import Foundation
import Testing
@testable import LocalData

private struct LegacyStringKey: StorageKey {
    typealias Value = String
    let name: String
    let domain: StorageDomain
    let security: SecurityPolicy = .none
    let serializer: Serializer<String> = .json
    let owner: String = "Legacy"
    let description: String = "Legacy string key"
    let availability: PlatformAvailability = .all
    let syncPolicy: SyncPolicy = .never
}

private struct ModernStringKey: StorageKey {
    typealias Value = String
    let name: String
    let domain: StorageDomain
    let security: SecurityPolicy = .none
    let serializer: Serializer<String> = .json
    let owner: String = "Modern"
    let description: String = "Modern string key"
    let availability: PlatformAvailability = .all
    let syncPolicy: SyncPolicy = .never
    let legacyKey: AnyStorageKey?

    var migration: AnyStorageMigration? {
        guard let legacyKey else { return nil }
        return AnyStorageMigration(
            SimpleLegacyMigration(destinationKey: self, sourceKey: legacyKey)
        )
    }
}

private struct PhoneOnlyKey: StorageKey {
    typealias Value = String
    let name: String
    let domain: StorageDomain
    let security: SecurityPolicy = .none
    let serializer: Serializer<String> = .json
    let owner: String = "PhoneOnly"
    let description: String = "Phone-only key"
    let availability: PlatformAvailability = .phoneOnly
    let syncPolicy: SyncPolicy = .never
}

private struct SourceStringKey: StorageKey {
    typealias Value = String
    let name: String
    let domain: StorageDomain
    let security: SecurityPolicy = .none
    let serializer: Serializer<String> = .json
    let owner: String = "Source"
    let description: String = "Source key"
    let availability: PlatformAvailability = .all
    let syncPolicy: SyncPolicy = .never
}

private struct DestinationIntKey: StorageKey {
    typealias Value = Int
    let name: String
    let domain: StorageDomain
    let security: SecurityPolicy = .none
    let serializer: Serializer<Int> = .json
    let owner: String = "Destination"
    let description: String = "Destination int key"
    let availability: PlatformAvailability = .all
    let syncPolicy: SyncPolicy = .never
}

@Suite(.serialized)
struct MigrationAdditionalTests {
    private let router: StorageRouter

    init() {
        let testBaseURL = FileManager.default.temporaryDirectory.appending(path: "MigrationAdditionalTests-\(UUID().uuidString)")
        router = StorageRouter(
            keychain: MockKeychainHelper(),
            encryption: EncryptionHelper(keychain: MockKeychainHelper()),
            file: FileStorageHelper(configuration: FileStorageConfiguration(baseURL: testBaseURL)),
            defaults: UserDefaultsHelper(defaults: UserDefaults(suiteName: "MigrationAdditionalTests.\(UUID().uuidString)")!)
        )
    }

    @Test func migrationHistoryTrackingTest() async throws {
        let legacyKey = LegacyStringKey(name: "legacy.history", domain: .userDefaults(suite: nil))
        let modernKey = ModernStringKey(
            name: "modern.history",
            domain: .userDefaults(suite: nil),
            legacyKey: .key(legacyKey)
        )

        try await router.set("history", for: legacyKey)
        _ = try await router.forceMigration(for: modernKey)

        let history = router.migrationHistory(for: modernKey)
        #expect(history != nil)
    }

    @Test func migrationFailureKeepsSourceTest() async throws {
        let sourceKey = SourceStringKey(name: "legacy.rollback", domain: .userDefaults(suite: nil))
        let destinationKey = DestinationIntKey(name: "modern.rollback", domain: .userDefaults(suite: nil))

        try await router.set("not-a-number", for: sourceKey)

        let migration = DefaultTransformingMigration(
            destinationKey: destinationKey,
            sourceKey: sourceKey
        ) { _ in
            throw MigrationError.transformationFailed("Invalid integer")
        }

        let result = try await migration.migrate(using: router, context: MigrationContext())
        #expect(result.success == false)
        #expect(try await router.exists(sourceKey) == true)
        #expect(try await router.exists(destinationKey) == false)
    }

    @Test func watchAvailabilityBlocksMigrationTest() async throws {
        let legacyKey = LegacyStringKey(name: "legacy.watch", domain: .userDefaults(suite: nil))
        let destinationKey = PhoneOnlyKey(name: "modern.watch", domain: .userDefaults(suite: nil))

        let migration = SimpleLegacyMigration(destinationKey: destinationKey, sourceKey: .key(legacyKey))
        let deviceInfo = DeviceInfo(
            platform: .watchOS,
            systemVersion: "10.0",
            model: "Watch",
            isSimulator: true
        )
        let context = MigrationContext(deviceInfo: deviceInfo)

        let shouldMigrate = try await migration.shouldMigrate(using: router, context: context)
        #expect(shouldMigrate == false)
    }

    @Test func largeDataMigrationTest() async throws {
        let legacyKey = LegacyStringKey(name: "legacy.large", domain: .userDefaults(suite: nil))
        let modernKey = ModernStringKey(
            name: "modern.large",
            domain: .userDefaults(suite: nil),
            legacyKey: .key(legacyKey)
        )

        let largeValue = String(repeating: "a", count: 1_200_000)
        try await router.set(largeValue, for: legacyKey)

        let migration = SimpleLegacyMigration(destinationKey: modernKey, sourceKey: .key(legacyKey))
        let result = try await migration.migrate(using: router, context: MigrationContext())
        #expect(result.success == true)

        let migratedValue = try await router.get(modernKey)
        #expect(migratedValue == largeValue)
    }

    @Test func typeErasureMigrationTest() async throws {
        let legacyKey = LegacyStringKey(name: "legacy.erased", domain: .userDefaults(suite: nil))
        let modernKey = ModernStringKey(
            name: "modern.erased",
            domain: .userDefaults(suite: nil),
            legacyKey: .key(legacyKey)
        )

        try await router.set("erased", for: legacyKey)
        let migration = AnyStorageMigration(
            SimpleLegacyMigration(destinationKey: modernKey, sourceKey: .key(legacyKey))
        )

        let shouldMigrate = try await migration.shouldMigrate(using: router, context: MigrationContext())
        #expect(shouldMigrate == true)

        let result = try await migration.migrate(using: router, context: MigrationContext())
        #expect(result.success == true)
    }
}