/// Author: Francis A. Shanahan
/// http://www.FrancisShanahan.com

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Collections.Specialized;

/// <summary>
/// Summary description for amazonUtility
/// </summary>
public class amazonUtility
{
    public amazonUtility()
    {
        //
        // TODO: Add constructor logic here
        //
    }

    /// <summary>
    /// Simple helper function to parse out values from the querystring
    /// </summary>
    /// <param name="myQueryString"></param>
    /// <param name="strKey"></param>
    /// <param name="strDefault"></param>
    /// <returns></returns>
    private static string CheckNull(NameValueCollection myQueryString, string strKey, string strDefault)
    {
        // If the desired key is present...
        if (myQueryString[strKey] != null)
        {
            // return its value
            return strKey + "=" + myQueryString[strKey] + "&";
        }
        else
        {
            // if a default was specified, return it
            if (strDefault != "")
                return strKey + "=" + strDefault + "&";
        }
        // Otherwise return the empty string
        return "";
    }

    /// <summary>
    /// Takes the Querystring and builds a valid Amazon REST url from it.
    /// </summary>
    /// <param name="myRequest">The page request object</param>
    /// <returns></returns>
    public static string BuildAmazonURI(NameValueCollection myQueryString)
    {
        string strURI = "";
        string strRoot = "http://webservices.amazon.com/onca/xml?Service=AWSECommerceService&";
        string strAccessKeyId = "AWSAccessKeyId=" + ConfigurationManager.AppSettings["AWSAccessKeyId"] + "&";
        string strAssociateTag = "AssociateTag=" + ConfigurationManager.AppSettings["AssociateTag"] + "&";

        string strOperation = CheckNull(myQueryString, "Operation", "ItemSearch");
        string strResponseGroup = CheckNull(myQueryString, "ResponseGroup", "Large");
        string strItemId = CheckNull(myQueryString, "ItemId", "");
        string strKeywords = CheckNull(myQueryString, "Keywords", "");
        string strSearchIndex = CheckNull(myQueryString, "SearchIndex", "");
        string strDirector = CheckNull(myQueryString, "Director", "");
        string strAuthor = CheckNull(myQueryString, "Author", "");
        string strArtist = CheckNull(myQueryString, "Artist", "");
        string strActor = CheckNull(myQueryString, "Actor", "");

        // Return the concatenated URI
        strURI = strRoot + strAccessKeyId +
            strOperation + strResponseGroup +
            strItemId + strKeywords +
            strSearchIndex + strDirector +
            strAuthor + strArtist + strActor
            ;
        return strURI;
    }
}