using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.Logging;

namespace StellaOps.Provcache.Api;

public static partial class ProvcacheEndpointExtensions
{
    /// <summary>
    /// GET /v1/provcache/metrics
    /// </summary>
    private static async Task<IResult> GetMetricsAsync(
        IProvcacheService provcacheService,
        ILogger<ProvcacheApiEndpoints> logger,
        CancellationToken cancellationToken)
    {
        logger.LogDebug("GET /v1/provcache/metrics");

        try
        {
            var metrics = await provcacheService.GetMetricsAsync(cancellationToken);

            var hitRate = metrics.TotalRequests > 0
                ? (double)metrics.TotalHits / metrics.TotalRequests
                : 0;

            return Results.Ok(new ProvcacheMetricsResponse
            {
                TotalRequests = metrics.TotalRequests,
                TotalHits = metrics.TotalHits,
                TotalMisses = metrics.TotalMisses,
                TotalInvalidations = metrics.TotalInvalidations,
                HitRate = hitRate,
                CurrentEntryCount = metrics.CurrentEntryCount,
                AvgLatencyMs = metrics.AvgLatencyMs,
                P99LatencyMs = metrics.P99LatencyMs,
                ValkeyCacheHealthy = metrics.ValkeyCacheHealthy,
                PostgresRepositoryHealthy = metrics.PostgresRepositoryHealthy,
                CollectedAt = metrics.CollectedAt
            });
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "Error getting cache metrics");
            return InternalError("Metrics retrieval failed");
        }
    }
}