// Add Exif Caption.jsx
// 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.

//************************************************************************
//
// Caption constants.  Change these if you want to.
//
//************************************************************************

// Copyright string
c_CaptionCopyright     = "Copyright © Shaun Ivory";
c_CaptionFont          = "TrebuchetMS";

// Caption text
c_CaptionGpsPrefix     = "Location:"
c_CaptionDateTimeTaken = "Date taken:"
c_CaptionModel         = "Camera:"
c_CaptionExposureTime  = "Exposure time:"
c_CaptionAperture      = "Aperture:"
c_CaptionFocalLength   = "Focal length:"
c_CaptionIsoRating     = "ISO:"

//************************************************************************
//
// Date and time constants.  Change these if you want to.
//
//************************************************************************

c_MonthsArray = 
[
    "Jan",
    "Feb",
    "Mar",
    "Apr",
    "May",
    "Jun",
    "Jul",
    "Aug",
    "Sep",
    "Oct",
    "Nov",
    "Dec"
];

c_AM = "am"
c_PM = "pm"

//************************************************************************
//
// Colors
//
//************************************************************************

function CreateSolidRgbColor(r, g, b)
{
    var result = new SolidColor;
    result.rgb.red = r;
    result.rgb.green = g;
    result.rgb.blue = b;
    return result;
}

var colorCaptionBackground = CreateSolidRgbColor(255, 255, 255);
var colorFrame             = CreateSolidRgbColor(0, 0, 0);
var colorText              = CreateSolidRgbColor(0, 0, 0);

//************************************************************************
//
// Include EXIF constants and methods.
//
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
// Note the this is not a comment: it includes the contents
// of Shaun's Exif Helpers.inc in this script!
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
//
//************************************************************************

//@include "Shaun's Exif Helpers.inc"

//************************************************************************
//
// Functions
//
//************************************************************************

//
// Photoshop CS formats the latitude and longitude strings
// oddly:
//
//      Example: 47.00 38.00' 33.60"
//
// There is no degrees symbol after the degrees, and
// they leave useless zeroes on the right side of the decimal
// point for both degrees and minutes.  This function parses
// the numbers from the latitude and longitude strings, and
// inserts the correct characters where they belong:
//
//      Example: 47° 38' 33.6"
//
// It returns an empty string if the string is in an unexpected
// form or doesn't exist.
//
function CorrectlyFormatLatitudeOrLongitude(strLatLong)
{
    var strResult = new String("");

    // Copy the input string
    var strSource = new String(strLatLong);

    // Find the first space
    nIndex = strSource.indexOf(" ");
    if (nIndex >= 0)
    {
        // Copy up to the first space
        strDegrees = strSource.substr(0, nIndex);

        // Skip this part, plus the space
        strSource = strSource.substr(nIndex + 1);

        // Find the tick mark
        nIndex = strSource.indexOf("'");
        if (nIndex >= 0)
        {
            // Copy up to the tick mark
            strMinutes = strSource.substr(0, nIndex);

            // Skip this chunk, plus the tick and space
            strSource = strSource.substr(nIndex + 2);

            // Find the seconds mark: "
            nIndex = strSource.indexOf("\"");
            if (nIndex >= 0)
            {
                // Copy up to the seconds
                strSeconds = strSource.substr(0, nIndex);

                // Get rid of extraneous trailing zeroes
                var nDegrees = parseFloat(strDegrees);
                var nMinutes = parseFloat(strMinutes);
                var nSeconds = parseFloat(strSeconds);

                // Use the correct symbols
                strResult = nDegrees.toString() + "° " + nMinutes.toString() + "' " + nSeconds.toString() + "\"";
            }
        }
    }

    return strResult;
}

//
// This function gets the GPS location fields and formats them correctly
//
// It returns an empty string if they don't exist
//
function GetFormattedGpsData()
{
    var strResult = new String("");

    // Get the fields
    strLatitude = GetRawExifValueIfPresent(c_ExifGpsLatitude);
    strLatitudeRef = GetRawExifValueIfPresent(c_ExifGpsLatitudeRef);
    strLongitude = GetRawExifValueIfPresent(c_ExifGpsLongitude);
    strLongitudeRef = GetRawExifValueIfPresent(c_ExifGpsLongitudeRef);

    // Do all of them exist?
    if (strLatitude.length && strLatitudeRef.length && strLongitude.length && strLongitudeRef.length)
    {
        // Parse and reformat the latitude and longitude
        strFinalLatitude = CorrectlyFormatLatitudeOrLongitude(strLatitude);
        strFinalLongitude = CorrectlyFormatLatitudeOrLongitude(strLongitude);

        // Are they still valid?
        if (strFinalLatitude.length && strFinalLongitude.length)
        {
            // Create the result (with the constant prefix)
            strResult = c_CaptionGpsPrefix + " " + strFinalLatitude + " " + strLatitudeRef + ", " + strFinalLongitude + " " + strLongitudeRef;
        }
    }
    return strResult;
}

//
// EXIF dates are formatted kind of funny, with colons
// between the date tokens:
//
//      Example: 2005:04:13 16:22:47
//
// This function parses the numbers out of the string
// and formats it like this:
//
//      Example: Apr 13, 2005 4:22:47 pm
//
function CorrectlyFormatDateAndTime(strDateAndTime)
{
    var strResult = new String("");

    // Copy the input string
    var strSource = new String(strDateAndTime);

    // Find the first colon
    nIndex = strSource.indexOf(":");
    if (nIndex >= 0)
    {
        // Copy up to the first space
        strYear = strSource.substr(0, nIndex);

        // Skip past the colon
        strSource = strSource.substr(nIndex + 1);

        // Find the next colon
        nIndex = strSource.indexOf(":");
        if (nIndex >= 0)
        {
            // Copy up to colon
            strMonth = strSource.substr(0, nIndex);

            // Skip the colon
            strSource = strSource.substr(nIndex + 1);

            // Find the next space
            nIndex = strSource.indexOf(" ");
            if (nIndex >= 0)
            {
                // Copy up to the space
                strDay = strSource.substr(0, nIndex);

                // Skip the space
                strSource = strSource.substr(nIndex + 1);

                // Find the next colon
                nIndex = strSource.indexOf(":");
                if (nIndex >= 0)
                {
                    // Save the hours
                    strHours = strSource.substr(0, nIndex);

                    // Skip the colon
                    strSource = strSource.substr(nIndex + 1);

                    // Find the next colon
                    nIndex = strSource.indexOf(":");
                    if (nIndex >= 0)
                    {
                        // Save the minutes
                        strMinutes = strSource.substr(0, nIndex);

                        // Skip the colon
                        strSource = strSource.substr(nIndex + 1);

                        // Save the seconds
                        strSeconds = strSource;

                        // Assume it is AM
                        strAmPm = c_AM;

                        // Is it after noon?
                        if (strHours >= 12)
                        {
                            // Use PM
                            strAmPm = c_PM;

                            // If it is after 13:00, subtract 12
                            if (strHours >= 13)
                            {
                                strHours -= 12;
                            }
                        }

                        // If it is 12:xx AM, make it 12:xx instead of 00:xx
                        else if (strHours == 0)
                        {
                            strHours = 12;
                        }

                        // Format the string
                        strResult = c_MonthsArray[parseInt(strMonth) - 1] + " " + parseInt(strDay).toString() + ", " + strYear + " " + parseInt(strHours).toString() + ":" + strMinutes + ":" + strSeconds + " " + strAmPm;
                    }
                }
            }
        }
    }

    return strResult;
}

//
// If the value is not an empty string, prepend
// a caption and return the result
//
function GetPrefixedValue(strCaption, strValue)
{
    var strResult = new String("");
    if (strValue.length)
    {
        strResult = strCaption + " " + strValue;
    }
    return strResult;
}

//
// Get a simple EXIF property that doesn't need reformatting
// and prepend its title if the value is present
//
function GetPrefixedSimpleProperty(strCaption, strExifField)
{
    return GetPrefixedValue(strCaption, GetRawExifValueIfPresent(strExifField));
}

//
// Format the date and time
//
function GetFormattedDateTimeTaken()
{
    return GetPrefixedValue(c_CaptionDateTimeTaken, CorrectlyFormatDateAndTime(GetRawExifValueIfPresent(c_ExifDateTimeOriginal)));
}

//
// Get the model name of the camera.
// 
// Unfortunately, there is little consistency for EXIF makes and models.
// For example, the Nikon Coolpix 990 looks like this:
//
//      E990
//
// While the D2x looks like this:
//
//      NIKON D2X
//
// If your camera has a user-unfriendly name, you might want to modify
// this function to return a user-friendly name.
//
function GetFormattedModel()
{
    return GetPrefixedSimpleProperty(c_CaptionModel, c_ExifModel)
}

//
// EXIF exposure time
//
function GetFormattedExposureTime()
{
    return GetPrefixedSimpleProperty(c_CaptionExposureTime, c_ExifExposureTime);
}

//
// EXIF f-Stop
//
function GetFormattedAperture()
{
    return GetPrefixedSimpleProperty(c_CaptionAperture, c_ExifAperture);
}

//
// EXIF focal length
//
function GetFormattedFocalLength()
{
    return GetPrefixedSimpleProperty(c_CaptionFocalLength, c_ExifFocalLength);
}

//
// EXIF ISO rating
//
function GetFormattedIsoRating()
{
    return GetPrefixedSimpleProperty(c_CaptionIsoRating, c_ExifIsoSpeedRating);
}

//
// If strValue is not empty, add it to the array
//
function AddAvailableExifFieldToArray(availableFieldsArray, strValue)
{
    // If we have a string, add it to the end of the array
    if (strValue.length > 0)
    {
        availableFieldsArray[availableFieldsArray.length] = strValue;
    }
}

//
// Extract the year from the EXIF date-taken
//
function GetYearFromDateTaken()
{
    var strResult = new String("");

    // Get the EXIF date taken
    var strSource = GetRawExifValueIfPresent(c_ExifDateTimeOriginal);
    if (strSource.length)
    {
        // Find the first colon
        nIndex = strSource.indexOf(":");
        if (nIndex >= 0)
        {
            // Copy up to the first colon
            strResult = strSource.substr(0, nIndex);
        }
    }

    // If we don't have a string, use today's date
    if (strResult.length == 0)
    {
        strResult = ((new Date()).getYear() + 1900).toString();
    }
    return strResult;
}

//
// Format the copyright string
//
function GetFormattedCopyright()
{
    // Start with the copyright string
    var strResult = new String(c_CaptionCopyright);

    // Get the year
    var strYear = GetYearFromDateTaken();
    if (strYear.length != 0)
    {
        // Append it (after a comma and a space)
        strResult += ", " + strYear;
    }

    return strResult;
}

//
// Get all of the interesting EXIF fields, format them, and put them in a comma
// separated string for display.
//
function GetAllAvailableFields()
{
    // Add all of the fields to the array
    var AvailableFields = new Array;
    AddAvailableExifFieldToArray(AvailableFields, GetFormattedModel());
    AddAvailableExifFieldToArray(AvailableFields, GetFormattedExposureTime());
    AddAvailableExifFieldToArray(AvailableFields, GetFormattedAperture());
    AddAvailableExifFieldToArray(AvailableFields, GetFormattedFocalLength());
    AddAvailableExifFieldToArray(AvailableFields, GetFormattedIsoRating());
    AddAvailableExifFieldToArray(AvailableFields, GetFormattedGpsData());
    AddAvailableExifFieldToArray(AvailableFields, GetFormattedDateTimeTaken());

    // Turn it into one big string
    var strResult = new String;
    for (nCurrentEntry = 0; nCurrentEntry < AvailableFields.length; ++nCurrentEntry)
    {
        if (nCurrentEntry != 0)
        {
            strResult += ", ";
        }
        strResult += AvailableFields[nCurrentEntry];
    }
    return strResult;
}

//************************************************************************
//
// Begin script
//
//************************************************************************

function Main()
{
    if (app.documents.length > 0)
    {
        // Save the old background color and ruler units
        var oldRulerUnits = preferences.rulerUnits;
        var oldBackgroundColor = backgroundColor;

        try
        {
            // Turn off dialog boxes
            displayDialogs = DialogModes.NO;

            // Use inches for our scale
            preferences.rulerUnits = Units.INCHES;

            // Decide which axis is longer
            var nLongAxis = (activeDocument.height.value > activeDocument.width.value) ? activeDocument.height.value : activeDocument.width.value;

            // Calculate the border thickness
            var nBorderThickness = nLongAxis / 180;

            // How big do we want the font?
            var nFontHeight = activeDocument.width.value / 85;

            // Calculate the text area height
            var nTextAreaHeight = nFontHeight * 3;

            // Convert the font size to points
            var nFontHeightInPoints = nFontHeight * 72;

            // Add the frame
            backgroundColor = colorFrame;
            activeDocument.resizeCanvas(activeDocument.width.value + nBorderThickness*2, activeDocument.height.value + nBorderThickness*2, AnchorPosition.MIDDLECENTER);

            // Save the bottom of the image frame before we add the caption area
            var nBottomOfFrame = activeDocument.height.value;

            // Add the caption area
            backgroundColor = colorCaptionBackground;
            activeDocument.resizeCanvas(activeDocument.width.value, activeDocument.height.value + nTextAreaHeight, AnchorPosition.TOPCENTER);

            // Create the caption ("\u000D" is a new-line)
            var strCaption = GetFormattedCopyright() + "\u000D" + GetAllAvailableFields();

            // Create the text layer
            var newTextLayer = activeDocument.artLayers.add();
            newTextLayer.kind = LayerKind.TEXT;
            newTextLayer.textItem.font = c_CaptionFont;
            newTextLayer.textItem.position = [nBorderThickness, nBottomOfFrame + nFontHeight*0.8 + nBorderThickness];
            newTextLayer.textItem.size = nFontHeightInPoints;
            newTextLayer.textItem.color = colorText;
            newTextLayer.textItem.contents = strCaption;

        }
        catch (e)
        {
            alert(e);
        }

        // Restore the background color and ruler units
        backgroundColor = oldBackgroundColor;
        preferences.rulerUnits = oldRulerUnits;
    }
    else
    {
        alert("You don't have an image opened.  Please open an image before running this script.");
    }
}

Main();