1 files changed, 98 insertions, 0 deletions
diff --git a/src/com/android/customization/picker/clock/ui/viewmodel/ClockCarouselViewModel.kt b/src/com/android/customization/picker/clock/ui/viewmodel/ClockCarouselViewModel.kt
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+++ b/src/com/android/customization/picker/clock/ui/viewmodel/ClockCarouselViewModel.kt
@@ -0,0 +1,98 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.customization.picker.clock.ui.viewmodel
+
+import com.android.customization.picker.clock.domain.interactor.ClockPickerInteractor
+import kotlinx.coroutines.ExperimentalCoroutinesApi
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.distinctUntilChanged
+import kotlinx.coroutines.flow.flatMapLatest
+import kotlinx.coroutines.flow.map
+import kotlinx.coroutines.flow.mapLatest
+import kotlinx.coroutines.flow.mapNotNull
+
+/**
+ * Clock carousel view model that provides data for the carousel of clock previews. When there is
+ * only one item, we should show a single clock preview instead of a carousel.
+ */
+class ClockCarouselViewModel(
+    private val interactor: ClockPickerInteractor,
+) {
+    @OptIn(ExperimentalCoroutinesApi::class)
+    val allClockIds: Flow<List<String>> =
+        interactor.allClocks.mapLatest { allClocks ->
+            // Delay to avoid the case that the full list of clocks is not initiated.
+            delay(CLOCKS_EVENT_UPDATE_DELAY_MILLIS)
+            allClocks.map { it.clockId }
+        }
+
+    val seedColor: Flow<Int?> = interactor.seedColor
+
+    private val shouldShowCarousel = MutableStateFlow(false)
+    val isCarouselVisible: Flow<Boolean> =
+        combine(allClockIds.map { it.size > 1 }.distinctUntilChanged(), shouldShowCarousel) {
+                hasMoreThanOneClock,
+                shouldShowCarousel ->
+                hasMoreThanOneClock && shouldShowCarousel
+            }
+            .distinctUntilChanged()
+
+    @OptIn(ExperimentalCoroutinesApi::class)
+    val selectedIndex: Flow<Int> =
+        allClockIds
+            .flatMapLatest { allClockIds ->
+                interactor.selectedClockId.map { selectedClockId ->
+                    val index = allClockIds.indexOf(selectedClockId)
+                    if (index >= 0) {
+                        index
+                    } else {
+                        null
+                    }
+                }
+            }
+            .mapNotNull { it }
+
+    // Handle the case when there is only one clock in the carousel
+    private val shouldShowSingleClock = MutableStateFlow(false)
+    val isSingleClockViewVisible: Flow<Boolean> =
+        combine(allClockIds.map { it.size == 1 }.distinctUntilChanged(), shouldShowSingleClock) {
+                hasOneClock,
+                shouldShowSingleClock ->
+                hasOneClock && shouldShowSingleClock
+            }
+            .distinctUntilChanged()
+
+    val clockId: Flow<String> =
+        allClockIds
+            .map { allClockIds -> if (allClockIds.size == 1) allClockIds[0] else null }
+            .mapNotNull { it }
+
+    fun setSelectedClock(clockId: String) {
+        interactor.setSelectedClock(clockId)
+    }
+
+    fun showClockCarousel(shouldShow: Boolean) {
+        shouldShowCarousel.value = shouldShow
+        shouldShowSingleClock.value = shouldShow
+    }
+
+    companion object {
+        const val CLOCKS_EVENT_UPDATE_DELAY_MILLIS: Long = 100
+    }
+}