import SwiftUI

struct RootView: View {
    @StateObject private var localization = LocalizationStore()
    @EnvironmentObject private var analytics: HermesAnalyticsClient
    @EnvironmentObject private var repository: HermesRepository

    let onStartSession: (String) -> Void

    var body: some View {
        NavigationStack {
            ScrollView {
                VStack(alignment: .leading, spacing: 24) {
                    header
                    OnboardingView(onStartSession: { onStartSession(localization.localeCode) })
                    FeedView(onRetry: { onStartSession(localization.localeCode) })
                    RoundView(onRetry: { onStartSession(localization.localeCode) })
                    SessionView(onRetry: { onStartSession(localization.localeCode) })
                    SettingsView()
                }
                .padding(.horizontal, HermesTheme.screenPadding)
                .padding(.vertical, 24)
            }
            .background(HermesTheme.background.ignoresSafeArea())
            .navigationTitle(localization.string(for: "app.name"))
            .navigationBarTitleDisplayMode(.inline)
        }
        .environmentObject(localization)
        .onAppear {
            analytics.track("app_opened", attributes: ["screen_name": "home"])
            analytics.track("screen_viewed", attributes: ["screen_name": "home"])
        }
        .task(id: localization.localeCode) {
            onStartSession(localization.localeCode)
        }
        .task {
            while !Task.isCancelled {
                try? await Task.sleep(nanoseconds: 5_000_000_000)
                await analytics.flush(using: repository)
            }
        }
    }

    private var header: some View {
        HStack(alignment: .top) {
            VStack(alignment: .leading, spacing: 8) {
                Text(localization.string(for: "app.name"))
                    .font(.largeTitle.bold())
                    .foregroundStyle(HermesTheme.textPrimary)
                Text(localization.string(for: "app.subtitle"))
                    .font(.callout)
                    .foregroundStyle(HermesTheme.textSecondary)
            }

            Spacer(minLength: 12)

            localeToggle
        }
    }

    private var localeToggle: some View {
        HStack(spacing: 8) {
            localeButton(title: localization.localeName(for: "en"), localeCode: "en")
            localeButton(title: localization.localeName(for: "sv"), localeCode: "sv")
        }
    }

    private func localeButton(title: String, localeCode: String) -> some View {
        let isSelected = localization.localeCode == localeCode

        return Button {
            localization.setLocale(localeCode)
            analytics.track("locale_changed", attributes: ["locale_code": localeCode])
        } label: {
            Text(title)
                .font(.caption.weight(.bold))
                .padding(.horizontal, 12)
                .padding(.vertical, 8)
                .foregroundStyle(isSelected ? HermesTheme.background : HermesTheme.textPrimary)
                .background(isSelected ? HermesTheme.accent : HermesTheme.surfaceElevated)
                .clipShape(Capsule())
        }
    }
}