fix: Fix flaky ratings on mobile (#7916)

frontend/app/components/Domain/Recipe/RecipeRating.vue

@@ -1,38 +1,36 @@
 <template>
   <div @click.prevent>
-    <!-- User Rating -->
-    <v-hover v-slot="{ isHovering, props: hoverProps }">
-      <v-rating
-        v-if="isOwnGroup && (userRating || isHovering || !ratingsLoaded)"
-        v-bind="hoverProps"
-        :model-value="userRating"
-        active-color="secondary"
-        color="secondary-lighten-3"
-        length="5"
-        :density="small ? 'compact' : 'default'"
-        :size="small ? 'x-small' : undefined"
-        hover
-        clearable
-        @update:model-value="updateRating(+$event)"
-      />
-      <!-- Group Rating -->
-      <v-rating
-        v-else
-        v-bind="hoverProps"
-        :model-value="groupRating"
-        :half-increments="true"
-        active-color="grey-darken-1"
-        color="secondary-lighten-3"
-        length="5"
-        :density="small ? 'compact' : 'default'"
-        :size="small ? 'x-small' : undefined"
-        hover
-      />
-    </v-hover>
+    <!-- User Rating: shows the group average until the user rates the recipe themselves -->
+    <v-rating
+      v-if="isOwnGroup"
+      :model-value="displayRating"
+      :active-color="showGroupAverage ? 'grey-darken-1' : 'secondary'"
+      color="secondary-lighten-3"
+      length="5"
+      :half-increments="showGroupAverage"
+      :density="small ? 'compact' : 'default'"
+      :size="small ? 'x-small' : undefined"
+      :hover="canHover"
+      :clearable="!!userRatingDisplayValue"
+      @update:model-value="updateRating(+$event)"
+    />
+    <!-- Group Rating -->
+    <v-rating
+      v-else
+      :model-value="groupRating"
+      :half-increments="true"
+      active-color="grey-darken-1"
+      color="secondary-lighten-3"
+      length="5"
+      :density="small ? 'compact' : 'default'"
+      :size="small ? 'x-small' : undefined"
+      readonly
+    />
   </div>
 </template>
 
 <script setup lang="ts">
+import { useMediaQuery } from "@vueuse/core";
 import { useLoggedInState } from "~/composables/use-logged-in-state";
 import { useUserSelfRatings } from "~/composables/use-users";
 
@@ -51,42 +49,61 @@ const props = withDefaults(defineProps<Props>(), {
 });
 
 const modelValue = defineModel<number>({ default: 0 });
+const groupRating = computed(() => modelValue.value);
 
 const { isOwnGroup } = useLoggedInState();
-const { userRatings, setRating, ready: ratingsLoaded } = useUserSelfRatings();
+const { userRatings, setRating } = useUserSelfRatings();
 
-const userRating = computed(() => {
-  return userRatings.value.find(r => r.recipeId === props.recipeId)?.rating ?? undefined;
+// on touch devices a tap fires mouseenter without a matching mouseleave, which leaves v-rating
+// rendering the stuck hover value instead of the model value
+const canHover = useMediaQuery("(hover: hover) and (pointer: fine)");
+
+const userRating = computed<number | null>(() => {
+  return userRatings.value.find(r => r.recipeId === props.recipeId)?.rating ?? null;
 });
 
-// if a user unsets their rating, we don't want to fall back to the group rating since it's out of sync
-const hideGroupRating = ref(!!userRating.value);
-watch(
-  () => userRating.value,
-  () => {
-    if (userRating.value) {
-      hideGroupRating.value = true;
-    }
-  },
-);
+const localUserRating = ref(userRating.value);
 
-const groupRating = computed(() => {
-  return hideGroupRating.value ? 0 : modelValue.value;
+// while a write is in flight a refetch may still report the pre-click value, so ignore it
+const pendingWrites = ref(0);
+watch(userRating, (value) => {
+  if (!pendingWrites.value) {
+    localUserRating.value = value;
+  }
 });
 
-function updateRating(val?: number) {
+const userRatingDisplayValue = computed(() => localUserRating.value ?? 0);
+const showGroupAverage = computed(() => localUserRating.value === null);
+
+const displayRating = computed(() => {
+  return showGroupAverage.value ? groupRating.value : userRatingDisplayValue.value;
+});
+
+async function updateRating(val?: number) {
   if (!isOwnGroup.value) {
     return;
   }
 
-  if (val === userRating.value) {
-    val = 0;
+  // the group average can be a half value, but user ratings are always whole stars
+  let rating = Math.round(val ?? 0);
+  if (rating === localUserRating.value) {
+    rating = 0;
   }
 
-  if (!props.emitOnly) {
-    setRating(props.slug, val || 0, null);
+  localUserRating.value = rating;
+
+  if (props.emitOnly) {
+    modelValue.value = rating;
+    return;
+  }
+
+  pendingWrites.value++;
+  try {
+    await setRating(props.slug, rating, null);
+  }
+  finally {
+    pendingWrites.value--;
   }
-  modelValue.value = val ?? 0;
 }
 </script>