Improve signature navigation and toolbar functionality

Enhanced signature navigation logic to track the last viewed signature (`_lastViewedSignatureId`) and enable cross-page navigation. Updated next/previous navigation to handle both signed and unsigned signatures, with automatic page changes and scrolling to the relevant element.

Added a signature counter to the toolbar, displaying total, signed, and unsigned counts. Improved `renderSignatureButtons()` to filter out applied signatures and updated `clearSignatureButtons()` to manage visibility based on the current page.

Integrated Blazor callbacks (`OnPageChangedBySignatureNav()` and `OnSignatureNavChanged`) for UI updates. Fixed visibility issues where applied signatures appeared on incorrect pages.

COPILOT_CONTEXT_EN.md

@@ -437,6 +437,14 @@ Our use case is **visual/image stamping** at specific page coordinates
 | **14** | **2025-01-26** | **JavaScript: `pdfViewer.applySignature()` creates HTML overlay (230px box, #f8f9fa background)** |
 | **14** | **2025-01-26** | **German date format: dd.MM.yyyy (e.g., 26.01.2025) via `toLocaleDateString('de-DE')`** |
 | **14** | **2025-01-26** | **XSS protection: `escapeHtml()` function sanitizes user-provided text** |
+| **15** | **2025-01-26** | **Fixed: Applied signatures now only visible on their respective pages (display: none on other pages)** |
+| **15** | **2025-01-26** | **Fixed: `clearSignatureButtons()` now hides/shows applied signatures based on current page** |
+| **15** | **2025-01-26** | **Added signature navigation toolbar: "Nächste Unterschrift" / "Vorherige Unterschrift" buttons** |
+| **15** | **2025-01-26** | **Signature counter displays total/signed/unsigned counts (e.g., "2 / 5" with "3 offen" badge)** |
+| **15** | **2025-01-26** | **Implemented cross-page signature navigation (auto page change + scroll to signature)** |
+| **15** | **2025-01-26** | **JavaScript: `goToNextSignature()` and `goToPreviousSignature()` with Blazor callbacks** |
+| **15** | **2025-01-26** | **Fixed: `renderSignatureButtons()` now filters out already-applied signatures** |
+| **15** | **2025-01-26** | **Blazor callback: `OnPageChangedBySignatureNav()` triggers signature button re-rendering** |
 
 ---
 

EnvelopeGenerator.ReceiverUI/wwwroot/js/pdf-viewer.js

@@ -481,6 +481,7 @@ window.pdfViewer = {
     // Signature button functionality
     signatureButtons: [],
     appliedSignatures: [],  // Track which signatures have been applied
+    _lastViewedSignatureId: null,  // Track last viewed signature for navigation
 
     /**
      * Gets signature navigation state (for toolbar display)
@@ -525,13 +526,19 @@ window.pdfViewer = {
             return false;
         }
 
-        // TÜM sayfalar aras?nda ilk imzalanmam?? imzay? bul
-        const appliedIds = new Set(this.appliedSignatures.map(s => s.id));
-        const nextSignature = this._allSignatures.find(sig => !appliedIds.has(sig.id));
-        
-        if (!nextSignature) {
-            return false; // Hepsi imzalanm??
+        // Mevcut görüntülenen imzan?n index'ini bul
+        let currentIndex = -1;
+        if (this._lastViewedSignatureId) {
+            currentIndex = this._allSignatures.findIndex(s => s.id === this._lastViewedSignatureId);
         }
+        
+        // Bir sonraki imzay? al (imzalanm?? olup olmad???na bakmadan)
+        const nextIndex = currentIndex + 1;
+        if (nextIndex >= this._allSignatures.length) {
+            return false; // Son imzaday?z
+        }
+        
+        const nextSignature = this._allSignatures[nextIndex];
 
         // Farkl? sayfadaysa sayfa de?i?tir
         if (nextSignature.page !== this.pageNum) {
@@ -555,14 +562,26 @@ window.pdfViewer = {
             await new Promise(resolve => setTimeout(resolve, 150));
         }
         
-        // Mevcut sayfadaki (art?k yeni sayfa olabilir) butonu bul
-        const button = this.signatureButtons.find(btn => 
-            parseInt(btn.getAttribute('data-signature-id')) === nextSignature.id
-        );
+        // Son görüntülenen imzay? kaydet
+        this._lastViewedSignatureId = nextSignature.id;
         
-        // Butonu görünür hale getir (scroll ile)
-        if (button) {
-            this.scrollToButton(button);
+        // ?mza imzalanm?? m? kontrol et
+        const isApplied = this.appliedSignatures.some(s => s.id === nextSignature.id);
+        
+        if (isApplied) {
+            // ?mzalanm?? - overlay container'? bul ve scroll yap
+            const container = document.querySelector(`.applied-signature[data-signature-id="${nextSignature.id}"]`);
+            if (container) {
+                this.scrollToElement(container);
+            }
+        } else {
+            // ?mzalanmam?? - butonu bul ve scroll yap
+            const button = this.signatureButtons.find(btn => 
+                parseInt(btn.getAttribute('data-signature-id')) === nextSignature.id
+            );
+            if (button) {
+                this.scrollToButton(button);
+            }
         }
 
         // Counter'? güncelle (Blazor'a bildir)
@@ -578,12 +597,23 @@ window.pdfViewer = {
      * Scrolls to signature position and changes page if necessary.
      */
     async goToPreviousSignature(dotNetRef) {
-        if (this.appliedSignatures.length === 0) {
+        if (!this._allSignatures || this._allSignatures.length === 0) {
             return false;
         }
 
-        // Get last applied signature
-        const lastSig = this.appliedSignatures[this.appliedSignatures.length - 1];
+        // Mevcut görüntülenen imzan?n index'ini bul
+        let currentIndex = this._allSignatures.length;  // Varsay?lan: son imzadan sonra
+        if (this._lastViewedSignatureId) {
+            currentIndex = this._allSignatures.findIndex(s => s.id === this._lastViewedSignatureId);
+        }
+        
+        // Bir önceki imzay? al
+        const prevIndex = currentIndex - 1;
+        if (prevIndex < 0) {
+            return false; // ?lk imzaday?z
+        }
+        
+        const prevSignature = this._allSignatures[prevIndex];
         
         // Change page if needed
         if (lastSig.page !== this.pageNum) {
@@ -607,10 +637,26 @@ window.pdfViewer = {
             await new Promise(resolve => setTimeout(resolve, 150));
         }
 
-        // Find applied signature container
-        const container = document.querySelector(`.applied-signature[data-signature-id="${lastSig.id}"]`);
-        if (container) {
-            this.scrollToElement(container);
+        // Son görüntülenen imzay? kaydet
+        this._lastViewedSignatureId = prevSignature.id;
+        
+        // ?mza imzalanm?? m? kontrol et
+        const isApplied = this.appliedSignatures.some(s => s.id === prevSignature.id);
+        
+        if (isApplied) {
+            // ?mzalanm?? - overlay container'? bul ve scroll yap
+            const container = document.querySelector(`.applied-signature[data-signature-id="${prevSignature.id}"]`);
+            if (container) {
+                this.scrollToElement(container);
+            }
+        } else {
+            // ?mzalanmam?? - butonu bul ve scroll yap
+            const button = this.signatureButtons.find(btn => 
+                parseInt(btn.getAttribute('data-signature-id')) === prevSignature.id
+            );
+            if (button) {
+                this.scrollToButton(button);
+            }
         }
 
         // Notify Blazor