// Shaun's Exif Helpers.inc
// Version 1.0
// Shaun Ivory (shaun@ivory.org)
//
// Feel free to modify this script.  If you do anything interesting with it,
// please let me know.

// EXIF constants
c_ExifGpsLatitudeRef   = "GPS Latitude Ref"
c_ExifGpsLatitude      = "GPS Latitude"
c_ExifGpsLongitudeRef  = "GPS Longitude Ref"
c_ExifGpsLongitude     = "GPS Longitude"
c_ExifGpsAltitudeRef   = "GPS Altitude Ref"
c_ExifGpsAltitude      = "GPS Altitude"
c_ExifGpsTimeStamp     = "GPS Time Stamp"
c_ExifMake             = "Make"
c_ExifModel            = "Model"
c_ExifExposureTime     = "Exposure Time"
c_ExifAperture         = "F-Stop"
c_ExifExposureProgram  = "Exposure Program"
c_ExifIsoSpeedRating   = "ISO Speed Ratings"
c_ExifDateTimeOriginal = "Date Time Original"
c_ExifMaxApertureValue = "Max Aperture Value"
c_ExifMeteringMode     = "Metering Mode"
c_ExifLightSource      = "Light Source"
c_ExifFlash            = "Flash"
c_ExifFocalLength      = "Focal Length"
c_ExifColorSpace       = "Color Space"
c_ExifWidth            = "Pixel X Dimension"
c_ExifHeight           = "Pixel Y Dimension"


function GetRawExifValueIfPresent(strExifValueName)
{
    // Empty string means it wasn't found
    var strResult = new String("");

    // Make sure there is a current document
    if (app.documents.length)
    {
        // Loop through each element in the EXIF properties array
        for (nCurrentElement = 0, nCount = 0; nCurrentElement < activeDocument.info.exif.length; ++nCurrentElement)
        {
            // Get the current element as a string
            var strCurrentRecord = new String(activeDocument.info.exif[nCurrentElement]);

            // Find the first comma
            var nComma = strCurrentRecord.indexOf(",");
            if (nComma >= 0)
            {
                // Everything before the comma is the field name
                var strCurrentExifName = strCurrentRecord.substr(0, nComma);

                // Is it a valid string?
                if (strCurrentExifName.length)
                {
                    // Is this our element?
                    if (strCurrentExifName == strExifValueName)
                    {
                        // Everything after the comma is the value, so
                        // save it and exit the loop
                        strResult = strCurrentRecord.substr(nComma + 1);
                        break;
                    }
                }
            }
        }
    }
    return strResult;
}