feat: add hero image processing and API for serving variants

- Introduced a new script `prepare-hero-variants.mjs` to generate responsive hero image variants in WebP format.
- Added a fallback image `hero_fallback.png` for each variant.
- Created an API endpoint `hero-images.get.js` to retrieve available hero image variants and their fallback images.
- Implemented directory and file checks to ensure the existence of required images before serving.

android-app/app/src/main/java/de/harheimertc/data/ApiService.kt

@@ -409,6 +409,15 @@ data class HomepageSectionConfigDto(
 data class HomepageDto(
     val sections: List<HomepageSectionDto> = emptyList(),
 )
+data class HeroImageVariantDto(
+    val key: String = "",
+    val mobileWebp: String = "",
+    val desktopWebp: String = "",
+    val fallback: String = "",
+)
+data class HeroImagesResponse(
+    val variants: List<HeroImageVariantDto> = emptyList(),
+)
 data class SeitenDto(
     val ueberUns: String = "",
     val geschichte: String = "",
@@ -578,6 +587,9 @@ interface ApiService {
     @GET("/api/config")
     suspend fun config(): Response<ConfigResponse>
 
+    @GET("/api/hero-images")
+    suspend fun heroImages(): Response<HeroImagesResponse>
+
     @PUT("/api/config")
     suspend fun updateConfig(@Body request: ConfigResponse): Response<ConfigResponse>
 

android-app/app/src/main/java/de/harheimertc/repositories/HomeRepository.kt

@@ -3,12 +3,14 @@ package de.harheimertc.repositories
 import de.harheimertc.BuildConfig
 import de.harheimertc.data.ApiService
 import de.harheimertc.data.HomepageSectionDto
+import de.harheimertc.data.HeroImageVariantDto
 import de.harheimertc.data.NewsDto
 import de.harheimertc.data.SeasonDto
 import de.harheimertc.data.SpielDto
 import de.harheimertc.data.SpielplanResponse
 import de.harheimertc.data.TerminDto
 import io.sentry.Sentry
+import kotlin.random.Random
 import javax.inject.Inject
 import javax.inject.Singleton
 
@@ -19,6 +21,7 @@ data class HomeData(
     val selectedSpielplanSeason: String?,
     val news: List<NewsDto>,
     val homepageSections: List<HomepageSectionDto>,
+    val heroImageUrl: String? = null,
     val diagnostics: List<String> = emptyList(),
 )
 
@@ -135,6 +138,35 @@ class HomeRepository @Inject constructor(private val api: ApiService) {
                 )
             }
         }.getOrDefault(emptyList())
+
+        val heroImageUrl = runCatching {
+            val response = api.heroImages()
+            if (!response.isSuccessful) {
+                val errorBody = response.errorBody()?.string().orEmpty()
+                diagnostics += buildDiagnostic(
+                    endpoint = "GET /api/hero-images",
+                    requestPayload = "none",
+                    httpCode = response.code(),
+                    responseBody = errorBody,
+                    throwable = null,
+                )
+                error("Hero-Bilder konnten nicht geladen werden (HTTP ${response.code()}).")
+            }
+            val variants = response.body()?.variants.orEmpty()
+            pickRandomHeroImage(variants)
+        }.onFailure { error ->
+            captureLoadIssue("fetchHomeData.heroImages", error)
+            if (diagnostics.none { it.contains("GET /api/hero-images") }) {
+                diagnostics += buildDiagnostic(
+                    endpoint = "GET /api/hero-images",
+                    requestPayload = "none",
+                    httpCode = null,
+                    responseBody = null,
+                    throwable = error,
+                )
+            }
+        }.getOrNull()
+
         HomeData(
             termine = termine,
             spiele = spiele,
@@ -142,6 +174,7 @@ class HomeRepository @Inject constructor(private val api: ApiService) {
             selectedSpielplanSeason = spielplanResponse?.season,
             news = news,
             homepageSections = homepageSections,
+            heroImageUrl = heroImageUrl,
             diagnostics = diagnostics,
         )
     }.onFailure { error ->
@@ -194,4 +227,22 @@ class HomeRepository @Inject constructor(private val api: ApiService) {
             append("Throwable: ").append(throwableInfo)
         }
     }
+
+    private fun pickRandomHeroImage(variants: List<HeroImageVariantDto>): String? {
+        if (variants.isEmpty()) return null
+        val valid = variants.filter { it.fallback.isNotBlank() }
+        if (valid.isEmpty()) return null
+        val selected = valid[Random.nextInt(valid.size)]
+        return toAbsoluteUrl(selected.fallback)
+    }
+
+    private fun toAbsoluteUrl(pathOrUrl: String): String {
+        if (pathOrUrl.startsWith("http://") || pathOrUrl.startsWith("https://")) {
+            return pathOrUrl
+        }
+
+        val base = BuildConfig.API_BASE_URL.trimEnd('/')
+        val path = if (pathOrUrl.startsWith('/')) pathOrUrl else "/$pathOrUrl"
+        return "$base$path"
+    }
 }

android-app/app/src/main/java/de/harheimertc/ui/screens/home/HomeScreen.kt

@@ -53,7 +53,6 @@ import androidx.hilt.navigation.compose.hiltViewModel
 import de.harheimertc.ui.navigation.NavigationViewModel
 import androidx.navigation.NavController
 import coil.compose.AsyncImage
-import de.harheimertc.BuildConfig
 import de.harheimertc.data.HomepageSectionDto
 import de.harheimertc.data.NewsDto
 import de.harheimertc.data.SeasonDto
@@ -172,7 +171,9 @@ fun HomeScreen(
             if (!section.enabled) return@forEachIndexed
             val sectionKey = homeSectionKey(section)
             when (section.id) {
-                "banner" -> item(key = "home_section_${sectionKey}_$index") { WebHero() }
+                "banner" -> item(key = "home_section_${sectionKey}_$index") {
+                    WebHero(imageUrl = state.heroImageUrl)
+                }
                 "termine" -> item(key = "home_section_${sectionKey}_$index") {
                     HomeTermineSection(
                         termine = state.termine,
@@ -496,7 +497,7 @@ private fun HomeSpielplanTeamWidgetSection(
 }
 
 @Composable
-private fun WebHero() {
+private fun WebHero(imageUrl: String?) {
     val years = Calendar.getInstance().get(Calendar.YEAR) - 1954
     Box(
         modifier = Modifier
@@ -505,12 +506,14 @@ private fun WebHero() {
             .background(Brush.verticalGradient(listOf(Color(0xFFFAFAFA), Color(0xFFF4F4F5)))),
         contentAlignment = Alignment.Center,
     ) {
-        AsyncImage(
-            model = "${BuildConfig.API_BASE_URL}images/club_about_us.png",
-            contentDescription = null,
-            modifier = Modifier.matchParentSize().alpha(0.10f),
-            contentScale = ContentScale.Crop,
-        )
+        if (!imageUrl.isNullOrBlank()) {
+            AsyncImage(
+                model = imageUrl,
+                contentDescription = null,
+                modifier = Modifier.matchParentSize().alpha(0.10f),
+                contentScale = ContentScale.Crop,
+            )
+        }
         Column(
             modifier = Modifier.fillMaxWidth().padding(horizontal = 22.dp, vertical = 58.dp),
             horizontalAlignment = Alignment.CenterHorizontally,

android-app/app/src/main/java/de/harheimertc/ui/screens/home/HomeViewModel.kt

@@ -34,6 +34,7 @@ data class HomeSpielplanTeamOption(
 
 data class HomeUiState(
     val loading: Boolean = true,
+    val heroImageUrl: String? = null,
     val termine: List<TerminDto> = emptyList(),
     val spiele: List<SpielDto> = emptyList(),
     val news: List<NewsDto> = emptyList(),
@@ -87,6 +88,7 @@ class HomeViewModel @Inject constructor(
                     )
                     _state.value = HomeUiState(
                         loading = false,
+                        heroImageUrl = data.heroImageUrl,
                         termine = data.termine
                             .filter { it.asDateTime()?.isBefore(LocalDateTime.now()) != true }
                             .sortedBy { it.asDateTime() }

android-app/gradle.properties

@@ -8,8 +8,8 @@ LOCAL_API_BASE_URL=https://harheimertc.tsschulz.de/
 PRODUCTION_API_BASE_URL=https://harheimertc.de/
 
 # Android app versioning for Play Store uploads
-ANDROID_VERSION_CODE=18
-ANDROID_VERSION_NAME=0.9.13
+ANDROID_VERSION_CODE=19
+ANDROID_VERSION_NAME=0.9.14
 
 # Temporary hotfix: disable R8 minification for release to avoid Retrofit generic signature stripping.
 RELEASE_MINIFY_ENABLED=false