import SwiftUI
import IndieBackup

/// App version, and backup/restore (indie-backup skill).
struct SettingsTabView: View {
    @Environment(BoardIndexStore.self) private var index
    @Environment(\.backupController) private var backupController

    var body: some View {
        NavigationStack {
            Form {
                Section {
                    LabeledContent("Version") {
                        Text(Bundle.main.object(forInfoDictionaryKey: "CFBundleShortVersionString") as? String ?? "—")
                    }
                }

                backupSection
            }
            .navigationTitle("Settings")
        }
        // Idempotent (BoardIndexStore.start()), and harmless if BoardsTabView already called it —
        // this tab can be the first one the user opens, and `backupController` only ever appears
        // once `index.home` resolves.
        .task { index.start() }
    }

    /// `backupController` is `nil` until `MobileApp` has a resolved `CloudHome` to build one from
    /// — which is also exactly the condition under which there is a `Documents/` folder to back
    /// up. Everything short of that gets the same quiet explanation rather than a section that
    /// looks broken or, worse, a crash on a nil root.
    @ViewBuilder
    private var backupSection: some View {
        if let backupController {
            BackupsSectionView(controller: backupController)
        } else {
            Section {
                switch index.phase {
                case .idle, .loading:
                    LabeledContent("Backup") {
                        ProgressView()
                    }
                case .unavailable, .ready:
                    // `.ready` can appear briefly here too: `backupController` lags one runloop
                    // turn behind `index.home` resolving (MobileApp's `.task(id:)`).
                    Label("Backup and restore need iCloud Drive.", systemImage: "icloud.slash")
                        .foregroundStyle(.secondary)
                }
            } footer: {
                Text("Sign into iCloud in Settings, then come back here to back up your boards.")
            }
        }
    }
}