import Foundation
import UserNotifications

enum PingService {
    private static var previousPingStates: [String: Bool] = [:]

    static func ping(hostname: String, apiKey: String, notificationsEnabled: Bool = true) async -> Bool {
        guard let url = URL(string: "https://\(hostname)/api/v2/ping") else {
            print("❌ [PingService] Invalid URL for \(hostname)")
            return false
        }

        var request = URLRequest(url: url)
        request.httpMethod = "GET"
        request.setValue(apiKey, forHTTPHeaderField: "X-API-KEY")
        request.timeoutInterval = 10

        do {
            let (data, response) = try await URLSession.shared.data(for: request)
            if let httpResponse = response as? HTTPURLResponse, httpResponse.statusCode != 200 {
                if let responseString = String(data: data, encoding: .utf8) {
                    print("❌ [PingService] HTTP \(httpResponse.statusCode): \(responseString)")
                }
                handlePingFailure(for: hostname, notificationsEnabled: notificationsEnabled)
                return false
            }

            if let result = try? JSONDecoder().decode([String: String].self, from: data), result["response"] == "pong" {
                handlePingSuccess(for: hostname, notificationsEnabled: notificationsEnabled)
                return true
            } else {
                handlePingFailure(for: hostname, notificationsEnabled: notificationsEnabled)
                return false
            }
        } catch {
            print("❌ [PingService] Error pinging \(hostname): \(error)")
            handlePingFailure(for: hostname, notificationsEnabled: notificationsEnabled)
            return false
        }
    }

    private static func handlePingSuccess(for hostname: String, notificationsEnabled: Bool) {
        let wasPreviouslyDown = previousPingStates[hostname] == false
        previousPingStates[hostname] = true

        if wasPreviouslyDown && notificationsEnabled {
            sendNotification(title: "Server Online", body: "\(hostname) is now online")
        }
    }

    private static func handlePingFailure(for hostname: String, notificationsEnabled: Bool) {
        let wasPreviouslyUp = previousPingStates[hostname] != false
        previousPingStates[hostname] = false

        if wasPreviouslyUp && notificationsEnabled {
            sendNotification(title: "Server Offline", body: "\(hostname) is offline")
        }
    }

    private static func sendNotification(title: String, body: String) {
        let content = UNMutableNotificationContent()
        content.title = title
        content.body = body
        content.sound = .default

        let request = UNNotificationRequest(identifier: UUID().uuidString, content: content, trigger: nil)
        UNUserNotificationCenter.current().add(request)
    }
}