package jalview.util;

import java.awt.Image;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.util.HashMap;
import java.util.Map;
import java.util.Properties;

import javax.swing.ImageIcon;

import jalview.bin.Cache;

public class ChannelProperties
{

  private static final String CHANNEL_PROPERTIES_FILENAME = "/channel_properties";

  private Properties channelProps = new Properties();

  private static final Properties defaultProps;

  private Map<String, Image> imageMap = new HashMap<String, Image>();

  private static ChannelProperties instance;

  private boolean initDone = false;

  static
  {
    defaultProps = new Properties();
    // these should be kept up to date, but in real life they should never
    // actually be used anyway.
    defaultProps.put("app_name", "Jalview");
    defaultProps.put("banner", "/default_images/jalview_banner.png");
    defaultProps.put("logo.16", "/default_images/jalview_logo-16.png");
    defaultProps.put("logo.32", "/default_images/jalview_logo-32.png");
    defaultProps.put("logo.38", "/default_images/jalview_logo-38.png");
    defaultProps.put("logo.48", "/default_images/jalview_logo-48.png");
    defaultProps.put("logo.64", "/default_images/jalview_logo-64.png");
    defaultProps.put("logo.128", "/default_images/jalview_logo-128.png");
    defaultProps.put("logo.256", "/default_images/jalview_logo-256.png");
    defaultProps.put("logo.512", "/default_images/jalview_logo-512.png");
    defaultProps.put("rotatable_logo.48",
            "/default_images/rotatable_jalview_logo-38.png");
    defaultProps.put("uod_banner", "/default_images/UoD_banner.png");
    defaultProps.put("default_appbase",
            "https://www.jalview.org/getdown/release/1.8");
  }

  private boolean init()
  {
    if (initDone)
    {
      return initDone;
    }
    // load channel_properties
    URL channelPropsURL = getClass()
            .getResource(CHANNEL_PROPERTIES_FILENAME);
    if (channelPropsURL == null)
    {
      // fallback
      System.err.println("Failed to find '" + CHANNEL_PROPERTIES_FILENAME
              + "' filem using defaults");
      channelProps = defaultProps;
      return false;
    }
    else
    {
      try
      {
        InputStream channelPropsIS = channelPropsURL.openStream();
        channelProps.load(channelPropsIS);
        channelPropsIS.close();
      } catch (IOException e)
      {
        Cache.log.warn(e.getMessage());
        return false;
      }
    }
    initDone = true;
    return initDone;
  }

  private ChannelProperties()
  {
    init();
  }

  public static ChannelProperties getChannelProperties()
  {
    if (instance == null)
    {
      instance = new ChannelProperties();
    }
    return instance;
  }

  private static Properties channelProps()
  {
    return getChannelProperties().channelProps;
  }

  private static Map<String, Image> imageMap()
  {
    return getChannelProperties().imageMap;
  }

  /*
   * getProperty(key) will get property value from channel_properties for key.
   * If no property for key is found, it will fall back to using the defaultProps defined for this class.
   */
  public static String getProperty(String key)
  {
    return getProperty(key, null, true);
  }

  /*
   * getProperty(key, defaultVal) will get property value from channel_properties for key.
   * If no property for key is found, it will return defaultVal and NOT fall back to the class defaultProps.
   */
  public static String getProperty(String key, String defaultVal)
  {
    return getProperty(key, defaultVal, false);
  }

  private static String getProperty(String key, String defaultVal,
          boolean useClassDefaultProps)
  {
    if (channelProps() != null)
    {
      if (channelProps().containsKey(key))
      {
        return channelProps().getProperty(key,
                useClassDefaultProps ? defaultProps.getProperty(key)
                        : defaultVal);
      }
      else
      {
        System.err.println("Failed to get channel property '" + key + "'");
      }
    }
    return null;
  }

  public static Image getImage(String key)
  {
    Image img = null;
    if (imageMap().containsKey(key))
    {
      img = imageMap().get(key);
    }
    // Catch a previously untried or failed load
    if (img == null)
    {
      String path = getProperty(key);
      if (path == null)
      {
        return null;
      }
      URL imageURL = getChannelProperties().getClass().getResource(path);
      img = new ImageIcon(imageURL).getImage();
      if (img == null)
      {
        System.err.println(
                "Failed to load channel image " + key + "=" + path);
      }
      else
      {
        imageMap().put(key, img);
      }
    }
    return img;
  }
}