using System;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Networking;

public class OpenSeaMapLayer : MonoBehaviour
{
    // Overlay transparency
    [Range(0, 1)]
    public float alpha = 1;

    private float _alpha = 1;

    private void LoadTileOverlay(OnlineMapsTile tile)
    {
 
        var url = "http://tiles.openseamap.org/seamark/" + tile.zoom + "/" + tile.x + "/" + tile.y + ".png";

        OnlineMapsWWW www = new OnlineMapsWWW(url);
        www.OnComplete += OnDownloadComplete;
        www.customFields["tile"] = tile;
    }

    private Texture2D texture;

    private void OnDownloadComplete(OnlineMapsWWW www)
    {
        OnlineMapsTile tile = www.customFields["tile"] as OnlineMapsTile;
        if (tile == null || tile.status == OnlineMapsTileStatus.disposed || tile.status == OnlineMapsTileStatus.error) return;

        texture = new Texture2D(256, 256);
        www.LoadImageIntoTexture(texture);
        tile.overlayBackTexture = texture;  
        www.Dispose();
        Resources.UnloadUnusedAssets();
    }

    private void OnStartDownloadTile(OnlineMapsTile tile)
    {
        tile.status = OnlineMapsTileStatus.loading;

        // Load overlay for tile.
        LoadTileOverlay(tile);

        // Load the tile using a standard loader.
        OnlineMapsTileManager.StartDownloadTile(tile);

    }

    private void Start()
    {
        if (OnlineMapsCache.instance != null)
        {
            // Subscribe to the cache events.
            OnlineMapsCache.instance.OnLoadedFromCache += LoadTileOverlay;
        }

        OnlineMapsTileManager.OnStartDownloadTile += OnStartDownloadTile;
    }

    private void Update()
    {
        // Update the transparency of overlay.
        if (Math.Abs(_alpha - alpha) > float.Epsilon)
        {
            _alpha = alpha;
            lock (OnlineMapsTile.lockTiles)
            {
                foreach (OnlineMapsTile tile in OnlineMaps.instance.tileManager.tiles) tile.overlayBackAlpha = alpha;
            }
        }
    }
}