import SwiftUI
import OrgSocialKit

struct GroupsView: View {
    @State private var viewModel = GroupsViewModel()

    var body: some View {
        NavigationStack {
            Group {
                if viewModel.isLoadingGroups {
                    ProgressView()
                        .frame(maxWidth: .infinity, maxHeight: .infinity)
                } else if let error = viewModel.groupsError {
                    ContentUnavailableView {
                        Label("Groups unavailable", systemImage: "person.3.slash")
                    } description: {
                        Text(error)
                    } actions: {
                        Button("Retry") { Task { await viewModel.loadGroups() } }
                            .buttonStyle(.bordered)
                    }
                } else if viewModel.groups.isEmpty {
                    ContentUnavailableView(
                        "No groups",
                        systemImage: "person.3",
                        description: Text("No groups are registered on this relay.")
                    )
                } else {
                    List(viewModel.groups) { group in
                        NavigationLink(value: group) {
                            Label(group.name, systemImage: "person.3.fill")
                        }
                    }
                }
            }
            .navigationTitle("Groups")
            .task { await viewModel.loadGroups() }
            .navigationDestination(for: GroupsViewModel.GroupItem.self) { group in
                GroupPostsView(group: group, viewModel: viewModel)
            }
        }
    }
}

private struct GroupPostsView: View {
    let group: GroupsViewModel.GroupItem
    var viewModel: GroupsViewModel
    @State private var showCompose = false

    var body: some View {
        Group {
            if viewModel.isLoadingPosts {
                ProgressView()
                    .frame(maxWidth: .infinity, maxHeight: .infinity)
            } else if let error = viewModel.postsError {
                ContentUnavailableView {
                    Label("Could not load posts", systemImage: "exclamationmark.triangle")
                } description: {
                    Text(error)
                } actions: {
                    Button("Retry") { Task { await viewModel.loadPosts(for: group) } }
                        .buttonStyle(.bordered)
                }
            } else if viewModel.posts.isEmpty {
                ContentUnavailableView(
                    "No posts",
                    systemImage: "bubble.left.and.bubble.right",
                    description: Text("This group has no posts yet.")
                )
            } else {
                List {
                    ForEach(viewModel.posts, id: \.timestamp) { post in
                        PostRowView(post: post)
                            .listRowSeparator(.visible)
                            .listRowSeparatorTint(Color.secondary.opacity(0.2))
                            .listRowInsets(EdgeInsets(top: 12, leading: 16, bottom: 12, trailing: 16))
                            .listRowBackground(Color.clear)
                    }
                }
                .listStyle(.plain)
                .navigationDestination(for: URL.self) { ProfileView(feedURL: $0) }
                .navigationDestination(for: ThreadRoute.self) {
                    ThreadView(postURL: $0.postURL, relayURL: $0.relayURL)
                }
            }
        }
        .navigationTitle(group.name)
        .navigationBarTitleDisplayMode(.inline)
        .toolbar {
            ToolbarItem(placement: .navigationBarTrailing) {
                Button { showCompose = true } label: {
                    Image(systemName: "square.and.pencil")
                }
            }
        }
        .sheet(isPresented: $showCompose) {
            let relayBase = UserDefaults.standard.string(forKey: "relayURL") ?? "https://relay.org-social.org"
            ComposeView(group: "\(group.name) \(relayBase)")
        }
        .task { await viewModel.loadPosts(for: group) }
    }
}