using System;
using System.Linq;
using System.Net.Http;
using System.Text.Json;
using System.Threading.Tasks;

namespace Gott.Services
{
    public class GoogleCheckResult
    {
        public string Status { get; set; }     // "ok", "invalid", "disabled", "error"
        public string Message { get; set; }
        public string[] Models { get; set; }
    }

    public static class GoogleKeyChecker
    {
        public static async Task<GoogleCheckResult> CheckKeyAsync(IHttpClientFactory httpFactory, string apiKey)
        {
            try
            {
                var client = httpFactory.CreateClient();
                client.Timeout = TimeSpan.FromSeconds(30);

                // Gemini / Generative Language API – listet verfügbare Modelle
                var url = "https://generativelanguage.googleapis.com/v1/models?key=" + apiKey;
                var resp = await client.GetAsync(url);
                var statusCode = (int)resp.StatusCode;

                if (statusCode == 400)
                    return new GoogleCheckResult { Status = "invalid", Message = "API-Key ungültig (400)" };

                if (statusCode == 403)
                {
                    // Key gültig, aber Gemini API nicht aktiviert (z.B. Maps-Key)
                    var errorBody = await resp.Content.ReadAsStringAsync();
                    if (errorBody.Contains("API_KEY_INVALID", StringComparison.OrdinalIgnoreCase))
                        return new GoogleCheckResult { Status = "invalid", Message = "API-Key ungültig (403)" };

                    return new GoogleCheckResult { Status = "disabled", Message = "Key gültig, aber Gemini API nicht aktiviert (403)" };
                }

                if (statusCode == 429)
                    return new GoogleCheckResult { Status = "rate_limited", Message = "Rate Limited (429)" };

                if (statusCode >= 400)
                    return new GoogleCheckResult { Status = "error", Message = "API-Fehler (" + statusCode + ")" };

                // 200 OK → Key gültig + Gemini API aktiv
                var body = await resp.Content.ReadAsStringAsync();
                var doc = JsonDocument.Parse(body);

                string[] models = Array.Empty<string>();
                if (doc.RootElement.TryGetProperty("models", out var modelsArr))
                {
                    var interestingPrefixes = new[] { "gemini" };
                    models = modelsArr.EnumerateArray()
                        .Where(m => m.TryGetProperty("name", out _))
                        .Select(m => m.GetProperty("name").GetString())
                        .Where(n => n != null)
                        .Select(n => n.StartsWith("models/", StringComparison.Ordinal) ? n.Substring(7) : n)
                        .Where(n => interestingPrefixes.Any(p => n.StartsWith(p, StringComparison.OrdinalIgnoreCase)))
                        .Distinct()
                        .OrderBy(x => x)
                        .ToArray();
                }

                // Plan-Erkennung
                string plan;
                if (models.Any(m => m.Contains("2.5", StringComparison.OrdinalIgnoreCase)
                                 || m.Contains("ultra", StringComparison.OrdinalIgnoreCase)))
                    plan = "Premium";
                else if (models.Any(m => m.Contains("pro", StringComparison.OrdinalIgnoreCase)))
                    plan = "Standard";
                else if (models.Any(m => m.Contains("flash", StringComparison.OrdinalIgnoreCase)))
                    plan = "Basic";
                else
                    plan = "Free";

                return new GoogleCheckResult
                {
                    Status = "ok",
                    Message = models.Length + " Gemini-Modelle · " + plan,
                    Models = models
                };
            }
            catch (Exception ex)
            {
                return new GoogleCheckResult { Status = "error", Message = ex.Message };
            }
        }
    }
}