VAExif

import Foundation
import MobileCoreServices
import CoreLocation
import ImageIO

class VAExif: NSObject {
    var imageMetadata = NSMutableDictionary()

    private func dataFromImage(image: UIImage, metadata: NSMutableDictionary) -> NSData? {
        let imageData = NSMutableData()
        let mimetype = "image/jpeg"
        guard let uti = UTTypeCreatePreferredIdentifierForTag(kUTTagClassMIMEType, mimetype, nil)?.takeRetainedValue()else { return nil }
        let imageDestination: CGImageDestinationRef? = CGImageDestinationCreateWithData(imageData, uti, 1, nil)
        if imageDestination == nil {
            return nil
        } else {
            CGImageDestinationAddImage(imageDestination!, image.CGImage!, metadata)
            if CGImageDestinationFinalize(imageDestination!) == false {
                return nil
            }
        }
        return imageData
    }

    func convertToImageData(usingImage image: UIImage, andLocation location: CLLocation) -> NSData? {
        addLocation(location)
        return dataFromImage(image, metadata: imageMetadata)
    }

    private func addLocation(currentLocation: CLLocation) {
        var latitude: CLLocationDegrees = currentLocation.coordinate.latitude
        var longitude: CLLocationDegrees = currentLocation.coordinate.longitude
        var latitudeRef: String?
        var longitudeRef: String?
        if latitude < 0.0 {
            latitude *= -1
            latitudeRef = "S"
        } else {
            latitudeRef = "N"
        }
        if longitude < 0.0 {
            longitude *= -1
            longitudeRef = "W"
        } else {
            longitudeRef = "E"
        }
        self.gpsDictionary()[String(kCGImagePropertyGPSTimeStamp)] = self.getUTCFormattedDate(currentLocation.timestamp)
        self.gpsDictionary()[String(kCGImagePropertyGPSLatitudeRef)] = latitudeRef!
        self.gpsDictionary()[String(kCGImagePropertyGPSLatitude)] = Float(latitude)
        self.gpsDictionary()[String(kCGImagePropertyGPSLongitudeRef)] = longitudeRef!
        self.gpsDictionary()[String(kCGImagePropertyGPSLongitude)] = Float(longitude)
        self.gpsDictionary()[String(kCGImagePropertyGPSDOP)] = Float(currentLocation.horizontalAccuracy)
        self.gpsDictionary()[String(kCGImagePropertyGPSAltitude)] = Float(currentLocation.altitude)

    }

    private func getUTCFormattedDate(localDate: NSDate) -> String {
        let dateFormatter = NSDateFormatter()
        dateFormatter.dateFormat = "yyyy:MM:dd HH:mm:ss"
        return dateFormatter.stringFromDate(localDate)
    }

    private func gpsDictionary() -> NSMutableDictionary {
        return self.dictionaryForKey(String(kCGImagePropertyGPSDictionary))
    }

    private func exifData() -> NSMutableDictionary {
        return self.imageMetadata
    }
    private func dictionaryForKey(key: String) -> NSMutableDictionary {
        if let  dict = self.imageMetadata[key] as? NSMutableDictionary {
            return dict
        } else {
            let dict = NSMutableDictionary()
            self.imageMetadata[key] = dict
            return dict
        }

    }
}