using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net.Http;
using System.Text;
using System.Text.Json;
using System.Text.Json.Nodes;
using System.Threading.Tasks;
using Gott.Models;

namespace Gott.Services
{
    public class KreaService
    {
        private readonly IHttpClientFactory _httpFactory;
        private readonly ServerSettingsService _settings;
        private readonly string _imagesDir;

        private string _token => _settings.Get("KreaToken");

        private const string BASE_URL = "https://api.krea.ai";

        public static readonly Dictionary<string, string> IMAGE_MODELS = new Dictionary<string, string>
        {
            { "flux",                 "/generate/image/bfl/flux-1-dev" },
            { "flux-kontext",         "/generate/image/bfl/flux-1-kontext-dev" },
            { "flux-1.1-pro",         "/generate/image/bfl/flux-1.1-pro" },
            { "flux-1.1-pro-ultra",   "/generate/image/bfl/flux-1.1-pro-ultra" },
            { "nano-banana",          "/generate/image/google/nano-banana" },
            { "nano-banana-pro",      "/generate/image/google/nano-banana-pro" },
            { "imagen-3",             "/generate/image/google/imagen-3" },
            { "imagen-4",             "/generate/image/google/imagen-4" },
            { "imagen-4-fast",        "/generate/image/google/imagen-4-fast" },
            { "imagen-4-ultra",       "/generate/image/google/imagen-4-ultra" },
            { "ideogram-2-turbo",     "/generate/image/ideogram/ideogram-2-turbo" },
            { "ideogram-3",           "/generate/image/ideogram/ideogram-3" },
            { "seedream-3",           "/generate/image/bytedance/seedream-3" },
            { "seedream-4",           "/generate/image/bytedance/seedream-4" },
            { "chatgpt-image",        "/generate/image/openai/gpt-image" },
            { "runway-gen-4",         "/generate/image/runway/gen-4" },
            { "z-image",              "/generate/image/z-image/z-image" },
            { "qwen-2512",            "/generate/image/qwen/2512" },
            { "nano-banana-2",        "/generate/image/google/nano-banana-2" },
            { "seedream-5-lite",      "/generate/image/bytedance/seedream-5-lite" },
            { "seededit",             "/generate/image/bytedance/seededit" },
        };

        // Models that don't support width/height/steps/guidance
        private static readonly HashSet<string> MINIMAL_MODELS = new HashSet<string>
        {
            "seedream-3", "runway-gen-4", "seedream-5-lite", "seededit"
        };

        public bool IsConfigured => !string.IsNullOrWhiteSpace(_token);

        public KreaService(IHttpClientFactory httpFactory, ServerSettingsService settings, string dataDir)
        {
            _httpFactory = httpFactory;
            _settings = settings;
            _imagesDir = Path.Combine(dataDir, "images");
            Directory.CreateDirectory(_imagesDir);
        }

        public async Task<KreaImageRecord> GenerateAsync(
            string prompt,
            string model = "flux",
            int width = 1024,
            int height = 1024,
            int steps = 25,
            double guidanceScale = 3.0,
            string seed = null,
            int batchSize = 1)
        {
            if (!IMAGE_MODELS.TryGetValue(model, out var endpoint))
                throw new ArgumentException($"Unbekanntes Model: {model}. Verfügbar: {string.Join(", ", IMAGE_MODELS.Keys)}");

            var timestamp = DateTimeOffset.UtcNow.ToUnixTimeSeconds();
            var record = new KreaImageRecord
            {
                Id = timestamp.ToString(),
                Prompt = prompt,
                Model = model,
                Width = width,
                Height = height,
                Steps = steps,
                GuidanceScale = guidanceScale,
                Seed = seed,
                BatchSize = Math.Max(1, Math.Min(4, batchSize)),
                Status = "pending",
                CreatedAt = DateTimeOffset.UtcNow.ToString("o"),
            };

            // Build payload
            // Hinweis: Krea unterstützt 'batchSize' nicht mehr ("batch size is no longer supported,
            // submit one request per output") -> wir senden pro gewünschtem Bild eine eigene Anfrage.
            var payload = new Dictionary<string, object>();
            payload["prompt"] = prompt;

            if (!MINIMAL_MODELS.Contains(model))
            {
                payload["width"] = width;
                payload["height"] = height;
                payload["steps"] = steps;
                payload["guidance_scale_flux"] = guidanceScale;
            }

            if (model == "seedream-3")
                payload["model"] = "seedream-3-0-t2i-250415";

            if (!string.IsNullOrEmpty(seed))
                payload["seed"] = seed;

            // Submit job(s)
            var client = _httpFactory.CreateClient();
            client.DefaultRequestHeaders.Add("Authorization", $"Bearer {_token}");
            client.DefaultRequestHeaders.Add("Accept", "application/json");
            client.DefaultRequestHeaders.Add("User-Agent", "Mozilla/5.0 (compatible; Gott/1.0)");

            var json = JsonSerializer.Serialize(payload);

            // Eine Anfrage pro gewünschtem Bild (batchSize wird serverseitig nicht mehr akzeptiert).
            var jobs = new List<JsonNode>();
            for (int b = 0; b < record.BatchSize; b++)
            {
                var content = new StringContent(json, Encoding.UTF8, "application/json");

                var response = await client.PostAsync($"{BASE_URL}{endpoint}", content);
                var responseBody = await response.Content.ReadAsStringAsync();

                if (!response.IsSuccessStatusCode)
                    throw new Exception($"Krea API Fehler {(int)response.StatusCode}: {responseBody}");

                var node = JsonNode.Parse(responseBody);
                if (node is JsonArray arr)
                    jobs.AddRange(arr.Where(j => j != null));
                else if (node != null)
                    jobs.Add(node);
            }

            // Wait for all jobs
            var allUrls = new List<string>();
            var jobResults = new List<JsonNode>();

            foreach (var job in jobs)
            {
                var jobId = job["job_id"]?.GetValue<string>()
                    ?? throw new Exception("Kein job_id in Response");

                var result = await WaitForJobAsync(client, jobId);
                var urls = result["result"]?["urls"]?.AsArray();
                if (urls != null)
                    foreach (var u in urls)
                        allUrls.Add(u.GetValue<string>());

                jobResults.Add(result);
            }

            // Download images
            var savedFiles = await SaveImagesAsync(client, allUrls, timestamp);

            // Save metadata
            var metaFile = await SaveMetadataAsync(timestamp, record, allUrls, savedFiles, jobResults);

            record.Status = "completed";
            record.Files = savedFiles;
            record.Urls = allUrls;
            record.MetaFile = metaFile;
            record.CompletedAt = DateTimeOffset.UtcNow.ToString("o");

            return record;
        }

        private async Task<JsonNode> WaitForJobAsync(HttpClient client, string jobId, int timeoutSeconds = 120)
        {
            var deadline = DateTime.UtcNow.AddSeconds(timeoutSeconds);
            while (DateTime.UtcNow < deadline)
            {
                var resp = await client.GetAsync($"{BASE_URL}/jobs/{jobId}");
                var body = await resp.Content.ReadAsStringAsync();
                var job = JsonNode.Parse(body);
                var status = job["status"]?.GetValue<string>();

                if (status == "completed") return job;
                if (status == "failed") throw new Exception($"Job fehlgeschlagen: {body}");
                if (status == "cancelled") throw new Exception("Job wurde abgebrochen");

                await Task.Delay(2000);
            }
            throw new TimeoutException($"Job {jobId} hat nicht innerhalb von {timeoutSeconds}s geantwortet");
        }

        private async Task<List<string>> SaveImagesAsync(HttpClient client, List<string> urls, long timestamp)
        {
            var saved = new List<string>();
            for (int i = 0; i < urls.Count; i++)
            {
                var url = urls[i];
                try
                {
                    var resp = await client.GetAsync(url);
                    var bytes = await resp.Content.ReadAsByteArrayAsync();

                    // Determine extension
                    var ext = ".webp";
                    var contentType = resp.Content.Headers.ContentType?.MediaType ?? "";
                    var extMap = new Dictionary<string, string>
                    {
                        { "image/png", ".png" },
                        { "image/jpeg", ".jpg" },
                        { "image/webp", ".webp" },
                        { "image/gif", ".gif" },
                    };
                    if (extMap.TryGetValue(contentType, out var mappedExt))
                        ext = mappedExt;

                    var filename = $"{timestamp}-{i + 1}{ext}";
                    var filepath = Path.Combine(_imagesDir, filename);
                    await File.WriteAllBytesAsync(filepath, bytes);
                    saved.Add(filename); // Nur Dateiname, kein Pfad
                }
                catch (Exception ex)
                {
                    Console.WriteLine($"[KreaService] Fehler beim Download von {url}: {ex.Message}");
                }
            }
            return saved;
        }

        private async Task<string> SaveMetadataAsync(
            long timestamp,
            KreaImageRecord record,
            List<string> urls,
            List<string> savedFiles,
            List<JsonNode> jobResults)
        {
            var meta = new
            {
                timestamp,
                timestamp_iso = DateTimeOffset.FromUnixTimeSeconds(timestamp).ToString("o"),
                input = new
                {
                    prompt = record.Prompt,
                    model = record.Model,
                    width = record.Width,
                    height = record.Height,
                    steps = record.Steps,
                    guidance_scale = record.GuidanceScale,
                    seed = record.Seed,
                    batch_size = record.BatchSize,
                },
                output = new
                {
                    urls,
                    files = savedFiles,
                    image_count = urls.Count,
                },
                jobs = jobResults.Select(j => j.ToJsonString()).ToList(),
            };

            var metaPath = Path.Combine(_imagesDir, $"{timestamp}.json");
            var json = JsonSerializer.Serialize(meta, new JsonSerializerOptions { WriteIndented = true });
            await File.WriteAllTextAsync(metaPath, json);
            return $"{timestamp}.json";
        }

        public List<KreaImageRecord> ListImages()
        {
            var result = new List<KreaImageRecord>();
            if (!Directory.Exists(_imagesDir)) return result;

            foreach (var metaFile in Directory.GetFiles(_imagesDir, "*.json").OrderByDescending(f => f))
            {
                try
                {
                    var json = File.ReadAllText(metaFile);
                    var node = JsonNode.Parse(json);
                    var timestamp = node["timestamp"]?.GetValue<long>() ?? 0;
                    var input = node["input"];
                    var output = node["output"];

                    var files = output?["files"]?.AsArray()
                        .Select(f => f.GetValue<string>()).ToList() ?? new List<string>();

                    result.Add(new KreaImageRecord
                    {
                        Id = timestamp.ToString(),
                        Prompt = input?["prompt"]?.GetValue<string>(),
                        Model = input?["model"]?.GetValue<string>(),
                        Width = input?["width"]?.GetValue<int>() ?? 1024,
                        Height = input?["height"]?.GetValue<int>() ?? 1024,
                        Steps = input?["steps"]?.GetValue<int>() ?? 25,
                        GuidanceScale = input?["guidance_scale"]?.GetValue<double>() ?? 3.0,
                        Seed = input?["seed"]?.GetValue<string>(),
                        BatchSize = input?["batch_size"]?.GetValue<int>() ?? 1,
                        Status = "completed",
                        Files = files,
                        Urls = output?["urls"]?.AsArray()
                            .Select(u => u.GetValue<string>()).ToList() ?? new List<string>(),
                        CreatedAt = node["timestamp_iso"]?.GetValue<string>(),
                        MetaFile = Path.GetFileName(metaFile),
                    });
                }
                catch { /* ungültige Meta-Datei überspringen */ }
            }

            return result;
        }

        public string GetImagePath(string filename)
        {
            var path = Path.Combine(_imagesDir, filename);
            return File.Exists(path) ? path : null;
        }
    }
}