package io.github.moulberry.notenoughupdates.util;

public class LerpingInteger {

    private int timeSpent;
    private long lastMillis;
    private int timeToReachTarget;

    private int targetValue;
    private int lerpValue;

    public LerpingInteger(int initialValue, int timeToReachTarget) {
        this.targetValue = this.lerpValue = initialValue;
        this.timeToReachTarget = timeToReachTarget;
    }

    public LerpingInteger(int initialValue) {
        this(initialValue, 200);
    }

    public void tick() {
        int lastTimeSpent = timeSpent;
        this.timeSpent += System.currentTimeMillis() - lastMillis;

        float lastDistPercentToTarget = lastTimeSpent/(float)timeToReachTarget;
        float distPercentToTarget = timeSpent/(float)timeToReachTarget;
        float fac = (1-lastDistPercentToTarget)/lastDistPercentToTarget;

        int startValue = lerpValue - (int)((targetValue - lerpValue)/fac);

        int dist = targetValue - startValue;
        if(dist == 0) return;

        int oldLerpValue = lerpValue;
        if(distPercentToTarget >= 1) {
            lerpValue = targetValue;
        } else {
            lerpValue = startValue + (int)(dist*distPercentToTarget);
        }

        if(lerpValue == oldLerpValue) {
            timeSpent = lastTimeSpent;
        } else {
            this.lastMillis = System.currentTimeMillis();
        }
    }

    public void resetTimer() {
        this.timeSpent = 0;
        this.lastMillis = System.currentTimeMillis();
    }

    public void setTarget(int targetValue) {
        this.targetValue = targetValue;
    }

    public void setValue(int value) {
        this.targetValue = this.lerpValue = value;
    }

    public int getValue() {
        return lerpValue;
    }

    public int getTarget() {
        return targetValue;
    }
}