import SwiftUI

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

    @State private var task: Task<Void, Never>?

    var body: some View {
        VStack(alignment: .leading, spacing: 16) {
            header

            Text("Wir schreiben jetzt die Supervision-Plist auf dein iPhone und starten es neu. Das dauert ~60 Sekunden. **Trenne das USB-Kabel nicht.**")
                .foregroundStyle(.secondary)

            statusBox

            logViewer

            Spacer()

            navigationBar
        }
        .padding(40)
        .onAppear { startIfNeeded() }
        .onDisappear { task?.cancel() }
    }

    private var header: some View {
        HStack {
            Image(systemName: "lock.shield")
                .font(.system(size: 30))
                .foregroundStyle(.tint)
            Text("Supervisieren")
                .font(.title).bold()
        }
    }

    @ViewBuilder
    private var statusBox: some View {
        if model.supervisionRunning {
            HStack(spacing: 8) {
                ProgressView().controlSize(.small)
                Text("supervise-magic läuft …")
            }
            .padding(10)
            .background(Color.blue.opacity(0.08))
            .cornerRadius(6)
        } else if let err = model.supervisionError {
            HStack(alignment: .top, spacing: 8) {
                Image(systemName: "xmark.octagon")
                    .foregroundStyle(.red)
                Text(err).font(.callout)
            }
            .padding(10)
            .background(Color.red.opacity(0.08))
            .cornerRadius(6)
        } else if !model.supervisionLog.isEmpty {
            HStack {
                Image(systemName: "checkmark.circle.fill").foregroundStyle(.green)
                Text("Supervisieren abgeschlossen.")
            }
            .padding(10)
            .background(Color.green.opacity(0.08))
            .cornerRadius(6)
        }
    }

    private var logViewer: some View {
        ScrollViewReader { proxy in
            ScrollView {
                LazyVStack(alignment: .leading, spacing: 2) {
                    ForEach(Array(model.supervisionLog.enumerated()), id: \.offset) { idx, line in
                        Text(line)
                            .font(.system(.caption, design: .monospaced))
                            .foregroundStyle(line.contains("[stderr]") ? .orange : .secondary)
                            .id(idx)
                    }
                }
                .padding(8)
                .frame(maxWidth: .infinity, alignment: .leading)
            }
            .background(Color.black.opacity(0.04))
            .cornerRadius(6)
            .frame(maxHeight: 220)
            .onChange(of: model.supervisionLog.count) { _, newCount in
                if newCount > 0 { proxy.scrollTo(newCount - 1, anchor: .bottom) }
            }
        }
    }

    private var navigationBar: some View {
        HStack {
            Button("Zurück") { model.goTo(.preflight) }
                .buttonStyle(.bordered)
                .disabled(model.supervisionRunning)
            Spacer()
            if model.supervisionError != nil {
                Button("Neu versuchen") { startSupervise() }
                    .buttonStyle(.bordered)
            }
            Button("Weiter →") { model.advance() }
                .buttonStyle(.borderedProminent)
                .disabled(model.supervisionRunning || model.supervisionLog.isEmpty || model.supervisionError != nil)
        }
    }

    private func startIfNeeded() {
        if model.supervisionLog.isEmpty && !model.supervisionRunning && model.supervisionError == nil {
            startSupervise()
        }
    }

    private func startSupervise() {
        model.supervisionLog = []
        model.supervisionError = nil
        model.supervisionRunning = true
        task?.cancel()
        task = Task { @MainActor in
            do {
                _ = try await SuperviseRunner.supervise(organizationName: "ReBreak", force: true) { line in
                    model.supervisionLog.append(line)
                }
                model.supervisionRunning = false
                model.device?.isSupervised = true
            } catch {
                model.supervisionError = error.localizedDescription
                model.supervisionRunning = false
            }
        }
    }
}