using System;
using System.Text.Json;
using System.Threading.Tasks;
using Gott.Extensions;
using Gott.Services;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Routing;

namespace Gott.Endpoints;

public static class TelegramEndpoint
{
    public static void MapTelegramEndpoints(this IEndpointRouteBuilder app)
    {
        // Webhook (von Telegram aufgerufen – keine Cookie-Auth!)
        app.MapPost("/api/telegram/webhook", HandleWebhook);

        // Link-Code generieren (aus Web-UI, braucht Auth)
        app.MapPost("/api/telegram/link", HandleCreateLink);

        // Webhook registrieren (Admin)
        app.MapPost("/api/telegram/register-webhook", HandleRegisterWebhook);

        // Telegram-Status (ob konfiguriert – für Frontend)
        app.MapGet("/api/telegram/status", HandleStatus);

        // Webhook-Info (Admin)
        app.MapGet("/api/telegram/webhook-info", HandleWebhookInfo);
    }

    private static async Task HandleWebhook(HttpRequest req, HttpResponse res, TelegramService telegram)
    {
        if (!telegram.IsConfigured)
        {
            res.StatusCode = 404;
            return;
        }

        // Secret-Token prüfen
        var secret = req.Headers["X-Telegram-Bot-Api-Secret-Token"].ToString();
        if (secret != telegram.WebhookSecret)
        {
            res.StatusCode = 403;
            return;
        }

        try
        {
            var body = await JsonSerializer.DeserializeAsync<JsonElement>(req.Body);
            // Fire-and-forget – Telegram erwartet schnelle 200 OK Antwort
            _ = Task.Run(async () =>
            {
                try { await telegram.HandleUpdate(body); }
                catch (Exception ex) { Console.Error.WriteLine($"[Telegram] Fehler: {ex.Message}"); }
            });
        }
        catch
        {
            // Malformed JSON – ignorieren
        }

        res.StatusCode = 200;
    }

    private static async Task HandleCreateLink(HttpRequest req, HttpResponse res, DatabaseService db, TelegramService telegram)
    {
        if (!telegram.IsConfigured)
        {
            res.StatusCode = 400;
            await res.WriteAsJsonAsync(new { error = "Telegram Bot nicht konfiguriert" });
            return;
        }

        var userId = req.HttpContext.GetUserId();
        var body = await JsonSerializer.DeserializeAsync<JsonElement>(req.Body);

        if (!body.TryGetProperty("sessionId", out var sidEl))
        {
            res.StatusCode = 400;
            await res.WriteAsJsonAsync(new { error = "sessionId required" });
            return;
        }

        var sessionId = sidEl.GetString();
        var session = await db.GetSession(sessionId);
        if (session == null || session.UserId != userId)
        {
            res.StatusCode = 404;
            await res.WriteAsJsonAsync(new { error = "Session nicht gefunden" });
            return;
        }

        var agentId = session.AgentId;
        var code = await db.CreateTelegramLinkCode(userId, sessionId, agentId);

        await res.WriteAsJsonAsync(new { code, expiresInSeconds = 300 });
    }

    private static async Task HandleRegisterWebhook(HttpRequest req, HttpResponse res, TelegramService telegram)
    {
        if (!req.HttpContext.IsAdmin())
        {
            res.StatusCode = 403;
            await res.WriteAsJsonAsync(new { error = "Admin required" });
            return;
        }

        var body = await JsonSerializer.DeserializeAsync<JsonElement>(req.Body);
        if (!body.TryGetProperty("baseUrl", out var urlEl))
        {
            res.StatusCode = 400;
            await res.WriteAsJsonAsync(new { error = "baseUrl required" });
            return;
        }

        var result = await telegram.RegisterWebhook(urlEl.GetString());
        await res.WriteAsJsonAsync(new { result });
    }

    private static async Task HandleStatus(HttpResponse res, TelegramService telegram)
    {
        await res.WriteAsJsonAsync(new { configured = telegram.IsConfigured });
    }

    private static async Task HandleWebhookInfo(HttpRequest req, HttpResponse res, TelegramService telegram)
    {
        if (!req.HttpContext.IsAdmin())
        {
            res.StatusCode = 403;
            await res.WriteAsJsonAsync(new { error = "Admin required" });
            return;
        }

        var result = await telegram.GetWebhookInfo();
        res.ContentType = "application/json";
        await res.WriteAsync(result);
    }
}