using UnityEngine;
using UnityEngine.UI;
using sam;

public class WorldMapDataVisualizer : MonoBehaviour
{
    public float tileWidth = 0.5f;
    float htw; //half tile width
    AreaVariableSubsession avs;

    Image mapImage;
    Texture2D texture;

    int texW;
    int texH;
    int scaleFactor;

    Color[] origImage;

    ProductData data;
    ProductVariable prodvar;

    void Start()
    {
        avs = GetComponentInParent<AreaVariableSubsession>();
        htw = 0.5f * tileWidth;

        mapImage = GetComponent<Image>();
        texture = mapImage.mainTexture as Texture2D;
        texW = texture.width;
        texH = texture.height;
        scaleFactor = texW / 720;

        if ((texH != (scaleFactor*360)) || (texW != (2*texH)))
        {
            Debug.LogError($"WorldMapDataVisualizer: invalid texture size {texW} x {texH}");
        }

        if (origImage == null)
        {
            origImage = texture.GetPixels().Clone() as Color[];
        }
    }

    public void OnProductSelected(ProductData pd)
    {
        data = pd;
    }

    public void OnVariableSelected(int vi)
    {
        prodvar = data.profile.variables[vi];
        Color[] img = origImage.Clone() as Color[];

        foreach (ProductDataPoint dp in avs.latLonDictionaries[0].Values)
        {
            RasterizeDataPoint(dp, img);
        }

        texture.SetPixels(img);
        texture.Apply();
    }

    void RasterizeDataPoint(ProductDataPoint dp, Color[] img)
    {
        Color c = avs.GetDataPointColor(dp);

        float lat = dp.latitude + 90.0f - htw; // y axis
        float lon = dp.longitude + 180f - htw; // x axis

        int ilat = Mathf.RoundToInt(lat * 2 * scaleFactor);
        int ilon = Mathf.RoundToInt(lon * 2 * scaleFactor);

        int p = (ilat * texW) + ilon;
        for (int j=0; j < scaleFactor; j++, p += texW)
        {
            for (int i=0; i < scaleFactor; i++)
            {
                img[p + i] = Color.Lerp(img[p + i], c, c.a);
            }
        }
    }

    private void OnDestroy()
    {
        texture.SetPixels(origImage);
        texture.Apply();
    }
}