import SwiftUI
import AppKit

struct EnrollView: View {
    @Environment(WizardModel.self) private var model

    @State private var downloadStatus: String?
    @State private var localPath: String?

    var body: some View {
        VStack(alignment: .leading, spacing: 20) {
            header

            Text("Jetzt installierst du das **minimale** MDM-Enrollment-Profile, damit dein iPhone mit unserem NanoMDM-Server (mdm.rebreak.org) sprechen kann. Das Profile bringt **keine Restrictions** — nur den MDM-Channel. Restrictions kommen später per Sideload-Lock.")
                .foregroundStyle(.secondary)

            instructions

            Spacer()

            navigationBar
        }
        .padding(40)
        .onAppear { downloadProfile() }
    }

    private var header: some View {
        HStack {
            Image(systemName: "doc.badge.gearshape")
                .font(.system(size: 30))
                .foregroundStyle(.tint)
            Text("MDM-Enrollment")
                .font(.title).bold()
        }
    }

    private var instructions: some View {
        VStack(alignment: .leading, spacing: 14) {
            stepRow(number: 1, text: "Profile wird automatisch vom Server runtergeladen.")
            if let status = downloadStatus {
                HStack(spacing: 8) {
                    Image(systemName: localPath != nil ? "checkmark.circle.fill" : "arrow.down.circle")
                        .foregroundStyle(localPath != nil ? .green : .secondary)
                    Text(status).font(.caption).foregroundStyle(.secondary)
                }
                .padding(.leading, 36)
            }

            stepRow(number: 2, text: "Klick „Per AirDrop senden\" → wähle dein iPhone im Sheet.")
            stepRow(number: 3, text: "Am iPhone: AirDrop-Dialog akzeptieren → Settings öffnet sich automatisch.")
            stepRow(number: 4, text: "Settings → „Installieren\" tappen → 6-stelligen Geräte-Code eingeben → „Installieren\" bestätigen.")
            stepRow(number: 5, text: "Zurück hier klick auf „Enrollment fertig → Weiter\".")
        }
    }

    private func stepRow(number: Int, text: String) -> some View {
        HStack(alignment: .top, spacing: 12) {
            ZStack {
                Circle().fill(Color.accentColor)
                Text("\(number)").foregroundStyle(.white).bold()
            }
            .frame(width: 24, height: 24)
            Text(text)
                .fixedSize(horizontal: false, vertical: true)
            Spacer()
        }
    }

    private var navigationBar: some View {
        HStack {
            Button("Zurück") { model.goTo(.supervise) }
                .buttonStyle(.bordered)
            Spacer()
            if let path = localPath {
                Button("Per AirDrop senden") {
                    sendViaAirDrop(path: path)
                }
                .buttonStyle(.borderedProminent)

                Button("…im Finder zeigen") {
                    NSWorkspace.shared.activateFileViewerSelecting([URL(fileURLWithPath: path)])
                }
                .buttonStyle(.bordered)
            }
            Button("Enrollment fertig → Weiter") {
                model.device?.isEnrolled = true
                model.advance()
            }
            .buttonStyle(.bordered)
        }
    }

    private func downloadProfile() {
        let dest = "/tmp/rebreak-enrollment.mobileconfig"
        downloadStatus = "Lade von mdm.rebreak.org …"
        Task {
            do {
                guard let url = URL(string: "https://mdm.rebreak.org/enrollment/rebreak-enrollment.mobileconfig") else {
                    throw URLError(.badURL)
                }
                let (data, response) = try await URLSession.shared.data(from: url)
                guard let http = response as? HTTPURLResponse, http.statusCode == 200 else {
                    throw URLError(.badServerResponse)
                }
                try data.write(to: URL(fileURLWithPath: dest))
                await MainActor.run {
                    localPath = dest
                    downloadStatus = "Geladen: \(dest) (\(data.count) Bytes)"
                }
            } catch {
                await MainActor.run {
                    downloadStatus = "Download fehlgeschlagen: \(error.localizedDescription)"
                }
            }
        }
    }

    private func sendViaAirDrop(path: String) {
        let url = URL(fileURLWithPath: path)
        guard let service = NSSharingService(named: .sendViaAirDrop), service.canPerform(withItems: [url]) else {
            NSWorkspace.shared.activateFileViewerSelecting([url])
            return
        }
        service.perform(withItems: [url])
    }
}