import SwiftUI
import WaterfallGrid

struct ThumbnailGridView<Item: Hashable & Identifiable, Content: View>: View {
  let items: [Item]
  let columnCount: Int
  let useAlternativeGrid: Bool
  let columnsData: [[Item]]
  let content: (Item) -> Content

  private var resolvedColumnCount: Int {
    max(columnCount, 1)
  }

  private var resolvedColumnsData: [[Item]] {
    let clippedColumnsData = Array(columnsData.prefix(resolvedColumnCount))
    let missingColumnCount = resolvedColumnCount - clippedColumnsData.count

    if missingColumnCount <= 0 {
      return clippedColumnsData
    }

    return clippedColumnsData + Array(repeating: [], count: missingColumnCount)
  }

  var body: some View {
    if useAlternativeGrid {
      HStack(alignment: .top) {
        ForEach(Array(resolvedColumnsData.enumerated()), id: \.offset) { _, columnItems in
          LazyVStack {
            ForEach(columnItems, id: \.id) { item in
              content(item)
                .id(item.id)
            }
          }
          .transaction { $0.animation = nil }
        }
      }
      #if os(macOS)
        .padding(8)
      #else
        .padding(.horizontal)
      #endif
      .transition(.opacity)
    } else {
      WaterfallGrid(items, id: \.id) { item in
        content(item)
          .id(item.id)
      }
      .gridStyle(columns: resolvedColumnCount)
      .transaction { $0.animation = nil }
      #if os(macOS)
        .padding(8)
      #else
        .padding(.horizontal)
      #endif
      .transition(.opacity)
    }
  }
}