using Microsoft.EntityFrameworkCore;
using PnvPanel.Application.Auth;
using PnvPanel.Application.Common.Interfaces;
using PnvPanel.Application.Common.Messaging;
using PnvPanel.Application.Common.Models;

namespace PnvPanel.Application.Configs.GetConfigLink;

public sealed class GetConfigLinkQueryHandler(IAppDbContext dbContext, IXuiPanelGateway gateway, ICurrentUser currentUser)
    : IQueryHandler<GetConfigLinkQuery, Result<ConfigLinkDto>>
{
    public async Task<Result<ConfigLinkDto>> Handle(GetConfigLinkQuery query, CancellationToken cancellationToken)
    {
        if (currentUser.UserId is not { } userId)
            return Result.Failure<ConfigLinkDto>(AuthErrors.Unauthorized);

        var config = await dbContext.VpnConfigs.AsNoTracking()
            .FirstOrDefaultAsync(c => c.Id == query.ConfigId && c.UserId == userId, cancellationToken);
        if (config is null)
            return Result.Failure<ConfigLinkDto>(ConfigErrors.NotFound);

        var inbound = await dbContext.Inbounds.AsNoTracking().FirstOrDefaultAsync(i => i.Id == config.InboundId, cancellationToken);
        if (inbound is null)
            return Result.Failure<ConfigLinkDto>(ConfigErrors.InboundNotAvailable);

        var node = await dbContext.Nodes.AsNoTracking().FirstOrDefaultAsync(n => n.Id == inbound.NodeId, cancellationToken);
        if (node is null)
            return Result.Failure<ConfigLinkDto>(ConfigErrors.NodeDisabled);

        var linkResult = await gateway.BuildConnectionStringAsync(
            node, inbound, config.ClientExternalId, config.Label ?? config.ClientEmail, node.BaseAddress.Host, cancellationToken);

        if (!linkResult.IsSuccess)
            return Result.Failure<ConfigLinkDto>(linkResult.Error);

        return Result.Success(new ConfigLinkDto(linkResult.Value, config.SubscriptionToken));
    }
}