Implement autoredirect

static/crossroad.css

@@ -61,6 +61,14 @@ abbr[title] {
     height: 100%;
 }
 
+.flex-hcenter {
+    display: flex;
+    flex-direction: row;
+    justify-content: center;
+    width: 100%;
+    height: 100%;
+}
+
 .flex-row {
     display: flex;
     flex-direction: row;
@@ -76,6 +84,13 @@ abbr[title] {
     flex-direction: column-reverse;
 }
 
+.flex-vevenly {
+    display: flex;
+    flex-direction: column;
+    justify-content: space-evenly;
+    height: 100%;
+}
+
 .half-width {
     min-width: 50%;
 }

static/crossroad.html

@@ -29,7 +29,12 @@
                     <button onclick="showAddInstanceDialog()">Add an instance</button>
                 </div>
                 <div class="half-width">
-                    <button id="redirect">Redirect</button>
+                    <div class="flex-hcenter">
+                        <div class="flex-vevenly">
+                            <button id="redirect">Redirect</button>
+                            <button id="redirectAlways">Redirect always</button>
+                        </div>
+                    </div>
                 </div>
             </div>
         </dialog>

static/crossroad.mts

@@ -13,6 +13,7 @@ const detailsDialog = findDialogOrFail(document.body, "#instanceDetails");
 const addDialog = findDialogOrFail(document.body, "#addInstance");
 const instanceSelectForm = findFormOrFail(document.body, "#instanceSelectForm");
 const redirectButton = findButtonOrFail(document.body, "#redirect");
+const redirectAlwaysButton = findButtonOrFail(document.body, "#redirectAlways");
 
 export const {
     showAddInstanceDialog,
@@ -48,24 +49,73 @@ function createInstanceSelectOptions() {
         instanceSelectForm.appendChild(div);
     }
     const firstInput = instanceSelectForm.querySelector("input");
-    if (firstInput) {
-        firstInput.checked = true;
-        redirectButton.disabled = false;
-    } else {
-        redirectButton.disabled = true;
-    }
+    if (firstInput) firstInput.checked = true;
+    setRedirectButtonState(firstInput !== null);
 }
 
 createInstanceSelectOptions();
 storageManager.addSaveCallback(createInstanceSelectOptions);
 
-function redirect() {
-    // Can be assumed to not fail because the button is disabled if there are no options and the first one is selected by default
-    const option = findInputOrFail(instanceSelectForm, `input[name="${radioButtonName}"]:checked`).value;
-    const url = URL.parse(option)!;
+function setRedirectButtonState(enabled: boolean) {
+    redirectButton.disabled = !enabled;
+    redirectAlwaysButton.disabled = !enabled;
+}
+
+export function getTargetSoftwareOrGroup(): string {
     const currentURL = URL.parse(location.href)!;
-    url.pathname = currentURL.pathname.replace(/\/.*?\//, "/");
+    const target = currentURL.pathname.match(/\/+([^\/]*)\/?/)?.[1];
+    if (target == null) throw new Error("Crossroad was served on an invalid path (likely a backend routing mistake)");
+    const softwareName = Object.entries(knownSoftware.software).find(([name, software]) => software.aliases.includes(target))?.[0];
+    if (softwareName) return softwareName;
+    const groupName = Object.entries(knownSoftware.groups).find(([name, group]) => group.aliases.includes(target))?.[0];
+    if (groupName) return groupName;
+    throw new Error("Could not identify target software or group");
+}
+
+function getTargetPath(): string {
+    const currentURL = URL.parse(location.href)!;
+    return currentURL.pathname.replace(/\/+[^\/]*\/?/, "/");
+}
+
+function getSelectedOption(): string | null {
+    try {
+        return findInputOrFail(instanceSelectForm, `input[name="${radioButtonName}"]:checked`).value;
+    } catch {
+        return null;
+    }
+}
+
+function autoRedirect() {
+    const targetSoftware = getTargetSoftwareOrGroup();
+    const preferredFor = storageManager.storage.instances.find(instance => instance.preferredFor?.includes(targetSoftware));
+    if (preferredFor) redirect(preferredFor.origin);
+}
+
+autoRedirect();
+
+function setAutoRedirect(option: string) {
+    const instance = storageManager.storage.instances.find(e => e.origin === option);
+    if (!instance) throw new Error("Invalid argument");
+    instance.preferredFor ??= [];
+    instance.preferredFor.push(getTargetSoftwareOrGroup());
+    storageManager.save();
+}
+
+redirectAlwaysButton.addEventListener("click", e => {
+    // Can be assumed to not fail because the button is disabled if there are no options and the first one is selected by default
+    const option = getSelectedOption()!;
+    setAutoRedirect(option);
+    redirect(option);
+});
+
+function redirect(to: string) {
+    const url = URL.parse(to);
+    if (url === null) throw new Error("Couldn't parse destination");
+    url.pathname = getTargetPath();
     location.href = url.toString();
 }
 
-redirectButton.addEventListener("click", e => redirect());
+redirectButton.addEventListener("click", e => {
+    // Can be assumed to not fail because the button is disabled if there are no options and the first one is selected by default
+    redirect(getSelectedOption()!);
+});

static/storage_manager.mts

@@ -25,6 +25,11 @@ export type Instance = {
      * Make sure to sanitize this! Could lead to XSS
      */
     iconURL?: string,
+    /**
+     * The list of software names and groups the user prefers to autoredirect to this instance
+     * @example ["sharkey", "misskey-compliant"]
+     */
+    preferredFor?: string[],
 }
 
 type LocalStorage = {