import SwiftUI

struct MessageBoardView: View {
  @Environment(HotlineState.self) private var model: HotlineState
  
  @State private var composerDisplayed: Bool = false
  @State private var composerText: String = ""
  
  var body: some View {
    NavigationStack {
      if self.model.access?.contains(.canReadMessageBoard) != false {
        if self.model.messageBoardLoaded && self.model.messageBoard.isEmpty {
          self.emptyBoardView
        }
        else {
          self.messageBoardView
        }
      }
      else {
        self.disabledBoardView
      }
    }
    .sheet(isPresented: $composerDisplayed) {
      MessageBoardEditorView()
        .frame(maxWidth: .infinity, maxHeight: .infinity)
        .frame(idealWidth: 450, idealHeight: 350)
    }
    .toolbar {
      ToolbarItem(placement:.primaryAction) {
        Button {
          self.composerDisplayed.toggle()
        } label: {
          Image(systemName: "square.and.pencil")
        }
        .disabled(self.model.access?.contains(.canPostMessageBoard) == false)
        .help("Post to Message Board")
      }
    }
    .task {
      if !self.model.messageBoardLoaded {
        let _ = try? await self.model.getMessageBoard()
      }
    }
  }
  
  private var disabledBoardView: some View {
    ContentUnavailableView {
      Label("Message Board Disabled", systemImage: "quote.bubble")
    } description: {
      Text("This server has turned off the message board")
    }
  }
  
  private var emptyBoardView: some View {
    ContentUnavailableView {
      Label("No Posts", systemImage: "quote.bubble")
    } description: {
      Text("Message board posts will appear here")
    }
  }
  
  private var messageBoardView: some View {
    ScrollView {
      LazyVStack(alignment: .leading) {
        ForEach(self.model.messageBoard, id: \.self) { msg in
          Text(LocalizedStringKey(msg))
            .tint(Color("Link Color"))
            .lineLimit(100)
            .lineSpacing(4)
            .padding()
            .textSelection(.enabled)
          Divider()
        }
      }
      Spacer()
    }
    .overlay {
      if !self.model.messageBoardLoaded {
        VStack {
          ProgressView()
            .controlSize(.large)
        }
        .frame(maxWidth: .infinity)
      }
    }
    .background(Color(nsColor: .textBackgroundColor))
  }
}

#Preview {
  MessageBoardView()
    .environment(HotlineState())
}