import SwiftUI

struct CommunityEventDetailView: View {
    let event: CommunityEvent
    @StateObject private var viewModel = CommunityEventViewModel()

    var body: some View {
        ScrollView {
            VStack(alignment: .leading, spacing: 16) {
                eventHeader
                eventInfoSection
                eventDescription
                rsvpSection
                participantsSection
            }
            .padding(.horizontal)
            .padding(.bottom, 32)
        }
        .navigationTitle(event.title)
        .navigationBarTitleDisplayMode(.inline)
        .onAppear {
            Task {
                await viewModel.selectEvent(id: event.id)
            }
        }
    }

    private var eventHeader: some View {
        VStack(spacing: 12) {
            HStack {
                Image(systemName: event.eventType.icon)
                    .font(.system(size: 40))
                    .foregroundColor(event.eventType.color)
                VStack(alignment: .leading, spacing: 4) {
                    Text(event.eventType.displayName)
                        .font(.title2)
                        .fontWeight(.bold)
                    if let distance = event.distanceKm {
                        Text("\(distance) km \u2022 \(event.location)")
                    } else {
                        Text(event.location)
                    }
                    .font(.subheadline)
                    .foregroundColor(.secondary)
                }
                Spacer()
            }

            Divider()

            HStack(spacing: 20) {
                infoItem(label: "Date", value: formatDate(event.startDate))
                infoItem(label: "Participants", value: "\(event.participantCount)")
                if let difficulty = event.difficulty {
                    infoItem(label: "Difficulty", value: difficulty.displayName)
                }
            }
        }
        .padding()
        .background(Color.secondary.opacity(0.1))
        .cornerRadius(12)
    }

    private func infoItem(label: String, value: String) -> some View {
        VStack(alignment: .leading, spacing: 2) {
            Text(label)
                .font(.caption)
                .foregroundColor(.secondary)
            Text(value)
                .font(.subheadline)
                .fontWeight(.medium)
        }
    }

    private var eventInfoSection: some View {
        VStack(alignment: .leading, spacing: 8) {
            Text("Event Details")
                .font(.headline)
            VStack(alignment: .leading, spacing: 6) {
                detailRow(label: "Organizer", value: event.organizerName)
                detailRow(label: "Location", value: event.location)
                detailRow(label: "Start", value: formatDateTime(event.startDate))
                detailRow(label: "End", value: formatDateTime(event.endDate))
                if let max = event.maxParticipants {
                    detailRow(label: "Capacity", value: "\(event.participantCount)/\(max)")
                }
            }
        }
    }

    private func detailRow(label: String, value: String) -> some View {
        HStack {
            Text(label)
                .font(.subheadline)
                .foregroundColor(.secondary)
                .frame(width: 100, alignment: .leading)
            Text(value)
                .font(.subheadline)
                .fontWeight(.medium)
        }
    }

    private var eventDescription: some View {
        VStack(alignment: .leading, spacing: 4) {
            Text("About This Event")
                .font(.headline)
            Text(event.description)
                .font(.subheadline)
                .foregroundColor(.secondary)
        }
    }

    private var rsvpSection: some View {
        VStack(alignment: .leading, spacing: 12) {
            Text("Your RSVP")
                .font(.headline)

            HStack(spacing: 12) {
                rsvpButton(title: "Going", icon: "checkmark.circle", status: .going, color: .green)
                rsvpButton(title: "Maybe", icon: "questionmark.circle", status: .maybe, color: .orange)
                rsvpButton(title: "Not Going", icon: "xmark.circle", status: .notGoing, color: .red)
            }
        }
    }

    private func rsvpButton(title: String, icon: String, status: RSVPStatus, color: Color) -> some View {
        Button {
            Task {
                await viewModel.RSVP(eventId: event.id, status: status)
            }
        } label: {
            VStack(spacing: 4) {
                Image(systemName: event.rsvpStatus == status ? "\(icon).fill" : icon)
                    .foregroundColor(event.rsvpStatus == status ? color : .secondary)
                Text(title)
                    .font(.caption)
                    .foregroundColor(event.rsvpStatus == status ? color : .secondary)
            }
            .frame(maxWidth: .infinity)
            .padding(.vertical, 8)
            .background(event.rsvpStatus == status ? color.opacity(0.15) : Color.secondary.opacity(0.08))
            .cornerRadius(8)
        }
    }

    private var participantsSection: some View {
        VStack(alignment: .leading, spacing: 8) {
            Text("Participants (\(event.participantCount))")
                .font(.headline)

            ForEach(viewModel.participants) { participant in
                HStack(spacing: 12) {
                    Circle()
                        .fill(Color.secondary.opacity(0.2))
                        .frame(width: 32, height: 32)
                    Text(participant.name)
                        .font(.subheadline)
                    Spacer()
                    Text(participant.rsvpStatus.rawValue.capitalized)
                        .font(.caption)
                        .foregroundColor(participant.rsvpStatus == .going ? .green : .secondary)
                }
            }
        }
    }

    private func formatDate(_ date: Date) -> String {
        let formatter = DateFormatter()
        formatter.dateStyle = .medium
        formatter.timeStyle = .none
        return formatter.string(from: date)
    }

    private func formatDateTime(_ date: Date) -> String {
        let formatter = DateFormatter()
        formatter.dateStyle = .short
        formatter.timeStyle = .short
        return formatter.string(from: date)
    }
}

#Preview {
    NavigationView {
        CommunityEventDetailView(event: sampleEvent)
    }
}

private var sampleEvent: CommunityEvent {
    CommunityEvent(
        id: "1",
        title: "Sunday Morning Group Run",
        description: "Join us for a friendly morning run through the park. All paces welcome!",
        eventType: .groupRun,
        location: "Central Park",
        latitude: 40.7851,
        longitude: -73.9683,
        startDate: Date().addingTimeInterval(7 * 24 * 3600),
        endDate: Date().addingTimeInterval(7 * 24 * 3600 + 3600),
        distanceKm: 10,
        organizerId: "user1",
        organizerName: "Running Club",
        maxParticipants: 50,
        participantCount: 23,
        imageUrl: nil,
        difficulty: .beginner,
        rsvpStatus: .pending,
        createdAt: Date()
    )
}