using System;
using UnityEngine;

public class JumpToLocation : MonoBehaviour
{
    public double destinationLng;
    public double destinationLat;
    public float destinationZoom;

    public float duration;

    public AnimationCurve zoomCurve;
    public AnimationCurve locationCurve;

    private bool started;
    private float progress;
    private float originZoom;
    private double originMercatX;
    private double originMercatY;
    private double destinationMercatX;
    private double destinationMercatY;
    private float farZoom;

    private void OnGUI()
    {
        if (started)
        {
            if (GUILayout.Button("Stop")) started = false;
        }
        else if (GUILayout.Button("Start")) StartAnimation();
    }

    private void StartAnimation()
    {
        started = true;
        progress = 0;

        originZoom = OnlineMaps.instance.floatZoom;
        
        if (Math.Abs(destinationZoom) < float.Epsilon) destinationZoom = originZoom;

        OnlineMaps.instance.GetPosition(out originMercatX, out originMercatY);

        Vector2 center;
        int z;

        OnlineMapsUtils.GetCenterPointAndZoom(new[]
        {
            new Vector2((float)originMercatX, (float)originMercatY),
            new Vector2((float)destinationLng, (float)destinationLat)
        }, out center, out z);
        farZoom = z;

        destinationMercatX = destinationLng;
        destinationMercatY = destinationLat;

        OnlineMapsUtils.LatLongToMercat(ref originMercatX, ref originMercatY);
        OnlineMapsUtils.LatLongToMercat(ref destinationMercatX, ref destinationMercatY);

        double dx = originMercatX - destinationMercatX;
        if (dx < -0.5) destinationMercatX -= 1;
        else if (dx > 0.5) destinationMercatX += 1;
    }

    private void Update()
    {
        if (!started) return;

        progress += Time.deltaTime / duration;

        if (progress >= 1)
        {
            progress = 0;
            OnlineMaps.instance.SetPositionAndZoom(destinationLng, destinationLat, destinationZoom);
            started = false;
            return;
        }

        float lp = locationCurve.Evaluate(progress);
        float zp = zoomCurve.Evaluate(progress);
        double mx = (destinationMercatX - originMercatX) * lp + originMercatX;
        if (mx < 0) mx += 1;
        else if (mx > 1) mx -= 1;

        double my = (destinationMercatY - originMercatY) * lp + originMercatY;
        float z = progress < 0.5 ? originZoom : destinationZoom;
        z = (farZoom - z) * zp + z;
        int zs = 1 << (int) z;

        mx = mx * zs;
        my = my * zs;

        OnlineMaps.instance.projection.TileToCoordinates(mx, my, (int)z, out mx, out my);

        OnlineMaps.instance.SetPositionAndZoom(mx, my, z);

    }
}