<%@ WebHandler Language="C#" Class="LiveImage" %>

using System;
using System.Web;
using System.IO;

public class LiveImage : IHttpHandler {
    
    /* SYNTAX FOR USING THIS TOOL */
    /*
     * LiveImage.ashx?img=[PathToImage]&height=[height]&width=[width][&aspect=1]
     * 
     * where
     * 
     *  - [PathToImage] is the path to the source image, relative to the site root
     *  - [height] is the desired height of the image
     *  - [width] is the desired width of the image
     *  - [&aspect=1] -- add this parameter to preserve the photos original aspect ratio, leave it out to allow it to deform
   */


    public void ProcessRequest (HttpContext context)
    {
        string ImageLocation = context.Request["img"];

        if (ImageLocation != null && ImageLocation.Length > 0)
        {
            string sImageHeight = context.Request["height"];
            string sImageWidth = context.Request["width"];
            string sAspect = context.Request["aspect"];

            if (context.Request["preset"] != null)
            {
                switch (context.Request["preset"])
                {
                    case "large":
                        sImageWidth = "640";
                        sImageHeight = "480";
                        sAspect = "1";
                        break;
                    case "medium":
                        sImageWidth = "360";
                        sImageHeight = "360";
                        sAspect = "1";
                        break;
                    case "small":
                        sImageWidth = "212";
                        sImageHeight = "212";
                        sAspect = "1";
                        break;
                    case "icon":
                        sImageWidth = "30";
                        sImageHeight = "30";
                        sAspect = "1";
                        break;
                    default:
                        sImageWidth = "300";
                        sImageHeight = "300";
                        sAspect = "1";
                        break;
                }
            }
            
            int ImageHeight = 0;
            if (sImageHeight != null)
                Int32.TryParse(sImageHeight, out ImageHeight);
            int ImageWidth = 0;
            if (sImageWidth != null)
                Int32.TryParse(sImageWidth, out ImageWidth);
            bool Aspect = (sAspect != null);

            
            if (!Aspect && (ImageHeight == 0 || ImageWidth == 0))
                throw new Exception("Must supply both width and height if not maintaining aspect ratio");

            if (ImageHeight != 0 || ImageWidth != 0)
            {
                // come up with the file's cached location
                int FileExtensionIndex = ImageLocation.LastIndexOf('.');
                if (FileExtensionIndex > -1)
                {
                    string FileExtension = ImageLocation.Substring(FileExtensionIndex);
                    string FileName = ImageLocation.Substring(0, FileExtensionIndex);
                    string CachedFilename = FileName.Replace("/", "-").Replace("~", "");

                    string CacheDirectory = context.Server.MapPath("~/ImageCache/");
                    string CacheFile = CachedFilename +
                                       "H" + (sImageHeight == null ? "" : sImageHeight) +
                                       "W" + (sImageWidth == null ? "" : sImageWidth) +
                                       "A" + (Aspect ? "1" : "0") + FileExtension;

                    if (File.Exists(CacheDirectory + CacheFile))
                        ImageLocation = "~/ImageCache/" + CacheFile; // found a cached image
                    else
                    {
                        // time to create the new image

                        // ensure the target directory exists
                        if (!Directory.Exists(CacheDirectory))
                            Directory.CreateDirectory(CacheDirectory);

                        // get the physical location of the raw file
                        string PhysicalLocation = context.Server.MapPath(ImageLocation);

                        // ensure that it exists
                        if (File.Exists(PhysicalLocation))
                        {
                            System.Drawing.Image img = Graphix.GetSizedImage(PhysicalLocation, ImageWidth, ImageHeight, Aspect);
                            img.Save(CacheDirectory + CacheFile);
                            ImageLocation = "~/ImageCache/" + CacheFile; // found a cached image    
                        }
                    }
                }
            }

            context.Response.Redirect(ImageLocation);
        }
    }

    public bool IsReusable {
        get {
            return false;
        }
    }

}