// swiftlint:disable file_length

import SwiftUI

// swiftlint:disable:next type_body_length
struct GenericListView<T: Identifiable & Hashable & GenericItem>: View {
  @EnvironmentObject private var settings: SettingsManager
  @EnvironmentObject private var manager: BooruManager
  @Binding var selectedTab: Int
  @State private var searchText: String = ""
  @State private var isShowingRemoveAllConfirmation = false
  @Binding var isPresented: Bool
  @State private var isNewCollectionAlertPresented = false
  @State private var newCollectionName = ""
  @State private var itemPendingCollectionAssignment: UUID?
  @State private var isCollectionErrorAlertPresented = false
  @State private var selectedCollectionOption: CollectionPickerOption = .all
  @State private var sort: SettingsBookmarkSort = .dateAdded
  @State private var isCollectionPickerPresented = false
  @State private var isProviderPickerPresented = false
  @State private var selectedProvider: BooruProvider?
  let allowBookmarking: Bool
  let title: String
  let emptyMessage: String
  let emptyIcon: String
  let emptyDescription: String
  let removeAllMessage: String
  let removeAllButtonText: String
  let items: [T]
  let removeAction: (IndexSet) -> Void
  let removeActionUUID: (UUID) -> Void
  let removeAllAction: () -> Void
  @State private var folderHierarchy = FolderHierarchy(folders: [])
  @State private var displayedItems: [T] = []
  @State private var shuffleOrderByIdentifier: [UUID: Int] = [:]
  @State private var shuffleSourceIdentifiers: [UUID] = []
  @State private var shouldRefreshShuffleOrder = true

  private func refreshFolderHierarchy() {
    folderHierarchy = FolderHierarchy(folders: settings.folders)
  }

  private func matchesSelectedCollection(for item: T) -> Bool {
    switch selectedCollectionOption {
    case .all:
      return true

    case .uncategorized:
      return item.folder == nil

    case .folder(let folderIdentifier):
      return item.folder == folderIdentifier

    case .topLevelFolder(let topLevelName):
      guard let itemFolderIdentifier = item.folder,
        let itemFolder = folderHierarchy.folder(for: itemFolderIdentifier)
      else {
        return false
      }

      return itemFolder.topLevelName == topLevelName

    case .topLevelUncategorized(let topLevelName):
      guard let itemFolderIdentifier = item.folder,
        let itemFolder = folderHierarchy.folder(for: itemFolderIdentifier)
      else {
        return false
      }

      return itemFolder.name == topLevelName
    }
  }

  private func sortedItems(from unsortedItems: [T]) -> [T] {
    if allowBookmarking {
      return unsortedItems.sorted { $0.date > $1.date }
    }

    return unsortedItems.sorted { (leftItem: T, rightItem: T) in
      switch sort {
      case .dateAdded:
        return leftItem.date > rightItem.date

      case .lastVisited:
        return leftItem.lastVisit > rightItem.lastVisit

      case .visitCount:
        return leftItem.visitedCount > rightItem.visitedCount

      case .shuffle:
        return leftItem.date > rightItem.date
      }
    }
  }

  private func refreshShuffleOrder(for itemsToShuffle: [T]) {
    let currentIdentifiers = itemsToShuffle.map(\.id)

    if shouldRefreshShuffleOrder || shuffleSourceIdentifiers != currentIdentifiers {
      var refreshedShuffleOrderByIdentifier: [UUID: Int] = [:]
      let shuffledIdentifiers = currentIdentifiers.shuffled()

      for (identifierIndex, identifier) in shuffledIdentifiers.enumerated() {
        refreshedShuffleOrderByIdentifier[identifier] = identifierIndex
      }

      shuffleOrderByIdentifier = refreshedShuffleOrderByIdentifier
      shuffleSourceIdentifiers = currentIdentifiers
      shouldRefreshShuffleOrder = false
    }
  }

  private func shuffledItems(from itemsToShuffle: [T]) -> [T] {
    itemsToShuffle.sorted { leftItem, rightItem in
      let leftIndex = shuffleOrderByIdentifier[leftItem.id] ?? Int.max
      let rightIndex = shuffleOrderByIdentifier[rightItem.id] ?? Int.max

      if leftIndex != rightIndex {
        return leftIndex < rightIndex
      }

      return leftItem.id.uuidString < rightItem.id.uuidString
    }
  }

  private func refreshDisplayedItems() {
    let normalizedSearchText = searchText.lowercased()
    let matchingItems = items.filter { item in
      let matchesSearch =
        normalizedSearchText.isEmpty
        || item.tags
          .joined(separator: " ")
          .lowercased()
          .contains(normalizedSearchText)
      let matchesProvider =
        selectedProvider == nil
        || item.provider == selectedProvider

      return matchesSelectedCollection(for: item) && matchesSearch && matchesProvider
    }

    if !allowBookmarking, sort == .shuffle {
      refreshShuffleOrder(for: matchingItems)
      displayedItems = shuffledItems(from: matchingItems)
      return
    }

    displayedItems = sortedItems(from: matchingItems)
  }

  @ViewBuilder private var listContent: some View {
    List {
      if displayedItems.isEmpty, !searchText.isEmpty || selectedCollectionOption != .all {
        Text("No matching items found")
          .foregroundColor(.secondary)
      }

      ForEach(displayedItems, id: \.id) { item in
        itemButtonContent(item: item)
      }
      .onDelete { offsets in
        let itemsToRemove = offsets.compactMap { index in
          index < displayedItems.count ? displayedItems[index] : nil
        }
        let originalIndices = IndexSet(
          itemsToRemove.compactMap { itemToRemove in
            items.firstIndex { $0.id == itemToRemove.id }
          }
        )

        removeAction(originalIndices)
      }
    }
  }

  private func isProviderBookmarked(_ provider: BooruProvider) -> Bool {
    settings.bookmarks.contains { $0.provider == provider }
  }

  private func isCollectionPopulated(_ folder: UUID?) -> Bool {
    settings.bookmarks.contains { $0.folder == folder }
  }

  var body: some View {
    NavigationStack {
      VStack(spacing: 0) {
        if items.isEmpty {
          ContentUnavailableView(
            emptyMessage,
            systemImage: emptyIcon,
            description: Text(emptyDescription)
          )
        } else {
          #if os(macOS)
            if !settings.folders.isEmpty, !allowBookmarking {
              Picker("Sort", selection: $sort) {
                ForEach(SettingsBookmarkSort.allCases, id: \.rawValue) { sortMode in
                  Text(sortMode.rawValue).tag(sortMode)
                }
              }
              .padding()
              .pickerStyle(.menu)

              Picker("Collection", selection: $selectedCollectionOption) {
                Text(CollectionPickerOption.all.name(settings: settings))
                  .tag(CollectionPickerOption.all)

                if items.contains(where: { $0.folder == nil }) {
                  Text(CollectionPickerOption.uncategorized.name(settings: settings))
                    .tag(CollectionPickerOption.uncategorized)
                }

                ForEach(folderHierarchy.rootFolders, id: \.id) { folder in
                  Text(folder.name).tag(CollectionPickerOption.folder(folder.id))
                }

                ForEach(folderHierarchy.sortedTopLevelNames, id: \.self) { topLevelName in
                  Menu {
                    Button(action: {
                      selectedCollectionOption = .topLevelFolder(topLevelName)
                    }) {
                      Text("All \(topLevelName)")
                    }

                    if folderHierarchy.hasTopLevelUncategorized(forTopLevelName: topLevelName) {
                      Button(action: {
                        selectedCollectionOption = .topLevelUncategorized(topLevelName)
                      }) {
                        Text("Uncategorized")
                      }
                    }

                    Divider()

                    ForEach(
                      folderHierarchy.folders(forTopLevelName: topLevelName),
                      id: \.id
                    ) { folder in
                      Button(action: {
                        selectedCollectionOption = .folder(folder.id)
                      }) {
                        Text(folder.shortName)
                      }
                    }
                  } label: {
                    Text(topLevelName)
                  }
                }
              }
              .padding(.bottom)
              .padding(.horizontal)
              .pickerStyle(.menu)

              Picker("Provider", selection: $selectedProvider) {
                Text("All").tag(nil as BooruProvider?)

                ForEach(BooruProvider.allCases, id: \.rawValue) { provider in
                  if isProviderBookmarked(provider) {
                    Text(provider.rawValue).tag(provider)
                  }
                }
              }
              .padding(.bottom)
              .padding(.horizontal)
              .pickerStyle(.menu)
            }
          #endif

          if allowBookmarking {
            listContent
              #if os(iOS)
                .searchable(text: $searchText, placement: .navigationBarDrawer)
              #endif
          } else {
            listContent.searchable(text: $searchText)
          }
        }
      }
    }
    .navigationTitle(title)
    .refreshable { settings.syncFromCloud() }
    .toolbar {
      #if os(macOS)
        ToolbarItem {
          Button(action: {
            settings.syncFromCloud()
          }) {
            Label("Refresh", systemImage: "arrow.clockwise")
          }
        }
      #endif

      #if os(macOS)
        ToolbarItem {
          Button(
            role: .destructive,
            action: {
              isShowingRemoveAllConfirmation = true
            }
          ) {
            Label("Remove All", systemImage: "trash")
          }
        }
      #endif

      #if os(iOS)
        ToolbarItemGroup(placement: .secondaryAction) {
          if !allowBookmarking {
            Menu {
              Picker("Sort By", selection: $sort) {
                ForEach(SettingsBookmarkSort.allCases, id: \.rawValue) { sortMode in
                  Text(sortMode.rawValue).tag(sortMode)
                }
              }
            } label: {
              Label("Sort By", systemImage: "arrow.up.arrow.down")
            }

            Menu {
              Button(action: {
                selectedCollectionOption = .all
              }) {
                Label("All", systemImage: "folder")
              }

              if items.contains(where: { $0.folder == nil }) {
                Button(action: {
                  selectedCollectionOption = .uncategorized
                }) {
                  Label("Uncategorized", systemImage: "folder.badge.questionmark")
                }
              }

              ForEach(folderHierarchy.rootFolders, id: \.id) { folder in
                Button(action: {
                  selectedCollectionOption = .folder(folder.id)
                }) {
                  Label(folder.name, systemImage: "folder")
                }
              }

              ForEach(folderHierarchy.sortedTopLevelNames, id: \.self) { topLevelName in
                Menu {
                  Button(action: {
                    selectedCollectionOption = .topLevelFolder(topLevelName)
                  }) {
                    Label("All \(topLevelName)", systemImage: "folder.fill")
                  }

                  if folderHierarchy.hasTopLevelUncategorized(forTopLevelName: topLevelName) {
                    Button(action: {
                      selectedCollectionOption = .topLevelUncategorized(topLevelName)
                    }) {
                      Label("Uncategorized", systemImage: "folder.badge.questionmark")
                    }
                  }

                  Divider()

                  ForEach(
                    folderHierarchy.folders(forTopLevelName: topLevelName),
                    id: \.id
                  ) { folder in
                    Button(action: {
                      selectedCollectionOption = .folder(folder.id)
                    }) {
                      Label(folder.shortName, systemImage: "folder")
                    }
                  }
                } label: {
                  Label(topLevelName, systemImage: "folder.fill")
                }
              }
            } label: {
              Label("Collection", systemImage: "folder")
            }

            Menu {
              Picker("Provider", selection: $selectedProvider) {
                Text("All").tag(nil as BooruProvider?)

                ForEach(BooruProvider.allCases, id: \.rawValue) { provider in
                  Text(provider.rawValue)
                    .tag(provider)
                    .selectionDisabled(!isProviderBookmarked(provider))
                }
              }
            } label: {
              Label("Provider", systemImage: "globe")
            }

            Button(
              role: .destructive,
              action: {
                isShowingRemoveAllConfirmation = true
              }
            ) {
              Label("Delete All", systemImage: "trash")
            }
          }
        }
      #endif
    }
    .onAppear {
      refreshFolderHierarchy()
      refreshDisplayedItems()
    }
    .onChange(of: items) {
      refreshDisplayedItems()
    }
    .onChange(of: searchText) {
      refreshDisplayedItems()
    }
    .onChange(of: selectedCollectionOption) {
      refreshDisplayedItems()
    }
    .onChange(of: selectedProvider) {
      refreshDisplayedItems()
    }
    .onChange(of: sort) {
      if sort == .shuffle {
        shouldRefreshShuffleOrder = true
      }

      refreshDisplayedItems()
    }
    .onChange(of: settings.folders) {
      refreshFolderHierarchy()
      refreshDisplayedItems()
    }
    .alert(
      removeAllMessage,
      isPresented: $isShowingRemoveAllConfirmation
    ) {
      Button(removeAllButtonText, role: .destructive) {
        removeAllAction()
      }

      Button("Cancel", role: .cancel) { () }
    }
    .collectionAlerts(
      isNewCollectionAlertPresented: $isNewCollectionAlertPresented,
      newCollectionName: $newCollectionName,
      isCollectionErrorAlertPresented: $isCollectionErrorAlertPresented
    ) { newCollectionName in
      let newFolder = SettingsFolder(name: newCollectionName)

      settings.folders.append(newFolder)

      if let id = itemPendingCollectionAssignment {
        settings.updateBookmarkFolder(withID: id, folder: newFolder.id)
      }

      itemPendingCollectionAssignment = nil
    }
  }

  func itemButtonContent(item: T) -> some View {
    Button(action: {
      let previousProvider = settings.preferredBooru

      settings.preferredBooru = item.provider
      manager.searchText = item.tags.joined(separator: " ")
      selectedTab = 0

      isPresented.toggle()

      if previousProvider == settings.preferredBooru {
        let localManager = manager
        let localSettings = settings

        Task(priority: .userInitiated) {
          await localManager.performSearch(settings: localSettings)
        }
      }

      if !allowBookmarking {
        settings.incrementBookmarkVisitCount(withID: item.id)
        settings.updateBookmarkLastVisit(withID: item.id)
      }
    }) {
      GenericItemView(
        item: item,
        removeAction: removeActionUUID
      )
    }
    .contextMenu {
      Button(action: {
        manager.searchText += " \(item.tags.joined(separator: " "))"
        manager.selectedPost = nil

        let localManager = manager
        let localSettings = settings

        isPresented.toggle()

        Task(priority: .userInitiated) {
          await localManager.performSearch(settings: localSettings)
        }
      }) {
        Label("Add Tag to Search", systemImage: "plus")
      }

      if allowBookmarking {
        let isBookmarked = settings.bookmarks.contains { $0.tags == item.tags }

        Button(action: {
          if isBookmarked {
            settings.removeBookmark(withTags: item.tags)
          } else {
            settings.addBookmark(provider: settings.preferredBooru, tags: item.tags)
          }
        }) {
          if isBookmarked {
            Label("Remove Bookmark", systemImage: "bookmark.fill")
          } else {
            Label("Bookmark Tag\(item.tags.count == 1 ? "" : "s")", systemImage: "bookmark")
          }
        }
      }

      Menu {
        FolderMenuView(
          folderHierarchy: folderHierarchy,
          onSelectFolder: { folderIdentifier in
            settings.updateBookmarkFolder(withID: item.id, folder: folderIdentifier)
          },
          onCreateTopLevelUncategorized: { topLevelName in
            let newFolder = SettingsFolder(name: topLevelName)

            settings.folders.append(newFolder)
            settings.updateBookmarkFolder(withID: item.id, folder: newFolder.id)
          },
          isFolderDisabled: { folderIdentifier in
            item.folder == folderIdentifier
          }
        )

        Button(action: {
          itemPendingCollectionAssignment = item.id
          isNewCollectionAlertPresented = true
        }) {
          Label("New Collection", systemImage: "plus")
        }
      } label: {
        Label("\(item.folder != nil ? "Move" : "Add") to Collection", systemImage: "folder")
      }

      if item.folder != nil {
        Button(action: {
          settings.updateBookmarkFolder(withID: item.id, folder: nil)
        }) {
          Label("Remove from Collection", systemImage: "folder.badge.minus")
        }
      }

      Button(
        role: .destructive,
        action: {
          removeActionUUID(item.id)
        }
      ) {
        Label("Delete", systemImage: "trash")
      }
    }
    #if os(macOS)
      .buttonStyle(.plain)
    #endif
  }
}