IceCubesApp/IceCubesAppWidgetsExtension/ListsWidget/ListsWidget.swift

import DesignSystem
import Models
import Network
import SwiftUI
import Timeline
import WidgetKit

struct ListsWidgetProvider: AppIntentTimelineProvider {
  func placeholder(in _: Context) -> PostsWidgetEntry {
    .init(date: Date(),
          title: "List name",
          statuses: [.placeholder()],
          images: [:])
  }

  func snapshot(for configuration: ListsWidgetConfiguration, in context: Context) async -> PostsWidgetEntry {
    if let entry = await timeline(for: configuration, context: context).entries.first {
      return entry
    }
    return .init(date: Date(),
                 title: "List name",
                 statuses: [],
                 images: [:])
  }

  func timeline(for configuration: ListsWidgetConfiguration, in context: Context) async -> Timeline<PostsWidgetEntry> {
    await timeline(for: configuration, context: context)
  }

  private func timeline(for configuration: ListsWidgetConfiguration, context: Context) async -> Timeline<PostsWidgetEntry> {
    do {
      guard let account = configuration.account, let timeline = configuration.timeline else {
        return Timeline(entries: [.init(date: Date(),
                                        title: "List name",
                                        statuses: [],
                                        images: [:])],
                        policy: .atEnd)
      }
      let filter: TimelineFilter = .list(list: timeline.list)
      let statuses = await loadStatuses(for: filter,
                                        account: account,
                                        widgetFamily: context.family)
      let images = try await loadImages(urls: statuses.map { $0.account.avatar })
      return Timeline(entries: [.init(date: Date(),
                                      title: filter.title,
                                      statuses: statuses,
                                      images: images)], policy: .atEnd)
    } catch {
      return Timeline(entries: [.init(date: Date(),
                                      title: "List name",
                                      statuses: [],
                                      images: [:])],
                      policy: .atEnd)
    }
  }
}

struct ListsPostWidget: Widget {
  let kind: String = "ListsPostWidget"

  var body: some WidgetConfiguration {
    AppIntentConfiguration(kind: kind,
                           intent: ListsWidgetConfiguration.self,
                           provider: ListsWidgetProvider())
    { entry in
      PostsWidgetView(entry: entry)
        .containerBackground(Color("WidgetBackground").gradient, for: .widget)
    }
    .configurationDisplayName("List timeline")
    .description("Show the latest post for the selected list")
    .supportedFamilies([.systemSmall, .systemMedium, .systemLarge, .systemExtraLarge])
  }
}

#Preview(as: .systemMedium) {
  ListsPostWidget()
} timeline: {
  PostsWidgetEntry(date: .now,
                   title: "List name",
                   statuses: [.placeholder(), .placeholder(), .placeholder(), .placeholder()],
                   images: [:])
}