using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Text;
using System.Xml;

namespace GetDateImageTaken
{
    class GetDateTaken
    {
        /// <summary>
        /// Gets the date a picture was taken.
        /// </summary>
        /// <param name="args">Full path to the image file, including path and file name.</param>
        static void Main(string[] args)
        {
            try
            {
                if (args.Length == 1)
                {
                    FileInfo imgFile = new FileInfo(args[0]);
                    if (imgFile.Exists)
                    {
                        DateTime dateTaken = GetEXIFDateTaken(imgFile.FullName);
                        Console.WriteLine("The picture was taken: {0}", dateTaken.ToString());
                    }
                    else
                    {
                        Console.WriteLine("File does not exist!");
                    }
                }
                else if (args.Length > 1)
                {
                    Console.WriteLine("Too many arguments passed!");
                }
                else
                {
                    Console.WriteLine("File path missing!");
                }
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);
            }
            
        }

        /// <summary>
        /// Gets the date a picture was taken from the EXIF metadata and returns it in a DateTime object.
        /// </summary>
        /// <param name="FullPath">Full path to the image file, including directory and file name.</param>
        /// <returns>DateTime object</returns>
        public static DateTime GetEXIFDateTaken(string filePathAndName)
        {
            // Load the image
            Bitmap img = new Bitmap(filePathAndName);

            // Convert the HEX ID value (remove the "0x" prefix) to an integer
            int id = int.Parse("9003", System.Globalization.NumberStyles.AllowHexSpecifier); //36867

            // Get the 'Date Created' Property Item 
            PropertyItem prop = img.GetPropertyItem(id);
            byte[] asciiBytes = prop.Value;

            // Convert the EXIF byte array to a string
            string strDate = System.Text.Encoding.ASCII.GetString(asciiBytes);

            // Convert the string to a DateTime object
            DateTime dateTaken = ConvertEXIFStringToDate(strDate);

            return dateTaken;
        }

        /// <summary>
        /// Massages the uniquely formatted EXIF DateCreated string and converts it to a DateTime object.
        /// </summary>
        /// <param name="date">format is "YYYY:MM:DD HH:MM:SS"</param>
        /// <returns>DateTime object</returns>
        private static DateTime ConvertEXIFStringToDate(string date)
        {
            DateTime dateCreated = new DateTime();

            // Pull out the year, month, day and time individually from the string
            string dateYear = date.Substring(0, 4);
            string dateMonth = date.Substring(5, 2);
            string dateDay = date.Substring(8, 2);
            string dateHourMinSec = date.Substring(11, 8);

            // Create a stringbuilder that is formatted for conversion to DateTime
            StringBuilder sbDateCreated = new StringBuilder();
            sbDateCreated.Append(dateMonth + "/");
            sbDateCreated.Append(dateDay + "/");
            sbDateCreated.Append(dateYear + " ");
            sbDateCreated.Append(dateHourMinSec);

            // Convert the string to DateTime
            dateCreated = Convert.ToDateTime(sbDateCreated.ToString());

            return dateCreated;
        }
    }
}