut rx: tauri::async_runtime::Receiver<tauri_plugin_sh
                 }
                 tauri_plugin_shell::process::CommandEvent::Stderr(output) => {
                     let output_str = String::from_utf8_lossy(&output);
+                    // Strip exactly one trailing newline to avoid double newlines
+                    let output_str = output_str.strip_suffix('\n').unwrap_or(&output_str);
                     add_log(format!("📥 Backend Error: {}", output_str));
                     
                     // Look for error indicators

frontend/src-tauri/src/commands/files.rs

@@ -1,49 +1,47 @@
 use crate::utils::add_log;
 use std::sync::Mutex;
 
-// Store the opened file path globally
+// Store the opened file paths globally (supports multiple files)
-static OPENED_FILE: Mutex<Option<String>> = Mutex::new(None);
+static OPENED_FILES: Mutex<Vec<String>> = Mutex::new(Vec::new());
 
-// Set the opened file path (called by macOS file open events)
+// Add an opened file path
-#[cfg(target_os = "macos")]
+pub fn add_opened_file(file_path: String) {
-pub fn set_opened_file(file_path: String) {
+    let mut opened_files = OPENED_FILES.lock().unwrap();
-    let mut opened_file = OPENED_FILE.lock().unwrap();
+    opened_files.push(file_path.clone());
-    *opened_file = Some(file_path.clone());
+    add_log(format!("📂 File stored for later retrieval: {}", file_path));
-    add_log(format!("📂 File opened via file open event: {}", file_path));
 }
 
-// Command to get opened file path (if app was launched with a file)
+// Command to get opened file paths (if app was launched with files)
 #[tauri::command]
-pub async fn get_opened_file() -> Result<Option<String>, String> {
+pub async fn get_opened_files() -> Result<Vec<String>, String> {
-    // First check if we have a file from macOS file open events
+    let mut all_files: Vec<String> = Vec::new();
-    {
+
-        let opened_file = OPENED_FILE.lock().unwrap();
+    // Get files from command line arguments (Windows/Linux 'Open With Stirling' behaviour)
-        if let Some(ref file_path) = *opened_file {
-            add_log(format!("📂 Returning stored opened file: {}", file_path));
-            return Ok(Some(file_path.clone()));
-        }
-    }
-    
-    // Fallback to command line arguments (Windows/Linux)
     let args: Vec<String> = std::env::args().collect();
-    
+    let pdf_files: Vec<String> = args.iter()
-    // Look for a PDF file argument (skip the first arg which is the executable)
+        .skip(1)
-    for arg in args.iter().skip(1) {
+        .filter(|arg| std::path::Path::new(arg).exists())
-        if arg.ends_with(".pdf") && std::path::Path::new(arg).exists() {
+        .cloned()
-            add_log(format!("📂 PDF file opened via command line: {}", arg));
+        .collect();
-            return Ok(Some(arg.clone()));
+
-        }
+    all_files.extend(pdf_files);
+
+    // Add any files sent via events or other instances (macOS 'Open With Stirling' behaviour, also Windows/Linux extra files)
+    {
+        let opened_files = OPENED_FILES.lock().unwrap();
+        all_files.extend(opened_files.clone());
     }
-    
+
-    Ok(None)
+    add_log(format!("📂 Returning {} opened file(s)", all_files.len()));
+    Ok(all_files)
 }
 
-// Command to clear the opened file (after processing)
+// Command to clear the opened files (after processing)
 #[tauri::command]
-pub async fn clear_opened_file() -> Result<(), String> {
+pub async fn clear_opened_files() -> Result<(), String> {
-    let mut opened_file = OPENED_FILE.lock().unwrap();
+    let mut opened_files = OPENED_FILES.lock().unwrap();
-    *opened_file = None;
+    opened_files.clear();
-    add_log("📂 Cleared opened file".to_string());
+    add_log("📂 Cleared opened files".to_string());
     Ok(())
 }
 

frontend/src-tauri/src/commands/mod.rs

@@ -4,6 +4,4 @@ pub mod files;
 
 pub use backend::{start_backend, cleanup_backend};
 pub use health::check_backend_health;
-pub use files::{get_opened_file, clear_opened_file};
+pub use files::{get_opened_files, clear_opened_files, add_opened_file};
-#[cfg(target_os = "macos")]
-pub use files::set_opened_file;

frontend/src-tauri/src/lib.rs

@@ -1,13 +1,9 @@
-use tauri::{RunEvent, WindowEvent};
+use tauri::{RunEvent, WindowEvent, Emitter, Manager};
-#[cfg(target_os = "macos")]
-use tauri::Emitter;
 
 mod utils;
 mod commands;
 
-use commands::{start_backend, check_backend_health, get_opened_file, clear_opened_file, cleanup_backend};
+use commands::{start_backend, check_backend_health, get_opened_files, clear_opened_files, cleanup_backend, add_opened_file};
-#[cfg(target_os = "macos")]
-use commands::set_opened_file;
 use utils::{add_log, get_tauri_logs};
 
 #[cfg_attr(mobile, tauri::mobile_entry_point)]
@@ -15,12 +11,35 @@ pub fn run() {
   tauri::Builder::default()
     .plugin(tauri_plugin_shell::init())
     .plugin(tauri_plugin_fs::init())
+    .plugin(tauri_plugin_single_instance::init(|app, args, _cwd| {
+      // This callback runs when a second instance tries to start
+      add_log(format!("📂 Second instance detected with args: {:?}", args));
+
+      // Scan args for PDF files (skip first arg which is the executable)
+      for arg in args.iter().skip(1) {
+        if std::path::Path::new(arg).exists() {
+          add_log(format!("📂 Forwarding file to existing instance: {}", arg));
+
+          // Store file for later retrieval (in case frontend isn't ready yet)
+          add_opened_file(arg.clone());
+
+          // Also emit event for immediate handling if frontend is ready
+          let _ = app.emit("file-opened", arg.clone());
+
+          // Bring the existing window to front
+          if let Some(window) = app.get_webview_window("main") {
+            let _ = window.set_focus();
+            let _ = window.unminimize();
+          }
+        }
+      }
+    }))
     .setup(|_app| {
       add_log("🚀 Tauri app setup started".to_string());
       add_log("🔍 DEBUG: Setup completed".to_string());
       Ok(())
     })
-    .invoke_handler(tauri::generate_handler![start_backend, check_backend_health, get_opened_file, clear_opened_file, get_tauri_logs])
+    .invoke_handler(tauri::generate_handler![start_backend, check_backend_health, get_opened_files, clear_opened_files, get_tauri_logs])
     .build(tauri::generate_context!())
     .expect("error while building tauri application")
     .run(|app_handle, event| {
@@ -45,8 +64,9 @@ pub fn run() {
               let file_path = url_str.strip_prefix("file://").unwrap_or(url_str);
               if file_path.ends_with(".pdf") {
                 add_log(format!("📂 Processing opened PDF: {}", file_path));
-                set_opened_file(file_path.to_string());
+                add_opened_file(file_path.to_string());
-                let _ = app_handle.emit("macos://open-file", file_path.to_string());
+                // Use unified event name for consistency across platforms
+                let _ = app_handle.emit("file-opened", file_path.to_string());
               }
             }
           }
@@ -58,4 +78,4 @@ pub fn run() {
         }
       }
     });
-}
+}

frontend/src-tauri/tauri.conf.json

@@ -22,7 +22,7 @@
   },
   "bundle": {
     "active": true,
-    "targets": ["deb", "rpm", "dmg", "msi"],
+    "targets": ["deb", "rpm", "dmg", "app", "msi"],
     "icon": [
       "icons/icon.png",
       "icons/icon.icns",

frontend/src/desktop/hooks/useAppInitialization.ts

@@ -1,4 +1,4 @@
-import { useEffect } from 'react';
+import { useEffect, useRef } from 'react';
 import { useBackendInitializer } from '@app/hooks/useBackendInitializer';
 import { useOpenedFile } from '@app/hooks/useOpenedFile';
 import { fileOpenService } from '@app/services/fileOpenService';
@@ -17,31 +17,78 @@ export function useAppInitialization(): void {
   // Get file management actions
   const { addFiles } = useFileManagement();
 
-  // Handle file opened with app (Tauri mode)
+  // Handle files opened with app (Tauri mode)
-  const { openedFilePath, loading: openedFileLoading } = useOpenedFile();
+  const { openedFilePaths, loading: openedFileLoading } = useOpenedFile();
 
-  // Load opened file and add directly to FileContext
+  // Track if we've already loaded the initial files to prevent duplicate loads
+  const initialFilesLoadedRef = useRef(false);
+
+  // Load opened files and add directly to FileContext
   useEffect(() => {
-    if (openedFilePath && !openedFileLoading) {
+    if (openedFilePaths.length > 0 && !openedFileLoading && !initialFilesLoadedRef.current) {
-      const loadOpenedFile = async () => {
+      initialFilesLoadedRef.current = true;
-        try {
-          const fileData = await fileOpenService.readFileAsArrayBuffer(openedFilePath);
-          if (fileData) {
-            // Create a File object from the ArrayBuffer
-            const file = new File([fileData.arrayBuffer], fileData.fileName, {
-              type: 'application/pdf'
-            });
 
-            // Add directly to FileContext
+      const loadOpenedFiles = async () => {
-            await addFiles([file]);
+        try {
-            console.log('[Desktop] Opened file added to FileContext:', fileData.fileName);
+          const filesArray: File[] = [];
+
+          // Load all files in parallel
+          await Promise.all(
+            openedFilePaths.map(async (filePath) => {
+              try {
+                const fileData = await fileOpenService.readFileAsArrayBuffer(filePath);
+                if (fileData) {
+                  const file = new File([fileData.arrayBuffer], fileData.fileName, {
+                    type: 'application/pdf'
+                  });
+                  filesArray.push(file);
+                  console.log('[Desktop] Loaded file:', fileData.fileName);
+                }
+              } catch (error) {
+                console.error('[Desktop] Failed to load file:', filePath, error);
+              }
+            })
+          );
+
+          if (filesArray.length > 0) {
+            // Add all files to FileContext at once
+            await addFiles(filesArray);
+            console.log(`[Desktop] ${filesArray.length} opened file(s) added to FileContext`);
           }
         } catch (error) {
-          console.error('[Desktop] Failed to load opened file:', error);
+          console.error('[Desktop] Failed to load opened files:', error);
         }
       };
 
-      loadOpenedFile();
+      loadOpenedFiles();
     }
-  }, [openedFilePath, openedFileLoading, addFiles]);
+  }, [openedFilePaths, openedFileLoading, addFiles]);
+
+  // Listen for runtime file-opened events (from second instances on Windows/Linux)
+  useEffect(() => {
+    const handleRuntimeFileOpen = async (filePath: string) => {
+      try {
+        console.log('[Desktop] Runtime file-opened event received:', filePath);
+        const fileData = await fileOpenService.readFileAsArrayBuffer(filePath);
+        if (fileData) {
+          // Create a File object from the ArrayBuffer
+          const file = new File([fileData.arrayBuffer], fileData.fileName, {
+            type: 'application/pdf'
+          });
+
+          // Add directly to FileContext
+          await addFiles([file]);
+          console.log('[Desktop] Runtime opened file added to FileContext:', fileData.fileName);
+        }
+      } catch (error) {
+        console.error('[Desktop] Failed to load runtime opened file:', error);
+      }
+    };
+
+    // Set up event listener and get cleanup function
+    const unlisten = fileOpenService.onFileOpened(handleRuntimeFileOpen);
+
+    // Clean up listener on unmount
+    return unlisten;
+  }, [addFiles]);
 }

frontend/src/desktop/hooks/useOpenedFile.ts

@@ -2,28 +2,28 @@ import { useState, useEffect } from 'react';
 import { fileOpenService } from '@app/services/fileOpenService';
 
 export function useOpenedFile() {
-  const [openedFilePath, setOpenedFilePath] = useState<string | null>(null);
+  const [openedFilePaths, setOpenedFilePaths] = useState<string[]>([]);
   const [loading, setLoading] = useState(true);
 
   useEffect(() => {
     const checkForOpenedFile = async () => {
-      console.log('🔍 Checking for opened file...');
+      console.log('🔍 Checking for opened file(s)...');
       try {
-        const filePath = await fileOpenService.getOpenedFile();
+        const filePaths = await fileOpenService.getOpenedFiles();
-        console.log('🔍 fileOpenService.getOpenedFile() returned:', filePath);
+        console.log('🔍 fileOpenService.getOpenedFiles() returned:', filePaths);
-        
+
-        if (filePath) {
+        if (filePaths.length > 0) {
-          console.log('✅ App opened with file:', filePath);
+          console.log(`✅ App opened with ${filePaths.length} file(s):`, filePaths);
-          setOpenedFilePath(filePath);
+          setOpenedFilePaths(filePaths);
-          
+
-          // Clear the file from service state after consuming it
+          // Clear the files from service state after consuming them
-          await fileOpenService.clearOpenedFile();
+          await fileOpenService.clearOpenedFiles();
         } else {
-          console.log('ℹ️ No file was opened with the app');
+          console.log('ℹ️ No files were opened with the app');
         }
 
       } catch (error) {
-        console.error('❌ Failed to check for opened file:', error);
+        console.error('❌ Failed to check for opened files:', error);
       } finally {
         setLoading(false);
       }
@@ -34,7 +34,7 @@ export function useOpenedFile() {
     // Listen for runtime file open events (abstracted through service)
     const unlistenRuntimeEvents = fileOpenService.onFileOpened((filePath: string) => {
       console.log('📂 Runtime file open event:', filePath);
-      setOpenedFilePath(filePath);
+      setOpenedFilePaths(prev => [...prev, filePath]);
     });
 
     // Cleanup function
@@ -43,5 +43,5 @@ export function useOpenedFile() {
     };
   }, []);
 
-  return { openedFilePath, loading };
+  return { openedFilePaths, loading };
 }

frontend/src/desktop/services/fileOpenService.ts

@@ -1,22 +1,22 @@
 import { invoke, isTauri } from '@tauri-apps/api/core';
 
 export interface FileOpenService {
-  getOpenedFile(): Promise<string | null>;
+  getOpenedFiles(): Promise<string[]>;
   readFileAsArrayBuffer(filePath: string): Promise<{ fileName: string; arrayBuffer: ArrayBuffer } | null>;
-  clearOpenedFile(): Promise<void>;
+  clearOpenedFiles(): Promise<void>;
   onFileOpened(callback: (filePath: string) => void): () => void; // Returns unlisten function
 }
 
 class TauriFileOpenService implements FileOpenService {
-  async getOpenedFile(): Promise<string | null> {
+  async getOpenedFiles(): Promise<string[]> {
     try {
-      console.log('🔍 Calling invoke(get_opened_file)...');
+      console.log('🔍 Calling invoke(get_opened_files)...');
-      const result = await invoke<string | null>('get_opened_file');
+      const result = await invoke<string[]>('get_opened_files');
-      console.log('🔍 invoke(get_opened_file) returned:', result);
+      console.log('🔍 invoke(get_opened_files) returned:', result);
       return result;
     } catch (error) {
-      console.error('❌ Failed to get opened file:', error);
+      console.error('❌ Failed to get opened files:', error);
-      return null;
+      return [];
     }
   }
 
@@ -37,13 +37,13 @@ class TauriFileOpenService implements FileOpenService {
     }
   }
 
-  async clearOpenedFile(): Promise<void> {
+  async clearOpenedFiles(): Promise<void> {
     try {
-      console.log('🔍 Calling invoke(clear_opened_file)...');
+      console.log('🔍 Calling invoke(clear_opened_files)...');
-      await invoke('clear_opened_file');
+      await invoke('clear_opened_files');
-      console.log('✅ Successfully cleared opened file');
+      console.log('✅ Successfully cleared opened files');
     } catch (error) {
-      console.error('❌ Failed to clear opened file:', error);
+      console.error('❌ Failed to clear opened files:', error);
     }
   }
 
@@ -67,15 +67,9 @@ class TauriFileOpenService implements FileOpenService {
             return;
           }
 
-          // Listen for macOS native file open events
+          // Listen for unified file open events (all platforms)
-          const unlistenMacOS = await listen('macos://open-file', (event) => {
+          const unlisten = await listen('file-opened', (event) => {
-            console.log('📂 macOS native file open event:', event.payload);
+            console.log('📂 File open event received:', event.payload);
-            callback(event.payload as string);
-          });
-
-          // Listen for fallback file open events
-          const unlistenFallback = await listen('file-opened', (event) => {
-            console.log('📂 Fallback file open event:', event.payload);
             callback(event.payload as string);
           });
 
@@ -83,8 +77,7 @@ class TauriFileOpenService implements FileOpenService {
           if (!isCleanedUp) {
             cleanup = () => {
               try {
-                unlistenMacOS();
+                unlisten();
-                unlistenFallback();
                 console.log('✅ File event listeners cleaned up');
               } catch (error) {
                 console.error('❌ Error during file event cleanup:', error);
@@ -93,8 +86,7 @@ class TauriFileOpenService implements FileOpenService {
           } else {
             // Clean up immediately if cleanup was called during setup
             try {
-              unlistenMacOS();
+              unlisten();
-              unlistenFallback();
             } catch (error) {
               console.error('❌ Error during immediate cleanup:', error);
             }
@@ -118,9 +110,9 @@ class TauriFileOpenService implements FileOpenService {
 }
 
 class WebFileOpenService implements FileOpenService {
-  async getOpenedFile(): Promise<string | null> {
+  async getOpenedFiles(): Promise<string[]> {
     // In web mode, there's no file association support
-    return null;
+    return [];
   }
 
   async readFileAsArrayBuffer(_filePath: string): Promise<{ fileName: string; arrayBuffer: ArrayBuffer } | null> {
@@ -128,7 +120,7 @@ class WebFileOpenService implements FileOpenService {
     return null;
   }
 
-  async clearOpenedFile(): Promise<void> {
+  async clearOpenedFiles(): Promise<void> {
     // In web mode, no file clearing needed
   }