feat(search): relevance ranking + websearch_to_tsquery (#13)

src/InboxIntel.Infrastructure/Analytics/AnalyticsService.cs

@@ -133,13 +133,13 @@ public class AnalyticsService : IAnalyticsService
         var emails = _db.Emails.Where(e => e.UserId == userId);
 
         var allMail = await emails.CountAsync(ct);
-        var inbox   = await emails.CountAsync(e => e.IsInInbox, ct);
-        var unread  = await emails.CountAsync(e => e.IsUnread, ct);
+        var inbox = await emails.CountAsync(e => e.IsInInbox, ct);
+        var unread = await emails.CountAsync(e => e.IsUnread, ct);
         var starred = await emails.CountAsync(e => e.IsStarred, ct);
-        var trash   = await emails.CountAsync(e => e.IsTrashed, ct);
-        var large   = await emails.CountAsync(e => e.SizeEstimateBytes > 5_000_000, ct);
-        var cutoff  = DateTimeOffset.UtcNow.AddYears(-1);
-        var old     = await emails.CountAsync(e => e.SentAtUtc < cutoff, ct);
+        var trash = await emails.CountAsync(e => e.IsTrashed, ct);
+        var large = await emails.CountAsync(e => e.SizeEstimateBytes > 5_000_000, ct);
+        var cutoff = DateTimeOffset.UtcNow.AddYears(-1);
+        var old = await emails.CountAsync(e => e.SentAtUtc < cutoff, ct);
 
         // Label-backed counts (SENT / DRAFT / SPAM are system Gmail labels)
         async Task<int> LabelCount(string gmailId)
@@ -153,9 +153,9 @@ public class AnalyticsService : IAnalyticsService
                 : 0;
         }
 
-        var sent   = await LabelCount("SENT");
+        var sent = await LabelCount("SENT");
         var drafts = await LabelCount("DRAFT");
-        var spam   = await LabelCount("SPAM");
+        var spam = await LabelCount("SPAM");
 
         // Category → smart-folder slug mapping
         var catCounts = await emails
@@ -167,31 +167,31 @@ public class AnalyticsService : IAnalyticsService
 
         var smartFolders = new Dictionary<string, int>
         {
-            ["automated"]    = Cat(EmailCategory.Notification),
-            ["finance"]      = Cat(EmailCategory.Finance),
-            ["social"]       = Cat(EmailCategory.Social),
-            ["shopping"]     = Cat(EmailCategory.Shopping) + Cat(EmailCategory.Promotional),
-            ["noreply"]      = Cat(EmailCategory.Notification),
-            ["gaming"]       = Cat(EmailCategory.Gaming),
-            ["sales"]        = Cat(EmailCategory.SeasonalSales),
-            ["ridesharing"]  = Cat(EmailCategory.RideSharing),
-            ["food"]         = Cat(EmailCategory.FoodDelivery),
-            ["wellness"]     = Cat(EmailCategory.Wellness),
+            ["automated"] = Cat(EmailCategory.Notification),
+            ["finance"] = Cat(EmailCategory.Finance),
+            ["social"] = Cat(EmailCategory.Social),
+            ["shopping"] = Cat(EmailCategory.Shopping) + Cat(EmailCategory.Promotional),
+            ["noreply"] = Cat(EmailCategory.Notification),
+            ["gaming"] = Cat(EmailCategory.Gaming),
+            ["sales"] = Cat(EmailCategory.SeasonalSales),
+            ["ridesharing"] = Cat(EmailCategory.RideSharing),
+            ["food"] = Cat(EmailCategory.FoodDelivery),
+            ["wellness"] = Cat(EmailCategory.Wellness),
             // New categories
-            ["travel"]        = Cat(EmailCategory.Travel),
+            ["travel"] = Cat(EmailCategory.Travel),
             ["subscriptions"] = Cat(EmailCategory.Subscriptions),
-            ["parcels"]       = Cat(EmailCategory.Parcels),
-            ["recruitment"]   = Cat(EmailCategory.Recruitment),
-            ["events"]        = Cat(EmailCategory.Events),
-            ["security"]      = Cat(EmailCategory.SecurityAlerts),
-            ["healthcare"]    = Cat(EmailCategory.Healthcare),
-            ["education"]     = Cat(EmailCategory.Education),
-            ["news"]          = Cat(EmailCategory.NewsMedia),
-            ["property"]      = Cat(EmailCategory.PropertyUtilities),
-            ["charity"]       = Cat(EmailCategory.Charity),
-            ["government"]    = Cat(EmailCategory.Government),
-            ["crypto"]        = Cat(EmailCategory.CryptoInvesting),
-            ["family"]        = Cat(EmailCategory.FamilySchool),
+            ["parcels"] = Cat(EmailCategory.Parcels),
+            ["recruitment"] = Cat(EmailCategory.Recruitment),
+            ["events"] = Cat(EmailCategory.Events),
+            ["security"] = Cat(EmailCategory.SecurityAlerts),
+            ["healthcare"] = Cat(EmailCategory.Healthcare),
+            ["education"] = Cat(EmailCategory.Education),
+            ["news"] = Cat(EmailCategory.NewsMedia),
+            ["property"] = Cat(EmailCategory.PropertyUtilities),
+            ["charity"] = Cat(EmailCategory.Charity),
+            ["government"] = Cat(EmailCategory.Government),
+            ["crypto"] = Cat(EmailCategory.CryptoInvesting),
+            ["family"] = Cat(EmailCategory.FamilySchool),
         };
 
         return new SidebarCountsDto(inbox, allMail, unread, starred, sent, drafts, trash, spam, large, old, smartFolders);

src/InboxIntel.Infrastructure/Search/SearchService.cs

@@ -10,7 +10,9 @@ namespace InboxIntel.Infrastructure.Search;
 /// <summary>
 /// Structured + full-text search. Structured filters compose as SQL WHERE
 /// clauses; free text uses PostgreSQL FTS via the generated SearchVector column
-/// (EF.Functions.ToTsVector/Matches translate to @@ / to_tsquery).
+/// (websearch_to_tsquery / @@ / ts_rank_cd). Results are relevance-ranked when a
+/// free-text query is present, date-ordered otherwise. See
+/// docs/discovery/05-search-redesign.md for the full multi-layer search design.
 /// </summary>
 public class SearchService : ISearchService
 {
@@ -58,16 +60,24 @@ public class SearchService : ISearchService
                 return new PagedResult<EmailSummaryDto> { Items = [], Page = r.Page, PageSize = r.PageSize, TotalCount = 0 };
         }
 
-        if (!string.IsNullOrWhiteSpace(r.Query))
-        {
-            // PostgreSQL full-text match against the generated tsvector.
-            var term = r.Query.Trim();
-            q = q.Where(e => e.SearchVector!.Matches(EF.Functions.PlainToTsQuery("english", term)));
-        }
+        // websearch_to_tsquery (vs. plainto_tsquery) understands quotes ("exact phrase"),
+        // OR, and -exclusions — the syntax users already expect from web search boxes.
+        var hasFreeTextQuery = !string.IsNullOrWhiteSpace(r.Query);
+        var term = r.Query?.Trim() ?? string.Empty;
+        if (hasFreeTextQuery)
+            q = q.Where(e => e.SearchVector!.Matches(EF.Functions.WebSearchToTsQuery("english", term)));
 
         var total = await q.CountAsync(ct);
-        var items = await q
-            .OrderByDescending(e => e.SentAtUtc)
+
+        // Relevance-ranked when there's a free-text query (ts_rank_cd via RankCoverDensity,
+        // recency as a tiebreaker); date-only otherwise — matches the existing browse
+        // behaviour when the user isn't searching for anything in particular.
+        var ranked = hasFreeTextQuery
+            ? q.OrderByDescending(e => e.SearchVector!.RankCoverDensity(EF.Functions.WebSearchToTsQuery("english", term)))
+               .ThenByDescending(e => e.SentAtUtc)
+            : q.OrderByDescending(e => e.SentAtUtc);
+
+        var items = await ranked
             .Skip((r.Page - 1) * r.PageSize)
             .Take(r.PageSize)
             .Select(e => new EmailSummaryDto(
@@ -79,7 +89,10 @@ public class SearchService : ISearchService
 
         return new PagedResult<EmailSummaryDto>
         {
-            Items = items, Page = r.Page, PageSize = r.PageSize, TotalCount = total
+            Items = items,
+            Page = r.Page,
+            PageSize = r.PageSize,
+            TotalCount = total
         };
     }
 }

src/InboxIntel.Infrastructure/Sync/HeuristicClassifier.cs

@@ -412,7 +412,7 @@ public static class HeuristicClassifier
     public static EmailCategory Classify(GmailMessageDetail d)
     {
         var subject = (d.Subject ?? string.Empty).ToLowerInvariant();
-        var from    = d.FromAddress.ToLowerInvariant();
+        var from = d.FromAddress.ToLowerInvariant();
 
         // 1. Security alerts — highest priority, overrides everything
         if (SecuritySubjectHints.Any(h => subject.Contains(h)))

src/InboxIntel.Infrastructure/Sync/SyncService.cs

@@ -268,8 +268,12 @@ public class SyncService : ISyncService
         {
             _db.Attachments.Add(new Attachment
             {
-                UserId = userId, EmailId = email.Id, FileName = Trunc(fileName, 512) ?? string.Empty,
-                MimeType = Trunc(mime, 255), SizeBytes = size, GmailAttachmentId = attId
+                UserId = userId,
+                EmailId = email.Id,
+                FileName = Trunc(fileName, 512) ?? string.Empty,
+                MimeType = Trunc(mime, 255),
+                SizeBytes = size,
+                GmailAttachmentId = attId
             });
         }
 
@@ -338,8 +342,11 @@ public class SyncService : ISyncService
         if (thread is not null) return thread;
         thread = new MailThread
         {
-            UserId = userId, GmailThreadId = gmailThreadId, Subject = Trunc(subject, 1024),
-            Snippet = Trunc(snippet, 2048), FirstMessageUtc = sentAt
+            UserId = userId,
+            GmailThreadId = gmailThreadId,
+            Subject = Trunc(subject, 1024),
+            Snippet = Trunc(snippet, 2048),
+            FirstMessageUtc = sentAt
         };
         _db.Threads.Add(thread);
         return thread;