using System.Collections.Generic;
using UnityEngine;

public class FogOverlay2 : MonoBehaviour
{
    private const int fogTextureResolution = 256;
    private const int fogTextureSize = fogTextureResolution * fogTextureResolution;

    public Color fogColor = new Color(1, 1, 1, .3f);
    public Color noFogColor = new Color(1, 1, 1, 0);
    public int minFogZoom = 13;

    private Texture2D defaultFog;
    private List<OnlineMapsVector2i> visitedTiles;

    private void ApplyPointToTiles(OnlineMapsVector2i newTile)
    {
        lock (OnlineMapsTile.tiles)
        {
            foreach (OnlineMapsTile tile in OnlineMapsTile.tiles)
            {
                Texture2D texture = tile.overlayBackTexture;
                if (texture == null) continue;

                if (tile.zoom == 17)
                {
                    if (visitedTiles.Contains(new OnlineMapsVector2i(tile.x, tile.y)))
                    {
                        OnlineMapsUtils.DestroyImmediate(tile.overlayBackTexture);
                        tile.overlayBackTexture = null;
                    }
                }
                else if (tile.zoom > 17)
                {
                    int ptx = tile.x / (1 << tile.zoom - 17);
                    int pty = tile.y / (1 << tile.zoom - 17);
                    if (visitedTiles.Contains(new OnlineMapsVector2i(ptx, pty)))
                    {
                        OnlineMapsUtils.DestroyImmediate(tile.overlayBackTexture);
                        tile.overlayBackTexture = null;
                    }
                }
                else
                {
                    double lng, lat, tx, ty;
                    OnlineMaps.instance.projection.TileToCoordinates(newTile.x, newTile.y, 17, out lng, out lat);
                    OnlineMaps.instance.projection.CoordinatesToTile(lng, lat, tile.zoom, out tx, out ty);

                    if ((int) tx == tile.x && (int) ty == tile.y)
                    {
                        double s = 1 << (17 - tile.zoom);
                        tx -= tile.x;
                        ty -= tile.y;

                        if (tx < 0 || tx > 1 || ty < 0 || ty > 1) continue;

                        double stx = tx * fogTextureResolution;
                        double sty = ty * fogTextureResolution;
                        double etx = stx + fogTextureResolution / s;
                        double ety = sty + fogTextureResolution / s;

                        int sx = (int)stx;
                        if (sx < 0) sx = 0;
                        else if (sx >= fogTextureResolution) continue;

                        int sy = (int)sty;
                        if (sy < 0) sy = 0;
                        else if (sy >= fogTextureResolution) continue;

                        int ex = (int)etx;
                        if (ex >= fogTextureResolution) ex = fogTextureResolution - 1;
                        else if (ex < 0) continue;

                        int ey = (int)ety;
                        if (ey >= fogTextureResolution) ey = fogTextureResolution - 1;
                        else if (ey < 0) continue;

                        Color[] colors = texture.GetPixels();

                        for (int y = sy; y < ey + 1; y++)
                        {
                            int cy = (fogTextureResolution - y - 1) * fogTextureResolution;
                            for (int x = sx; x < ex + 1; x++) colors[cy + x] = noFogColor;
                        }

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

    private void ApplyPointsToTile(OnlineMapsTile tile)
    {
        Texture2D texture = tile.overlayBackTexture;
        if (texture == null) return;

        int fr2 = fogTextureResolution - 1;

        if (tile.zoom == 17)
        {
            if (visitedTiles.Contains(new OnlineMapsVector2i(tile.x, tile.y)))
            {
                OnlineMapsUtils.DestroyImmediate(tile.overlayBackTexture);
                tile.overlayBackTexture = null;
            }
        }
        else if (tile.zoom > 17)
        {
            int ptx = tile.x / (1 << tile.zoom - 17);
            int pty = tile.y / (1 << tile.zoom - 17);
            if (visitedTiles.Contains(new OnlineMapsVector2i(ptx, pty)))
            {
                OnlineMapsUtils.DestroyImmediate(tile.overlayBackTexture);
                tile.overlayBackTexture = null;
            }
        }
        else
        {
            Color[] colors = null;
            bool textureChanged = false;

            foreach (OnlineMapsVector2i t in visitedTiles)
            {
                double s = 1 << (17 - tile.zoom);
                double tx = t.x / s - tile.x;
                double ty = t.y / s - tile.y;

                if (tx < 0 || tx > 1 || ty < 0 || ty > 1) continue;

                double fs = fogTextureResolution / s;

                double stx = tx * fogTextureResolution;
                double sty = ty * fogTextureResolution;
                double etx = stx + fs;
                double ety = sty + fs;

                int sx = (int)stx;
                if (sx < 0) sx = 0;
                else if (sx >= fogTextureResolution) continue;

                int sy = (int)sty;
                if (sy < 0) sy = 0;
                else if (sy >= fogTextureResolution) continue;

                int ex = (int)etx;
                if (ex >= fogTextureResolution) ex = fr2;
                else if (ex < 0) continue;

                int ey = (int)ety;
                if (ey >= fogTextureResolution) ey = fr2;
                else if (ey < 0) continue;

                textureChanged = true;
                if (colors == null) colors = texture.GetPixels();

                for (int y = sy; y < ey + 1; y++)
                {
                    int cy = (fr2 - y) * fogTextureResolution;
                    for (int x = sx; x < ex + 1; x++) colors[cy + x] = noFogColor;
                }
            }

            if (textureChanged)
            {
                texture.SetPixels(colors);
                texture.Apply();
            }
        }
    }

    private void OnLocationChanged(Vector2 newLocation)
    {
        double tx, ty;
        OnlineMaps.instance.projection.CoordinatesToTile(newLocation.x, newLocation.y, 17, out tx, out ty);
        OnlineMapsVector2i v = new OnlineMapsVector2i((int)tx, (int)ty);
        if (!visitedTiles.Contains(v))
        {
            visitedTiles.Add(v);
            ApplyPointToTiles(v);
        }
    }

    private void OnStartDownloadTile(OnlineMapsTile tile)
    {
        if (tile.zoom >= minFogZoom)
        {
            tile.overlayBackTexture = Instantiate(defaultFog) as Texture2D;
            tile.overlayBackTexture.name = tile.zoom + "x" + tile.x + "x" + tile.y;
            ApplyPointsToTile(tile);
        }
        OnlineMaps.instance.StartDownloadTile(tile);
    }

    private void Start()
    {
        visitedTiles = new List<OnlineMapsVector2i>();

        defaultFog = new Texture2D(fogTextureResolution, fogTextureResolution, TextureFormat.ARGB32, false);
        defaultFog.wrapMode = TextureWrapMode.Clamp;
        Color[] defaultFogColors = new Color[fogTextureSize];
        for (int i = 0; i < fogTextureSize; i++) defaultFogColors[i] = fogColor;
        defaultFog.SetPixels(defaultFogColors);
        defaultFog.Apply();

        if (OnlineMapsCache.instance != null)
        {
            OnlineMapsCache.instance.OnLoadedFromCache += OnLoadedFromCache;
            OnlineMapsCache.instance.OnStartDownloadTile += OnStartDownloadTile;
        }
        else OnlineMaps.instance.OnStartDownloadTile += OnStartDownloadTile;
        
        //OnlineMapsLocationService.instance.OnLocationChanged += OnLocationChanged;

        OnlineMapsControlBase.instance.OnMapClick += OnMapClick;
    }

    private void OnLoadedFromCache(OnlineMapsTile tile)
    {
        if (tile.zoom >= minFogZoom)
        {
            tile.overlayBackTexture = Instantiate(defaultFog) as Texture2D;
            tile.overlayBackTexture.name = tile.zoom + "x" + tile.x + "x" + tile.y;
            ApplyPointsToTile(tile);
        }
    }

    private void OnMapClick()
    {
        Vector2 newLocation = OnlineMapsControlBase.instance.GetCoords();
        double tx, ty;
        OnlineMaps.instance.projection.CoordinatesToTile(newLocation.x, newLocation.y, 17, out tx, out ty);
        OnlineMapsVector2i v = new OnlineMapsVector2i((int)tx, (int)ty);
        if (!visitedTiles.Contains(v))
        {
            visitedTiles.Add(v);
            ApplyPointToTiles(v);
        }
    }
}