using System.Diagnostics;
using BSO.Net;

namespace BSO.Server;

/// <summary>
/// Fake-Mitspieler zum Alleine-Testen: faehrt als "Bus" Kreise (20 m Radius, ~30 km/h) um die Stelle, an der der erste
/// Spieler im Spiel ist. Entfernt sich der Spieler mehr als 300 m, zieht der Kreis zu ihm um.
/// </summary>
public class TestBot
{
    const float Radius = 2000;          // cm
    const float SpeedCm = 30 / 0.036f;  // 30 km/h in cm/s
    const float Follow = 30000;         // cm
    static readonly TimeSpan SendInterval = TimeSpan.FromMilliseconds(100);

    public int Id { get; }
    public string Name => "Testbot";
    public PlayerState State { get; private set; }
    public bool HasState { get; private set; }

    readonly Stopwatch clock = Stopwatch.StartNew();
    TimeSpan lastSend;
    float centerX, centerY, angle;
    bool hasCenter;

    public TestBot(int id) => Id = id;

    /// <summary>Bewegt den Bot weiter; true = neuer Zustand ist faellig (10x pro Sekunde).</summary>
    public bool Tick(IEnumerable<PlayerState> players)
    {
        TimeSpan now = clock.Elapsed;
        if (now - lastSend < SendInterval) return false;
        float dt = (float)(now - lastSend).TotalSeconds;
        lastSend = now;

        PlayerState? target = players.Where(p => p.Mode != PlayerMode.Menu).Cast<PlayerState?>().FirstOrDefault();
        if (target == null) return false;
        PlayerState t = target.Value;
        float dx = t.X - centerX, dy = t.Y - centerY;
        if (!hasCenter || dx * dx + dy * dy > Follow * Follow)
        {
            centerX = t.X;
            centerY = t.Y;
            hasCenter = true;
            GameServer.Log($"Testbot faehrt jetzt Kreise um {centerX / 100:0} / {centerY / 100:0} m");
        }

        angle += SpeedCm / Radius * Math.Min(dt, 1);
        State = new PlayerState
        {
            Mode = PlayerMode.InBus,
            X = centerX + Radius * MathF.Cos(angle),
            Y = centerY + Radius * MathF.Sin(angle),
            Z = t.Z,
            Yaw = (angle * 180 / MathF.PI + 90) % 360, // Fahrtrichtung = Tangente
            Speed = SpeedCm
        };
        HasState = true;
        return true;
    }
}