Refactor(ToolViewScreenViewModel): Save tool detail in cache

app/src/main/kotlin/top/fatweb/oxygen/toolbox/ui/view/ToolViewScreenViewModel.kt

@@ -5,6 +5,8 @@ import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import dagger.hilt.android.lifecycle.HiltViewModel
 import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.FlowCollector
+import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.combine
@@ -13,6 +15,7 @@ import kotlinx.coroutines.flow.flowOf
 import kotlinx.coroutines.flow.stateIn
 import timber.log.Timber
 import top.fatweb.oxygen.toolbox.model.Result
+import top.fatweb.oxygen.toolbox.model.tool.ToolEntity
 import top.fatweb.oxygen.toolbox.navigation.ToolViewArgs
 import top.fatweb.oxygen.toolbox.repository.tool.StoreRepository
 import top.fatweb.oxygen.toolbox.repository.tool.ToolRepository
@@ -35,6 +38,8 @@ class ToolViewScreenViewModel @Inject constructor(
     private val toolId = toolViewArgs.toolId
     private val preview = toolViewArgs.preview
 
+    private val storeDetailCache = MutableStateFlow<Result<ToolEntity>?>(null)
+
 
     val toolViewUiState: StateFlow<ToolViewUiState> = toolViewUiState(
         savedStateHandle = savedStateHandle,
@@ -42,7 +47,8 @@ class ToolViewScreenViewModel @Inject constructor(
         toolId = toolId,
         preview = preview,
         storeRepository = storeRepository,
-        toolRepository = toolRepository
+        toolRepository = toolRepository,
+        storeDetailCache = storeDetailCache
     )
         .stateIn(
             scope = viewModelScope,
@@ -57,7 +63,8 @@ private fun toolViewUiState(
     toolId: String,
     preview: Boolean,
     storeRepository: StoreRepository,
-    toolRepository: ToolRepository
+    toolRepository: ToolRepository,
+    storeDetailCache: MutableStateFlow<Result<ToolEntity>?>
 ): Flow<ToolViewUiState> {
     val toolViewTemplate = toolRepository.toolViewTemplate
     val entityFlow =
@@ -67,32 +74,14 @@ private fun toolViewUiState(
         combine(entityFlow, toolViewTemplate, ::Pair).collect { (entityFlow, toolViewTemplate) ->
             if (entityFlow == null) {
                 savedStateHandle[IS_PREVIEW] = true
-                storeRepository.detail(username, toolId).collect {
-                    emit(
-                        when (it) {
-                            is Result.Success -> {
-                                val dist = it.data.dist!!
-                                val base = it.data.base!!
-                                ToolViewUiState.Success(
-                                    it.data.name,
-                                    processHtml(
-                                        toolViewTemplate = toolViewTemplate,
-                                        distBase64 = dist,
-                                        baseBase64 = base
-                                    )
-                                )
-                            }
-
-                            is Result.Loading -> ToolViewUiState.Loading
-                            is Result.Error -> {
-                                Timber.e("Can not load tool", it.exception)
-
-                                ToolViewUiState.Error
-                            }
-
-                            is Result.Fail -> ToolViewUiState.Error
-                        }
-                    )
+                val cachedDetail = storeDetailCache.value
+                if (cachedDetail != null) {
+                    emitResult(result = cachedDetail, toolViewTemplate = toolViewTemplate)
+                } else {
+                    storeRepository.detail(username, toolId).collect { result ->
+                        storeDetailCache.value = result
+                        emitResult(result = result, toolViewTemplate = toolViewTemplate)
+                    }
                 }
             } else {
                 savedStateHandle[IS_PREVIEW] = false
@@ -111,6 +100,36 @@ private fun toolViewUiState(
     }
 }
 
+private suspend fun FlowCollector<ToolViewUiState>.emitResult(
+    result: Result<ToolEntity>,
+    toolViewTemplate: String
+) {
+    emit(
+        when (result) {
+            is Result.Success -> {
+                val dist = result.data.dist!!
+                val base = result.data.base!!
+                ToolViewUiState.Success(
+                    result.data.name,
+                    processHtml(
+                        toolViewTemplate = toolViewTemplate,
+                        distBase64 = dist,
+                        baseBase64 = base
+                    )
+                )
+            }
+
+            is Result.Loading -> ToolViewUiState.Loading
+            is Result.Error -> {
+                Timber.e("Can not load tool", result.exception)
+                ToolViewUiState.Error
+            }
+
+            is Result.Fail -> ToolViewUiState.Error
+        }
+    )
+}
+
 sealed interface ToolViewUiState {
     data class Success(
         val toolName: String,