using System;
using System.Collections.Generic;
using System.Net;
using System.Text;
using System.Threading;
using UnityEngine;

/// <summary>
/// HTTP 서버 - Streamingle 웹 대시보드 UI를 제공합니다.
/// Resources/StreamingleDashboard/ 폴더에서 HTML, CSS, JS를 로드합니다.
/// RetargetingHTTPServer 패턴을 따릅니다.
/// </summary>
public class StreamingleDashboardServer
{
    private HttpListener listener;
    private Thread listenerThread;
    private bool isRunning = false;

    private int httpPort;
    private int wsPort;
    private int retargetingWsPort;

    private string cachedCSS = "";
    private string cachedTemplate = "";
    private string cachedJS = "";

    private List<string> boundAddresses = new List<string>();

    public bool IsRunning => isRunning;
    public IReadOnlyList<string> BoundAddresses => boundAddresses;

    public StreamingleDashboardServer(int httpPort, int wsPort, int retargetingWsPort = 0)
    {
        this.httpPort = httpPort;
        this.wsPort = wsPort;
        this.retargetingWsPort = retargetingWsPort;
    }

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

        LoadResources();

        try
        {
            listener = new HttpListener();
            boundAddresses.Clear();

            // http://+: 로 모든 인터페이스 바인딩 시도 (관리자 권한 또는 URL ACL 필요)
            bool wildcardBound = false;
            try
            {
                listener.Prefixes.Add($"http://+:{httpPort}/");
                listener.Start();
                wildcardBound = true;

                boundAddresses.Add($"http://localhost:{httpPort}");
                string localIP = GetLocalIPAddress();
                if (!string.IsNullOrEmpty(localIP))
                {
                    boundAddresses.Add($"http://{localIP}:{httpPort}");
                }
                Debug.Log("[StreamingleDashboard] 모든 인터페이스 바인딩 성공 (LAN 접속 가능)");
            }
            catch (Exception)
            {
                // 와일드카드 실패 시 리스너 재생성
                try { listener.Close(); } catch { }
                listener = new HttpListener();

                // LAN IP 직접 바인딩 시도
                string localIP = GetLocalIPAddress();
                bool lanBound = false;

                listener.Prefixes.Add($"http://localhost:{httpPort}/");
                boundAddresses.Add($"http://localhost:{httpPort}");

                listener.Prefixes.Add($"http://127.0.0.1:{httpPort}/");
                boundAddresses.Add($"http://127.0.0.1:{httpPort}");

                if (!string.IsNullOrEmpty(localIP))
                {
                    try
                    {
                        listener.Prefixes.Add($"http://{localIP}:{httpPort}/");
                        boundAddresses.Add($"http://{localIP}:{httpPort}");
                        lanBound = true;
                    }
                    catch (Exception)
                    {
                        // LAN IP 바인딩도 실패
                    }
                }

                listener.Start();

                if (lanBound)
                    Debug.Log($"[StreamingleDashboard] LAN IP 바인딩 성공 ({localIP})");
                else
                    Debug.LogWarning("[StreamingleDashboard] LAN 바인딩 실패. localhost만 접속 가능. 관리자 권한으로 실행하거나 다음 명령어를 실행하세요:\n" +
                        $"  netsh http add urlacl url=http://+:{httpPort}/ user=Everyone");
            }

            isRunning = true;

            listenerThread = new Thread(HandleRequests);
            listenerThread.IsBackground = true;
            listenerThread.Start();

            Debug.Log("[StreamingleDashboard] HTTP 서버 시작됨");
            foreach (var addr in boundAddresses)
            {
                Debug.Log($"[StreamingleDashboard] 대시보드 접속: {addr}");
            }
        }
        catch (Exception ex)
        {
            Debug.LogError($"[StreamingleDashboard] 서버 시작 실패: {ex.Message}");
        }
    }

    public void Stop()
    {
        if (!isRunning) return;

        isRunning = false;

        try
        {
            listener?.Stop();
            listener?.Close();
        }
        catch (Exception) { }

        Debug.Log("[StreamingleDashboard] HTTP 서버 중지됨");
    }

    private void LoadResources()
    {
        TextAsset cssAsset = Resources.Load<TextAsset>("StreamingleDashboard/dashboard_style");
        TextAsset templateAsset = Resources.Load<TextAsset>("StreamingleDashboard/dashboard_template");
        TextAsset jsAsset = Resources.Load<TextAsset>("StreamingleDashboard/dashboard_script");

        cachedCSS = cssAsset != null ? cssAsset.text : GetFallbackCSS();
        cachedTemplate = templateAsset != null ? templateAsset.text : GetFallbackTemplate();
        cachedJS = jsAsset != null ? jsAsset.text : GetFallbackJS();

        if (cssAsset == null || templateAsset == null || jsAsset == null)
        {
            Debug.LogWarning("[StreamingleDashboard] 일부 리소스를 로드할 수 없습니다. Fallback 사용 중.");
        }
    }

    private void HandleRequests()
    {
        while (isRunning)
        {
            try
            {
                HttpListenerContext context = listener.GetContext();
                ProcessRequest(context);
            }
            catch (HttpListenerException)
            {
                // 서버 종료 시 발생
            }
            catch (Exception ex)
            {
                if (isRunning)
                {
                    Debug.LogError($"[StreamingleDashboard] 요청 처리 오류: {ex.Message}");
                }
            }
        }
    }

    private void ProcessRequest(HttpListenerContext context)
    {
        try
        {
            string path = context.Request.Url.AbsolutePath;

            string responseContent;
            string contentType;

            if (path == "/" || path == "/index.html")
            {
                responseContent = GenerateHTML();
                contentType = "text/html; charset=utf-8";
            }
            else if (path == "/style.css")
            {
                responseContent = cachedCSS;
                contentType = "text/css; charset=utf-8";
            }
            else if (path == "/script.js")
            {
                responseContent = cachedJS
                    .Replace("{{WS_PORT}}", wsPort.ToString())
                    .Replace("{{RETARGETING_WS_PORT}}", retargetingWsPort.ToString());
                contentType = "application/javascript; charset=utf-8";
            }
            else
            {
                context.Response.StatusCode = 404;
                responseContent = "Not Found";
                contentType = "text/plain";
            }

            byte[] buffer = Encoding.UTF8.GetBytes(responseContent);
            context.Response.ContentType = contentType;
            context.Response.ContentLength64 = buffer.Length;
            context.Response.AddHeader("Cache-Control", "no-store, no-cache, must-revalidate, max-age=0");
            context.Response.OutputStream.Write(buffer, 0, buffer.Length);
            context.Response.Close();
        }
        catch (Exception ex)
        {
            Debug.LogError($"[StreamingleDashboard] 응답 처리 오류: {ex.Message}");
        }
    }

    private string GenerateHTML()
    {
        string html = cachedTemplate;
        html = html.Replace("{{CSS}}", cachedCSS);
        html = html.Replace("{{JS}}", cachedJS
            .Replace("{{WS_PORT}}", wsPort.ToString())
            .Replace("{{RETARGETING_WS_PORT}}", retargetingWsPort.ToString()));
        return html;
    }

    private string GetLocalIPAddress()
    {
        try
        {
            var host = Dns.GetHostEntry(Dns.GetHostName());
            foreach (var ip in host.AddressList)
            {
                if (ip.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork)
                {
                    return ip.ToString();
                }
            }
        }
        catch (Exception) { }
        return "";
    }

    private string GetFallbackCSS()
    {
        return @"
body { font-family: sans-serif; background: #0f172a; color: #f1f5f9; padding: 20px; }
.error { color: #ef4444; padding: 20px; text-align: center; }
";
    }

    private string GetFallbackTemplate()
    {
        return @"
<!DOCTYPE html>
<html>
<head>
    <meta charset=""UTF-8"">
    <title>Streamingle Dashboard</title>
    <style>{{CSS}}</style>
</head>
<body>
    <div class=""error"">
        리소스 파일을 찾을 수 없습니다.<br>
        Assets/Resources/StreamingleDashboard/ 폴더에 파일이 있는지 확인해주세요.
    </div>
</body>
</html>";
    }

    private string GetFallbackJS()
    {
        return "console.error('JavaScript resource not found');";
    }
}