Rasalas · akrost · Apr 10, 2026
diff --git a/AGENTS.md b/AGENTS.md
@@ -40,19 +40,19 @@ make tauri-dev        # Tauri development
 - **MessageHandler.js** - Email state management (collection, pinning, sorting, selection)
 - **FileHandler.js** - Drag-drop handling, delegates parsing to injected parsers
 - **utils.js** - MSG/EML parsing logic using `@kenjiuno/msgreader` and custom MIME parser
-- **tauri-bridge.js** - IPC layer for native features (file ops, dialogs, system viewer)
+- **tauri-bridge.js** - IPC layer for native features (file ops, Save As dialog, updates)
 
 ### UI Layer (src/js/ui/)
 
 - **UIManager.js** - Delegates to specialized sub-managers
 - **MessageListRenderer.js** - Sidebar list with virtual scrolling
 - **MessageContentRenderer.js** - Email body with HTML sanitization and inline images
-- **AttachmentModalManager.js** - Attachment preview/download with system viewer support
+- **AttachmentModalManager.js** - Attachment preview modal and download (web + Tauri Save As)
 - **VirtualList.js** - Performance optimization for large email lists
 
 ### Desktop App (src-tauri/)
 
-- **lib.rs** - Tauri commands: file reading, system viewer, Save As dialog
+- **lib.rs** - Tauri commands: file reading, Save As dialog
 - Single-instance enforcement, file associations (.msg, .eml), auto-update
 
 ## Key Patterns

diff --git a/src-tauri/src/lib.rs b/src-tauri/src/lib.rs
@@ -13,61 +13,6 @@ fn read_file_as_bytes(path: String) -> Result<Vec<u8>, String> {
     std::fs::read(&path).map_err(|e| format!("Failed to read file {}: {}", path, e))
 }
 
-/// Save a base64-encoded file to temp directory and open with system viewer
-#[tauri::command]
-fn open_file_with_system(base64_content: String, file_name: String) -> Result<(), String> {
-    use base64::{Engine as _, engine::general_purpose::STANDARD};
-
-    // Decode base64 content
-    let bytes = STANDARD.decode(&base64_content)
-        .map_err(|e| format!("Failed to decode base64: {}", e))?;
-
-    // Create temp file path
-    let temp_dir = std::env::temp_dir();
-    let temp_path = temp_dir.join(&file_name);
-
-    // Write to temp file
-    let mut file = std::fs::File::create(&temp_path)
-        .map_err(|e| format!("Failed to create temp file: {}", e))?;
-    file.write_all(&bytes)
-        .map_err(|e| format!("Failed to write temp file: {}", e))?;
-
-    // Open with system default application
-    #[cfg(target_os = "macos")]
-    {
-        std::process::Command::new("open")
-            .arg(&temp_path)
-            .spawn()
-            .map_err(|e| format!("Failed to open file: {}", e))?;
-    }
-
-    #[cfg(target_os = "windows")]
-    {
-        use std::os::windows::process::CommandExt;
-        const CREATE_NO_WINDOW: u32 = 0x08000000;
-
-        // Use cmd.exe's start command - more reliable than PowerShell for opening files
-        // The empty "" is required as start interprets the first quoted arg as window title
-        // CREATE_NO_WINDOW prevents the console window from flashing
-        std::process::Command::new("cmd")
-            .args(["/c", "start", ""])
-            .arg(&temp_path)
-            .creation_flags(CREATE_NO_WINDOW)
-            .spawn()
-            .map_err(|e| format!("Failed to open file: {}", e))?;
-    }
-
-    #[cfg(target_os = "linux")]
-    {
-        std::process::Command::new("xdg-open")
-            .arg(&temp_path)
-            .spawn()
-            .map_err(|e| format!("Failed to open file: {}", e))?;
-    }
-
-    Ok(())
-}
-
 /// Save a file with a "Save As" dialog
 #[tauri::command]
 async fn save_file_with_dialog(
@@ -182,7 +127,7 @@ pub fn run() {
 
             Ok(())
         })
-        .invoke_handler(tauri::generate_handler![read_file_as_bytes, get_pending_files, open_file_with_system, save_file_with_dialog]);
+        .invoke_handler(tauri::generate_handler![read_file_as_bytes, get_pending_files, save_file_with_dialog]);
 
     builder
         .build(tauri::generate_context!())

diff --git a/src/js/tauri-bridge.js b/src/js/tauri-bridge.js
@@ -89,30 +89,6 @@ export function getFileName(filePath) {
     return parts[parts.length - 1];
 }
 
-/**
- * Open a file with the system's default application (Tauri only)
- * Saves the file to a temp location and opens it
- * @param {string} base64Data - Base64 data URL (data:mime/type;base64,...)
- * @param {string} fileName - Original filename
- * @returns {Promise<void>}
- */
-export async function openWithSystemViewer(base64Data, fileName) {
-    if (!isTauri()) {
-        throw new Error('openWithSystemViewer is only available in Tauri');
-    }
-
-    const { invoke } = await import('@tauri-apps/api/core');
-
-    // Extract the base64 content (remove data:mime/type;base64, prefix)
-    const base64Content = base64Data.split(',')[1];
-
-    // Call Rust command to save and open the file
-    await invoke('open_file_with_system', {
-        base64Content,
-        fileName,
-    });
-}
-
 /**
  * Save a file with a "Save As" dialog (Tauri only)
  * @param {string} base64Data - Base64 data URL (data:mime/type;base64,...)

diff --git a/src/js/ui/AttachmentModalManager.js b/src/js/ui/AttachmentModalManager.js
@@ -1,4 +1,4 @@
-import { isTauri, openWithSystemViewer, saveFileWithDialog } from '../tauri-bridge.js';
+import { isTauri, saveFileWithDialog } from '../tauri-bridge.js';
 import { extractEml } from '../utils.js';
 
 /**
@@ -41,6 +41,7 @@ export class AttachmentModalManager {
         this.imageViewerFallbackWidth = 960;
         this.imageViewerFallbackHeight = 720;
         this.inlineImageMetadataBySource = new Map();
+        this._pdfPreviewObjectUrl = null;
 
         // Navigation stack for nested content (e.g., attachments within nested emails)
         this.navigationStack = [];
@@ -288,13 +289,34 @@ export class AttachmentModalManager {
     }
 
     /**
-     * Checks if a MIME type is PDF
+     * True when filename ends with .pdf (case-insensitive)
+     * @param {string} fileName
+     * @returns {boolean}
+     */
+    _hasPdfExtension(fileName) {
+        return /\.pdf$/i.test(fileName || '');
+    }
+
+    /**
+     * MIME types often used when the real type is unknown but file is binary
+     * @param {string} mimeType
+     * @returns {boolean}
+     */
+    _isGenericBinaryMime(mimeType) {
+        const m = (mimeType || '').toLowerCase();
+        return !m || m === 'application/octet-stream' || m === 'binary/octet-stream';
+    }
+
+    /**
+     * Checks if an attachment is PDF by MIME and/or .pdf extension with generic MIME
      * @param {string} mimeType - MIME type to check
-     * @returns {boolean} True if the MIME type is PDF
+     * @param {string} [fileName=''] - Original filename
+     * @returns {boolean} True if the attachment should be previewed as PDF
      */
-    isPdf(mimeType) {
-        if (!mimeType) return false;
-        return mimeType.toLowerCase() === 'application/pdf';
+    isPdf(mimeType, fileName = '') {
+        const m = (mimeType || '').toLowerCase();
+        if (m === 'application/pdf') return true;
+        return this._hasPdfExtension(fileName) && this._isGenericBinaryMime(mimeType);
     }
 
     /**
@@ -326,38 +348,15 @@ export class AttachmentModalManager {
     /**
      * Checks if an attachment can be previewed in the modal
      * @param {string} mimeType - MIME type to check
+     * @param {string} [fileName=''] - Original filename (used for PDF-by-extension)
      * @returns {boolean} True if the attachment is previewable
      */
-    isPreviewable(mimeType) {
-        return this.isPreviewableImage(mimeType) || this.isPdf(mimeType) || this.isText(mimeType) || this.isPreviewableEml(mimeType);
-    }
-
-    /**
-     * Checks if an attachment should be opened with system viewer (Tauri PDF)
-     * @param {Object} attachment - Attachment object
-     * @returns {boolean} True if should use system viewer
-     */
-    _shouldOpenWithSystemViewer(attachment) {
-        return isTauri() && this.isPdf(attachment.attachMimeTag);
-    }
-
-    /**
-     * Opens a PDF with the system viewer (Tauri only)
-     * @param {Object} attachment - Attachment object
-     */
-    _openPdfWithSystemViewer(attachment) {
-        openWithSystemViewer(attachment.contentBase64, attachment.fileName)
-            .catch(err => {
-                console.error('Failed to open PDF with system viewer:', err);
-                if (this.showToast) {
-                    this.showToast('Failed to open PDF', 'error');
-                }
-            });
+    isPreviewable(mimeType, fileName = '') {
+        return this.isPreviewableImage(mimeType) || this.isPdf(mimeType, fileName) || this.isText(mimeType) || this.isPreviewableEml(mimeType);
     }
 
     /**
      * Opens the attachment preview modal for a specific attachment
-     * In Tauri, PDFs are opened with the system viewer instead of the modal
      * @param {Object} attachment - Attachment object to preview
      */
     open(attachment) {
@@ -366,16 +365,10 @@ export class AttachmentModalManager {
         // Clear navigation stack when opening a new attachment
         this.clearNavigationStack();
 
-        // In Tauri, open PDFs with system viewer (WebKit has issues with data: URLs)
-        if (this._shouldOpenWithSystemViewer(attachment)) {
-            this._openPdfWithSystemViewer(attachment);
-            return;
-        }
-
         // Build list of previewable attachments if not already set
         if (this.currentAttachments) {
             this.previewableAttachments = this.currentAttachments.filter(att =>
-                this.isPreviewable(att.attachMimeTag)
+                this.isPreviewable(att.attachMimeTag, att.fileName)
             );
         }
 
@@ -405,6 +398,7 @@ export class AttachmentModalManager {
      */
     renderAttachmentPreview(attachment) {
         this.resetImagePreviewState();
+        this._revokePdfPreviewObjectUrl();
 
         // Set filename with breadcrumb if navigating from nested content
         this.updateFilenameWithBreadcrumb(attachment.fileName);
@@ -421,12 +415,27 @@ export class AttachmentModalManager {
         // Render appropriate preview
         if (this.isPreviewableImage(attachment.attachMimeTag)) {
             this.renderImagePreview(attachment);
-        } else if (this.isPdf(attachment.attachMimeTag)) {
-            // Use object tag for better PDF compatibility with data: URLs
+        } else if (this.isPdf(attachment.attachMimeTag, attachment.fileName)) {
             const pdfObject = document.createElement('object');
-            pdfObject.data = attachment.contentBase64;
             pdfObject.type = 'application/pdf';
-            pdfObject.innerHTML = `<p class="text-center p-4">PDF cannot be displayed. <a href="${attachment.contentBase64}" download="${attachment.fileName}" class="text-blue-500 underline">Download here</a></p>`;
+            try {
+                const base64Data = attachment.contentBase64?.split(',')[1];
+                if (!base64Data) {
+                    throw new Error('Invalid base64 data format');
+                }
+                const binary = atob(base64Data);
+                const bytes = new Uint8Array(binary.length);
+                for (let i = 0; i < binary.length; i++) {
+                    bytes[i] = binary.charCodeAt(i);
+                }
+                const blob = new Blob([bytes], { type: 'application/pdf' });
+                this._pdfPreviewObjectUrl = URL.createObjectURL(blob);
+                pdfObject.data = this._pdfPreviewObjectUrl;
+            } catch (err) {
+                console.error('Error building PDF preview:', err);
+                pdfObject.removeAttribute('data');
+            }
+            pdfObject.innerHTML = `<p class="text-center p-4">PDF cannot be displayed. <a href="${attachment.contentBase64}" download="${this.escapeHtml(attachment.fileName)}" class="text-blue-500 underline">Download here</a></p>`;
             this.attachmentModalContent.appendChild(pdfObject);
         } else if (this.isText(attachment.attachMimeTag)) {
             // Decode base64 to text
@@ -625,6 +634,16 @@ export class AttachmentModalManager {
         this.attachmentModalSourceLink.hidden = false;
     }
 
+    /**
+     * Releases the blob URL for the in-modal PDF preview
+     */
+    _revokePdfPreviewObjectUrl() {
+        if (this._pdfPreviewObjectUrl) {
+            URL.revokeObjectURL(this._pdfPreviewObjectUrl);
+            this._pdfPreviewObjectUrl = null;
+        }
+    }
+
     /**
      * Resets image-specific preview state
      */
@@ -872,9 +891,9 @@ export class AttachmentModalManager {
                 attachmentsList.className = 'nested-email-attachments-list';
 
                 emailData.attachments.forEach(att => {
-                    const isPreviewable = this.isPreviewable(att.attachMimeTag);
+                    const isPreviewable = this.isPreviewable(att.attachMimeTag, att.fileName);
                     const isImage = this.isPreviewableImage(att.attachMimeTag);
-                    const isPdf = this.isPdf(att.attachMimeTag);
+                    const isPdf = this.isPdf(att.attachMimeTag, att.fileName);
                     const isText = this.isText(att.attachMimeTag);
                     const isEml = this.isPreviewableEml(att.attachMimeTag);
 
@@ -928,9 +947,6 @@ export class AttachmentModalManager {
                             if (downloadBtn) {
                                 e.stopPropagation();
                                 this.downloadAttachment(att);
-                            } else if (this._shouldOpenWithSystemViewer(att)) {
-                                // PDF in Tauri: open with system viewer instead of modal preview
-                                this._openPdfWithSystemViewer(att);
                             } else {
                                 this.pushToStack(attachment);
                                 this.renderAttachmentPreview(att);
@@ -1037,6 +1053,7 @@ export class AttachmentModalManager {
     close() {
         if (!this.attachmentModal) return;
 
+        this._revokePdfPreviewObjectUrl();
         this.attachmentModal.classList.remove('active');
         this.attachmentModalContent.innerHTML = '';
         this.attachmentModalContent.classList.remove('attachment-modal-content--image');

diff --git a/src/js/ui/MessageContentRenderer.js b/src/js/ui/MessageContentRenderer.js
@@ -469,7 +469,7 @@ export class MessageContentRenderer {
      */
     renderAttachmentItems(items) {
         return items.map(({ attachment, index }) => {
-            const isPreviewable = this.attachmentModal?.isPreviewable(attachment.attachMimeTag);
+            const isPreviewable = this.attachmentModal?.isPreviewable(attachment.attachMimeTag, attachment.fileName);
 
             if (isPreviewable) {
                 return `
@@ -529,7 +529,7 @@ export class MessageContentRenderer {
      */
     getAttachmentItemIcon(attachment) {
         const isImage = this.attachmentModal?.isPreviewableImage(attachment.attachMimeTag);
-        const isPdf = this.attachmentModal?.isPdf(attachment.attachMimeTag);
+        const isPdf = this.attachmentModal?.isPdf(attachment.attachMimeTag, attachment.fileName);
         const isText = this.attachmentModal?.isText(attachment.attachMimeTag);
         const isEml = this.attachmentModal?.isPreviewableEml(attachment.attachMimeTag);