Apply second code review fixes: robustness and correctness

- AiAssistantService: 90s HTTP timeout; RefineWithCorrections uses 29.99 example
  price and explicit "Never return 0" instruction; treat returned 0 as missing and
  keep original price instead
- EbayAuthService: shared static HttpClient for all auth/token calls; SemaphoreSlim
  double-checked locking on GetAppTokenAsync to prevent concurrent token fetches
- EbayPriceResearchService: 15s timeout; require ≥5 samples before suggesting;
  trim top/bottom 10% outliers; BEST_MATCH sort avoids spam/broken listing bias
- PhotoAnalysisView: spinner-show inside try (Issue 1); decimal→double casts use
  Math.Round to avoid 19.99→19.989... drift (Issue 6); Dispatcher.CheckAccess guard
  for off-thread callers (Issue 7); save toast always restarts instead of silently
  dropping rapid saves, eliminating any stuck-flag path (Issue 8)

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

EbayListingTool/Services/AiAssistantService.cs

@@ -16,7 +16,7 @@ public class AiAssistantService
 {
     private readonly string _apiKey;
     private readonly string _model;
-    private static readonly HttpClient _http = new();
+    private static readonly HttpClient _http = new() { Timeout = TimeSpan.FromSeconds(90) };
 
     private const string ApiUrl = "https://openrouter.ai/api/v1/chat/completions";
 
@@ -142,20 +142,25 @@ public class AiAssistantService
     public async Task<(string Title, string Description, decimal Price, string PriceReasoning)>
         RefineWithCorrectionsAsync(string title, string description, decimal price, string corrections)
     {
+        var priceContext = price > 0
+            ? $"Current price: £{price:F2}\n\n"
+            : "";
+
         var prompt =
             "You are an expert eBay UK seller. I have a listing with incorrect details that need fixing.\n\n" +
             $"Current title: {title}\n" +
             $"Current description:\n{description}\n\n" +
-            $"Current price: £{price:F2}\n\n" +
+            priceContext +
             $"CORRECTIONS FROM SELLER: {corrections}\n\n" +
             "Rewrite the listing incorporating these corrections. " +
             "Return ONLY valid JSON — no markdown, no explanation:\n" +
             "{\n" +
             "  \"title\": \"corrected eBay UK title, max 80 chars, keyword-rich\",\n" +
             "  \"description\": \"corrected full plain-text eBay UK description\",\n" +
-            "  \"price_suggested\": 0.00,\n" +
+            "  \"price_suggested\": 29.99,\n" +
             "  \"price_reasoning\": \"one sentence why this price\"\n" +
-            "}";
+            "}\n\n" +
+            "price_suggested MUST be a realistic GBP amount greater than 0. Never return 0.";
 
         var json = await CallAsync(prompt);
 
@@ -169,10 +174,11 @@ public class AiAssistantService
                 obj = JObject.Parse(m.Success ? m.Groups[1].Value : json.Trim());
             }
 
+            var parsedPrice = obj["price_suggested"]?.Value<decimal>() ?? 0;
             return (
                 obj["title"]?.ToString()       ?? title,
                 obj["description"]?.ToString() ?? description,
-                obj["price_suggested"]?.Value<decimal>() ?? price,
+                parsedPrice > 0 ? parsedPrice : price, // treat 0 as "not provided", keep original
                 obj["price_reasoning"]?.ToString() ?? ""
             );
         }

EbayListingTool/Services/EbayAuthService.cs

@@ -18,6 +18,10 @@ public class EbayAuthService
     // App-level (client credentials) token — no user login needed, used for Browse API
     private string? _appToken;
     private DateTime _appTokenExpiry = DateTime.MinValue;
+    private readonly SemaphoreSlim _appTokenLock = new(1, 1); // prevents concurrent token fetches
+
+    // Shared HttpClient for all auth/token calls — avoids socket exhaustion from per-call `new HttpClient()`
+    private static readonly HttpClient _http = new();
 
     private static readonly string[] Scopes =
     [
@@ -114,19 +118,19 @@ public class EbayAuthService
             ? "https://api.sandbox.ebay.com/identity/v1/oauth2/token"
             : "https://api.ebay.com/identity/v1/oauth2/token";
 
-        using var http = new HttpClient();
         var credentials = Convert.ToBase64String(
             Encoding.UTF8.GetBytes($"{_settings.ClientId}:{_settings.ClientSecret}"));
-        http.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", credentials);
 
-        var body = new FormUrlEncodedContent(new Dictionary<string, string>
+        using var codeRequest = new HttpRequestMessage(HttpMethod.Post, tokenUrl);
+        codeRequest.Headers.Authorization = new AuthenticationHeaderValue("Basic", credentials);
+        codeRequest.Content = new FormUrlEncodedContent(new Dictionary<string, string>
         {
             ["grant_type"] = "authorization_code",
             ["code"] = code,
             ["redirect_uri"] = _settings.RuName
         });
 
-        var response = await http.PostAsync(tokenUrl, body);
+        var response = await _http.SendAsync(codeRequest);
         var json = await response.Content.ReadAsStringAsync();
 
         if (!response.IsSuccessStatusCode)
@@ -152,19 +156,19 @@ public class EbayAuthService
             ? "https://api.sandbox.ebay.com/identity/v1/oauth2/token"
             : "https://api.ebay.com/identity/v1/oauth2/token";
 
-        using var http = new HttpClient();
         var credentials = Convert.ToBase64String(
             Encoding.UTF8.GetBytes($"{_settings.ClientId}:{_settings.ClientSecret}"));
-        http.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", credentials);
 
-        var body = new FormUrlEncodedContent(new Dictionary<string, string>
+        using var refreshRequest = new HttpRequestMessage(HttpMethod.Post, tokenUrl);
+        refreshRequest.Headers.Authorization = new AuthenticationHeaderValue("Basic", credentials);
+        refreshRequest.Content = new FormUrlEncodedContent(new Dictionary<string, string>
         {
             ["grant_type"]    = "refresh_token",
             ["refresh_token"] = _token!.RefreshToken,
             ["scope"]         = string.Join(" ", Scopes)
         });
 
-        var response = await http.PostAsync(tokenUrl, body);
+        var response = await _http.SendAsync(refreshRequest);
         var json = await response.Content.ReadAsStringAsync();
 
         if (!response.IsSuccessStatusCode)
@@ -180,12 +184,13 @@ public class EbayAuthService
     {
         try
         {
-            using var http = new HttpClient();
-            http.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
             var url = _settings.Sandbox
                 ? "https://apiz.sandbox.ebay.com/commerce/identity/v1/user/"
                 : "https://apiz.ebay.com/commerce/identity/v1/user/";
-            var json = await http.GetStringAsync(url);
+            using var idRequest = new HttpRequestMessage(HttpMethod.Get, url);
+            idRequest.Headers.Authorization = new AuthenticationHeaderValue("Bearer", accessToken);
+            var idResponse = await _http.SendAsync(idRequest);
+            var json = await idResponse.Content.ReadAsStringAsync();
             var obj = JObject.Parse(json);
             return obj["username"]?.ToString() ?? "Unknown";
         }
@@ -202,6 +207,14 @@ public class EbayAuthService
     /// </summary>
     public async Task<string> GetAppTokenAsync()
     {
+        // Fast path — no lock needed for a read when token is valid
+        if (_appToken != null && DateTime.UtcNow < _appTokenExpiry)
+            return _appToken;
+
+        await _appTokenLock.WaitAsync();
+        try
+        {
+            // Re-check inside lock (another thread may have refreshed while we waited)
             if (_appToken != null && DateTime.UtcNow < _appTokenExpiry)
                 return _appToken;
 
@@ -212,22 +225,22 @@ public class EbayAuthService
                 ? "https://api.sandbox.ebay.com/identity/v1/oauth2/token"
                 : "https://api.ebay.com/identity/v1/oauth2/token";
 
-        using var http = new HttpClient();
             var credentials = Convert.ToBase64String(
                 Encoding.UTF8.GetBytes($"{_settings.ClientId}:{_settings.ClientSecret}"));
-        http.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", credentials);
 
-        var body = new FormUrlEncodedContent(new Dictionary<string, string>
+            using var request = new HttpRequestMessage(HttpMethod.Post, tokenUrl);
+            request.Headers.Authorization = new AuthenticationHeaderValue("Basic", credentials);
+            request.Content = new FormUrlEncodedContent(new Dictionary<string, string>
             {
                 ["grant_type"] = "client_credentials",
                 ["scope"]      = "https://api.ebay.com/oauth/api_scope"
             });
 
-        var response = await http.PostAsync(tokenUrl, body);
+            var response = await _http.SendAsync(request);
             var json     = await response.Content.ReadAsStringAsync();
 
             if (!response.IsSuccessStatusCode)
-            throw new HttpRequestException($"App token request failed: {json}");
+                throw new HttpRequestException($"App token request failed ({(int)response.StatusCode})");
 
             var obj = JObject.Parse(json);
             _appToken       = obj["access_token"]!.ToString();
@@ -235,6 +248,11 @@ public class EbayAuthService
             _appTokenExpiry = DateTime.UtcNow.AddSeconds(expiresIn - 300); // 5-min buffer
             return _appToken;
         }
+        finally
+        {
+            _appTokenLock.Release();
+        }
+    }
 
     public void Disconnect()
     {

EbayListingTool/Services/EbayPriceResearchService.cs

@@ -10,7 +10,12 @@ public class LivePriceResult
     public decimal       Min    => Prices.Count > 0 ? Prices.Min() : 0;
     public decimal       Max    => Prices.Count > 0 ? Prices.Max() : 0;
     public decimal       Median => Prices.Count > 0 ? Percentile(50) : 0;
-    public decimal       Suggested  => Prices.Count > 0 ? Percentile(40)  : 0; // 40th pct: competitive but not lowest
+
+    // Require ≥5 samples before offering a suggestion; 40th pct = competitive but not cheapest
+    public decimal Suggested => Prices.Count >= MinSampleSize ? Percentile(40) : 0;
+    public bool    HasSuggestion => Prices.Count >= MinSampleSize;
+
+    internal const int MinSampleSize = 5;
 
     private decimal Percentile(int pct)
     {
@@ -27,14 +32,16 @@ public class LivePriceResult
 public class EbayPriceResearchService
 {
     private readonly EbayAuthService _auth;
-    private static readonly HttpClient _http = new();
+
+    // 15-second timeout — price lookup is non-critical; don't leave spinner hanging
+    private static readonly HttpClient _http = new() { Timeout = TimeSpan.FromSeconds(15) };
 
     public EbayPriceResearchService(EbayAuthService auth)
     {
         _auth = auth;
     }
 
-    public async Task<LivePriceResult> GetLivePricesAsync(string query, int limit = 20)
+    public async Task<LivePriceResult> GetLivePricesAsync(string query, int limit = 30)
     {
         if (string.IsNullOrWhiteSpace(query))
             return new LivePriceResult();
@@ -42,12 +49,13 @@ public class EbayPriceResearchService
         var token   = await _auth.GetAppTokenAsync();
         var baseUrl = _auth.BaseUrl;
 
+        // Omit sort= to use eBay BEST_MATCH — price-sorted results are biased toward
+        // the cheapest (broken/spam) listings; BEST_MATCH gives a more representative sample
         using var request = new HttpRequestMessage(HttpMethod.Get,
             $"{baseUrl}/buy/browse/v1/item_summary/search" +
             $"?q={Uri.EscapeDataString(query)}" +
             $"&filter=buyingOptions%3A%7BFIXED_PRICE%7D" +
-            $"&limit={limit}" +
+            $"&limit={limit}");
-            $"&sort=price");
 
         request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
         request.Headers.Add("X-EBAY-C-MARKETPLACE-ID", "EBAY_GB");
@@ -56,7 +64,7 @@ public class EbayPriceResearchService
         var json     = await response.Content.ReadAsStringAsync();
 
         if (!response.IsSuccessStatusCode)
-            throw new HttpRequestException($"eBay Browse API error ({(int)response.StatusCode}): {json}");
+            throw new HttpRequestException($"eBay Browse API error ({(int)response.StatusCode})");
 
         var obj    = JObject.Parse(json);
         var items  = obj["itemSummaries"] as JArray ?? new JArray();
@@ -75,6 +83,15 @@ public class EbayPriceResearchService
             }
         }
 
+        // Trim top and bottom 10% to remove outliers (spammers, broken items, typos).
+        // Only trim when there are enough data points to make it worthwhile.
+        if (prices.Count >= 10)
+        {
+            prices.Sort();
+            int trim = (int)Math.Floor(prices.Count * 0.10);
+            prices = prices.Skip(trim).Take(prices.Count - 2 * trim).ToList();
+        }
+
         return new LivePriceResult { Prices = prices };
     }
 }

EbayListingTool/Views/PhotoAnalysisView.xaml.cs

@@ -248,7 +248,7 @@ public partial class PhotoAnalysisView : UserControl
 
             TitleBox.Text             = newTitle;
             DescriptionBox.Text       = newDesc;
-            PriceOverride.Value       = (double)newPrice;
+            PriceOverride.Value       = (double)Math.Round(newPrice, 2); // Issue 6
             PriceSuggestedText.Text   = newPrice > 0 ? $"£{newPrice:F2}" : "—";
 
             _lastResult.Title          = newTitle;
@@ -338,7 +338,7 @@ public partial class PhotoAnalysisView : UserControl
             PriceRangeBar.Visibility = Visibility.Collapsed;
         }
 
-        PriceOverride.Value = (double)r.PriceSuggested;
+        PriceOverride.Value = (double)Math.Round(r.PriceSuggested, 2); // Issue 6
 
         // Price reasoning
         PriceReasoningText.Text = r.PriceReasoning;
@@ -361,13 +361,20 @@ public partial class PhotoAnalysisView : UserControl
     {
         if (_priceService == null) return;
 
-        // Show spinner
+        // Issue 7: guard against off-thread callers (fire-and-forget may lose sync context)
+        if (!Dispatcher.CheckAccess())
+        {
+            await Dispatcher.InvokeAsync(() => UpdateLivePricesAsync(query)).Task.Unwrap();
+            return;
+        }
+
+        try
+        {
+            // Issue 1: spinner-show inside try so a disposed control doesn't crash the caller
             LivePriceRow.Visibility     = Visibility.Visible;
             LivePriceSpinner.Visibility = Visibility.Visible;
             LivePriceStatus.Text        = "Checking live eBay UK prices…";
 
-        try
-        {
             var live = await _priceService.GetLivePricesAsync(query);
 
             if (live.Count == 0)
@@ -385,7 +392,7 @@ public partial class PhotoAnalysisView : UserControl
             // Update suggested price to 40th percentile (competitive but not cheapest)
             var suggested = live.Suggested;
             PriceSuggestedText.Text = $"£{suggested:F2}";
-            PriceOverride.Value     = (double)suggested;
+            PriceOverride.Value     = (double)Math.Round(suggested, 2); // Issue 6: avoid decimal→double drift
             if (_lastResult != null) _lastResult.PriceSuggested = suggested;
 
             // Update status label
@@ -395,10 +402,14 @@ public partial class PhotoAnalysisView : UserControl
                 $"(range £{live.Min:F2} – £{live.Max:F2})";
         }
         catch (Exception ex)
+        {
+            try
             {
                 LivePriceSpinner.Visibility = Visibility.Collapsed;
                 LivePriceStatus.Text        = $"Live price lookup unavailable: {ex.Message}";
             }
+            catch { /* control may be unloaded by the time catch runs */ }
+        }
     }
 
     private void TitleBox_TextChanged(object sender, TextChangedEventArgs e)
@@ -602,12 +613,13 @@ public partial class PhotoAnalysisView : UserControl
 
     // ---- Save toast ----
 
-    private bool _toastAnimating = false;
-
     private void ShowSaveToast()
     {
-        if (_toastAnimating) return;
+        // Issue 8: always restart — stop any in-progress hold timer and cancel the running
-        _toastAnimating = true;
+        // animation so the flag can never get permanently stuck and rapid saves feel responsive.
+        _holdTimer?.Stop();
+        _holdTimer = null;
+        ToastTranslate.BeginAnimation(TranslateTransform.YProperty, null); // cancel current animation
 
         SaveToast.Visibility = Visibility.Visible;
 
@@ -631,7 +643,6 @@ public partial class PhotoAnalysisView : UserControl
                 slideOut.Completed += (_, _) =>
                 {
                     SaveToast.Visibility = Visibility.Collapsed;
-                    _toastAnimating      = false;
                 };
                 ToastTranslate.BeginAnimation(TranslateTransform.YProperty, slideOut);
             };