feat: Trading API AddItem fallback when Inventory API publish fails (25002)

When sellerRegistrationCompleted=false (sandbox), PublishOffer returns 25002.
On 25002, PostListingAsync now falls back to Trading API AddItem SOAP call
using SellerProfiles (business policy IDs) for shipping/payment/returns.

Also adds ConditionNumericId to ListingDraft for Trading API numeric condition IDs.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

EbayListingTool/Models/ListingDraft.cs

@@ -172,6 +172,17 @@ public class ListingDraft : INotifyPropertyChanged
         _                                  => "USED_VERY_GOOD"
     };
 
+    // Numeric condition IDs for Trading API (AddItem)
+    public string ConditionNumericId => Condition switch
+    {
+        ItemCondition.New                  => "1000",
+        ItemCondition.OpenBox              => "1500",
+        ItemCondition.Refurbished          => "2500",
+        ItemCondition.Used                 => "3000",
+        ItemCondition.ForPartsOrNotWorking => "7000",
+        _                                  => "3000"
+    };
+
     public event PropertyChangedEventHandler? PropertyChanged;
     protected void OnPropertyChanged([CallerMemberName] string? name = null)
         => PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(name));

EbayListingTool/Services/EbayListingService.cs

@@ -1,5 +1,6 @@
 using System.Net.Http;
 using System.Net.Http.Headers;
+using System.Security;
 using System.Text;
 using EbayListingTool.Models;
 using Newtonsoft.Json;
@@ -92,8 +93,16 @@ public class EbayListingService
         // 4. Create offer
         var offerId = await CreateOfferAsync(draft, token);
 
-        // 5. Publish offer → get item ID
+        // 5. Publish offer → get item ID (fall back to Trading API if seller registration incomplete)
-        var itemId = await PublishOfferAsync(offerId, token);
+        string itemId;
+        try
+        {
+            itemId = await PublishOfferAsync(offerId, token);
+        }
+        catch (HttpRequestException ex) when (ex.Message.Contains("25002"))
+        {
+            itemId = await AddItemViaTradingApiAsync(draft, imageUrls, token);
+        }
 
         draft.EbayItemId = itemId;
         var domain = _auth.BaseUrl.Contains("sandbox") ? "sandbox.ebay.co.uk" : "ebay.co.uk";
@@ -405,6 +414,90 @@ public class EbayListingService
                ?? throw new InvalidOperationException("No listingId in publish response.");
     }
 
+    // ---- Trading API fallback (AddItem) ----
+
+    private async Task<string> AddItemViaTradingApiAsync(
+        ListingDraft draft, List<string> imageUrls, string token)
+    {
+        var tradingUrl = _auth.BaseUrl.Contains("sandbox")
+            ? "https://api.sandbox.ebay.com/ws/api.dll"
+            : "https://api.ebay.com/ws/api.dll";
+
+        var pictureXml = imageUrls.Count > 0
+            ? "<PictureDetails>" +
+              string.Concat(imageUrls.Select(u => $"<PictureURL>{u}</PictureURL>")) +
+              "</PictureDetails>"
+            : "";
+
+        var aspectsXml = draft.Aspects.Count > 0
+            ? "<ItemSpecifics>" +
+              string.Concat(draft.Aspects.Select(kv =>
+                  $"<NameValueList><Name>{SecurityElement.Escape(kv.Key)}</Name>" +
+                  $"<Value>{SecurityElement.Escape(kv.Value)}</Value></NameValueList>")) +
+              "</ItemSpecifics>"
+            : "";
+
+        var listingType = draft.Format == ListingFormat.Auction ? "Chinese" : "FixedPriceItem";
+        var duration    = draft.Format == ListingFormat.Auction ? "Days_7" : "GTC";
+
+        var soap = $"""
+            <?xml version="1.0" encoding="utf-8"?>
+            <AddItemRequest xmlns="urn:ebay:apis:eBLBaseComponents">
+              <RequesterCredentials><eBayAuthToken>{token}</eBayAuthToken></RequesterCredentials>
+              <ErrorLanguage>en_GB</ErrorLanguage>
+              <WarningLevel>High</WarningLevel>
+              <Item>
+                <Title>{SecurityElement.Escape(draft.Title)}</Title>
+                <Description><![CDATA[{draft.Description}]]></Description>
+                <PrimaryCategory><CategoryID>{SecurityElement.Escape(draft.CategoryId)}</CategoryID></PrimaryCategory>
+                <StartPrice>{draft.Price:F2}</StartPrice>
+                <ConditionID>{draft.ConditionNumericId}</ConditionID>
+                <Country>GB</Country>
+                <Currency>GBP</Currency>
+                <DispatchTimeMax>1</DispatchTimeMax>
+                <ListingDuration>{duration}</ListingDuration>
+                <ListingType>{listingType}</ListingType>
+                <Quantity>{draft.Quantity}</Quantity>
+                <Location>{SecurityElement.Escape(draft.Postcode)}</Location>
+                {pictureXml}
+                {aspectsXml}
+                <SellerProfiles>
+                  <SellerShippingProfile><ShippingProfileID>{_fulfillmentPolicyId}</ShippingProfileID></SellerShippingProfile>
+                  <SellerPaymentProfile><PaymentProfileID>{_paymentPolicyId}</PaymentProfileID></SellerPaymentProfile>
+                  <SellerReturnProfile><ReturnProfileID>{_returnPolicyId}</ReturnProfileID></SellerReturnProfile>
+                </SellerProfiles>
+              </Item>
+            </AddItemRequest>
+            """;
+
+        using var req = new HttpRequestMessage(HttpMethod.Post, tradingUrl);
+        req.Headers.Add("X-EBAY-API-SITEID",              "3");
+        req.Headers.Add("X-EBAY-API-COMPATIBILITY-LEVEL", "967");
+        req.Headers.Add("X-EBAY-API-CALL-NAME",           "AddItem");
+        req.Headers.Add("X-EBAY-API-IAF-TOKEN",           token);
+        req.Content = new StringContent(soap, Encoding.UTF8, "text/xml");
+
+        var res = await _photoHttp.SendAsync(req);
+        var xml = await res.Content.ReadAsStringAsync();
+
+        var ackMatch = System.Text.RegularExpressions.Regex.Match(xml, @"<Ack>(.*?)</Ack>");
+        var ack = ackMatch.Success ? ackMatch.Groups[1].Value : "Unknown";
+
+        if (ack is not ("Success" or "Warning"))
+        {
+            var errMatch = System.Text.RegularExpressions.Regex.Match(
+                xml, @"<ShortMessage>(.*?)</ShortMessage>");
+            var errMsg = errMatch.Success ? errMatch.Groups[1].Value : xml[..Math.Min(500, xml.Length)];
+            throw new HttpRequestException($"Trading API AddItem failed ({ack}): {errMsg}");
+        }
+
+        var idMatch = System.Text.RegularExpressions.Regex.Match(xml, @"<ItemID>(\d+)</ItemID>");
+        if (!idMatch.Success)
+            throw new InvalidOperationException("No ItemID in AddItem response.");
+
+        return idMatch.Groups[1].Value;
+    }
+
     // ---- Photo upload ----
 
     private async Task<List<string>> UploadPhotosAsync(List<string> photoPaths, string token)