using System;

namespace Unity.Services.Core.Telemetry.Internal
{
    static class CacheExtensions
    {
        public static bool IsEmpty<TPayload>(this CachedPayload<TPayload> self)
            where TPayload : ITelemetryPayload
        {
            return (self.Payload?.Count ?? 0) <= 0;
        }

        public static void AddRangeFrom(
            this CachedPayload<DiagnosticsPayload> self, CachedPayload<DiagnosticsPayload> payload)
        {
            var hasDiagnosticsToAdd = payload.Payload.Diagnostics.Count > 0;
            if (hasDiagnosticsToAdd)
            {
                self.Payload.Diagnostics.AddRange(payload.Payload.Diagnostics);
            }

            if (hasDiagnosticsToAdd
                && self.TimeOfOccurenceTicks <= 0)
            {
                self.TimeOfOccurenceTicks = payload.TimeOfOccurenceTicks;
            }
        }

        public static void Add<TPayload>(this CachedPayload<TPayload> self, ITelemetryEvent telemetryEvent)
            where TPayload : ITelemetryPayload
        {
            if (self.TimeOfOccurenceTicks == 0)
            {
                self.TimeOfOccurenceTicks = DateTime.UtcNow.Ticks;
            }

            self.Payload.Add(telemetryEvent);
        }
    }
}