using System;
using System.IO;
using System.Net;
using System.Threading;

namespace UPSNet 
{
    public class UPSApiFetcher : IDisposable 
    {
        // Configuration
        private string _apiUrl;
        private string _apiUrlOnce;
        private int _pollingInterval;
        private int _pollingIntervalOnce;
        
        // State tracking
        private Thread _workerThread;
        private bool _isRunning;
        private DateTime _lastSuccessfulFetch;
        private ManualResetEvent _sleepEvent = new ManualResetEvent(false);
        private readonly object _syncLock = new object();
        
        // API Response Data
        public int Success { get; private set; }
        public int ChargeLevel { get; private set; }
        public int BattMaxLevel { get; private set; }
        public bool OnState { get; private set; }
        public int ShutdownSuggestMode { get; private set; }
        public bool ShutdownSuggested { get; private set; }
        public bool OnTimedShutdown { get; private set; }
        public int TimedShutdownRemaining { get; private set; }
        public bool BatteryCritical { get; private set; }
        public int UPSLineFrom { get; private set; }
        public bool IsChargingOrBlink { get; private set; }
        public bool IsReachable { get; private set; }
        public DateTime LastUpdateTime { get; private set; }
        public bool IsOnRequestUrlOnce { get; private set; }
        
        private string json;
        
        // Event
        public event Action<UPSApiFetcher> StatusUpdated;

        public UPSApiFetcher(string apiUrl, int pollingIntervalMs = 1000) {
            _apiUrl = apiUrl;
            _pollingInterval = pollingIntervalMs;
        }

        public void SetApiUrl(string apiUrl, int pollingIntervalMs = 1000) {
            lock (_syncLock) {
                _apiUrl = apiUrl;
                _pollingInterval = pollingIntervalMs;
            }
        }

        public void SetApiUrlOnce(string apiUrl, int pollingIntervalMs = 500)  {
            lock (_syncLock){
                _apiUrlOnce = apiUrl;
                _pollingIntervalOnce = pollingIntervalMs;
                IsOnRequestUrlOnce = true;
                _sleepEvent.Set(); // Wake up thread for immediate fetch
            }
        }

        public void Start() {
            if (_isRunning) return;

            _isRunning = true;
            _workerThread = new Thread(WorkerLoop){
                IsBackground = true,
                Priority = ThreadPriority.Normal//ThreadPriority.BelowNormal
            };
            _workerThread.Start();
        }

        public void Stop() {
            _isRunning = false;
            _sleepEvent.Set(); // Wake thread to exit
            _workerThread.Join(1000);
        }

        public void FetchNow() {
            _sleepEvent.Set(); // Wake thread for immediate fetch
        }

        private void WorkerLoop() {
            while (_isRunning) {
                FetchApiData();
                
                // Wait for next interval or immediate fetch
                int interval;
                lock (_syncLock) {
                    interval = IsOnRequestUrlOnce ? _pollingIntervalOnce : _pollingInterval;
                }
                _sleepEvent.WaitOne(interval);
                _sleepEvent.Reset();
            }
        }

        private void FetchApiData() {
            try {
                string currentUrl;
                lock (_syncLock) {
                    currentUrl = IsOnRequestUrlOnce ? _apiUrlOnce : _apiUrl;
                }

                var request = WebRequest.Create(currentUrl);
                request.Timeout = 5000;
                
                // Add Basic Authentication for V2 compatibility
                string credentials = Convert.ToBase64String(System.Text.Encoding.ASCII.GetBytes("admin:admin123"));
                request.Headers[HttpRequestHeader.Authorization] = "Basic " + credentials;

                using (var response = (HttpWebResponse)request.GetResponse())
                using (var stream = response.GetResponseStream())
                using (var reader = new StreamReader(stream)) {
                	string tmp = reader.ReadToEnd();
                	if (json!=tmp){
                		json = tmp;
                    	ParseJsonResponse(json);
                	}
                    IsReachable = true;
                    _lastSuccessfulFetch = DateTime.Now;
                    LastUpdateTime = DateTime.Now;
                    lock (_syncLock) {
                        if (IsOnRequestUrlOnce) {
                            IsOnRequestUrlOnce = false;
                        }
                    }
                }
            }catch{
                UpdateReachability();
            }finally{
                StatusUpdated.Invoke(this);
            }
        }

        private void UpdateReachability(){
            if ((DateTime.Now - _lastSuccessfulFetch).TotalSeconds > 5) {
                IsReachable = false;
                LastUpdateTime = DateTime.Now;
            }
        }

        private void ParseJsonResponse(string json) {
            try {
                json = json.Trim('{', '}', ' ', '\n', '\r', '\t');
                string[] pairs = json.Split(',');

                foreach (string pair in pairs) {
                    string[] keyValue = pair.Split(':');
                    if (keyValue.Length != 2) continue;

                    string key = keyValue[0].Trim().Trim('"');
                    string value = keyValue[1].Trim().Trim('"');

                    switch (key.ToLower()){
                        case "success":
                            Success = int.Parse(value);
                            break;
                        case "chargelv":
                            ChargeLevel = int.Parse(value);
                            break;
                        case "shutdownsuggestmode":
                            ShutdownSuggestMode = int.Parse(value);
                            break;
                        case "shutdownsuggest":
                            ShutdownSuggested = int.Parse(value) > 0;
                            break;
                        case "timedshutdown":
                            OnTimedShutdown = int.Parse(value) > 0;
                            break;
                        case "shutdownremain":
                            TimedShutdownRemaining = int.Parse(value);
                            break;
                        case "battcritical":
                            BatteryCritical = int.Parse(value) > 0;
                            break;
                        case "line":
                            UPSLineFrom = int.Parse(value);
                            break;
                        case "battblink":
                            IsChargingOrBlink = int.Parse(value) > 0;
                            break;
                        case "state":
                            OnState = int.Parse(value) > 0;
                            break;
                        case "battmax":
                            BattMaxLevel = int.Parse(value);
                            break;
                    }
                }
            }catch{
                // Keep previous values on parse error
            }
        }

        public void Dispose(){
            Stop();
            _sleepEvent.Dispose();
        }
    }
}