import Foundation
import NetworkExtension
import UIKit
import Combine

class WiFiConnectionManager: ObservableObject {
    @Published var isConnecting = false
    @Published var connectionStatus: ConnectionStatus = .idle
    
    enum ConnectionStatus {
        case idle
        case connecting
        case connected
        case failed(String)
    }
    
    static let shared = WiFiConnectionManager()
    
    private init() {}
    
    func connectToWiFi(ssid: String, password: String, completion: @escaping (Bool, String?) -> Void) {
        guard #available(iOS 11.0, *) else {
            completion(false, "iOS 11+ required for WiFi connection")
            return
        }
        
        DispatchQueue.main.async {
            self.isConnecting = true
            self.connectionStatus = .connecting
        }
        
        // 创建WiFi配置
        let configuration = NEHotspotConfiguration(ssid: ssid, passphrase: password, isWEP: false)
        configuration.joinOnce = true
        
        // 应用配置
        NEHotspotConfigurationManager.shared.apply(configuration) { [weak self] error in
            DispatchQueue.main.async {
                self?.isConnecting = false
                
                if let error = error {
                    let errorMessage = self?.handleWiFiError(error)
                    self?.connectionStatus = .failed(errorMessage ?? "Unknown error")
                    completion(false, errorMessage)
                } else {
                    self?.connectionStatus = .connected
                    completion(true, nil)
                }
            }
        }
    }
    
    private func handleWiFiError(_ error: Error) -> String {
        let errorCode = (error as NSError).code
        
        switch errorCode {
        case NEHotspotConfigurationError.userDenied.rawValue:
            return "wifi_user_denied".localized
        case NEHotspotConfigurationError.alreadyAssociated.rawValue:
            return "wifi_already_connected".localized
        case NEHotspotConfigurationError.invalidSSID.rawValue:
            return "wifi_invalid_ssid".localized
        case NEHotspotConfigurationError.invalidWPAPassphrase.rawValue:
            return "wifi_invalid_password".localized
        default:
            return "wifi_connection_failed".localized
        }
    }
    
    func resetStatus() {
        DispatchQueue.main.async {
            self.connectionStatus = .idle
            self.isConnecting = false
        }
    }
}

// MARK: - WiFi连接扩展
extension WiFiConnectionManager {
    func connectWithFallback(ssid: String, password: String, completion: @escaping (Bool, String?) -> Void) {
        connectToWiFi(ssid: ssid, password: password) { [weak self] success, error in
            if success {
                completion(true, nil)
            } else {
                // 如果NEHotspotConfiguration失败，尝试降级方案
                self?.tryFallbackConnection(ssid: ssid, password: password, completion: completion)
            }
        }
    }
    
    private func tryFallbackConnection(ssid: String, password: String, completion: @escaping (Bool, String?) -> Void) {
        // 尝试打开系统WiFi设置
        let systemWifiURLString = "App-Prefs:root=WIFI"
        if let url = URL(string: systemWifiURLString) {
            if UIApplication.shared.canOpenURL(url) {
                UIApplication.shared.open(url) { success in
                    if success {
                        completion(false, "wifi_opened_settings".localized)
                    } else {
                        completion(false, String(format: "wifi_manual_setup_instruction".localized, ssid, password))
                    }
                }
                return
            }
        }
        
        // 最终降级方案：显示手动设置指导
        completion(false, String(format: "wifi_manual_setup_instruction".localized, ssid, password))
    }
}