using System.IO;
using System.Text.Json;
using FinlyticCore.Dtos;
using FinlyticCore.Dtos.News;
using FinlyticCore.Dtos.Sentiment;
using FinlyticCore.Models;
using FinlyticCore.Util;
using FinlyticNews.Entities;
using FinlyticNews.Services;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

namespace FinlyticNews.Util;

/// <summary>
/// A managed MQTT client for broadcasting completed news articles and responding to RPC requests.
/// </summary>
public class NewsMqttClient : ManagedMqttClient, IHostedService
{
    private readonly IServiceScopeFactory _scopeFactory;
    private readonly ILogger<NewsMqttClient> _logger;
    private readonly IConfiguration _configuration;

    public NewsMqttClient(
        ILogger<NewsMqttClient> logger,
        IServiceScopeFactory scopeFactory,
        IConfiguration configuration) : base(logger)
    {
        _scopeFactory = scopeFactory;
        _logger = logger;
        _configuration = configuration;
    }

    /// <inheritdoc />
    public async Task StartAsync(CancellationToken cancellationToken)
    {
        var config = new MqttConfiguration
        {
            Host = _configuration["MQTT:Host"] ?? _configuration["MQTT__Host"] ?? "localhost",
            Port = Convert.ToInt32(_configuration["MQTT:Port"] ?? _configuration["MQTT__Port"] ?? "1883"),
            ClientId = $"{(_configuration["MQTT:ClientId"] ?? _configuration["MQTT__ClientId"] ?? "FinlyticNews")}_{Guid.NewGuid()}"
        };

        _logger.LogInformation("Starting News MQTT client. Host: {Host}, ClientId: {ClientId}", config.Host, config.ClientId);
        await ConnectAsync(config);
    }

    /// <inheritdoc />
    public async Task StopAsync(CancellationToken cancellationToken)
    {
        _logger.LogInformation("Stopping News MQTT client and disconnecting.");
        await DisconnectAsync();
    }

    /// <inheritdoc />
    protected override async Task OnConnectedAsync()
    {
        _logger.LogInformation("News MQTT client connected. Subscribing to RPC topics...");
        
        // ZUSAMMENGELEGT: Unified News Fetching (news_Get deckt news_GetDaily mit ab)
        await SubscribeAsync("services/request/news_Get/#");
        await SubscribeAsync("services/request/news_GetById/#");
        await SubscribeAsync("services/request/news_GetPending/#");
        await SubscribeAsync("services/request/news_UpdateStatus/#");
        await SubscribeAsync("services/request/health_Ping/#");
        await SubscribeAsync("services/config/updated/#");
    }

    /// <summary>
    /// Broadcasts a newly processed news article to downstream subscribers.
    /// </summary>
    public async Task BroadcastArticleAsync(NewsArticleDto article)
    {
        // 1. Primärer System-Broadcast
        const string topic = "services/news/completed";
        _logger.LogInformation("Broadcasting completed article to MQTT topic: {Topic}. ID: {Id}", topic, article.Id);
        await PublishAsync(topic, article);

        // 2. Zielgerichteter ISIN-Stream für Echtzeit-Frontend-Feeds
        var firstIsin = article.MatchedAssets.FirstOrDefault()?.Isin;
        if (!string.IsNullOrWhiteSpace(firstIsin))
        {
            string isinTopic = $"finlytic/news/stream/{firstIsin.Trim().ToLowerInvariant()}";
            await PublishAsync(isinTopic, article);
        }
    }

    /// <inheritdoc />
    protected override async Task OnMessageReceivedAsync(string topic, string payload)
    {
        if (string.IsNullOrWhiteSpace(topic)) return;

        // 1. System Config Updates
        if (topic.StartsWith("services/config/updated", StringComparison.OrdinalIgnoreCase))
        {
            if (topic.EndsWith("FinlyticNews", StringComparison.OrdinalIgnoreCase))
            {
                await OnConfigUpdatedAsync(payload);
            }
            return;
        }

        var segments = topic.Split('/');
        if (segments.Length < 4) return;

        var channel = segments[2];
        var correlationId = segments[^1];

        // 2. Unified RPC Dispatching via Switch
        switch (channel)
        {
            case "news_Get":
            case "news_GetDaily": // Abwärtskompatibel weitergeleitet
                await OnGetNewsAsync(payload, correlationId);
                break;

            case "news_GetById":
                await OnGetNewsByIdAsync(payload, correlationId);
                break;

            case "news_GetPending":
                await OnGetPendingNewsAsync(payload, correlationId);
                break;

            case "news_UpdateStatus":
                await OnUpdateNewsStatusAsync(payload, correlationId);
                break;

            case "health_Ping":
                await OnHealthPingAsync(segments, correlationId);
                break;

            default:
                _logger.LogDebug("Received unhandled RPC channel: {Channel}", channel);
                break;
        }
    }

    private async Task OnGetNewsAsync(string payload, string correlationId)
    {
        _logger.LogInformation("Received RPC news_Get request. Correlation: {CorrelationId}", correlationId);

        int limit = 20;
        int offset = 0;
        string? isin = null;
        DateTime? date = null;
        string? status = null;
        string? searchQuery = null;

        if (!string.IsNullOrWhiteSpace(payload))
        {
            try
            {
                using var doc = JsonDocument.Parse(payload);
                var root = doc.RootElement;
                
                if (root.TryGetProperty("limit", out var limitProp) && limitProp.TryGetInt32(out var parsedLimit)) limit = parsedLimit;
                if (root.TryGetProperty("offset", out var offsetProp) && offsetProp.TryGetInt32(out var parsedOffset)) offset = parsedOffset;
                
                if (root.TryGetProperty("isin", out var isinProp) && isinProp.ValueKind == JsonValueKind.String) isin = isinProp.GetString();
                if (root.TryGetProperty("symbol", out var symProp) && symProp.ValueKind == JsonValueKind.String && string.IsNullOrEmpty(isin)) isin = symProp.GetString();
                
                if (root.TryGetProperty("status", out var stProp) && stProp.ValueKind == JsonValueKind.String) status = stProp.GetString();
                if (root.TryGetProperty("query", out var qProp) && qProp.ValueKind == JsonValueKind.String) searchQuery = qProp.GetString();
                
                if (root.TryGetProperty("date", out var dProp) && dProp.ValueKind == JsonValueKind.String)
                {
                    var dStr = dProp.GetString();
                    if (!string.IsNullOrWhiteSpace(dStr))
                    {
                        if (string.Equals(dStr, "today", StringComparison.OrdinalIgnoreCase))
                            date = DateTime.UtcNow.Date;
                        else if (DateTime.TryParse(dStr, out var parsedDate))
                            date = parsedDate.Date;
                    }
                }

                if (root.TryGetProperty("hasSentiment", out var hsProp))
                {
                    bool isTrue = hsProp.ValueKind == JsonValueKind.True ||
                        (hsProp.ValueKind == JsonValueKind.String && bool.TryParse(hsProp.GetString(), out var b) && b);
                    if (isTrue && string.IsNullOrEmpty(status)) status = "Analyzed";
                }
            }
            catch (Exception ex)
            {
                _logger.LogWarning(ex, "Failed to parse RPC payload on news_Get");
            }
        }

        try
        {
            using var scope = _scopeFactory.CreateScope();
            var dbService = scope.ServiceProvider.GetRequiredService<INewsDbService>();

            var articles = await dbService.GetFilteredNewsAsync(limit, offset, isin, date, status, searchQuery);
            var dtos = (await Task.WhenAll(articles.Select(a => MapToDtoAsync(a)))).ToList();

            string responseTopic = $"services/response/news_Get/{correlationId}";
            _logger.LogInformation("Publishing RPC response to {ResponseTopic} with {Count} articles.", responseTopic, dtos.Count);
            await PublishAsync(responseTopic, dtos);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Failed to compile RPC response for news_Get");
        }
    }

    private async Task OnGetNewsByIdAsync(string payload, string correlationId)
    {
        _logger.LogInformation("Received RPC news_GetById request. Correlation: {CorrelationId}", correlationId);
        string responseTopic = $"services/response/news_GetById/{correlationId}";

        if (string.IsNullOrWhiteSpace(payload))
        {
            await PublishAsync(responseTopic, (object?)null);
            return;
        }

        try
        {
            var request = JsonSerializer.Deserialize<ArticleRequest>(payload, FinlyticJsonSerializerContext.Default.ArticleRequest);
            var targetIdStr = request?.ArticleId ?? request?.Id;

            if (Guid.TryParse(targetIdStr, out var articleId))
            {
                using var scope = _scopeFactory.CreateScope();
                var dbService = scope.ServiceProvider.GetRequiredService<INewsDbService>();
                var article = await dbService.GetArticleByIdAsync(articleId);

                if (article != null)
                {
                    var dto = await MapToDtoAsync(article);
                    await PublishAsync(responseTopic, dto);
                    return;
                }
            }
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Failed to execute RPC news_GetById");
        }

        await PublishAsync(responseTopic, (object?)null);
    }

    private async Task OnGetPendingNewsAsync(string payload, string correlationId)
    {
        _logger.LogInformation("Received RPC news_GetPending request. Correlation: {CorrelationId}", correlationId);
        int limit = 10;

        if (!string.IsNullOrWhiteSpace(payload))
        {
            try
            {
                using var doc = JsonDocument.Parse(payload);
                if (doc.RootElement.TryGetProperty("limit", out var limitProp) && limitProp.TryGetInt32(out var parsedLimit))
                {
                    limit = Math.Min(parsedLimit, 10);
                }
            }
            catch { }
        }

        try
        {
            using var scope = _scopeFactory.CreateScope();
            var dbService = scope.ServiceProvider.GetRequiredService<INewsDbService>();

            var pendingArticles = await dbService.GetArticlesByStatusAsync("Pending");
            var dtos = (await Task.WhenAll(pendingArticles.Take(limit).Select(a => MapToDtoAsync(a)))).ToList();

            string responseTopic = $"services/response/news_GetPending/{correlationId}";
            _logger.LogInformation("Publishing RPC news_GetPending response to {ResponseTopic} with {Count} articles.", responseTopic, dtos.Count);
            await PublishAsync(responseTopic, dtos);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Failed to publish RPC pending news response");
        }
    }

    private async Task OnUpdateNewsStatusAsync(string payload, string correlationId)
    {
        _logger.LogInformation("Received RPC news_UpdateStatus request. Correlation: {CorrelationId}", correlationId);
        UpdateNewsStatusResponse response;

        try
        {
            var request = JsonSerializer.Deserialize<UpdateNewsStatusRequest>(payload, FinlyticJsonSerializerContext.Default.UpdateNewsStatusRequest);
            if (request != null && request.Id != Guid.Empty)
            {
                using var scope = _scopeFactory.CreateScope();
                var dbService = scope.ServiceProvider.GetRequiredService<INewsDbService>();

                await dbService.UpdateArticleStatusAsync(request.Id, request.Status);
                response = new UpdateNewsStatusResponse(true, "Status updated successfully.");
            }
            else
            {
                response = new UpdateNewsStatusResponse(false, "Invalid payload.");
            }
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Failed to execute RPC news_UpdateStatus");
            response = new UpdateNewsStatusResponse(false, ex.Message);
        }

        string responseTopic = $"services/response/news_UpdateStatus/{correlationId}";
        await PublishAsync(responseTopic, response);
    }

    private async Task OnConfigUpdatedAsync(string payload)
    {
        _logger.LogInformation("Received config update event for FinlyticNews.");
        try
        {
            using var doc = JsonDocument.Parse(payload);
            if (doc.RootElement.TryGetProperty("settings", out var settingsProp))
            {
                var dict = JsonSerializer.Deserialize<Dictionary<string, string>>(settingsProp.GetRawText());
                if (dict != null && dict.Count > 0)
                {
                    using var scope = _scopeFactory.CreateScope();
                    var settingsDb = scope.ServiceProvider.GetRequiredService<ISettingsDbService>();
                    await settingsDb.UpdateSettingsFromDictionaryAsync(dict);
                    _logger.LogInformation("Successfully persisted {Count} updated settings.", dict.Count);
                }
            }
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error processing MQTT config update event");
        }
    }

    private async Task OnHealthPingAsync(string[] segments, string correlationId)
    {
        // Zerlegt den Topic-Pfad z. B. services/request/health_Ping/FinlyticNews/{correlationId}
        bool isForMe = segments.Length >= 5 && segments[3].Equals("FinlyticNews", StringComparison.OrdinalIgnoreCase);

        if (isForMe)
        {
            string respTopic = $"services/response/health_Ping/{correlationId}";
            await PublishAsync(respTopic, new ServiceHealthResponse("FinlyticNews", "Online", DateTime.UtcNow, "Connected"));
            _logger.LogInformation("Responded to live health_Ping RPC request [CorrelationId: {CorrelationId}].", correlationId);
        }
    }

    /// <summary>
    /// Maps a NewsArticleEntity to a NewsArticleDto while performing zero-latency disk lookups for sentiment summaries.
    /// </summary>
    private async Task<NewsArticleDto> MapToDtoAsync(NewsArticleEntity a)
    {
        string? sentimentLabel = null;
        double? sentimentScore = null;
        double? confidence = null;
        FinBertResultDto? finbertResult = null;

        try
        {
            var targetId = a.Id.ToString();
            IsinAnalysisEntry? sentimentEntry = null;

            // 1. Snappy Local Disk Check for Article File
            var articlePath = Path.Combine(Directory.GetCurrentDirectory(), "data", "summaries", "articles", $"{targetId}.json");
            if (File.Exists(articlePath))
            {
                try
                {
                    var json = await File.ReadAllTextAsync(articlePath);
                    sentimentEntry = JsonSerializer.Deserialize<IsinAnalysisEntry>(json, FinlyticJsonSerializerContext.Default.IsinAnalysisEntry);
                }
                catch { }
            }

            // 2. ISIN Summary File Fallback
            if (sentimentEntry == null && a.MatchedAssets != null && a.MatchedAssets.Count > 0)
            {
                foreach (var asset in a.MatchedAssets)
                {
                    if (string.IsNullOrWhiteSpace(asset.Isin)) continue;
                    var isinPath = Path.Combine(Directory.GetCurrentDirectory(), "data", "summaries", "isin", $"{asset.Isin.Trim()}.json");

                    if (File.Exists(isinPath))
                    {
                        try
                        {
                            var json = await File.ReadAllTextAsync(isinPath);
                            var isinDoc = JsonSerializer.Deserialize<IsinSentimentSummaryDto>(json, FinlyticJsonSerializerContext.Default.IsinSentimentSummaryDto);
                            var match = isinDoc?.Analyses?.FirstOrDefault(entry => 
                                string.Equals(entry.Article?.ArticleId?.Trim(), targetId, StringComparison.OrdinalIgnoreCase));

                            if (match != null)
                            {
                                sentimentEntry = match;
                                break;
                            }
                        }
                        catch { }
                    }
                }
            }

            if (sentimentEntry?.FinbertResult != null)
            {
                finbertResult = sentimentEntry.FinbertResult;
                sentimentLabel = finbertResult.Label;
                sentimentScore = finbertResult.CompoundScore;
                confidence = finbertResult.Confidence;
            }
        }
        catch (Exception ex)
        {
            _logger.LogTrace(ex, "[MapToDtoAsync] Sentiment fetch skipped for article {Id}", a.Id);
        }

        return new NewsArticleDto
        {
            Id = a.Id,
            Title = a.Title,
            Author = a.Author,
            Summary = a.Summary,
            ContentRaw = a.ContentRaw,
            Language = a.Language,
            SourceUrl = a.SourceUrl,
            ScrapedAt = a.ScrapedAt,
            PublishedAt = a.PublishedAt,
            Status = a.Status,
            Sentiment = sentimentLabel,
            SentimentScore = sentimentScore,
            Confidence = confidence,
            FinbertResult = finbertResult,
            MatchedAssets = (a.MatchedAssets ?? []).Select(m => new MatchedAssetDto
            {
                Name = m.Name,
                Isin = m.Isin
            }).ToList()
        };
    }
}