import SwiftUI
import OrgSocialKit

struct DiscoverView: View {
    @State private var viewModel = DiscoverViewModel()

    var body: some View {
        NavigationStack {
            Group {
                if viewModel.isLoading && viewModel.users.isEmpty {
                    VStack(spacing: 16) {
                        ProgressView()
                        Text("Loading profiles from relay...")
                            .font(.subheadline)
                            .foregroundStyle(.secondary)
                    }
                    .frame(maxWidth: .infinity, maxHeight: .infinity)
                } else if let error = viewModel.errorMessage, viewModel.users.isEmpty {
                    ContentUnavailableView {
                        Label("Discover unavailable", systemImage: "person.slash")
                    } description: {
                        Text(error)
                    } actions: {
                        Button("Retry") { Task { await viewModel.load() } }
                            .buttonStyle(.bordered)
                    }
                } else if viewModel.users.isEmpty {
                    ContentUnavailableView(
                        "No profiles found",
                        systemImage: "person.3",
                        description: Text("No other users registered on this relay.")
                    )
                } else {
                    List(viewModel.users) { user in
                        DiscoverUserRow(user: user, viewModel: viewModel)
                    }
                    .listStyle(.plain)
                    .navigationDestination(for: URL.self) { ProfileView(feedURL: $0) }
                }
            }
            .navigationTitle("Discover")
            .toolbar {
                ToolbarItem(placement: .navigationBarTrailing) {
                    if viewModel.isLoading {
                        ProgressView()
                    } else {
                        Button {
                            Task { await viewModel.load() }
                        } label: {
                            Image(systemName: "arrow.clockwise")
                        }
                    }
                }
            }
            .task { await viewModel.load() }
        }
    }
}

private struct DiscoverUserRow: View {
    let user: DiscoverViewModel.DiscoverUser
    var viewModel: DiscoverViewModel
    @State private var isToggling = false

    var body: some View {
        HStack(spacing: 12) {
            NavigationLink(value: user.feedURL) {
                HStack(spacing: 12) {
                    AvatarView(url: user.avatar, nick: user.nick, size: 44)

                    VStack(alignment: .leading, spacing: 3) {
                        if let nick = user.nick {
                            Text("@\(nick)")
                                .font(.subheadline.weight(.semibold))
                        }
                        if let desc = user.description {
                            Text(desc)
                                .font(.caption)
                                .foregroundStyle(.secondary)
                                .lineLimit(2)
                        } else {
                            Text(user.feedURL.host ?? user.feedURL.absoluteString)
                                .font(.caption)
                                .foregroundStyle(.secondary)
                                .lineLimit(1)
                        }
                    }
                }
            }

            Spacer()

            if isToggling {
                ProgressView()
                    .frame(width: 72)
            } else {
                Button {
                    isToggling = true
                    Task {
                        if user.isFollowing {
                            await viewModel.unfollow(user: user)
                        } else {
                            await viewModel.follow(user: user)
                        }
                        isToggling = false
                    }
                } label: {
                    Text(user.isFollowing ? "Unfollow" : "Follow")
                        .font(.subheadline)
                        .fontWeight(user.isFollowing ? .regular : .semibold)
                        .frame(width: 72)
                }
                .buttonStyle(.bordered)
                .tint(user.isFollowing ? .secondary : .accentColor)
            }
        }
        .padding(.vertical, 4)
    }
}