using System;
using UnityEngine;

namespace InfinityCode.OnlineMapsSupport
{
    public class OpenSeaMapLayer : MonoBehaviour
    {
        // Overlay transparency
        [Range(0, 1)]
        public float alpha = 1;
    
        private float _alpha = 1;
    
        private void LoadTileOverlay(OnlineMapsTile tile)
        {
     
            var url = "https://tiles.openseamap.org/seamark/" + tile.zoom + "/" + tile.x + "/" + tile.y + ".png";
    
            OnlineMapsWWW www = new OnlineMapsWWW(url);
            www.OnComplete += OnDownloadComplete;
            www.customFields["tile"] = tile;
        }
    
        private void OnDownloadComplete(OnlineMapsWWW www)
        {
            OnlineMapsTile tile = www.customFields["tile"] as OnlineMapsTile;
            if (tile == null || tile.status == OnlineMapsTileStatus.disposed || tile.status == OnlineMapsTileStatus.error) return;
    
            Texture2D texture = new Texture2D(256, 256);
            www.LoadImageIntoTexture(texture);
            tile.overlayBackTexture = texture;
        }
    
        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;
                }
            }
        }
    }
}