using Knot.Shared.Kernel;
using Knot.Shared.Kernel.Configuration;
using Microsoft.Extensions.Configuration;
using MediatR;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks;

namespace Host.Application.WebRtc.Queries;

public record IceServerDto(string[] Urls, string? Username = null, string? Credential = null);
public record IceServersResultDto(List<IceServerDto> IceServers);

public record GetIceServersQuery : IQuery<IceServersResultDto>;

internal sealed class GetIceServersQueryHandler : IQueryHandler<GetIceServersQuery, IceServersResultDto>
{
    private readonly IConfiguration _configuration;
    private readonly ISettingsService _settingsService;

    public GetIceServersQueryHandler(IConfiguration configuration, ISettingsService settingsService)
    {
        _configuration = configuration;
        _settingsService = settingsService;
    }

    public Task<Result<IceServersResultDto>> Handle(GetIceServersQuery request, CancellationToken cancellationToken)
    {
        var settings = _settingsService.Current;
        if (!settings.EnableCalls)
        {
            return Task.FromResult(Result.Failure<IceServersResultDto>(new Error(
                Knot.Shared.Kernel.Constants.Errors.DisabledByAdmin, 
                "Сервис отключен администратором."
            )));
        }

        var turnUrl = !string.IsNullOrEmpty(settings.TurnHost)
            ? $"turn:{settings.TurnHost}:{settings.TurnPort}"
            : _configuration["WebRtc:TurnUrl"];

        var turnUsername = !string.IsNullOrEmpty(settings.TurnUser)
            ? settings.TurnUser
            : _configuration["WebRtc:TurnUsername"];

        var turnSecret = !string.IsNullOrEmpty(settings.TurnSecret)
            ? settings.TurnSecret
            : _configuration["WebRtc:TurnPassword"];

        var iceServers = new List<IceServerDto>();

        if (!string.IsNullOrEmpty(turnUrl))
        {
            var stunUrl = turnUrl.Replace("turn:", "stun:");
            iceServers.Add(new IceServerDto(new[] { stunUrl }));

            if (!string.IsNullOrEmpty(turnUsername))
            {
                iceServers.Add(new IceServerDto(
                    new[] { turnUrl, turnUrl + "?transport=tcp" },
                    turnUsername,
                    !string.IsNullOrEmpty(turnSecret) ? turnSecret : turnUsername
                ));
            }
            else
            {
                iceServers.Add(new IceServerDto(new[] { turnUrl, turnUrl + "?transport=tcp" }));
            }
        }

        return Task.FromResult(Result.Success(new IceServersResultDto(iceServers)));
    }
}