using FinlyticNews.Database;
using FinlyticNews.Entities;
using Microsoft.EntityFrameworkCore;

namespace FinlyticNews.Services;

/// <summary>
/// Service interface for retrieving and persisting runtime settings in PostgreSQL for FinlyticNews.
/// </summary>
public interface ISettingsDbService
{
    /// <summary>
    /// Retrieves current news settings from database, initializing default values if empty.
    /// </summary>
    Task<NewsSettingsEntity> GetSettingsAsync();

    /// <summary>
    /// Persists updated settings to PostgreSQL.
    /// </summary>
    Task<NewsSettingsEntity> SaveSettingsAsync(NewsSettingsEntity settings);

    /// <summary>
    /// Updates settings from a key-value dictionary received via Admin Panel MQTT events.
    /// </summary>
    Task UpdateSettingsFromDictionaryAsync(Dictionary<string, string> dictionary);
}

/// <summary>
/// EF Core implementation of <see cref="ISettingsDbService"/>.
/// </summary>
public class SettingsDbService : ISettingsDbService
{
    private readonly NewsDbContext _context;

    /// <summary>
    /// Initializes a new instance of the <see cref="SettingsDbService"/> class.
    /// </summary>
    /// <param name="context">The database context mapping database tables.</param>
    public SettingsDbService(NewsDbContext context)
    {
        _context = context;
    }

    /// <inheritdoc />
    public async Task<NewsSettingsEntity> GetSettingsAsync()
    {
        var settings = await _context.Settings.AsNoTracking().FirstOrDefaultAsync();
        if (settings == null)
        {
            settings = new NewsSettingsEntity { Id = Guid.NewGuid() };
            _context.Settings.Add(settings);
            await _context.SaveChangesAsync();
            _context.ChangeTracker.Clear();
        }
        return settings;
    }

    /// <inheritdoc />
    public async Task<NewsSettingsEntity> SaveSettingsAsync(NewsSettingsEntity settings)
    {
        var existing = await _context.Settings.FirstOrDefaultAsync();
        if (existing == null)
        {
            if (settings.Id == Guid.Empty) settings.Id = Guid.NewGuid();
            _context.Settings.Add(settings);
        }
        else
        {
            existing.PollingFrequencyMinutes = settings.PollingFrequencyMinutes;
            existing.ArticleRetentionDays = settings.ArticleRetentionDays;
            existing.DefaultPageSize = settings.DefaultPageSize;
            existing.ScrapingIntervalMinutes = settings.ScrapingIntervalMinutes;
            existing.N8nWebhookUrl = settings.N8nWebhookUrl;
            existing.UpdatedAt = settings.UpdatedAt;
            _context.Settings.Update(existing);
        }
        await _context.SaveChangesAsync();
        return settings;
    }

    /// <inheritdoc />
    public async Task UpdateSettingsFromDictionaryAsync(Dictionary<string, string> dictionary)
    {
        var settings = await GetSettingsAsync();

        foreach (var (key, value) in dictionary)
        {
            if (string.Equals(key, "PollingFrequencyMinutes", StringComparison.OrdinalIgnoreCase) && int.TryParse(value, out var pfm))
                settings.PollingFrequencyMinutes = pfm;
            else if (string.Equals(key, "ArticleRetentionDays", StringComparison.OrdinalIgnoreCase) && int.TryParse(value, out var ard))
                settings.ArticleRetentionDays = ard;
            else if (string.Equals(key, "DefaultPageSize", StringComparison.OrdinalIgnoreCase) && int.TryParse(value, out var dps))
                settings.DefaultPageSize = dps;
            else if (string.Equals(key, "ScrapingIntervalMinutes", StringComparison.OrdinalIgnoreCase) && int.TryParse(value, out var sim))
                settings.ScrapingIntervalMinutes = sim;
            else if (string.Equals(key, "N8nWebhookUrl", StringComparison.OrdinalIgnoreCase) && !string.IsNullOrWhiteSpace(value))
                settings.N8nWebhookUrl = value.Trim();
        }

        settings.UpdatedAt = DateTime.UtcNow;
        await SaveSettingsAsync(settings);
    }
}