feat: Add update checker to verify new versions on GitHub

- Add /api/check-update endpoint that queries GitHub API
- Compare current commit hash with latest on dev branch
- Add check button next to version in menu
- Show spinning icon during check, green checkmark when done
- Display "Update available" link when newer version exists
- Handle rate limits and network errors gracefully

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/routes/api.py

@@ -7,6 +7,7 @@ import json
 import re
 import base64
 import time
+import requests
 from datetime import datetime
 from io import BytesIO
 from flask import Blueprint, jsonify, request, send_file
@@ -1999,6 +2000,126 @@ def get_version():
     }), 200
 
 
+# GitHub repository for update checks
+GITHUB_REPO = "MarekWo/mc-webui"
+GITHUB_BRANCH = "dev"  # Check updates against dev branch
+
+
+@api_bp.route('/check-update', methods=['GET'])
+def check_update():
+    """
+    Check if a newer version is available on GitHub.
+
+    Compares current commit hash with latest commit on GitHub.
+
+    Query parameters:
+        branch (str): Branch to check (default: dev)
+
+    Returns:
+        JSON with update status:
+        {
+            "success": true,
+            "update_available": true,
+            "current_version": "2026.01.18+abc1234",
+            "current_commit": "abc1234",
+            "latest_commit": "def5678",
+            "latest_date": "2026.01.20",
+            "latest_message": "feat: New feature",
+            "github_url": "https://github.com/MarekWo/mc-webui/commits/dev"
+        }
+    """
+    from app.version import VERSION_STRING
+
+    try:
+        branch = request.args.get('branch', GITHUB_BRANCH)
+
+        # Extract current commit hash from VERSION_STRING (format: YYYY.MM.DD+hash or YYYY.MM.DD+hash+dirty)
+        current_commit = None
+        if '+' in VERSION_STRING:
+            parts = VERSION_STRING.split('+')
+            if len(parts) >= 2:
+                current_commit = parts[1]  # Get hash part (skip date, ignore +dirty)
+
+        if not current_commit or current_commit == 'unknown':
+            return jsonify({
+                'success': False,
+                'error': 'Cannot determine current version. Run version freeze first.'
+            }), 400
+
+        # Fetch latest commit from GitHub API
+        github_api_url = f"https://api.github.com/repos/{GITHUB_REPO}/commits/{branch}"
+        headers = {
+            'Accept': 'application/vnd.github.v3+json',
+            'User-Agent': 'mc-webui-update-checker'
+        }
+
+        response = requests.get(github_api_url, headers=headers, timeout=10)
+
+        if response.status_code == 403:
+            return jsonify({
+                'success': False,
+                'error': 'GitHub API rate limit exceeded. Try again later.'
+            }), 429
+
+        if response.status_code != 200:
+            return jsonify({
+                'success': False,
+                'error': f'GitHub API error: {response.status_code}'
+            }), 502
+
+        data = response.json()
+        latest_full_sha = data.get('sha', '')
+        latest_commit = latest_full_sha[:7]  # Short hash (7 chars like git default)
+
+        # Get commit details
+        commit_info = data.get('commit', {})
+        latest_message = commit_info.get('message', '').split('\n')[0]  # First line only
+        commit_date = commit_info.get('committer', {}).get('date', '')
+
+        # Parse date to YYYY.MM.DD format
+        latest_date = ''
+        if commit_date:
+            try:
+                dt = datetime.fromisoformat(commit_date.replace('Z', '+00:00'))
+                latest_date = dt.strftime('%Y.%m.%d')
+            except ValueError:
+                latest_date = commit_date[:10]
+
+        # Compare commits (case-insensitive, compare first 7 chars)
+        update_available = current_commit.lower()[:7] != latest_commit.lower()[:7]
+
+        return jsonify({
+            'success': True,
+            'update_available': update_available,
+            'current_version': VERSION_STRING,
+            'current_commit': current_commit[:7],
+            'latest_commit': latest_commit,
+            'latest_date': latest_date,
+            'latest_message': latest_message,
+            'github_url': f"https://github.com/{GITHUB_REPO}/commits/{branch}"
+        }), 200
+
+    except requests.Timeout:
+        return jsonify({
+            'success': False,
+            'error': 'GitHub API request timed out'
+        }), 504
+
+    except requests.RequestException as e:
+        logger.error(f"Error checking for updates: {e}")
+        return jsonify({
+            'success': False,
+            'error': f'Network error: {str(e)}'
+        }), 502
+
+    except Exception as e:
+        logger.error(f"Error checking for updates: {e}")
+        return jsonify({
+            'success': False,
+            'error': str(e)
+        }), 500
+
+
 @api_bp.route('/read_status/mark_read', methods=['POST'])
 def mark_read_api():
     """

app/static/css/style.css

@@ -364,6 +364,16 @@ main {
     height: 100%;
 }
 
+/* Spin animation for update check button */
+.spin {
+    animation: spin 1s linear infinite;
+}
+
+@keyframes spin {
+    from { transform: rotate(0deg); }
+    to { transform: rotate(360deg); }
+}
+
 /* Empty State */
 .empty-state {
     text-align: center;

app/static/js/app.js

@@ -398,6 +398,14 @@ function setupEventListeners() {
         }
     });
 
+    // Check for app updates button
+    const checkUpdateBtn = document.getElementById('checkUpdateBtn');
+    if (checkUpdateBtn) {
+        checkUpdateBtn.addEventListener('click', async function() {
+            await checkForAppUpdates();
+        });
+    }
+
     // Date selector (archive selection)
     document.getElementById('dateSelector').addEventListener('change', function(e) {
         currentArchiveDate = e.target.value || null;
@@ -1321,6 +1329,59 @@ function showNotification(message, type = 'info') {
     toast.show();
 }
 
+/**
+ * Check for app updates from GitHub
+ */
+async function checkForAppUpdates() {
+    const btn = document.getElementById('checkUpdateBtn');
+    const icon = document.getElementById('checkUpdateIcon');
+    const versionText = document.getElementById('versionText');
+
+    if (!btn || !icon) return;
+
+    // Show loading state
+    btn.disabled = true;
+    icon.className = 'bi bi-arrow-repeat spin';
+
+    try {
+        const response = await fetch('/api/check-update');
+        const data = await response.json();
+
+        if (data.success) {
+            if (data.update_available) {
+                // Update available - show green with link
+                versionText.innerHTML = `${data.current_version} <a href="${data.github_url}" target="_blank" class="text-success" title="Update available: ${data.latest_date}+${data.latest_commit}"><i class="bi bi-arrow-up-circle-fill"></i> Update available</a>`;
+                icon.className = 'bi bi-check-circle-fill text-success';
+                showNotification(`Update available: ${data.latest_date}+${data.latest_commit}`, 'success');
+            } else {
+                // Up to date
+                icon.className = 'bi bi-check-circle text-success';
+                showNotification('You are running the latest version', 'success');
+                // Reset icon after 3 seconds
+                setTimeout(() => {
+                    icon.className = 'bi bi-arrow-repeat';
+                }, 3000);
+            }
+        } else {
+            // Error
+            icon.className = 'bi bi-exclamation-triangle text-warning';
+            showNotification(data.error || 'Failed to check for updates', 'warning');
+            setTimeout(() => {
+                icon.className = 'bi bi-arrow-repeat';
+            }, 3000);
+        }
+    } catch (error) {
+        console.error('Error checking for updates:', error);
+        icon.className = 'bi bi-exclamation-triangle text-danger';
+        showNotification('Network error checking for updates', 'danger');
+        setTimeout(() => {
+            icon.className = 'bi bi-arrow-repeat';
+        }, 3000);
+    } finally {
+        btn.disabled = false;
+    }
+}
+
 /**
  * Scroll to bottom of messages
  */

app/templates/base.html

@@ -58,8 +58,13 @@
             <h5 class="offcanvas-title"><i class="bi bi-menu-button-wide"></i> Menu</h5>
             <button type="button" class="btn-close" data-bs-dismiss="offcanvas"></button>
         </div>
-        <div class="px-3 pb-2 text-muted small border-bottom">
-            <i class="bi bi-tag"></i> {{ version }}
+        <div class="px-3 pb-2 text-muted small border-bottom d-flex align-items-center justify-content-between">
+            <span id="versionDisplay">
+                <i class="bi bi-tag"></i> <span id="versionText">{{ version }}</span>
+            </span>
+            <button id="checkUpdateBtn" class="btn btn-sm btn-outline-secondary py-0 px-1" title="Check for updates">
+                <i class="bi bi-arrow-repeat" id="checkUpdateIcon"></i>
+            </button>
         </div>
         <div class="offcanvas-body">
             <div class="list-group list-group-flush">