import Foundation
import Observation
import SwiftData

/// Composition root for the iOS app. Owns the SwiftData cache container and the
/// iCloud sync engine, and drives the one-shot launch sequence. Injected into the
/// view tree via `.environment(...)`.
@Observable
@MainActor
final class AppServices {
    let container: ModelContainer
    let syncEngine: SyncEngine
    let watchBridge: PhoneConnectivityBridge
    let workoutLauncher = WorkoutLauncher()
    let workoutHealthWriter: WorkoutHealthWriter

    /// Ephemeral live-run state fed by the watch, observed by the mirror UI. Not persisted.
    let liveRunState: LiveRunState

    private var bootstrapTask: Task<Void, Never>?

    init() {
        let container = WorkoutsModelContainer.make()
        self.container = container
        self.syncEngine = SyncEngine(container: container)
        let liveRunState = LiveRunState()
        self.liveRunState = liveRunState
        self.watchBridge = PhoneConnectivityBridge(container: container, syncEngine: syncEngine, liveRunState: liveRunState)
        let writer = WorkoutHealthWriter(container: container, syncEngine: syncEngine)
        self.workoutHealthWriter = writer
        syncEngine.onWorkoutCompleted = { [weak writer] doc in writer?.workoutCompleted(doc) }
        syncEngine.onWatchMetricsArrived = { [weak writer] id in writer?.watchMetricsArrived(workoutID: id) }
        #if DEBUG
        if ScreenshotSeed.isActive { ScreenshotSeed.populate(container.mainContext) }
        #endif
    }

    /// Launch step: resolve iCloud and reconcile the cache. Idempotent — repeated
    /// callers await the same one-shot task.
    func bootstrap() async {
        if let bootstrapTask { await bootstrapTask.value; return }
        let task = Task { @MainActor [weak self] in
            guard let self else { return }
            await self.syncEngine.connect()
            self.watchBridge.activate()
            // Past the iCloud gate and cache is reconciled: request Health access and
            // back-fill any recently-completed workout that never reached Health.
            self.workoutHealthWriter.authorizeIfNeeded()
            self.workoutHealthWriter.sweepRecentlyCompleted()
        }
        bootstrapTask = task
        await task.value
    }
}