import SwiftUI

struct MainView: View {
  @StateObject private var appState: AppState

  init(appState: AppState? = nil) {
    let appState = appState ?? AppState()
    _appState = StateObject(wrappedValue: appState)
  }

  var body: some View {
    ZStack {
      VStack(spacing: 0) {
        // Header (Universal)
        HStack {
          Text("Haven")
            .font(.custom("Avenir Next Medium", size: 18))

          Spacer()

          // Tab Bar
          HStack(spacing: 16) {
            TabButton(icon: "safari", tab: .explore, activeTab: $appState.activeTab)
            TabButton(icon: "folder", tab: .local, activeTab: $appState.activeTab)
            TabButton(icon: "heart", tab: .favorites, activeTab: $appState.activeTab)
            TabButton(icon: "clock", tab: .history, activeTab: $appState.activeTab)
            TabButton(icon: "gearshape", tab: .settings, activeTab: $appState.activeTab)
          }
        }
        .padding()
        .background(VisualEffectView(material: .headerView, blendingMode: .behindWindow))

        Divider()

        // Content
        ZStack {
          switch appState.activeTab {
          case .explore:
            ExploreView(appState: appState)
          case .local:
            LocalView(appState: appState)
          case .favorites:
            FavoritesView(appState: appState)
          case .history:
            HistoryView(appState: appState)
          case .settings:
            SettingsView(appState: appState)
          }
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity)
      }
    }
    .frame(width: 450, height: 640)
    .background(Color(nsColor: .windowBackgroundColor))
    .onAppear {
      Task { await appState.fetchWallpapers() }
    }
  }
}

// MARK: - Subviews

struct ExploreView: View {
  @ObservedObject var appState: AppState

  var body: some View {
    VStack(spacing: 0) {
      // Controls
      HStack {
        HStack {
          Image(systemName: "magnifyingglass")
            .foregroundColor(.secondary)
          TextField("Search...", text: $appState.searchText)
        }
        .padding(8)
        .background(Color(nsColor: .controlBackgroundColor))
        .cornerRadius(8)

        Menu {
          Section("Categories") {
            Toggle("General", isOn: $appState.categories.general)
            Toggle("Anime", isOn: $appState.categories.anime)
            Toggle("People", isOn: $appState.categories.people)
          }

          Section("Purity") {
            Toggle("SFW", isOn: $appState.purity.sfw)
            Toggle("Sketchy", isOn: $appState.purity.sketchy)
          }

          Divider()

          Picker("Resolution", selection: $appState.selectedResolution) {
            ForEach(appState.availableResolutions, id: \.self) { resolutionOption($0) }
          }
          Picker("Ratio", selection: $appState.selectedRatio) {
            ForEach(appState.availableRatios, id: \.self) { ratioOption($0) }
          }
        } label: {
          Image(systemName: "slider.horizontal.3")
        }

        .menuStyle(.borderlessButton)
        .frame(width: 30)

        Button(action: refreshAction) {
          Image(systemName: "arrow.clockwise")
        }
        .buttonStyle(.plain)
        .frame(width: 30)
      }
      .padding()
      .onChange(of: appState.selectedResolution) { _ in Task { await appState.fetchWallpapers() } }
      .onChange(of: appState.selectedRatio) { _ in Task { await appState.fetchWallpapers() } }

      Divider()

      // Feed-mode selector: Latest, Toplist, Random. The active mode is
      // visually emphasised; taps update appState.feedMode and trigger
      // a reset fetch via the Combine observer in AppState.
      HStack(spacing: 10) {
        ForEach(FeedMode.allCases) { mode in
          FeedModePill(mode: mode, isActive: appState.feedMode == mode) { select(mode) }
        }
      }
      .padding(.horizontal)
      .padding(.vertical, 10)

      Divider()

      WallpaperGrid(
        wallpapers: appState.wallpapers, appState: appState, onEndReached: loadMoreAction)
    }
  }

  func resolutionOption(_ resolution: String) -> some View { Text(resolution).tag(resolution) }
  func ratioOption(_ ratio: String) -> some View { Text(ratio).tag(ratio) }
  func refresh() async { await appState.fetchWallpapers(reset: true) }
  func refreshAction() { Task { await refresh() } }
  func select(_ mode: FeedMode) {
    if appState.feedMode != mode { appState.feedMode = mode }
  }
  func loadMore() async { await appState.loadMore() }
  func loadMoreAction() { Task { await loadMore() } }
}

struct FeedModePill: View {
  let mode: FeedMode
  let isActive: Bool
  let action: () -> Void

  private var tint: Color {
    switch mode {
    case .latest: return Color(red: 0.45, green: 0.85, blue: 0.30)  // green
    case .toplist: return Color(red: 0.85, green: 0.40, blue: 0.85)  // magenta
    case .random: return Color(red: 0.98, green: 0.55, blue: 0.20)  // orange
    }
  }

  var body: some View {
    Button(action: action) {
      HStack(spacing: 6) {
        Image(systemName: mode.systemImage)
        Text(mode.displayName)
          .font(.system(size: 13, weight: .medium))
      }
      .padding(.horizontal, 14)
      .padding(.vertical, 8)
      .frame(maxWidth: .infinity)
      .foregroundColor(isActive ? .white : tint)
      .background(
        RoundedRectangle(cornerRadius: 10)
          .fill(isActive ? tint : Color.clear)
      )
      .overlay(
        RoundedRectangle(cornerRadius: 10)
          .stroke(tint.opacity(isActive ? 0 : 0.6), lineWidth: 1.5)
      )
    }
    .buttonStyle(.plain)
  }
}

struct FavoritesView: View {
  @ObservedObject var appState: AppState

  var body: some View {
    if appState.favoritesManager.favorites.isEmpty {
      EmptyState(icon: "heart.slash", text: "No favorites yet")
    } else {
      WallpaperGrid(
        wallpapers: appState.favoritesManager.favorites, appState: appState, onEndReached: nil)
    }
  }
}

struct HistoryView: View {
  @ObservedObject var appState: AppState

  var body: some View {
    VStack {
      if !appState.historyManager.history.isEmpty {
        HStack {
          Spacer()
          Button("Clear History") { clearHistory() }
            .font(.caption)
            .buttonStyle(.link)
        }
        .padding(.horizontal)
        .padding(.top, 8)
      }

      if appState.historyManager.history.isEmpty {
        EmptyState(icon: "clock.arrow.circlepath", text: "No history yet")
      } else {
        WallpaperGrid(
          wallpapers: appState.historyManager.history, appState: appState, onEndReached: nil)
      }
    }
  }

  func clearHistory() { appState.historyManager.clearHistory() }
}

struct SettingsView: View {
  @ObservedObject var appState: AppState

  var body: some View {
    VStack(alignment: .leading, spacing: 24) {
      VStack(alignment: .leading, spacing: 12) {
        Text("Storage")
          .font(.headline)

        Toggle("Launch at Login", isOn: $appState.launchAtLogin)
        Toggle("Save wallpapers locally", isOn: $appState.saveToFolderEnabled)

        if appState.saveToFolderEnabled {
          HStack {
            Text("Location")
            Spacer()
            Text(URL(fileURLWithPath: appState.saveFolderPath).lastPathComponent)
              .foregroundColor(.secondary)
              .lineLimit(1)
              .truncationMode(.middle)
            Button("Change…") { selectFolder() }
          }
        }
      }

      Spacer()

      Button(role: .destructive, action: quit) {
        Text("Quit Haven")
          .frame(maxWidth: .infinity)
      }
      .controlSize(.large)
    }
    .padding()
    .frame(maxWidth: .infinity, maxHeight: .infinity, alignment: .top)
  }

  func selectFolder() { appState.selectSaveFolder() }
  func quit() { appState.quit() }
}

struct EmptyState: View {
  let icon: String
  let text: String

  var body: some View {
    VStack(spacing: 16) {
      Image(systemName: icon)
        .font(.system(size: 48))
        .foregroundColor(.gray.opacity(0.5))
      Text(text)
        .foregroundColor(.secondary)
    }
    .frame(maxWidth: .infinity, maxHeight: .infinity)
  }
}

struct TabButton: View {
  let icon: String
  let tab: AppTab
  @Binding var activeTab: AppTab

  var body: some View {
    Button(action: select) {
      Image(systemName: icon)
        .symbolVariant(activeTab == tab ? .fill : .none)
        .foregroundColor(activeTab == tab ? .accentColor : .secondary)
        .font(.system(size: 18))
    }
    .buttonStyle(.plain)
  }

  func select() { activeTab = tab }
}

// Redeclaring this as it was in the original file, or we can move to a separate file
struct VisualEffectView: NSViewRepresentable {
  let material: NSVisualEffectView.Material
  let blendingMode: NSVisualEffectView.BlendingMode

  func makeNSView(context: Context) -> NSVisualEffectView {
    let visualEffectView = NSVisualEffectView()
    visualEffectView.material = material
    visualEffectView.blendingMode = blendingMode
    visualEffectView.state = .active
    return visualEffectView
  }

  func updateNSView(_ nsView: NSVisualEffectView, context: Context) {
    nsView.material = material
    nsView.blendingMode = blendingMode
  }
}