import SwiftUI

struct PostGridTabSwitcherView: View {
  @EnvironmentObject var settings: SettingsManager
  @State private var tabs: [PostGridTab] = []
  @State private var selectedTabID: UUID?
  @Binding private var selectedTab: Int
  @State private var searchText: String = ""
  @Binding private var selectedPost: (post: BooruPost?, manager: BooruManager?)

  init(selectedTab: Binding<Int>, selectedPost: Binding<(post: BooruPost?, manager: BooruManager?)>)
  {
    let initialTab = PostGridTab(manager: BooruManager())

    _tabs = State(initialValue: [initialTab])
    _selectedTabID = State(initialValue: initialTab.id)
    _selectedTab = selectedTab
    _selectedPost = selectedPost

    Task { await initialTab.manager.fetchPosts(page: 1, tags: [], replace: true) }
  }

  private var activeManager: BooruManager? {
    if let selectedID = selectedTabID,
      let activeTab = tabs.first(where: { $0.id == selectedID })
    {
      return activeTab.manager
    }

    return nil
  }

  var body: some View {
    VStack(spacing: 0) {
      #if !os(macOS)
        ScrollView(.horizontal, showsIndicators: false) {
          HStack {
            ForEach(tabs) { tab in
              PostGridTabButtonView(
                title: tab.manager.searchText.isEmpty ? "New Tab" : tab.manager.searchText,
                isSelected: tab.id == selectedTabID,
                onSelect: { selectedTabID = tab.id },
                onClose: {
                  if tabs.count > 1 {
                    tabs.removeAll { $0.id == tab.id }

                    if selectedTabID == tab.id {
                      selectedTabID = tabs.first!.id
                    }
                  }
                }
              )
            }

            Button(
              action: {
                let newTab = PostGridTab(manager: BooruManager())

                tabs.append(newTab)

                selectedTabID = newTab.id

                Task { await newTab.manager.fetchPosts(page: 1, tags: [], replace: true) }
              }
            ) {
              Image(systemName: "plus")
            }
          }
          .padding(.horizontal)
        }
        .background(Color(.systemGray6))

        HStack {
          TextField(
            "Tags",
            text: $searchText
          ) {
            if let manager = activeManager {
              manager.searchText = searchText

              Task { manager.performSearch(settings: settings) }
            }
          }
          .textFieldStyle(PlainTextFieldStyle())
          .padding(.vertical, 8)
          .padding(.horizontal, 12)
          .background(Color(.systemGray5))
          .clipShape(RoundedRectangle(cornerRadius: 9))

          if !searchText.isEmpty {
            Button(action: {
              searchText = ""

              if let manager = activeManager {
                manager.searchText = ""

                Task { manager.performSearch(settings: settings) }
              }
            }) {
              Image(systemName: "xmark.circle.fill")
                .foregroundColor(.secondary)
            }
            .buttonStyle(PlainButtonStyle())
          }
        }
        .padding(.horizontal)
        .padding(.vertical, 12)
        .background(Color(.systemGray6))
      #endif

      ZStack {
        PostGridTabSwitcherContentView(
          selectedTabID: $selectedTabID,
          selectedPost: $selectedPost,
          selectedTab: $selectedTab,
          tabs: $tabs
        )
      }
    }
    .onChange(of: selectedTabID) { _, newValue in
      if let selectedID = newValue,
        let activeTab = tabs.first(where: { $0.id == selectedID })
      {
        searchText = activeTab.manager.searchText
      }
    }
  }
}