using Microsoft.EntityFrameworkCore;
using PnvPanel.Application.Common.Interfaces;
using PnvPanel.Application.Common.Messaging;
using PnvPanel.Application.Common.Models;
using PnvPanel.Domain.Activation;
using PnvPanel.Domain.Configs;
using PnvPanel.Domain.Nodes;

namespace PnvPanel.Application.Admin.Stats;

public sealed class GetStatsQueryHandler(IAppDbContext dbContext, IIdentityService identityService)
    : IQueryHandler<GetStatsQuery, Result<StatsDto>>
{
    public async Task<Result<StatsDto>> Handle(
        GetStatsQuery query,
        CancellationToken cancellationToken
    )
    {
        var userStats = await identityService.GetUserStatsAsync(cancellationToken);

        var pendingActivations = await dbContext.ActivationRequests.CountAsync(
            r => r.Status == ActivationStatus.Pending,
            cancellationToken
        );

        var totalNodes = await dbContext.Nodes.CountAsync(cancellationToken);
        var onlineNodes = await dbContext.Nodes.CountAsync(
            n => n.Status == NodeStatus.Online,
            cancellationToken
        );

        var totalConfigs = await dbContext.VpnConfigs.CountAsync(cancellationToken);
        var activeConfigs = await dbContext.VpnConfigs.CountAsync(
            c => c.Status == ConfigStatus.Active,
            cancellationToken
        );

        var trafficTotals = await dbContext
            .VpnConfigs.GroupBy(_ => 1)
            .Select(g => new { Up = g.Sum(c => c.UsedUpBytes), Down = g.Sum(c => c.UsedDownBytes) })
            .FirstOrDefaultAsync(cancellationToken);

        return Result.Success(
            new StatsDto(
                userStats.Total,
                userStats.Activated,
                pendingActivations,
                totalNodes,
                onlineNodes,
                totalConfigs,
                activeConfigs,
                trafficTotals?.Up ?? 0,
                trafficTotals?.Down ?? 0
            )
        );
    }
}