feat: support URL parameters for layer presets and visibility (#1530)

public/main.js

@@ -378,6 +378,8 @@ function focusOn() {
   const url = new URL(window.location.href);
   const params = url.searchParams;
 
+  applyURLLayers(params);
+
   const fromMGCG = params.get("from") === "MFCG" && document.referrer;
   if (fromMGCG) {
     if (params.get("seed").length === 13) {

public/modules/ui/layers.js

@@ -1063,3 +1063,56 @@ function getLayer(id) {
   if (id === "toggleTrade") return $("#tradeAnimation");
   if (id === "toggleRulers") return $("#ruler");
 }
+
+function applyURLLayers(params) {
+  const presetParam = params.get("preset");
+  const layersParam = params.get("layers");
+
+  if (!presetParam && !layersParam) return;
+
+  const normalize = str => str.toLowerCase().replace(/[^a-z0-9]/g, "");
+
+  if (presetParam) {
+    let matchedPreset = null;
+    const lowerParam = presetParam.toLowerCase().trim();
+    for (const key in presets) {
+      if (key.toLowerCase() === lowerParam) {
+        matchedPreset = key;
+        break;
+      }
+    }
+    if (!matchedPreset) {
+      const selectEl = document.getElementById("layersPreset");
+      if (selectEl) {
+        for (const option of selectEl.options) {
+          const optionText = option.text.toLowerCase();
+          if (optionText.includes(lowerParam) || lowerParam.includes(optionText)) {
+            matchedPreset = option.value;
+            break;
+          }
+        }
+      }
+    }
+    if (matchedPreset) {
+      handleLayersPresetChange(matchedPreset);
+    }
+  }
+
+  if (layersParam) {
+    const visibleNames = layersParam.split(",").map(s => normalize(s));
+    document.querySelectorAll("#mapLayers > li").forEach(el => {
+      const idNormalized = normalize(el.id);
+      const idWithoutToggleNormalized = normalize(el.id.replace(/^toggle/, ""));
+      const textNormalized = normalize(el.innerText || el.textContent || "");
+
+      const shouldBeOn = visibleNames.some(
+        name => name === idNormalized || name === idWithoutToggleNormalized || name === textNormalized
+      );
+
+      const isOn = layerIsOn(el.id);
+      if (shouldBeOn && !isOn) el.click();
+      if (isOn && !shouldBeOn) el.click();
+    });
+  }
+}
+