using System.Net;
using System.Text;
using System.Text.Json;

namespace PesaplexZk4500Bridge;

internal class Program
{
    private const string Host = "http://127.0.0.1:5055/";

    static void Main()
    {
        Console.Title = "Pesaplex ZK4500 Bridge";

        Console.WriteLine("Starting Pesaplex ZK4500 Bridge...");
        Console.WriteLine("Listening on " + Host);

        var scanner = new Zk4500Scanner();

        if (!scanner.Initialize())
        {
            Console.WriteLine("WARNING: ZK4500 scanner not initialized.");
            Console.WriteLine("Check driver, SDK DLL files, and USB connection.");
        }

        using var listener = new HttpListener();
        listener.Prefixes.Add(Host);
        listener.Start();

        Console.WriteLine("Bridge ready.");
        Console.WriteLine("Test URL: " + Host + "status");

        while (true)
        {
            var context = listener.GetContext();
            HandleRequest(context, scanner);
        }
    }

    private static void HandleRequest(HttpListenerContext context, Zk4500Scanner scanner)
    {
        try
        {
            AddCorsHeaders(context.Response);

            string path = context.Request.Url?.AbsolutePath.ToLower() ?? "/";

            if (context.Request.HttpMethod == "OPTIONS")
            {
                context.Response.StatusCode = 204;
                context.Response.Close();
                return;
            }

            if (path == "/status")
            {
                WriteJson(context.Response, new
                {
                    success = true,
                    service = "Pesaplex ZK4500 Bridge",
                    scannerReady = scanner.IsReady
                });

                return;
            }

            if (path == "/capture")
            {
                if (!scanner.IsReady)
                {
                    WriteJson(context.Response, new
                    {
                        success = false,
                        message = "ZK4500 scanner is not ready."
                    }, 400);

                    return;
                }

                string template = scanner.CaptureTemplate();

                if (string.IsNullOrWhiteSpace(template))
                {
                    WriteJson(context.Response, new
                    {
                        success = false,
                        message = "Fingerprint capture failed."
                    }, 400);

                    return;
                }

                WriteJson(context.Response, new
                {
                    success = true,
                    template = template,
                    message = "Fingerprint captured successfully."
                });

                return;
            }

            WriteJson(context.Response, new
            {
                success = false,
                message = "Route not found."
            }, 404);
        }
        catch (Exception ex)
        {
            WriteJson(context.Response, new
            {
                success = false,
                message = ex.Message
            }, 500);
        }
    }

    private static void AddCorsHeaders(HttpListenerResponse response)
    {
        response.Headers.Add("Access-Control-Allow-Origin", "https://vote.pesaplex.com");
        response.Headers.Add("Access-Control-Allow-Methods", "GET, POST, OPTIONS");
        response.Headers.Add("Access-Control-Allow-Headers", "Content-Type");
    }

    private static void WriteJson(HttpListenerResponse response, object data, int statusCode = 200)
    {
        string json = JsonSerializer.Serialize(data);

        byte[] buffer = Encoding.UTF8.GetBytes(json);

        response.StatusCode = statusCode;
        response.ContentType = "application/json";
        response.ContentEncoding = Encoding.UTF8;
        response.ContentLength64 = buffer.Length;

        response.OutputStream.Write(buffer, 0, buffer.Length);
        response.Close();
    }
}

public class Zk4500Scanner
{
    public bool IsReady { get; private set; }

    public bool Initialize()
    {
        /*
            IMPORTANT:
            This is where you connect the official ZKTeco SDK.

            After installing ZKFinger SDK for Windows, add the SDK DLL/reference.
            The SDK package normally includes driver files, demo files, and development documents.
        */

        try
        {
            // TODO: Replace this with real SDK initialization.
            // Example depends on the SDK version:
            //
            // zkfp2.Init();
            // zkfp2.OpenDevice(0);
            //
            // OR older SDK:
            // ZKFPEngX.InitEngine();

            IsReady = true;
            return true;
        }
        catch
        {
            IsReady = false;
            return false;
        }
    }

    public string CaptureTemplate()
    {
        /*
            TODO: Replace this method with real ZK4500 capture code.

            The real method should:
            1. Wait for finger placement.
            2. Capture fingerprint image.
            3. Extract fingerprint template.
            4. Return template as Base64 string.
        */

        Console.WriteLine("Waiting for fingerprint...");

        // Temporary test template so the website can test connection.
        // Remove this after SDK code is added.
        return Convert.ToBase64String(
            Encoding.UTF8.GetBytes("TEMP_ZK4500_TEMPLATE_" + DateTime.UtcNow.Ticks)
        );
    }
}