Add refresh button and license statement

Close #25, close #24

public/assets/js/csvxmlV2.js

@@ -1018,6 +1018,45 @@ class CsvxmlPage {
 
     }
 
+    renderFooter() {
+
+        const footer = document.createElement("footer");
+
+        const licenseStatement = document.createElement("p");
+        licenseStatement.textContent = "This work is licensed under the GNU Affero Public License Version 3.";
+        footer.appendChild(licenseStatement);
+
+        const footerOptions = document.createElement("div");
+
+        const codeLink = document.createElement("a");
+        codeLink.textContent = "Source code";
+        codeLink.href = "https://gitea.armuli.eu/museum-digital/csvxml";
+        footerOptions.appendChild(codeLink);
+
+        if ('serviceWorker' in navigator) {
+        const refreshB = document.createElement("span");
+        refreshB.textContent = "Reload application";
+        refreshB.setAttribute("tabindex", 1);
+        refreshB.addEventListener('click', function(e) {
+
+            Promise.all(['csvxml-cache-v1'].map(function(cache) {
+                caches.has(cache).then(function(hasCache) {
+                    if (hasCache === true) {
+                        caches.delete(cache).then(function(deletionStatus) {});
+                    }
+                })
+            }))
+            location.reload()
+
+        }, {passive: true, once: true});
+        footerOptions.appendChild(refreshB);
+        }
+
+        footer.appendChild(footerOptions);
+        document.body.appendChild(footer);
+
+    }
+
 }
 
 (async function() {
@@ -1056,6 +1095,7 @@ class CsvxmlPage {
         page.renderHelpTexts();
         page.renderUploader();
         page.renderMain();
+        page.renderFooter();
 
     }