import SwiftUI
import ProxyCore

struct SetupGuideView: View {
    @Environment(AppState.self) private var appState

    var isReady: Bool {
        appState.isVPNConnected && appState.hasSharedCertificate
    }

    var body: some View {
        VStack(spacing: 24) {
            // Status Banner
            HStack {
                Image(systemName: isReady ? "checkmark.circle.fill" : "exclamationmark.triangle.fill")
                    .font(.title2)
                VStack(alignment: .leading) {
                    Text(isReady ? "Ready to Capture" : "Setup Required")
                        .font(.headline)
                    Text(isReady ? "The tunnel and shared certificate are configured" : "Complete the steps below to start")
                        .font(.caption)
                        .foregroundStyle(.white.opacity(0.8))
                }
                Spacer()
            }
            .foregroundStyle(.white)
            .padding()
            .background(isReady ? Color.green : Color.orange, in: RoundedRectangle(cornerRadius: 12))

            Text("Follow these two steps to start capturing network traffic on your device.")
                .font(.subheadline)
                .foregroundStyle(.secondary)

            // Step 1: VPN
            stepRow(
                title: "VPN Extension Enabled",
                subtitle: appState.isVPNConnected
                    ? "VPN is running and capturing traffic"
                    : "Tap to enable VPN",
                isComplete: appState.isVPNConnected,
                action: {
                    Task { await appState.toggleVPN() }
                }
            )

            // Step 2: Certificate
            NavigationLink {
                CertificateView()
            } label: {
                HStack(spacing: 12) {
                    Image(systemName: appState.hasSharedCertificate ? "checkmark.circle.fill" : "circle")
                        .font(.title2)
                        .foregroundStyle(appState.hasSharedCertificate ? .green : .secondary)

                    VStack(alignment: .leading) {
                        Text("Shared Certificate Available")
                            .font(.subheadline.weight(.medium))
                            .foregroundStyle(appState.hasSharedCertificate ? .green : .primary)
                        Text(certificateSubtitle)
                            .font(.caption)
                            .foregroundStyle(.secondary)
                    }

                    Spacer()
                }
                .padding()
                .background(Color(.secondarySystemGroupedBackground), in: RoundedRectangle(cornerRadius: 12))
            }
            .buttonStyle(.plain)

            if let lastError = appState.lastRuntimeError {
                VStack(alignment: .leading, spacing: 8) {
                    Label("Latest Runtime Error", systemImage: "exclamationmark.triangle.fill")
                        .font(.subheadline.weight(.medium))
                        .foregroundStyle(.orange)
                    Text(lastError)
                        .font(.caption)
                        .foregroundStyle(.secondary)
                }
                .frame(maxWidth: .infinity, alignment: .leading)
                .padding()
                .background(Color(.secondarySystemGroupedBackground), in: RoundedRectangle(cornerRadius: 12))
            }

            Spacer()
        }
        .padding()
        .navigationTitle("Setup Guide")
        .navigationBarTitleDisplayMode(.inline)
    }

    private var certificateSubtitle: String {
        if !appState.isCertificateInstalled {
            return "Generate and install the Proxy CA certificate."
        }
        if !appState.hasSharedCertificate {
            return "The app has a CA, but the extension has not loaded the same one yet."
        }
        if appState.isHTTPSInspectionVerified {
            return "HTTPS inspection has been verified on live traffic."
        }
        return "Include a domain in SSL Proxying, trust the CA in Settings, then retry the request."
    }

    private func stepRow(title: String, subtitle: String, isComplete: Bool, action: @escaping () -> Void) -> some View {
        Button(action: action) {
            HStack(spacing: 12) {
                Image(systemName: isComplete ? "checkmark.circle.fill" : "circle")
                    .font(.title2)
                    .foregroundStyle(isComplete ? .green : .secondary)

                VStack(alignment: .leading) {
                    Text(title)
                        .font(.subheadline.weight(.medium))
                        .foregroundStyle(isComplete ? .green : .primary)
                    Text(subtitle)
                        .font(.caption)
                        .foregroundStyle(.secondary)
                }

                Spacer()
            }
            .padding()
            .background(Color(.secondarySystemGroupedBackground), in: RoundedRectangle(cornerRadius: 12))
        }
        .buttonStyle(.plain)
    }
}