punchnet-macos/Tun/Context/SDLContextBootstrap.swift

//
//  SDLContextBootstrap.swift
//  Tun
//
//  Created by Codex on 2026/5/28.
//

import Foundation

final class SDLContextBootstrap: @unchecked Sendable {
    private enum RuntimeState {
        case idle
        case starting
        case running
        case stopping
    }

    private weak var provider: PacketTunnelProvider?
    private let runtimeLock = NSLock()
    private var runtimeState: RuntimeState = .idle
    private var config: SDLConfiguration?
    private var rsaCipher: CCRSACipher?
    private var contextActor: SDLContextActor?
    private var startCompletionHandler: ((Error?) -> Void)?

    init(provider: PacketTunnelProvider) {
        self.provider = provider
    }

    func startCached(completionHandler: @escaping (Error?) -> Void) {
        self.runtimeLock.lock()
        let config = self.config
        let rsaCipher = self.rsaCipher
        self.runtimeLock.unlock()

        guard let config, let rsaCipher else {
            SDLLogger.fatal("[SDLContextBootstrap] startCached failed: missing cached runtime configuration", category: .app)
            completionHandler(TunnelError.invalidConfiguration)
            return
        }

        self.start(config: config, rsaCipher: rsaCipher, completionHandler: completionHandler)
    }

    func start(config: SDLConfiguration, rsaCipher: CCRSACipher, completionHandler: @escaping (Error?) -> Void) {
        guard let provider = self.provider else {
            SDLLogger.fatal("[SDLContextBootstrap] start rejected: provider released", category: .app)
            completionHandler(TunnelError.invalidContext)
            return
        }

        self.runtimeLock.lock()
        switch self.runtimeState {
        case .idle:
            SDLTunnelAppNotifier.shared.clear()

            let contextActor = SDLContextActor(
                provider: provider,
                config: config,
                rsaCipher: rsaCipher
            )

            self.config = config
            self.rsaCipher = rsaCipher
            self.contextActor = contextActor
            self.startCompletionHandler = completionHandler
            self.runtimeState = .starting
            self.runtimeLock.unlock()

            Task {
                do {
                    try await contextActor.start()
                    self.finishContextStart(contextActor, error: nil)
                } catch {
                    SDLLogger.fatal("[SDLContextBootstrap] context start failed: \(error)", category: .app)
                    self.finishContextStart(contextActor, error: error)
                }
            }

        case .starting, .running, .stopping:
            SDLLogger.fatal("[SDLContextBootstrap] start rejected: invalid runtime state \(self.runtimeState)", category: .app)
            self.runtimeLock.unlock()
            completionHandler(TunnelError.invalidContext)
        }
    }

    func stop(clearRuntimeConfiguration: Bool, completionHandler: @escaping () -> Void) {
        self.runtimeLock.lock()
        let contextActor = self.contextActor
        let startCompletionHandler = self.startCompletionHandler

        guard let contextActor else {
            SDLLogger.fatal("[SDLContextBootstrap] stop requested while context is nil, clearRuntimeConfiguration: \(clearRuntimeConfiguration)", category: .app)
            self.runtimeState = .idle
            self.startCompletionHandler = nil
            if clearRuntimeConfiguration {
                self.config = nil
                self.rsaCipher = nil
            }
            self.runtimeLock.unlock()
            startCompletionHandler?(TunnelError.invalidContext)
            completionHandler()
            return
        }

        self.contextActor = nil
        self.startCompletionHandler = nil
        self.runtimeState = .stopping
        if clearRuntimeConfiguration {
            self.config = nil
            self.rsaCipher = nil
        }
        self.runtimeLock.unlock()

        SDLLogger.fatal("[SDLContextBootstrap] stop will stop current context, clearRuntimeConfiguration: \(clearRuntimeConfiguration)", category: .app)
        startCompletionHandler?(TunnelError.invalidContext)

        Task {
            await contextActor.stop()
            self.markContextStopped()
            completionHandler()
        }
    }

    func currentContextActor() -> SDLContextActor? {
        self.runtimeLock.lock()
        let contextActor = self.contextActor
        self.runtimeLock.unlock()
        return contextActor
    }

    private func finishContextStart(_ contextActor: SDLContextActor, error: Error?) {
        self.runtimeLock.lock()
        guard self.contextActor === contextActor else {
            self.runtimeLock.unlock()
            return
        }

        let startCompletionHandler = self.startCompletionHandler
        self.startCompletionHandler = nil

        if let error {
            self.contextActor = nil
            self.runtimeState = .idle
        } else {
            self.runtimeState = .running
        }
        self.runtimeLock.unlock()

        startCompletionHandler?(error)
    }

    private func markContextStopped() {
        self.runtimeLock.lock()
        if self.contextActor == nil {
            self.runtimeState = .idle
        }
        self.runtimeLock.unlock()
    }
}