import DesignSystem
import Env
import Models
import Network
import Shimmer
import SwiftUI

public struct StatusesListView<Fetcher>: View where Fetcher: StatusesFetcher {
  @EnvironmentObject private var theme: Theme

  @ObservedObject private var fetcher: Fetcher
  // Whether this status is on a remote local timeline (many actions are unavailable if so)
  private let isRemote: Bool
  private let routerPath: RouterPath
  private let client: Client

  public init(fetcher: Fetcher,
              client: Client,
              routerPath: RouterPath,
              isRemote: Bool = false)
  {
    self.fetcher = fetcher
    self.isRemote = isRemote
    self.client = client
    self.routerPath = routerPath
  }

  public var body: some View {
    switch fetcher.statusesState {
    case .loading:
      ForEach(Status.placeholders()) { status in
        StatusRowView(viewModel: { .init(status: status, client: client, routerPath: routerPath) })
          .redacted(reason: .placeholder)
      }
    case .error:
      ErrorView(title: "status.error.title",
                message: "status.error.loading.message",
                buttonTitle: "action.retry")
      {
        Task {
          await fetcher.fetchNewestStatuses()
        }
      }
      .listRowSeparator(.hidden)

    case let .display(statuses, nextPageState):
      ForEach(statuses, id: \.viewId) { status in
        StatusRowView(viewModel: { StatusRowViewModel(status: status,
                                                      client: client,
                                                      routerPath: routerPath,
                                                      isRemote: isRemote)

          })
          .id(status.id)
          .onAppear {
            fetcher.statusDidAppear(status: status)
          }
          .onDisappear {
            fetcher.statusDidDisappear(status: status)
          }
      }
      switch nextPageState {
      case .hasNextPage:
        loadingRow
          .onAppear {
            Task {
              await fetcher.fetchNextPage()
            }
          }
      case .loadingNextPage:
        loadingRow
      case .none:
        EmptyView()
      }
    }
  }

  private var loadingRow: some View {
    HStack {
      Spacer()
      ProgressView()
      Spacer()
    }
    .padding(.horizontal, .layoutPadding)
  }
}