/*******************************************************************************
 * Copyright (c) 2012 Association for Decentralized Information Management
 * in Industry THTH ry.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.maps.osm;

import java.awt.Dimension;
import java.awt.Image;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URI;

import javax.imageio.IIOException;
import javax.imageio.ImageIO;

import org.simantics.maps.ProvisionException;
import org.simantics.maps.WebService;
import org.simantics.maps.tile.ITileProvider;
import org.simantics.maps.tile.TileKey;
import org.simantics.maps.wms.ServiceException;

/**
 * @author Tuukka Lehtonen
 * @see OSMGetMapQuery
 */
public class OSMTileProvider implements ITileProvider {

    private WebService  service;

    private int      tileSize;

    public OSMTileProvider(WebService service, int tileSize) {
        this.service = service;
        this.tileSize = tileSize;
    }

    @Override
    public URI getSource() {
        return service.getURI();
    }

    @Override
    public Rectangle2D getExtent() {
        return new Rectangle2D.Double(-180, -90, 360, 180);
    }

    @Override
    public Image get(TileKey key) throws ProvisionException {
        int level = key.getLevel();
        int x = key.getX();
        int y = key.getY();

        double xTiles = Math.pow(2, level + 1);
        double yTiles = Math.pow(2, level);

        if (level < 0)
            throw new IllegalArgumentException("invalid tile level " + level + " (tile=" + key +")");
        if (x < 0 || x >= (int) xTiles)
            throw new IllegalArgumentException("tile x out of bounds " + x + " (tile=" + key +")");
        if (y < 0 || y >= (int) yTiles)
            throw new IllegalArgumentException("tile y out of bounds " + y + " (tile=" + key +")");

        try {
            Rectangle2D r = new Rectangle2D.Double(x, y, 10, 10);

//            System.out.println("TileProvider: requesting " + key + ", bbox=" + r + ", size=" + tileSize);
            BufferedImage img = getMap(service, tileSize, tileSize, r, "image/png", level);//layers);
//            System.out.println("TileProvider: response: " + img);
            return img;
        } catch (MalformedURLException e) {
            throw new ProvisionException(e);
        } catch (IOException e) {
            throw new ProvisionException(e);
        }
    }

    
    /**
     * Get a bufferedimage of the map data for the geographical coordinates.
     * 
     * @param x
     * @param y
     * @param z
     * @return
     * @throws MalformedURLException 
     */
    public static BufferedImage getMap(WebService service, Dimension rasterSize, Rectangle2D bbox, String format, int level) throws MalformedURLException, IOException {
        return getMap(service, rasterSize.width, rasterSize.height, bbox, format, level);
    }

    /**
     * Get a bufferedimage of the map data for the geographical coordinates.
     * 
     * @param x
     * @param y
     * @param z
     * @return
     * @throws MalformedURLException 
     */
    public static BufferedImage getMap(WebService service, int rasterWidth, int rasterHeight, Rectangle2D bbox, String format, int level) throws MalformedURLException, IOException {
        if (rasterWidth == 0 || rasterHeight == 0)
            return new BufferedImage(0, 0, BufferedImage.TYPE_INT_ARGB);

        HttpURLConnection connection = null;
        try {
            connection = service.openConnection(("" + level + "/" + Math.round(bbox.getMinX()) + "/" + Math.round(bbox.getMinY())+".png"), null);

            // Execute the method.
            int statusCode = connection.getResponseCode();

            if (statusCode != HttpURLConnection.HTTP_OK) {
                System.err.println("Method failed: " + connection.getResponseMessage());
            }

//            for (Header h : method.getResponseHeaders()) {
//                System.out.println("HDR: " + h.getName() + ": " + h.getValue());
//            }

            String contentType = connection.getHeaderField("Content-Type");
            if (contentType != null) {
//                System.out.println("Content-Type: " + contentType);
                if (contentType.equals(format)) {
                    InputStream response = connection.getInputStream();
                    BufferedImage img = ImageIO.read(response);
                    if (img == null) {
                        throw new IIOException("ImageIO returned null, unable to decode stream as image data.");
                    }
                    return img;
                }
            }

            // Request failed,  produce as much debug information as possible.
            StringBuilder sb = new StringBuilder();
            sb.append("Response headers:\n");
            for (String h : connection.getHeaderFields().keySet()) {
                sb.append(h);
                sb.append(": ");
                sb.append(connection.getHeaderField(h));
                sb.append("\n");
            }
            String response = connection.getContent().toString();
            sb.append("Response body:\n");
            sb.append(response);
            throw new ServiceException("WMS GetMap request failed: " + connection.getURL().toString() + "\n" + sb.toString());
        } finally {
            // Release the connection.
            if (connection != null)
                connection.disconnect();
        }
    }

}