import SwiftUI
import SwiftData

@main
struct HealthProbeApp: App {
    @State private var appSettings = AppSettings()

    var sharedModelContainer: ModelContainer = {
        destroyLegacyStoreIfNeeded()
        do {
            return try createModelContainer()
        } catch {
            fatalError("Could not create ModelContainer: \(error)")
        }
    }()

    var body: some Scene {
        WindowGroup {
            ContentView()
                .environment(appSettings)
        }
        .modelContainer(sharedModelContainer)
    }

    // Removes the legacy store to avoid schema incompatibility.
    // The old store used TypeDistributionBin which is no longer in the schema.
    private static func destroyLegacyStoreIfNeeded() {
        let storeURL = URL.applicationSupportDirectory.appending(path: "HealthProbe.store")
        guard FileManager.default.fileExists(atPath: storeURL.path()) else { return }
        let candidates = [
            storeURL,
            storeURL.appendingPathExtension("shm"),
            storeURL.appendingPathExtension("wal"),
        ]
        for url in candidates { try? FileManager.default.removeItem(at: url) }
    }

    // Two separate ModelConfiguration instances:
    //   cloudKitConfig — CloudKit-enabled for audit data; OperationLog intentionally excluded
    //   localConfig    — local-only for OperationLog audit trail; never synced
    //
    // ⚠️ DeviceProfile is kept local-only (not synced to CloudKit) since it's device-specific
    //    cosmetic data (name, color tag) that should not cross devices.
    private static func createModelContainer() throws -> ModelContainer {
        let cloudKitModels = Schema([
            HealthSnapshot.self,
            TypeCount.self,
            YearlyCount.self,
            SnapshotDelta.self,
            TypeDelta.self,
            AnomalyRecord.self,
        ])
        let localModels = Schema([
            OperationLog.self,
            DeviceProfile.self,
        ])

        let appSupportURL = URL.applicationSupportDirectory
        try FileManager.default.createDirectory(at: appSupportURL, withIntermediateDirectories: true)

        let cloudConfig: ModelConfiguration
        let localConfig = ModelConfiguration(
            "local",
            schema: localModels,
            url: appSupportURL.appending(path: "HealthProbeLocal.store"),
            cloudKitDatabase: .none
        )

        #if targetEnvironment(simulator)
        cloudConfig = ModelConfiguration(
            "cloud",
            schema: cloudKitModels,
            url: appSupportURL.appending(path: "HealthProbeCloud.store"),
            cloudKitDatabase: .none
        )
        #else
        cloudConfig = ModelConfiguration(
            "cloud",
            schema: cloudKitModels,
            cloudKitDatabase: .private("iCloud.ro.xdev.healthprobe")
        )
        #endif

        let fullSchema = Schema([
            HealthSnapshot.self, TypeCount.self, YearlyCount.self,
            SnapshotDelta.self, TypeDelta.self, AnomalyRecord.self,
            OperationLog.self, DeviceProfile.self,
        ])
        do {
            return try ModelContainer(for: fullSchema, configurations: [cloudConfig, localConfig])
        } catch {
            // Recover from schema migration failures by removing the stores and retrying once
            let candidates: [URL] = [
                appSupportURL.appending(path: "HealthProbeCloud.store"),
                appSupportURL.appending(path: "HealthProbeCloud.store.shm"),
                appSupportURL.appending(path: "HealthProbeCloud.store.wal"),
                appSupportURL.appending(path: "HealthProbeLocal.store"),
                appSupportURL.appending(path: "HealthProbeLocal.store.shm"),
                appSupportURL.appending(path: "HealthProbeLocal.store.wal"),
            ]
            for url in candidates { try? FileManager.default.removeItem(at: url) }
            return try ModelContainer(for: fullSchema, configurations: [cloudConfig, localConfig])
        }
    }
}
