using System;
using System.Collections.Generic;
using System.Drawing;
using System.Globalization;
using System.IO;
using System.Runtime.InteropServices;
using System.Text;
using GrapeCity.ActiveReports.Extensibility;
using GrapeCity.ActiveReports.Samples.CustomResourceLocator.Properties;
namespace GrapeCity.ActiveReports.Samples.CustomResourceLocator
{
    /// Implementation of ResourceLocator which looks for resources in the My Pictures folder.
    internal sealed class MyPicturesLocator : ResourceLocator
    {
        private const string UriSchemeMyImages = "MyPictures:";
        /// Obtains and returns the resource, or returns null if it is not found.
        public override Resource GetResource(ResourceInfo resourceInfo)
        {
            
            Resource resource;
            string name = resourceInfo.Name;
            if (name == null || name.Length == 0)
            {
                throw new ArgumentException(Resources.ResourceNameIsNull, "name");
            }
            Uri uri = new Uri(name);
            if (uri.GetLeftPart(UriPartial.Scheme).StartsWith(UriSchemeMyImages, true, CultureInfo.InvariantCulture))
            {
                Stream stream = GetPictureFromSpecialFolder(uri);
                if (stream == null)
                {
                    stream = new MemoryStream();
                    Resources.NoImage.Save(stream, Resources.NoImage.RawFormat);
                }
                resource = new Resource(stream, uri);
            }
            else
            {
                throw new InvalidOperationException(Resources.ResourceSchemeIsNotSupported);
            }
            return resource;
        }
        /// Returns a stream containing the specified image from the My Pictures folder, or null if the picture is not found. 
                /// The path parameter is the URI of the image located in My Pictures, e.g. MyImages:logo.gif
        private static Stream GetPictureFromSpecialFolder(Uri path)
        {
            int startPathPos = UriSchemeMyImages.Length;
            if (startPathPos >= path.ToString().Length)
            {
                return null;
            }
            string pictureName = path.ToString().Substring(startPathPos);
            string myPicturesPath = Environment.GetFolderPath(Environment.SpecialFolder.MyPictures);
            if (!myPicturesPath.EndsWith("\\")) myPicturesPath += "\\";
             string picturePath = Path.Combine(myPicturesPath, pictureName);
            if (!File.Exists(picturePath)) return null;
            MemoryStream stream = new MemoryStream();
            try
            {
                Image picture = Image.FromFile(picturePath);
                picture.Save(stream, picture.RawFormat);
                stream.Position = 0;
            }
            catch(OutOfMemoryException) 
                        /// The file is not a valid image, or GDI+ doesn't support the image type.
            {
                return null;                            
            }
            catch(ExternalException) 
                        /// The image can't be saved.
            {
                return null;
            }
            return stream;
        }
    }
}