using System;
using System.Net;
using System.Net.Sockets;
using System.Reflection;
using System.Reflection.Metadata;
using System.Text;
using System.Text.Json;
using System.Threading;
using System.Threading.Tasks;

public class Peer {
    private readonly TcpListener _listener;
    private string _targetIp = "";
    private int _targetPort = 0;
    private int _port = 0;
    private string _name = "";
    private bool running = true;
    private bool hasConnected = false;
    private bool userOnline = false;

    public Peer(int port, string targetIp, int targetPort, string name) {
        _listener = new TcpListener(IPAddress.Any, port);
        _port = port;
        _targetIp = targetIp;
        _targetPort = targetPort;
        _name = name;
    }

    public async Task Start(){
        Task listen = StartListening();
        Task chat = StartChat();
        
        await Task.WhenAll(listen, chat);
    }

    private async Task StartListening(){
        _listener.Start();
        Console.WriteLine($"[info] Nasłuchuje na: 127.0.0.1:{_port}");
        while(running){
            try {
                TcpClient client = await _listener.AcceptTcpClientAsync();
                _ = Task.Run(() => HandleClient(client));
            } catch(Exception ex){
                Console.WriteLine($"[błąd] Wystąpił nieoczekiwany błąd przy nasłuchiwaniu: {ex.Message}");
            }
        } 
    }

    private async Task HandleClient(TcpClient client) {
        try {
            using NetworkStream stream = client.GetStream();
            using StreamReader reader = new(stream, Encoding.UTF8);
            while(running){
                string? message = await reader.ReadLineAsync();
                if(message == null) break;

                Content? contentData = JsonSerializer.Deserialize<Content>(message);
                if(contentData == null) break;

                ProcessMessage(contentData);
            }
        } catch(Exception ex){
            Console.WriteLine(ex.Message);
        }
    }
    
    private void ProcessMessage(Content contentData){
        try {
            ClearConsoleLine();
            Console.SetCursorPosition(0, Console.CursorTop - 1);
            if(contentData.Message == "!exit"){
                running = false;
                Console.WriteLine($"\n[info] Użytkownik {contentData.Sender} zakończył sesję");
            }

            if(contentData.Message.Contains("dołączył/a do sesji") && !userOnline){
                SendMessage($"jest online! Przywitaj się :D", false).Wait();
            }

            if(contentData.ByUser){
                Console.WriteLine($"\n[{contentData.SentAt}] {contentData.Sender}: {contentData.Message}");
            } else {
                Console.WriteLine($"\n[info] [{contentData.SentAt}] Użytkownik {contentData.Sender} {contentData.Message}");
            }

            Console.Write("> ");
        } catch (Exception ex) {
            Console.WriteLine(ex.Message);
        }
    }

    private async Task StartChat(){
        while(running){
            if(!hasConnected){
                await SendMessage("dołączył/a do sesji", false);
                hasConnected = true;
            }
            ClearConsoleLine();
            Console.SetCursorPosition(0, Console.CursorTop - 1);
            Console.Write("\n> ");
            string? message = Console.ReadLine();

            if(message == "!exit"){
                await SendMessage("!exit", false);
                await SendMessage("opuścił/a sesję", false);
                running = false;
                break;
            } else {
                await SendMessage(message ?? "", true);
            }

        }
    }

    private async Task SendMessage(string message, bool by_user){
        try {
            TcpClient client = new ();
            await client.ConnectAsync(_targetIp, _targetPort);
            
            Content data = new() { Sender = _name, IpAddress = $"127.0.0.1:{_port}", Message = message, SentAt = DateTime.Now, ByUser = by_user };
            string json = JsonSerializer.Serialize(data);

            using NetworkStream stream = client.GetStream();
            using StreamWriter writer = new(stream, Encoding.UTF8) { AutoFlush = true };
            await writer.WriteAsync(json);

            if(by_user){
                ClearConsoleLine();
                Console.SetCursorPosition(0, Console.CursorTop - 2);
                Console.WriteLine($"\n[{DateTime.Now}] Ja: {message}");
            }
        } catch(Exception ex){
            if(userOnline)
                Console.WriteLine($"[błąd] Nie udało się wysłać wiadomości: {ex.Message}");
        }
    }

    

    void ClearConsoleLine(){
        int cur = Console.CursorTop;
        Console.SetCursorPosition(0, Console.CursorTop);
        Console.Write(new string(' ', Console.WindowWidth)); 
        Console.SetCursorPosition(0, cur);
    }
}

public class Content {
    public string Sender { get; set; } = "";
    public string Message { get; set; } = "";
    public string IpAddress { get; set; } = "";
    public DateTime SentAt { get; set;}
    public bool ByUser { get; set; }
}