/// 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", "");
        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", "");
        string strListType = CheckNull(myQueryString, "ListType", "");
        string strName = CheckNull(myQueryString, "Name", "");
        string strFirstName = CheckNull(myQueryString, "FirstName", "");
        string strLastName = CheckNull(myQueryString, "LastName", "");
        string strEmail = CheckNull(myQueryString, "Email", "");
        string strListId = CheckNull(myQueryString, "ListId", "");
        string strItem1ASIN = CheckNull(myQueryString, "Item.1.ASIN", "");
        string strItem1Quantity = CheckNull(myQueryString, "Item.1.Quantity", "");
        string strMergeCart = CheckNull(myQueryString, "MergeCart", "");
        string strCartID = CheckNull(myQueryString, "CartId", "");
        string strItem1CartItemId = CheckNull(myQueryString, "Item.1.CartItemId", "");
        string strHMAC = CheckNull(myQueryString, "HMAC", "");
        string strBrowseNodeId = CheckNull(myQueryString, "BrowseNodeId", "");
string strCuisine = CheckNull(myQueryString, "Cuisine", "");
string strNeighborhood = CheckNull(myQueryString, "Neighborhood", "");
string strCity = CheckNull(myQueryString, "City", "");
        
        // Return the concatenated URI
        strURI = strRoot + strAccessKeyId +
            strOperation + strResponseGroup +
            strItemId + strKeywords +
            strSearchIndex + strDirector +
            strAuthor + strArtist + 
            strActor + strListType + 
            strName + strFirstName + 
            strLastName + strEmail + strListId +
            strItem1ASIN + strItem1Quantity + 
            strMergeCart + strCartID +
            strHMAC + strItem1CartItemId + strBrowseNodeId + 
            strCuisine + strNeighborhood + 
            strCity;    
        
        return strURI;
    }
}