package jalview.bin;

import java.awt.Toolkit;

public class HiDPISetting
{
  private static final int hidpiThreshold = 130;

  private static final int tallScreenThreshold = 1400;

  private static final String scalePropertyName = "sun.java2d.uiScale";

  private static final boolean isAMac;

  private static final boolean isLinux;

  private static final boolean isWindows;

  public static final String setHiDPIPropertyName = "setHiDPI";

  public static final String setHiDPIScalePropertyName = "setHiDPIScale";

  private static boolean setHiDPI = false;

  private static int setHiDPIScale = 0;

  public static int dpi = 0;

  public static int mindimension = 0;

  public static int width = 0;

  public static int scale = 0;

  private static boolean doneInit = false;

  private static boolean allowScalePropertyArg = false;

  static
  {
    isAMac = System.getProperty("os.name").indexOf("Mac") > -1;
    isLinux = System.getProperty("os.name").toLowerCase()
            .indexOf("linux") > -1;
    isWindows = System.getProperty("os.name").toLowerCase()
            .indexOf("windows") > -1;
  }

  private static void init()
  {
    if (doneInit)
    {
      return;
    }

    String setHiDPIProperty = System.getProperty(setHiDPIPropertyName);
    setHiDPI = setHiDPIProperty != null
            && setHiDPIProperty.equalsIgnoreCase("true");

    String setHiDPIScaleProperty = System
            .getProperty(setHiDPIScalePropertyName);
    if (setHiDPIScaleProperty != null)
    {
      try
      {
        setHiDPIScale = Integer.parseInt(setHiDPIScaleProperty);
      } catch (NumberFormatException e)
      {
        System.err.println(setHiDPIScalePropertyName + " property give ("
                + setHiDPIScaleProperty + ") but not parseable as integer");
      }
    }

    // try and get screen resolution
    try
    {
      dpi = Toolkit.getDefaultToolkit().getScreenResolution();
    } catch (Throwable t)
    {
      System.err.println("Cannot get screen resolution");
    }

    // try and get screen size height and width
    try
    {
      int height = Toolkit.getDefaultToolkit().getScreenSize().height;
      int width = Toolkit.getDefaultToolkit().getScreenSize().width;
      // using mindimension in case of portrait screens
      mindimension = Math.min(height, width);
    } catch (Throwable t)
    {
      System.err.println("Cannot get screen size height and width");
    }

    if (setHiDPI && setHiDPIScale > 0)
    {
      scale = setHiDPIScale;
    }
    else
    {
      // attempt at a formula for scaling based on screen dpi and mindimension.
      // scale
      // will be an integer >=1
      if (dpi > 0 && mindimension > 0)
      {
        scale = Math.min(dpi / hidpiThreshold,
                mindimension / tallScreenThreshold) + 1;
      }
      else if (dpi == 0 && mindimension > tallScreenThreshold)
      {
        // dpi couldn't be found but the screen has a large vertical pixel count
        scale = mindimension / tallScreenThreshold + 1;
      }
      /* do nothing if mindimension == 0 -- might be just a small HD screen (e.g. Gemini PDA)
      else if (mindimension == 0 && dpi > hidpiThreshold)
      {
      }
      */
    }

    // only make a change if scale is changed and other conditions (OS is linux)
    // apply, or if setHiDPI has been specified
    allowScalePropertyArg = (scale > 1 && isLinux) || setHiDPI;

    if (allowScalePropertyArg)
    {
      System.out.println("boolean setHiDPI=" + setHiDPI);
      System.out.println("DPI detected as " + dpi
              + ". Scaling factor set to " + scale + ".");
    }

    doneInit = true;
  }

  public static void setHiDPIScale(int s)
  {
    scale = s;
    allowScalePropertyArg = true;
    doneInit = true;
  }

  public static String getScalePropertyArg()
  {
    init();
    // HiDPI setting. Just looking at Linux to start with. Test with Windows.
    return allowScalePropertyArg ? "-D" + scalePropertyName + "=" + scale
            : null;
  }
}