import NetworkImage
import SwiftUI

struct PostGridThumbnailView: View {
  @EnvironmentObject var settings: SettingsManager
  @EnvironmentObject var manager: BooruManager
  let post: BooruPost
  let posts: [BooruPost]
  let isNestedView: Bool
  let endOfData: Bool
  let onLoadNextPage: () async -> Void
  let selectedPost: BooruPost?

  private var thumbnailURL: URL? {
    switch settings.thumbnailQuality {
    case .preview:
      post.previewURL

    case .sample:
      post.sampleURL

    case .original:
      post.fileURL
    }
  }

  @ViewBuilder
  private func primaryImageContent(image: Image) -> some View {
    let isFiltered =
      settings.blurRatings.contains(post.rating)
      && selectedPost?.id != post.id

    image
      .resizable()
      .aspectRatio(contentMode: .fit)
      .blur(radius: isFiltered ? 8 : 0)
      .clipped()
      .animation(.default, value: isFiltered)
      .clipShape(RoundedRectangle(cornerRadius: 8))
  }

  @ViewBuilder
  private func imageContent(image: Image) -> some View {
    if settings.uniformThumbnailGrid {
      GeometryReader { proxy in
        primaryImageContent(image: image)
          .frame(width: proxy.size.width, height: proxy.size.width)
      }
      .clipped()
      .aspectRatio(1, contentMode: .fit)
    } else {
      primaryImageContent(image: image)
    }
  }

  var body: some View {
    VStack {
      NetworkImage(
        url: thumbnailURL,
        transaction: Transaction(animation: .default)
      ) { image in
        if #available(iOS 18.0, macOS 15.0, *) {
          imageContent(image: image)
            .onScrollVisibilityChange { visible in
              if posts.count > 4, post == posts[posts.count - (posts.count / 4)],
                !endOfData, visible
              {
                Task(priority: .utility) { await onLoadNextPage() }
              }
            }
        } else {
          imageContent(image: image)
        }
      } placeholder: {
        PostGridThumbnailPlaceholderView()
      }
    }
  }
}