using System.Diagnostics;

namespace MyParking.Simulation.Core;

/// <summary>
/// 以固定周期推进离线仿真世界。
/// </summary>
public sealed class SimulationClock(
    SimulationWorld world,
    ILogger<SimulationClock> logger) : BackgroundService
{
    private static readonly TimeSpan TickInterval =
        TimeSpan.FromMilliseconds(20);

    protected override async Task ExecuteAsync(
        CancellationToken stoppingToken)
    {
        logger.LogInformation(
            "停车机器人离线仿真时钟已启动，周期{Period}ms。",
            TickInterval.TotalMilliseconds);

        using var timer = new PeriodicTimer(TickInterval);
        var stopwatch = Stopwatch.StartNew();
        var previousSeconds = stopwatch.Elapsed.TotalSeconds;

        while (await timer.WaitForNextTickAsync(stoppingToken))
        {
            var currentSeconds = stopwatch.Elapsed.TotalSeconds;
            var deltaTimeSeconds = Math.Clamp(
                currentSeconds - previousSeconds,
                0.001,
                0.1);

            previousSeconds = currentSeconds;
            world.Step(deltaTimeSeconds);
        }
    }
}