import Foundation

/// Decrypted content of the init config file (xuqm/config.xuqm).
/// Contains the appKey and optional server URL needed to bootstrap the SDK.
/// This is separate from XuqmLicenseSDK's LicenseFile (device activation).
public struct ConfigFileData: Codable, Sendable {
    public let appKey: String
    public let appName: String?
    public let companyName: String?
    public let packageName: String?
    public let iosBundleId: String?
    public let harmonyBundleName: String?
    public let baseUrl: String?
    public let serverUrl: String?
    public let issuedAt: String?
    public let expiresAt: String?

    public init(
        appKey: String,
        appName: String? = nil,
        companyName: String? = nil,
        packageName: String? = nil,
        iosBundleId: String? = nil,
        harmonyBundleName: String? = nil,
        baseUrl: String? = nil,
        serverUrl: String? = nil,
        issuedAt: String? = nil,
        expiresAt: String? = nil
    ) {
        self.appKey = appKey
        self.appName = appName
        self.companyName = companyName
        self.packageName = packageName
        self.iosBundleId = iosBundleId
        self.harmonyBundleName = harmonyBundleName
        self.baseUrl = baseUrl
        self.serverUrl = serverUrl
        self.issuedAt = issuedAt
        self.expiresAt = expiresAt
    }
}

@MainActor
public final class XuqmSDK: NSObject {

    public static let shared = XuqmSDK()
    public private(set) var config: SDKConfig?
    public private(set) var tokenStore: TokenStore?

    public private(set) var currentUserId: String?

    private var userSig: String?
    public private(set) var cachedDeviceToken: String?
    private var lastInitializedAppKey: String?
    private var isInitialized = false
    private var initContinuations: [CheckedContinuation<Void, Never>] = []

    // Module hooks — set by the convenience XuqmSDK module to wire feature modules
    public var onInitialize: (@MainActor @Sendable (SDKConfig) -> Void)?
    public var onLogin: (@MainActor @Sendable (String, String) async throws -> Void)?
    public var onLogout: (@MainActor @Sendable (String) async throws -> Void)?
    public var onDeviceToken: (@MainActor @Sendable (String, String) async throws -> Void)?

    private override init() {
        super.init()
    }

    /// Auto-initialize from the embedded config file (xuqm/config.xuqm).
    /// Reads and decrypts the config file directly — no external hooks needed.
    public func autoInitialize(debug: Bool = false) throws {
        guard let file = ConfigFileReader.read() else {
            throw XuqmSDKError.noConfigFile
        }
        let bundleId = Bundle.main.bundleIdentifier ?? ""
        if let configBundle = file.iosBundleId, !configBundle.isEmpty, configBundle != bundleId {
            throw XuqmSDKError.packageMismatch(license: configBundle, local: bundleId)
        }
        if let baseUrl = file.baseUrl {
            SDKEndpoints.configure(apiBaseURL: baseUrl)
        }
        if let serverUrl = file.serverUrl {
            SDKEndpoints.configure(imWebSocketURL: serverUrl + "/ws/im")
        }
        let cfg = SDKConfig(appKey: file.appKey, debug: debug)
        initialize(config: cfg)
    }

    public func initialize(config: SDKConfig) {
        if let lastInitializedAppKey, lastInitializedAppKey == config.appKey {
            return
        }
        self.config = config
        self.lastInitializedAppKey = config.appKey
        self.tokenStore = TokenStore()
        ApiClient.shared.configure(with: config)
        isInitialized = true
        let continuations = initContinuations
        initContinuations.removeAll()
        for cont in continuations {
            cont.resume()
        }
        onInitialize?(config)
    }

    public func requireConfig() -> SDKConfig {
        guard let config else {
            fatalError("XuqmSDK not initialized. Call XuqmSDK.shared.initialize() first.")
        }
        return config
    }

    public var initialized: Bool { isInitialized }

    public func awaitInitialization() async {
        guard !isInitialized else { return }
        await withCheckedContinuation { cont in
            initContinuations.append(cont)
        }
    }

    public func login(userId: String, userSig: String) async {
        if currentUserId == userId && self.userSig == userSig {
            return
        }
        self.currentUserId = userId
        self.userSig = userSig

        do {
            try await onLogin?(userId, userSig)
        } catch {
            // Module login failed; silently ignored per facade pattern
        }

        if let cachedDeviceToken {
            do {
                try await onDeviceToken?(cachedDeviceToken, userId)
            } catch {
                // Device token registration failed
            }
        }
    }

    public func logout() async {
        if let userId = currentUserId {
            do {
                try await onLogout?(userId)
            } catch {
                // Module logout failed
            }
        }

        tokenStore?.clear()
        currentUserId = nil
        userSig = nil
        cachedDeviceToken = nil
    }

    public func registerDeviceToken(_ deviceToken: Data) {
        let token = deviceToken.map { String(format: "%02x", $0) }.joined()
        self.cachedDeviceToken = token
        Task { @MainActor in
            if let userId = self.currentUserId {
                try? await self.onDeviceToken?(token, userId)
            }
        }
    }
}

public enum XuqmSDKError: Error {
    case noConfigFile
    case noLicenseFile
    case packageMismatch(license: String, local: String)
}