using System;
using System.Threading.Tasks;
using FinlyticCore.Models.Settings;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Logging;

namespace FinlyticCore.Services;

/// <summary>
/// Bietet kanalbasierte, dynamisch steuerbare Logging-Funktionalitäten über den <see cref="ISettingsService{TContext}"/>.
/// </summary>
/// <typeparam name="TContextClass">Die aufrufende Klasse (für Log-Kategorien).</typeparam>
/// <typeparam name="TDbContext">Der DbContext des Services für den Zugriff auf die Settings.</typeparam>
public interface IFinlyticLogger<TContextClass, TDbContext> where TDbContext : DbContext
{
    // --- Debug ---
    Task LogDebugAsync(SettingKey<bool> channelKey, string message, params object[] args);
    Task LogDebugAsync(SettingKey<bool> channelKey, Exception? exception, string message, params object[] args);

    // --- Info ---
    Task LogInfoAsync(SettingKey<bool> channelKey, string message, params object[] args);
    Task LogInfoAsync(SettingKey<bool> channelKey, Exception? exception, string message, params object[] args);

    // --- Warning ---
    Task LogWarningAsync(SettingKey<bool> channelKey, string message, params object[] args);
    Task LogWarningAsync(SettingKey<bool> channelKey, Exception? exception, string message, params object[] args);

    // --- Error ---
    Task LogErrorAsync(SettingKey<bool> channelKey, string message, params object[] args);
    Task LogErrorAsync(SettingKey<bool> channelKey, Exception? exception, string message, params object[] args);

    // --- Trace & Critical ---
    Task LogTraceAsync(SettingKey<bool> channelKey, string message, params object[] args);
    Task LogCriticalAsync(SettingKey<bool> channelKey, Exception? exception, string message, params object[] args);
}

/// <summary>
/// Kanalbasierte Logger-Implementierung, die Einstellungen und Stummschaltungen 
/// in Echtzeit aus dem <see cref="ISettingsService{TContext}"/> bezieht.
/// </summary>
public class FinlyticLogger<TContextClass, TDbContext> : IFinlyticLogger<TContextClass, TDbContext>
    where TDbContext : DbContext
{
    private readonly ILogger<TContextClass> _logger;
    private readonly ISettingsService<TDbContext> _settingsService;

    public FinlyticLogger(
        ILogger<TContextClass> logger,
        ISettingsService<TDbContext> settingsService)
    {
        _logger = logger ?? throw new ArgumentNullException(nameof(logger));
        _settingsService = settingsService ?? throw new ArgumentNullException(nameof(settingsService));
    }

    #region Debug

    public async Task LogDebugAsync(SettingKey<bool> channelKey, string message, params object[] args)
    {
        if (await ShouldLogAsync(channelKey, LogLevel.Debug))
        {
            _logger.LogDebug(message, args);
        }
    }

    public async Task LogDebugAsync(SettingKey<bool> channelKey, Exception? exception, string message, params object[] args)
    {
        if (await ShouldLogAsync(channelKey, LogLevel.Debug))
        {
            if (exception != null)
                _logger.LogDebug(exception, message, args);
            else
                _logger.LogDebug(message, args);
        }
    }

    #endregion

    #region Info

    public async Task LogInfoAsync(SettingKey<bool> channelKey, string message, params object[] args)
    {
        if (await ShouldLogAsync(channelKey, LogLevel.Information))
        {
            _logger.LogInformation(message, args);
        }
    }

    public async Task LogInfoAsync(SettingKey<bool> channelKey, Exception? exception, string message, params object[] args)
    {
        if (await ShouldLogAsync(channelKey, LogLevel.Information))
        {
            if (exception != null)
                _logger.LogInformation(exception, message, args);
            else
                _logger.LogInformation(message, args);
        }
    }

    #endregion

    #region Warning

    public async Task LogWarningAsync(SettingKey<bool> channelKey, string message, params object[] args)
    {
        if (await ShouldLogAsync(channelKey, LogLevel.Warning))
        {
            _logger.LogWarning(message, args);
        }
    }

    public async Task LogWarningAsync(SettingKey<bool> channelKey, Exception? exception, string message, params object[] args)
    {
        if (await ShouldLogAsync(channelKey, LogLevel.Warning))
        {
            if (exception != null)
                _logger.LogWarning(exception, message, args);
            else
                _logger.LogWarning(message, args);
        }
    }

    #endregion

    #region Error

    public async Task LogErrorAsync(SettingKey<bool> channelKey, string message, params object[] args)
    {
        if (await ShouldLogAsync(channelKey, LogLevel.Error))
        {
            _logger.LogError(message, args);
        }
    }

    public async Task LogErrorAsync(SettingKey<bool> channelKey, Exception? exception, string message, params object[] args)
    {
        if (await ShouldLogAsync(channelKey, LogLevel.Error))
        {
            if (exception != null)
                _logger.LogError(exception, message, args);
            else
                _logger.LogError(message, args);
        }
    }

    #endregion

    #region Trace & Critical

    public async Task LogTraceAsync(SettingKey<bool> channelKey, string message, params object[] args)
    {
        if (await ShouldLogAsync(channelKey, LogLevel.Trace))
        {
            _logger.LogTrace(message, args);
        }
    }

    public async Task LogCriticalAsync(SettingKey<bool> channelKey, Exception? exception, string message, params object[] args)
    {
        if (await ShouldLogAsync(channelKey, LogLevel.Critical))
        {
            if (exception != null)
                _logger.LogCritical(exception, message, args);
            else
                _logger.LogCritical(message, args);
        }
    }

    #endregion

    /// <summary>
    /// Prüft, ob ein spezifischer Kanal und die aufrufende Klasse aktives Logging erlauben.
    /// </summary>
    private async Task<bool> ShouldLogAsync(SettingKey<bool> channelKey, LogLevel level)
    {
        ArgumentNullException.ThrowIfNull(channelKey);

        try
        {
            return await _settingsService.GetSettingAsync(channelKey);
        }
        catch
        {
            return channelKey.DefaultValue;
        }
    }
}