using AutoMapper;
using DigitalData.Core.Application;
using DigitalData.Core.Abstraction.Application.DTO;
using EnvelopeGenerator.Application.Interfaces.Services;
using EnvelopeGenerator.Application.Dto;
using EnvelopeGenerator.Domain.Entities;
using EnvelopeGenerator.Application.Interfaces.Repositories;
using Microsoft.Extensions.Caching.Memory;
using Microsoft.Extensions.Logging;

namespace EnvelopeGenerator.Application.Services;

/// <summary>
/// 
/// </summary>
[Obsolete("Use MediatR")]
public class ConfigService : ReadService<IConfigRepository, ConfigDto, Config, int>, IConfigService
{
	private static readonly Guid DefaultConfigCacheId = Guid.NewGuid();

	private readonly IMemoryCache _cache;

    private readonly ILogger<ConfigService> _logger;

    /// <summary>
    /// 
    /// </summary>
    /// <param name="repository"></param>
    /// <param name="mapper"></param>
    /// <param name="memoryCache"></param>
    /// <param name="logger"></param>
	public ConfigService(IConfigRepository repository, IMapper mapper, IMemoryCache memoryCache, ILogger<ConfigService> logger) : base(repository, mapper)
    {
		_cache = memoryCache;
        _logger = logger;
    }

    /// <summary>
    /// 
    /// </summary>
    /// <returns></returns>
    public async Task<DataResult<ConfigDto>> ReadFirstAsync()
    {
        var config = await _repository.ReadFirstAsync();
        return config is null 
            ? Result.Fail<ConfigDto>().Notice(LogLevel.Error, Flag.DataIntegrityIssue, "There is no configuration in DB.")
            : Result.Success(_mapper.Map<ConfigDto>(config));
    }

	/// <summary>
	/// Reads the default configuration asynchronously.
	/// </summary>
	/// <remarks>
	/// The configuration is cached in memory upon the first retrieval. If the configuration is updated, 
	/// the application needs to be restarted for the changes to take effect as the memory cache will not be updated automatically.
	/// </remarks>
	/// <returns>
	/// A task that represents the asynchronous read operation. The task result contains the default configuration as a <see cref="ConfigDto"/>.
	/// </returns>
	/// <exception cref="InvalidOperationException">
	/// Thrown when the default configuration cannot be found.
	/// </exception>
	public async Task<ConfigDto> ReadDefaultAsync()
    {
        var config = await _cache.GetOrCreateAsync(DefaultConfigCacheId, _ => ReadFirstAsync().ThenAsync(
            Success: config => config,
            Fail: (mssg, ntc) =>
            {
                _logger.LogNotice(ntc);
                throw new InvalidOperationException("Default configuration cannot find.");
            })
        );

        return config!;
    }

    /// <summary>
    /// 
    /// </summary>
    /// <returns></returns>
    public async Task<string> ReadDefaultSignatureHost() => (await ReadDefaultAsync()).SignatureHost;
}