import SwiftUI
#if os(iOS)
import SafariServices
#endif

struct SetupStep: Identifiable {
    enum Status {
        case done, active, todo
    }

    let name: String
    var status: Status
    var detail: String?
    var signIn = false
    var signInURL: URL?

    var id: String {
        name
    }
}

func signInStep(_ name: String, hostname: String, state: String, authURL: URL?) -> SetupStep {
    if state == "Running" {
        return SetupStep(name: name, status: .done)
    }
    if state == "NeedsMachineAuth" {
        return SetupStep(name: name, status: .active, detail: "\(hostname) is waiting for a tailnet admin to approve it")
    }
    if state == "NeedsLogin" {
        return SetupStep(name: name, status: .active, detail: authURL == nil ? "Waiting for Tailscale's sign-in link…" : "\(hostname) is waiting for you", signIn: true, signInURL: authURL)
    }
    return SetupStep(name: name, status: .active, detail: "Waiting for Tailscale (\(state))…")
}

struct StepsCard: View {
    let title: String
    let detail: String
    let steps: [SetupStep]

    var body: some View {
        VStack(alignment: .leading, spacing: 0) {
            Text(title)
                .font(Fonts.font(17, weight: 700))
            Text(detail)
                .foregroundStyle(Palette.muted)
                .fixedSize(horizontal: false, vertical: true)
                .padding(.top, 4)
                .padding(.bottom, 10)
            ForEach(Array(steps.enumerated()), id: \.element.id) { i, step in
                if i > 0 {
                    Rectangle().fill(Palette.border).frame(height: 1)
                }
                StepRow(step: step)
            }
        }
        .padding(20)
        .frame(maxWidth: .infinity, alignment: .leading)
        .background(Palette.raised, in: RoundedRectangle(cornerRadius: 10))
        .overlay(RoundedRectangle(cornerRadius: 10).stroke(Palette.border))
        .frame(maxWidth: 460)
        .padding(16)
        .frame(maxWidth: .infinity, maxHeight: .infinity)
        #if os(macOS)
        .onAppear {
            Tailnet.shared.serviceWatchers += 1
        }
        .onDisappear {
            Tailnet.shared.serviceWatchers -= 1
        }
        #endif
    }
}

private struct StepRow: View {
    let step: SetupStep
    @State private var signingIn = false

    var body: some View {
        HStack(alignment: .center, spacing: 10) {
            icon
                .frame(width: 18, height: 18)
            VStack(alignment: .leading, spacing: 2) {
                Text(step.name)
                    .foregroundStyle(step.status == .todo ? Palette.muted : Palette.text)
                if let detail = step.detail {
                    Text(detail)
                        .font(Fonts.font(12))
                        .foregroundStyle(Palette.muted)
                        .textSelection(.enabled)
                        .fixedSize(horizontal: false, vertical: true)
                }
            }
            .frame(maxWidth: .infinity, alignment: .leading)
            if step.signIn {
                Button("Sign in") {
                    #if os(macOS)
                    if let url = step.signInURL {
                        openExternal(url)
                    }
                    #else
                    signingIn = true
                    #endif
                }
                .buttonStyle(WebButtonStyle(primary: true))
                .disabled(step.signInURL == nil)
                .fixedSize()
            }
        }
        .padding(.vertical, 8)
        #if os(iOS)
        .sheet(isPresented: $signingIn) {
            if let url = step.signInURL {
                SafariView(url: url)
                    .ignoresSafeArea()
            }
        }
        .onChange(of: step.signIn) {
            if !step.signIn {
                signingIn = false
            }
        }
        #endif
    }

    @ViewBuilder
    private var icon: some View {
        switch step.status {
        case .done:
            Image(systemName: "checkmark")
                .font(.system(size: 12, weight: .semibold))
                .foregroundStyle(Palette.ok)
        case .active:
            ProgressView()
                .controlSize(.small)
        case .todo:
            Image(systemName: "circle")
                .font(.system(size: 8))
                .foregroundStyle(Palette.muted)
        }
    }
}

#if os(iOS)
private struct SafariView: UIViewControllerRepresentable {
    let url: URL

    func makeUIViewController(context: Context) -> SFSafariViewController {
        SFSafariViewController(url: url)
    }

    func updateUIViewController(_ controller: SFSafariViewController, context: Context) {}
}
#endif