refactor(gmail): extract DTOs and static helpers from GmailController

Backlog item 3 (Wave 2), GmailController slice. Pure mechanical extraction, no behaviour change: - GmailDtos.cs: the 26 inline record DTOs, moved to a partial-class file so every existing GmailController.XyzDto reference (tests included) keeps working unchanged. - GmailParsing.cs: the 8 pure static helpers (ApplySyncBoundary, LooksLikeJobRelatedThread, ToConfidence, ExtractFirstEmail/RecruiterName/ CompanyName/RoleFromSubject, BuildPopupHtml), same partial-class approach. GmailController.cs: 1200 -> 1022 lines. 169/169 green. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
perf(gmail): narrow review-decision lookup to the single ThreadId
2026-07-11 20:45:48 +02:00 · 2026-07-11 20:38:26 +02:00 · 2026-07-11 20:37:01 +02:00
3 changed files with 209 additions and 187 deletions
@@ -13,7 +13,7 @@ namespace JobTrackerApi.Controllers;
 [ApiController]
 [Route("api/gmail")]
 [Authorize]
-public sealed class GmailController : ControllerBase
+public sealed partial class GmailController : ControllerBase
 {
    private readonly IGmailOAuthService _gmail;
    private readonly IGmailJobMatchingService _matching;
@@ -37,77 +37,6 @@ public sealed class GmailController : ControllerBase
    private IEmailProvider Email => _providers.Get("gmail")
        ?? throw new InvalidOperationException("Gmail email provider is not registered.");

-    public sealed record GmailImportResultDto(int Imported, int Skipped, string? ThreadId);
-    public sealed record GmailImportMessageResultDto(int Imported, int Skipped, string MessageId, string? ThreadId, Correspondence? Message);
-    public sealed record ImportGmailMessageRequest(int JobApplicationId, string MessageId);
-    public sealed record ImportGmailThreadRequest(int JobApplicationId, string ThreadId, string[] MessageIds);
-    public sealed record RefreshLinkedThreadsRequest(int JobApplicationId);
-    public sealed record GmailThreadRefreshThreadDto(string ThreadId, int Imported, int Skipped, int TotalMessages, string Status, DateTimeOffset? LatestMessageDate);
-    public sealed record GmailThreadRefreshResultDto(int JobApplicationId, int ThreadsChecked, int Imported, int Skipped, bool HasLinkedThreads, DateTimeOffset RefreshedAt, IReadOnlyList<GmailThreadRefreshThreadDto> Threads);
-    public sealed record GmailJobMatchReasonDto(string Label, string Value, int Points);
-    public sealed record GmailJobMatchedMessageDto(
-        string Id,
-        string ThreadId,
-        string Subject,
-        string From,
-        string To,
-        DateTimeOffset? Date,
-        string Snippet,
-        int Score,
-        string Confidence,
-        bool AlreadyImported,
-        IReadOnlyList<string> MatchedQueries,
-        IReadOnlyList<GmailJobMatchReasonDto> MatchReasons);
-    public sealed record GmailJobMatchedThreadDto(
-        string ThreadId,
-        string Subject,
-        int Score,
-        string Confidence,
-        bool HasImportedMessages,
-        int ImportedMessageCount,
-        int MessageCount,
-        DateTimeOffset? LatestDate,
-        IReadOnlyList<string> MatchedQueries,
-        IReadOnlyList<GmailJobMatchReasonDto> MatchReasons,
-        IReadOnlyList<GmailJobMatchedMessageDto> Messages);
-    public sealed record GmailJobMatchesResponseDto(
-        int JobApplicationId,
-        string JobTitle,
-        string CompanyName,
-        string? RecruiterName,
-        string? RecruiterEmail,
-        IReadOnlyList<string> Queries,
-        int CandidateMessageCount,
-        int CandidateThreadCount,
-        IReadOnlyList<GmailJobMatchedThreadDto> Threads);
-
-    public sealed record GmailReviewJobCandidateDto(int JobApplicationId, string JobTitle, string CompanyName, int Score, string Confidence, IReadOnlyList<GmailJobMatchReasonDto> Reasons);
-    public sealed record GmailReviewThreadDto(string ThreadId, string Subject, DateTimeOffset? LatestDate, int MessageCount, string Routing, bool HasImportedMessages, string? DecisionNote, IReadOnlyList<string> MatchedQueries, IReadOnlyList<GmailReviewJobCandidateDto> JobCandidates, IReadOnlyList<GmailJobMatchedMessageDto> Messages);
-    public sealed record GmailReviewQueueResponseDto(IReadOnlyList<string> Queries, int CandidateThreadCount, int AutoLinkThreadCount, int ReviewThreadCount, int UnmatchedThreadCount, IReadOnlyList<GmailReviewThreadDto> Threads);
-    public sealed record SaveGmailReviewDecisionRequest(string ThreadId, string Decision, int? JobApplicationId, string? Note);
-    public sealed record GmailManualSyncRequest(int? LookbackDays, int? MaxResultsPerQuery, bool? AutoImportHighConfidence, bool? IncludeSpamTrash);
-    public sealed record GmailManualSyncResultDto(int QueriesRun, int CandidateThreadCount, int AutoLinkedThreadCount, int ReviewThreadCount, int UnmatchedThreadCount, int ImportedMessages, int ImportedThreads, int SkippedMessages, int LookbackDays, bool IncludeSpamTrash, DateTimeOffset SyncedAt);
-    public sealed record GmailSuggestedJobCandidateDto(string ThreadId, string Subject, DateTimeOffset? LatestDate, string? CompanyName, string? RecruiterName, string? RecruiterEmail, string? SuggestedJobTitle, string Routing, IReadOnlyList<string> MatchedQueries, string Preview);
-    public sealed record GmailSuggestedJobsResponseDto(int Count, IReadOnlyList<GmailSuggestedJobCandidateDto> Items);
-    public sealed record CreateSuggestedGmailJobRequest(string ThreadId, string CompanyName, string JobTitle, string? RecruiterName, string? RecruiterEmail, string? Notes, string? Status);
-    public sealed record CreatedSuggestedGmailJobDto(int JobApplicationId, int CompanyId, string ThreadId, int Imported, int Skipped);
-    public sealed record RelinkGmailThreadRequest(int JobApplicationId, string ThreadId, bool RemoveFromOtherJobs, string? Note);
-    public sealed record GmailRelinkResultDto(string ThreadId, int JobApplicationId, int Imported, int Skipped, int UnlinkedMessages);
-    public sealed record UnlinkGmailThreadRequest(int JobApplicationId, string ThreadId, string? Note, string? NextDecision);
-    public sealed record GmailUnlinkResultDto(string ThreadId, int JobApplicationId, int RemovedMessages, string Decision);
-
-    public sealed record GmailConnectionStatusDto(
-        bool Connected,
-        string? GmailAddress,
-        DateTimeOffset? ConnectedAt,
-        DateTimeOffset? LastSyncedAt,
-        DateTimeOffset? LastSyncAttemptedAt,
-        DateTimeOffset? LastSyncSucceededAt,
-        string? LastSyncMode,
-        string? LastSyncSource,
-        string? LastSyncStatus,
-        string? LastSyncError);
-
    [HttpGet("status")]
    public async Task<ActionResult<GmailConnectionStatusDto>> Status(CancellationToken cancellationToken)
    {
@@ -671,7 +600,9 @@ public sealed class GmailController : ControllerBase
            imported++;
        }

-        UpsertReviewDecision(await _db.GmailReviewDecisions.Where(x => x.OwnerUserId == ownerUserId).ToListAsync(cancellationToken), ownerUserId, request.ThreadId.Trim(), "linked", job.Id, request.Notes);
+        var suggestedJobReviewDecision = await _db.GmailReviewDecisions
+            .FirstOrDefaultAsync(x => x.OwnerUserId == ownerUserId && x.ThreadId == request.ThreadId.Trim(), cancellationToken);
+        UpsertReviewDecision(suggestedJobReviewDecision, ownerUserId, request.ThreadId.Trim(), "linked", job.Id, request.Notes);
        await _db.SaveChangesAsync(cancellationToken);
        return Ok(new CreatedSuggestedGmailJobDto(job.Id, company.Id, request.ThreadId.Trim(), imported, skipped));
    }
@@ -725,8 +656,9 @@ public sealed class GmailController : ControllerBase
            imported++;
        }

-        var reviewDecisions = await _db.GmailReviewDecisions.Where(x => x.OwnerUserId == ownerUserId).ToListAsync(cancellationToken);
-        UpsertReviewDecision(reviewDecisions, ownerUserId, threadId, "linked", job.Id, request.Note);
+        var reviewDecision = await _db.GmailReviewDecisions
+            .FirstOrDefaultAsync(x => x.OwnerUserId == ownerUserId && x.ThreadId == threadId, cancellationToken);
+        UpsertReviewDecision(reviewDecision, ownerUserId, threadId, "linked", job.Id, request.Note);
        await _db.SaveChangesAsync(cancellationToken);
        return Ok(new GmailRelinkResultDto(threadId, job.Id, imported, skipped, unlinkedMessages));
    }
@@ -752,10 +684,11 @@ public sealed class GmailController : ControllerBase
            _db.Correspondences.RemoveRange(messages);
        }

-        var reviewDecisions = await _db.GmailReviewDecisions.Where(x => x.OwnerUserId == ownerUserId).ToListAsync(cancellationToken);
+        var reviewDecision = await _db.GmailReviewDecisions
+            .FirstOrDefaultAsync(x => x.OwnerUserId == ownerUserId && x.ThreadId == threadId, cancellationToken);
        var nextDecision = (request.NextDecision ?? "review").Trim().ToLowerInvariant();
        if (nextDecision is not ("review" or "suggested" or "rejected")) nextDecision = "review";
-        UpsertReviewDecision(reviewDecisions, ownerUserId, threadId, nextDecision, null, request.Note);
+        UpsertReviewDecision(reviewDecision, ownerUserId, threadId, nextDecision, null, request.Note);
        await _db.SaveChangesAsync(cancellationToken);
        return Ok(new GmailUnlinkResultDto(threadId, job.Id, messages.Count, nextDecision));
    }
@@ -1012,40 +945,6 @@ public sealed class GmailController : ControllerBase
        return _matching.BuildJobQueries(job, queryOverride);
    }

-    private static string ApplySyncBoundary(string query, int lookbackDays, bool includeSpamTrash)
-    {
-        var bounded = (query ?? string.Empty).Trim();
-        if (!bounded.Contains("newer_than:", StringComparison.OrdinalIgnoreCase))
-        {
-            bounded = string.IsNullOrWhiteSpace(bounded)
-                ? $"newer_than:{lookbackDays}d"
-                : $"{bounded} newer_than:{lookbackDays}d";
-        }
-
-        if (!includeSpamTrash)
-        {
-            if (!bounded.Contains("in:spam", StringComparison.OrdinalIgnoreCase)) bounded += " -in:spam";
-            if (!bounded.Contains("in:trash", StringComparison.OrdinalIgnoreCase)) bounded += " -in:trash";
-        }
-
-        return bounded.Trim();
-    }
-
-    private static bool LooksLikeJobRelatedThread(IReadOnlyList<GmailQueryMatchedMessage> orderedMessages)
-    {
-        var sample = string.Join("\n", orderedMessages.Select(item => string.Join(" ", new[] { item.Message.Subject, item.Message.From, item.Message.Snippet }.Where(value => !string.IsNullOrWhiteSpace(value)))));
-        if (string.IsNullOrWhiteSpace(sample)) return false;
-        return sample.Contains("interview", StringComparison.OrdinalIgnoreCase)
-            || sample.Contains("application", StringComparison.OrdinalIgnoreCase)
-            || sample.Contains("recruit", StringComparison.OrdinalIgnoreCase)
-            || sample.Contains("role", StringComparison.OrdinalIgnoreCase)
-            || sample.Contains("position", StringComparison.OrdinalIgnoreCase)
-            || sample.Contains("offer", StringComparison.OrdinalIgnoreCase)
-            || sample.Contains("follow up", StringComparison.OrdinalIgnoreCase)
-            || sample.Contains("follow-up", StringComparison.OrdinalIgnoreCase)
-            || sample.Contains("rejection", StringComparison.OrdinalIgnoreCase);
-    }
-
    private void UpsertReviewDecision(IDictionary<string, GmailReviewDecision> decisions, string ownerUserId, string threadId, string decision, int? jobApplicationId, string? note)
    {
        if (!decisions.TryGetValue(threadId, out var existing))
@@ -1065,9 +964,11 @@ public sealed class GmailController : ControllerBase
        existing.UpdatedAt = DateTimeOffset.UtcNow;
    }

-    private void UpsertReviewDecision(List<GmailReviewDecision> decisions, string ownerUserId, string threadId, string decision, int? jobApplicationId, string? note)
+    // Single-thread upsert: callers acting on exactly one ThreadId should load just that row
+    // (see the FirstOrDefaultAsync call sites below) rather than every review decision for the
+    // owner just to scan for one match.
+    private void UpsertReviewDecision(GmailReviewDecision? existing, string ownerUserId, string threadId, string decision, int? jobApplicationId, string? note)
    {
-        var existing = decisions.FirstOrDefault(x => x.ThreadId == threadId);
        if (existing is null)
        {
            existing = new GmailReviewDecision
@@ -1075,7 +976,6 @@ public sealed class GmailController : ControllerBase
                OwnerUserId = ownerUserId,
                ThreadId = threadId,
            };
-            decisions.Add(existing);
            _db.GmailReviewDecisions.Add(existing);
        }

@@ -1085,54 +985,6 @@ public sealed class GmailController : ControllerBase
        existing.UpdatedAt = DateTimeOffset.UtcNow;
    }

-    private static string ToConfidence(int score)
-    {
-        return score switch
-        {
-            >= 30 => "high",
-            >= 16 => "medium",
-            _ => "low"
-        };
-    }
-
-    private static string? ExtractFirstEmail(string? value)
-    {
-        if (string.IsNullOrWhiteSpace(value)) return null;
-        var match = System.Text.RegularExpressions.Regex.Match(value, @"[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,}", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
-        return match.Success ? match.Value : null;
-    }
-
-    private static string? ExtractRecruiterName(string? value)
-    {
-        if (string.IsNullOrWhiteSpace(value)) return null;
-        var trimmed = value.Split('<')[0].Trim().Trim('"');
-        return string.IsNullOrWhiteSpace(trimmed) || trimmed.Contains('@') ? null : trimmed;
-    }
-
-    private static string? ExtractCompanyName(string? from, string? subject)
-    {
-        var subjectText = (subject ?? string.Empty).Trim();
-        if (!string.IsNullOrWhiteSpace(subjectText))
-        {
-            var parts = subjectText.Split(new[] { '-', '–', '|' }, StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
-            if (parts.Length >= 2) return parts[0];
-        }
-
-        var recruiterName = ExtractRecruiterName(from);
-        return recruiterName is { Length: > 0 } && recruiterName.Contains(' ') ? recruiterName.Split(' ').Last() : null;
-    }
-
-    private static string? ExtractRoleFromSubject(string? subject)
-    {
-        if (string.IsNullOrWhiteSpace(subject)) return null;
-        var trimmed = subject.Trim();
-        if (trimmed.Contains("interview", StringComparison.OrdinalIgnoreCase))
-        {
-            return trimmed.Replace("interview", string.Empty, StringComparison.OrdinalIgnoreCase).Trim(' ', '-', ':');
-        }
-        return trimmed.Length <= 120 ? trimmed : trimmed[..120];
-    }
-
    private string GetRequiredOwnerUserId()
    {
        return User.FindFirstValue(ClaimTypes.NameIdentifier) ?? User.FindFirstValue("sub")
@@ -1167,29 +1019,4 @@ public sealed class GmailController : ControllerBase
        return $"{Request.Scheme}://{Request.Host}/api/gmail/oauth/callback";
    }

-    private static string BuildPopupHtml(bool success, string message)
-    {
-        var escaped = System.Net.WebUtility.HtmlEncode(message);
-        var status = success ? "connected" : "error";
-        var title = success ? "Gmail connected" : "Gmail connection failed";
-        var serializedMessage = System.Text.Json.JsonSerializer.Serialize(message);
-        return $@"<!doctype html>
-<html>
-<head>
-  <meta charset=""utf-8"" />
-  <title>Gmail connection</title>
-</head>
-<body style=""font-family:Segoe UI,Arial,sans-serif;padding:24px;line-height:1.5;"">
-  <h2>{title}</h2>
-  <p>{escaped}</p>
-  <p>You can close this window.</p>
-  <script>
-    if (window.opener) {{
-      window.opener.postMessage({{ source: 'jobtracker-gmail-oauth', status: '{status}', message: {serializedMessage} }}, '*');
-    }}
-    window.close();
-  </script>
-</body>
-</html>";
-    }
 }
@@ -0,0 +1,79 @@
+using JobTrackerApi.Models;
+
+namespace JobTrackerApi.Controllers;
+
+// DTOs for GmailController, split out for readability (Wave 2 safe refactor -- no behaviour
+// change; these were previously nested inline in the controller file).
+public partial class GmailController
+{
+    public sealed record GmailImportResultDto(int Imported, int Skipped, string? ThreadId);
+    public sealed record GmailImportMessageResultDto(int Imported, int Skipped, string MessageId, string? ThreadId, Correspondence? Message);
+    public sealed record ImportGmailMessageRequest(int JobApplicationId, string MessageId);
+    public sealed record ImportGmailThreadRequest(int JobApplicationId, string ThreadId, string[] MessageIds);
+    public sealed record RefreshLinkedThreadsRequest(int JobApplicationId);
+    public sealed record GmailThreadRefreshThreadDto(string ThreadId, int Imported, int Skipped, int TotalMessages, string Status, DateTimeOffset? LatestMessageDate);
+    public sealed record GmailThreadRefreshResultDto(int JobApplicationId, int ThreadsChecked, int Imported, int Skipped, bool HasLinkedThreads, DateTimeOffset RefreshedAt, IReadOnlyList<GmailThreadRefreshThreadDto> Threads);
+    public sealed record GmailJobMatchReasonDto(string Label, string Value, int Points);
+    public sealed record GmailJobMatchedMessageDto(
+        string Id,
+        string ThreadId,
+        string Subject,
+        string From,
+        string To,
+        DateTimeOffset? Date,
+        string Snippet,
+        int Score,
+        string Confidence,
+        bool AlreadyImported,
+        IReadOnlyList<string> MatchedQueries,
+        IReadOnlyList<GmailJobMatchReasonDto> MatchReasons);
+    public sealed record GmailJobMatchedThreadDto(
+        string ThreadId,
+        string Subject,
+        int Score,
+        string Confidence,
+        bool HasImportedMessages,
+        int ImportedMessageCount,
+        int MessageCount,
+        DateTimeOffset? LatestDate,
+        IReadOnlyList<string> MatchedQueries,
+        IReadOnlyList<GmailJobMatchReasonDto> MatchReasons,
+        IReadOnlyList<GmailJobMatchedMessageDto> Messages);
+    public sealed record GmailJobMatchesResponseDto(
+        int JobApplicationId,
+        string JobTitle,
+        string CompanyName,
+        string? RecruiterName,
+        string? RecruiterEmail,
+        IReadOnlyList<string> Queries,
+        int CandidateMessageCount,
+        int CandidateThreadCount,
+        IReadOnlyList<GmailJobMatchedThreadDto> Threads);
+
+    public sealed record GmailReviewJobCandidateDto(int JobApplicationId, string JobTitle, string CompanyName, int Score, string Confidence, IReadOnlyList<GmailJobMatchReasonDto> Reasons);
+    public sealed record GmailReviewThreadDto(string ThreadId, string Subject, DateTimeOffset? LatestDate, int MessageCount, string Routing, bool HasImportedMessages, string? DecisionNote, IReadOnlyList<string> MatchedQueries, IReadOnlyList<GmailReviewJobCandidateDto> JobCandidates, IReadOnlyList<GmailJobMatchedMessageDto> Messages);
+    public sealed record GmailReviewQueueResponseDto(IReadOnlyList<string> Queries, int CandidateThreadCount, int AutoLinkThreadCount, int ReviewThreadCount, int UnmatchedThreadCount, IReadOnlyList<GmailReviewThreadDto> Threads);
+    public sealed record SaveGmailReviewDecisionRequest(string ThreadId, string Decision, int? JobApplicationId, string? Note);
+    public sealed record GmailManualSyncRequest(int? LookbackDays, int? MaxResultsPerQuery, bool? AutoImportHighConfidence, bool? IncludeSpamTrash);
+    public sealed record GmailManualSyncResultDto(int QueriesRun, int CandidateThreadCount, int AutoLinkedThreadCount, int ReviewThreadCount, int UnmatchedThreadCount, int ImportedMessages, int ImportedThreads, int SkippedMessages, int LookbackDays, bool IncludeSpamTrash, DateTimeOffset SyncedAt);
+    public sealed record GmailSuggestedJobCandidateDto(string ThreadId, string Subject, DateTimeOffset? LatestDate, string? CompanyName, string? RecruiterName, string? RecruiterEmail, string? SuggestedJobTitle, string Routing, IReadOnlyList<string> MatchedQueries, string Preview);
+    public sealed record GmailSuggestedJobsResponseDto(int Count, IReadOnlyList<GmailSuggestedJobCandidateDto> Items);
+    public sealed record CreateSuggestedGmailJobRequest(string ThreadId, string CompanyName, string JobTitle, string? RecruiterName, string? RecruiterEmail, string? Notes, string? Status);
+    public sealed record CreatedSuggestedGmailJobDto(int JobApplicationId, int CompanyId, string ThreadId, int Imported, int Skipped);
+    public sealed record RelinkGmailThreadRequest(int JobApplicationId, string ThreadId, bool RemoveFromOtherJobs, string? Note);
+    public sealed record GmailRelinkResultDto(string ThreadId, int JobApplicationId, int Imported, int Skipped, int UnlinkedMessages);
+    public sealed record UnlinkGmailThreadRequest(int JobApplicationId, string ThreadId, string? Note, string? NextDecision);
+    public sealed record GmailUnlinkResultDto(string ThreadId, int JobApplicationId, int RemovedMessages, string Decision);
+
+    public sealed record GmailConnectionStatusDto(
+        bool Connected,
+        string? GmailAddress,
+        DateTimeOffset? ConnectedAt,
+        DateTimeOffset? LastSyncedAt,
+        DateTimeOffset? LastSyncAttemptedAt,
+        DateTimeOffset? LastSyncSucceededAt,
+        string? LastSyncMode,
+        string? LastSyncSource,
+        string? LastSyncStatus,
+        string? LastSyncError);
+}
@@ -0,0 +1,116 @@
+using JobTrackerApi.Services;
+
+namespace JobTrackerApi.Controllers;
+
+// Pure parsing/formatting helpers for GmailController, split out for readability (Wave 2 safe
+// refactor -- no behaviour change). All are static and side-effect free.
+public sealed partial class GmailController
+{
+    private static string ApplySyncBoundary(string query, int lookbackDays, bool includeSpamTrash)
+    {
+        var bounded = (query ?? string.Empty).Trim();
+        if (!bounded.Contains("newer_than:", StringComparison.OrdinalIgnoreCase))
+        {
+            bounded = string.IsNullOrWhiteSpace(bounded)
+                ? $"newer_than:{lookbackDays}d"
+                : $"{bounded} newer_than:{lookbackDays}d";
+        }
+
+        if (!includeSpamTrash)
+        {
+            if (!bounded.Contains("in:spam", StringComparison.OrdinalIgnoreCase)) bounded += " -in:spam";
+            if (!bounded.Contains("in:trash", StringComparison.OrdinalIgnoreCase)) bounded += " -in:trash";
+        }
+
+        return bounded.Trim();
+    }
+
+    private static bool LooksLikeJobRelatedThread(IReadOnlyList<GmailQueryMatchedMessage> orderedMessages)
+    {
+        var sample = string.Join("\n", orderedMessages.Select(item => string.Join(" ", new[] { item.Message.Subject, item.Message.From, item.Message.Snippet }.Where(value => !string.IsNullOrWhiteSpace(value)))));
+        if (string.IsNullOrWhiteSpace(sample)) return false;
+        return sample.Contains("interview", StringComparison.OrdinalIgnoreCase)
+            || sample.Contains("application", StringComparison.OrdinalIgnoreCase)
+            || sample.Contains("recruit", StringComparison.OrdinalIgnoreCase)
+            || sample.Contains("role", StringComparison.OrdinalIgnoreCase)
+            || sample.Contains("position", StringComparison.OrdinalIgnoreCase)
+            || sample.Contains("offer", StringComparison.OrdinalIgnoreCase)
+            || sample.Contains("follow up", StringComparison.OrdinalIgnoreCase)
+            || sample.Contains("follow-up", StringComparison.OrdinalIgnoreCase)
+            || sample.Contains("rejection", StringComparison.OrdinalIgnoreCase);
+    }
+
+    private static string ToConfidence(int score)
+    {
+        return score switch
+        {
+            >= 30 => "high",
+            >= 16 => "medium",
+            _ => "low"
+        };
+    }
+
+    private static string? ExtractFirstEmail(string? value)
+    {
+        if (string.IsNullOrWhiteSpace(value)) return null;
+        var match = System.Text.RegularExpressions.Regex.Match(value, @"[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,}", System.Text.RegularExpressions.RegexOptions.IgnoreCase);
+        return match.Success ? match.Value : null;
+    }
+
+    private static string? ExtractRecruiterName(string? value)
+    {
+        if (string.IsNullOrWhiteSpace(value)) return null;
+        var trimmed = value.Split('<')[0].Trim().Trim('"');
+        return string.IsNullOrWhiteSpace(trimmed) || trimmed.Contains('@') ? null : trimmed;
+    }
+
+    private static string? ExtractCompanyName(string? from, string? subject)
+    {
+        var subjectText = (subject ?? string.Empty).Trim();
+        if (!string.IsNullOrWhiteSpace(subjectText))
+        {
+            var parts = subjectText.Split(new[] { '-', '–', '|' }, StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries);
+            if (parts.Length >= 2) return parts[0];
+        }
+
+        var recruiterName = ExtractRecruiterName(from);
+        return recruiterName is { Length: > 0 } && recruiterName.Contains(' ') ? recruiterName.Split(' ').Last() : null;
+    }
+
+    private static string? ExtractRoleFromSubject(string? subject)
+    {
+        if (string.IsNullOrWhiteSpace(subject)) return null;
+        var trimmed = subject.Trim();
+        if (trimmed.Contains("interview", StringComparison.OrdinalIgnoreCase))
+        {
+            return trimmed.Replace("interview", string.Empty, StringComparison.OrdinalIgnoreCase).Trim(' ', '-', ':');
+        }
+        return trimmed.Length <= 120 ? trimmed : trimmed[..120];
+    }
+
+    private static string BuildPopupHtml(bool success, string message)
+    {
+        var escaped = System.Net.WebUtility.HtmlEncode(message);
+        var status = success ? "connected" : "error";
+        var title = success ? "Gmail connected" : "Gmail connection failed";
+        var serializedMessage = System.Text.Json.JsonSerializer.Serialize(message);
+        return $@"<!doctype html>
+<html>
+<head>
+  <meta charset=""utf-8"" />
+  <title>Gmail connection</title>
+</head>
+<body style=""font-family:Segoe UI,Arial,sans-serif;padding:24px;line-height:1.5;"">
+  <h2>{title}</h2>
+  <p>{escaped}</p>
+  <p>You can close this window.</p>
+  <script>
+    if (window.opener) {{
+      window.opener.postMessage({{ source: 'jobtracker-gmail-oauth', status: '{status}', message: {serializedMessage} }}, '*');
+    }}
+    window.close();
+  </script>
+</body>
+</html>";
+    }
+}