fix(weather): show complete weather widget gallery previews

ios/DPIPWidgets/DPIPWidgetProviderSupport.swift

@@ -280,6 +280,77 @@ struct DPIPWidgetTimelinePlanner: Sendable {
     }
 }
 
+/// In-memory presentation only; never passed to a cache writer or planner.
+struct DPIPWidgetSnapshotContent: Sendable {
+    let snapshot: CurrentWeatherWidgetSnapshot?
+    let forecast: ForecastWidgetSnapshot?
+}
+
+enum DPIPWidgetGalleryPreview {
+    /// Use a complete sample, rather than attaching invented forecast values
+    /// to a real observation. Also used by Canvas and WidgetKit placeholders.
+    static func sample(at date: Date) -> DPIPWidgetSnapshotContent {
+        var calendar = Calendar(identifier: .gregorian)
+        calendar.timeZone = TimeZone(identifier: "Asia/Taipei")!
+        let hour = calendar.component(.hour, from: date)
+        let isNight = hour < 6 || hour >= 18
+        let transition = calendar.nextDate(
+            after: date,
+            matching: DateComponents(hour: isNight ? 6 : 18, minute: 0),
+            matchingPolicy: .nextTime
+        )!
+        let nextHour = calendar.dateInterval(of: .hour, for: date)!.end
+        let conditions: [(String, Int, Double, Int)] = [
+            ("晴", 100, 28, 0),
+            ("多雲", 200, 28, 10),
+            ("多雲", 200, 27, 20),
+            ("多雲有雨", 206, 27, 60),
+            ("多雲有雨", 206, 26, 60),
+        ]
+        let points = conditions.enumerated().map { index, value in
+            let pointDate = nextHour.addingTimeInterval(Double(index) * 3_600)
+            let pointHour = calendar.component(.hour, from: pointDate)
+            return ForecastWidgetPoint(
+                time: String(format: "%02d:00", pointHour),
+                temperature: value.2,
+                weather: value.0,
+                weatherCode: value.1,
+                pop: value.3
+            )!
+        }
+        let milliseconds = Int64(date.timeIntervalSince1970 * 1_000)
+        return DPIPWidgetSnapshotContent(
+            snapshot: CurrentWeatherWidgetSnapshot(
+                schemaVersion: 7,
+                sourceIdentifier: "region:407",
+                regionCode: "407",
+                regionName: String(localized: "widget.preview_location"),
+                observationTime: Int(date.timeIntervalSince1970),
+                stationName: "西屯",
+                weather: "晴",
+                weatherCode: 100,
+                condition: .clear,
+                isNight: isNight,
+                nextDayNightTransitionTime: Int(transition.timeIntervalSince1970),
+                calibratedTimeOffsetMilliseconds: 0,
+                temperature: 28,
+                humidity: 76,
+                rain: 0,
+                windDirection: "北北西",
+                windSpeed: 1.3,
+                apparentTemperature: 30
+            ),
+            forecast: ForecastWidgetSnapshot(
+                sourceIdentifier: "region:407",
+                regionCode: "407",
+                updateTime: milliseconds,
+                receivedAt: milliseconds,
+                points: points
+            )
+        )
+    }
+}
+
 struct DPIPWidgetProviderDependencies: Sendable {
     typealias LoadSnapshot = DPIPWidgetTimelinePlanner.LoadSnapshot
     typealias LoadForecast = DPIPWidgetTimelinePlanner.LoadForecast
@@ -302,6 +373,49 @@ struct DPIPWidgetProviderDependencies: Sendable {
         loadSnapshot(target)
     }
 
+    /// WidgetKit snapshots remain cache-only. The gallery fallback is selected
+    /// here, outside getTimeline's planner and all persistence dependencies.
+    func snapshotContent(
+        for target: WidgetLocationTarget,
+        at date: Date,
+        family: WidgetFamily,
+        isPreview: Bool
+    ) -> DPIPWidgetSnapshotContent {
+        let current = snapshot(for: target)
+        let forecast = forecastSnapshot(
+            for: target, currentSnapshot: current, at: date, family: family
+        )
+        let cached = DPIPWidgetSnapshotContent(snapshot: current, forecast: forecast)
+        guard isPreview, target.sourceIdentifier != nil else { return cached }
+
+        // Small has no forecast: only the current-weather half needs a sample,
+        // and only when the cache holds nothing for this target.
+        guard ForecastWidgetFamilyPolicy.supportsForecast(family) else {
+            if let current, target.matches(snapshot: current) { return cached }
+            return DPIPWidgetSnapshotContent(
+                snapshot: DPIPWidgetGalleryPreview.sample(at: date).snapshot,
+                forecast: nil
+            )
+        }
+
+        if let current, target.matches(snapshot: current), let forecast,
+           forecast.sourceIdentifier == target.sourceIdentifier,
+           forecast.regionCode == current.regionCode,
+           ForecastWidgetExpiry.isUsable(
+               forecast, at: date,
+               calibratedTimeOffsetMilliseconds:
+                   current.calibratedTimeOffsetMilliseconds
+           ), !ForecastWidgetFamilyPolicy.visiblePoints(
+               in: forecast,
+               at: CurrentWeatherWidgetTimeCalibration(snapshot: current)
+                   .calibratedDate(fromDeviceDate: date),
+               family: family
+           ).isEmpty {
+            return cached
+        }
+        return DPIPWidgetGalleryPreview.sample(at: date)
+    }
+
     func forecastSnapshot(
         for target: WidgetLocationTarget,
         currentSnapshot: CurrentWeatherWidgetSnapshot?,

ios/DPIPWidgets/DPIPWidgets.swift

@@ -14,22 +14,20 @@ struct DPIPWidgetProvider: IntentTimelineProvider {
         self.dependencies = dependencies
     }
 
-    private func snapshot(
-        for configuration: WeatherWidgetConfigurationIntent
-    ) -> CurrentWeatherWidgetSnapshot? {
-        let target = WidgetLocationTarget(
-            identifier: configuration.location?.identifier
-        )
-
-        return dependencies.snapshot(for: target)
-    }
-
     func placeholder(in context: Context) -> DPIPWidgetEntry {
-        DPIPWidgetEntry(
-            date: .now,
-            snapshot: nil,
+        let date = Date.now
+        let sample = DPIPWidgetGalleryPreview.sample(at: date)
+        let content = DPIPWidgetSnapshotContent(
+            snapshot: sample.snapshot,
+            forecast: ForecastWidgetFamilyPolicy.supportsForecast(context.family)
+                ? sample.forecast : nil
+        )
+        return DPIPWidgetEntry(
+            date: date,
+            snapshot: content.snapshot,
             isStale: false,
-            isNight: false,
+            isNight: content.snapshot?.isNight ?? false,
+            forecast: content.forecast
         )
     }
 
@@ -38,12 +36,19 @@ struct DPIPWidgetProvider: IntentTimelineProvider {
         in context: Context,
         completion: @escaping (DPIPWidgetEntry) -> Void
     ) {
-        let snapshot = snapshot(for: configuration)
         let deviceNow = Date.now
         let target = WidgetLocationTarget(
             identifier: configuration.location?.identifier
         )
 
+        let content = dependencies.snapshotContent(
+            for: target,
+            at: deviceNow,
+            family: context.family,
+            isPreview: context.isPreview
+        )
+        let snapshot = content.snapshot
+
         let state = CurrentWeatherWidgetTimeline.state(
             snapshot: snapshot,
             at: deviceNow,
@@ -55,12 +60,7 @@ struct DPIPWidgetProvider: IntentTimelineProvider {
             snapshot: snapshot,
             isStale: state.isStale,
             isNight: state.isNight,
-            forecast: dependencies.forecastSnapshot(
-                for: target,
-                currentSnapshot: snapshot,
-                at: deviceNow,
-                family: context.family
-            )
+            forecast: content.forecast
         )
 
         completion(entry)
@@ -768,98 +768,30 @@ struct DPIPWidgets: Widget {
 struct DPIPWidgets_Previews: PreviewProvider {
     private static let previewNow = Date()
 
-    private static let previewTransitionTime = Int(
-        previewNow
-            .addingTimeInterval(6 * 60 * 60)
-            .timeIntervalSince1970
-    )
-
-    private static let previewForecast = ForecastWidgetSnapshot(
-        sourceIdentifier: "current-location",
-        regionCode: "407",
-
-        updateTime: 1_790_316_445_925,
-        receivedAt: 1_790_316_600_000,
-
-        points: [
-            ForecastWidgetPoint(
-                time: "01:00",
-                temperature: 26.0,
-                weather: "晴",
-                weatherCode: 100,
-                pop: 0
-            )!,
-            ForecastWidgetPoint(
-                time: "02:00",
-                temperature: 26.0,
-                weather: "多雲",
-                weatherCode: 200,
-                pop: 10
-            )!,
-            ForecastWidgetPoint(
-                time: "03:00",
-                temperature: 25.0,
-                weather: "多雲有雨",
-                weatherCode: 206,
-                pop: 60
-            )!,
-            ForecastWidgetPoint(
-                time: "04:00",
-                temperature: 25.0,
-                weather: "多雲有雷雨",
-                weatherCode: 214,
-                pop: 80
-            )!,
-            ForecastWidgetPoint(
-                time: "05:00",
-                temperature: 24.0,
-                weather: "多雲有霧",
-                weatherCode: 205,
-                pop: 20
-            )!,
-        ]    )
+    private static let previewContent = DPIPWidgetGalleryPreview.sample(at: previewNow)
 
     private static let previewEntry = DPIPWidgetEntry(
         date: previewNow,
-        snapshot: CurrentWeatherWidgetSnapshot(
-            schemaVersion: 7,
-            sourceIdentifier: "current-location",
-            regionCode: "407",
-            regionName: "西屯區",
-            observationTime: Int(previewNow.timeIntervalSince1970),
-            stationName: "西屯",
-            weather: "晴",
-            weatherCode: 100,
-            condition: .clear,
-            isNight: true,
-            nextDayNightTransitionTime: previewTransitionTime,
-            calibratedTimeOffsetMilliseconds: 0,
-            temperature: 28.0,
-            humidity: 76,
-            rain: 0.0,
-            windDirection: "北北西",
-            windSpeed: 1.3,
-            apparentTemperature: 30.2
-        ),
+        snapshot: previewContent.snapshot,
         isStale: false,
-        isNight: true,
-        forecast: previewForecast
+        isNight: previewContent.snapshot?.isNight ?? false,
+        forecast: previewContent.forecast
     )
 
     private static let missingOptionalDataEntry = DPIPWidgetEntry(
-        date: .now,
+        date: previewNow,
         snapshot: CurrentWeatherWidgetSnapshot(
             schemaVersion: 7,
-            sourceIdentifier: "current-location",
+            sourceIdentifier: "region:407",
             regionCode: "407",
-            regionName: "西屯區",
-            observationTime: Int(Date().timeIntervalSince1970),
+            regionName: String(localized: "widget.preview_location"),
+            observationTime: Int(previewNow.timeIntervalSince1970),
             stationName: "西屯",
             weather: "多雲",
             weatherCode: 200,
             condition: .cloudy,
-            isNight: false,
-            nextDayNightTransitionTime: 1_789_562_700,
+            isNight: previewContent.snapshot!.isNight,
+            nextDayNightTransitionTime: previewContent.snapshot!.nextDayNightTransitionTime,
             calibratedTimeOffsetMilliseconds: 0,
             temperature: 28.0,
             humidity: 76,
@@ -869,8 +801,8 @@ struct DPIPWidgets_Previews: PreviewProvider {
             apparentTemperature: nil,
         ),
         isStale: false,
-        isNight: false,
-        forecast: previewForecast
+        isNight: previewContent.snapshot!.isNight,
+        forecast: previewContent.forecast
     )
 
     @ViewBuilder

ios/DPIPWidgets/Localizable.xcstrings

@@ -625,6 +625,42 @@
         }
       }
     },
+    "widget.preview_location" : {
+      "comment" : "Example location label for a complete Widget Gallery sample; never a real observation.",
+      "extractionState" : "manual",
+      "localizations" : {
+        "en" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "Sample Location"
+          }
+        },
+        "ja" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "プレビュー地点"
+          }
+        },
+        "ko" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "미리보기 위치"
+          }
+        },
+        "zh-Hans" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "预览地点"
+          }
+        },
+        "zh-Hant" : {
+          "stringUnit" : {
+            "state" : "translated",
+            "value" : "預覽地點"
+          }
+        }
+      }
+    },
     "widget.rainfall" : {
       "extractionState" : "manual",
       "localizations" : {