divkit/client/ios/DivKitPlayground/WebPreview/UI/WebPreviewView.swift

import DivKit
import SwiftUI

struct WebPreviewView: View {
  @Environment(\.presentationMode)
  var presentationMode: Binding<PresentationMode>

  let url: URL

  private let model = WebPreviewModel()

  var body: some View {
    ViewWithHeader(
      "Web Preview",
      background: ThemeColor.divKit,
      presentationMode: presentationMode
    ) {
      WebPreviewViewRepresentable(
        blockProvider: model.blockProvider,
        divKitComponents: model.divKitComponents,
        onScreenshotTaken: model.sendScreenshot(_:)
      )
      .onAppear { [model, url] in
        model.connect(httpUrl: url)
      }
      .onDisappear { [model] in
        model.endConnection()
      }
    }
  }
}

private struct WebPreviewModel {
  private let socket = WebPreviewSocket()
  private(set) var divKitComponents: DivKitComponents!
  private(set) var blockProvider: DivBlockProvider!
  private(set) var payloadFactory: UIStatePayloadFactory!
  private var renderingTime: UIStatePayload.RenderingTime {
    UIStatePayload.RenderingTime(
      div_render_total: blockProvider.divRenderTime.webTime,
      div_parsing_data: blockProvider.divDataParsingTime.webTime,
      div_parsing_templates: blockProvider.divTemplateParsingTime.webTime
    )
  }

  init() {
    weak var weakBlockProvider: DivBlockProvider?
    divKitComponents = AppComponents.makeDivKitComponents(
      updateCardAction: { _, reason in
        switch reason {
        case let .patch(patch):
          weakBlockProvider?.update(patch: patch)
        case .timer:
          weakBlockProvider?.update(patch: nil)
        }
      }
    )
    blockProvider = DivBlockProvider(
      json: socket.response,
      divKitComponents: divKitComponents,
      shouldResetOnDataChange: false
    )
    weakBlockProvider = blockProvider
    payloadFactory = UIStatePayloadFactory(
      deviceInfo: DeviceInfo(),
      errors: blockProvider.$errors
    )
  }

  func connect(httpUrl: URL) {
    socket.connect(httpUrl: httpUrl)
  }

  func endConnection() {
    socket.endConnection()
  }

  func sendScreenshot(_ screenshotInfo: ScreenshotInfo) {
    socket.send(
      state: payloadFactory.makePayload(
        screenshotInfo: screenshotInfo,
        renderingTime: renderingTime
      )
    )
  }
}

extension TimeMeasure {
  fileprivate var webTime: UIStatePayload.RenderingTime.Time {
    .init(value: time?.value ?? 0, histogram_type: time?.status.histogramType ?? .cold)
  }
}

extension TimeMeasure.Status {
  fileprivate var histogramType: UIStatePayload.RenderingTime.HistogramType {
    switch self {
    case .cold:
      return .cold
    case .warm:
      return .warm
    }
  }
}