using System.Diagnostics;

namespace ONDServer.Enemies;

public class OpportunityTimer {
    public int Interval{ get; set; }
    public double MovementChance{
        get;
        set{
            field = value;
            GuaranteeSuccess(value >= 1);
        }
    }

    public bool Running => stopwatch.IsRunning;
    
    private Stopwatch stopwatch = new();
    private long stopwatchOffset = 0;
    
    private Random random = new();

    public OpportunityTimer(int intervalMs, double movementChance) {
        Interval = intervalMs;
        MovementChance = movementChance;
    }

    public OpportunityTimer(int intervalMs) {
        Interval = intervalMs;
        MovementChance = 1;
    }

    public void Start() {
        stopwatch.Start();
    }
    public void Stop() {
        stopwatch.Stop();
    }

    public bool Check() {
        if (stopwatch.ElapsedMilliseconds - stopwatchOffset >= Interval){
            int overshoot = (int)(stopwatch.ElapsedMilliseconds - stopwatchOffset - Interval);
            stopwatchOffset = stopwatch.ElapsedMilliseconds - overshoot;
            return true;
        }
        return false;
    }

    public bool Roll() => roll();
    private Func<bool> roll = () => true;
    
    public bool CheckAndRoll() {
        if (Check()) return Roll();
        return false;
    }

    public void GuaranteeSuccess(bool value) {
        roll = value ? () => true : () => random.NextDouble() <= MovementChance;
    }

}