Recs rebuild WS1b-1: Recommendations tab (read-only surface)

[erikdarlingdata]

Scope

The visible, read-only Recommendations tab (Dashboard-only) — WS1b of the recommendations-engine rebuild. Replaces the "Critical Issues" sub-tab with a "Recommendations" tab that renders the unified, de-duped RecommendationItem list (from the WS1a RecommendationsReader, already merged) as the approved layout: a card list grouped into collapsible Critical / Warning / Info sections.

Each card shows: a severity badge (glyph + label, theme status brush), the affected database (bracketed), a headline (Title), wrapped advice (AdviceText), a "Show T-SQL" expander revealing CopyPasteSql in a monospace block with a working Copy button, and Apply + Mute buttons.

Not in scope (deferred to WS1b-2): the Apply and Mute action wiring + the informed-consent gate. Apply + Mute render DISABLED with a tooltip "Available in the next update", so the full approved layout is reviewable with no half-working buttons. Not in scope: Lite (a later PR) — Lite is untouched here.

Visibility predicates (match the alert path)

• Apply shows only when Remediation != null (engine rows with a built, persisted action).
• Mute shows only when Source == Engine (the legacy store has no mute concept).

Header bar / actions (these ARE wired)

• Refresh — re-runs RecommendationsReader.GetRecommendationsAsync for the current server.
• Generate now — runs an on-demand AnalysisService.AnalyzeAsync(serverId, displayName, hoursBack: 4) for the current server (constructed exactly as AnalysisScheduler does: SqlServerPlanFetcher + AnalysisService, serverId via ServerIdHelper.GetDeterministicHashCode), then refreshes. I wired Generate-now live — the construction path is small and self-contained, so it did not pull in extra scope.
• Copy (per card) — clipboard write (trivial, wired).

States

• Loading — the existing LoadingOverlay spinner while reading.
• Empty — "All clear — no current recommendations."
• Insufficient data — the engine's own AnalysisService.InsufficientDataMessage (or a default "collecting data — recommendations appear after the engine has ≥24h of history"). Design note: this state is surfaced by Generate now (the engine owns the data-span determination via MinimumDataHours); the read-only Refresh path shows Empty/Loaded. This avoids duplicating the span-check SQL or widening AnalysisService's surface. A freshly-onboarded server therefore shows "All clear" on a plain Refresh and the "collecting data" message after Generate now.

File:line changelog

New files

• Dashboard/Controls/RecommendationsViewModel.cs — the pure, WPF-free core: RecommendationsViewModel.FromItems/Loading/InsufficientData (groups by CanonicalSeverity into Critical→Warning→Info sections, empty sections omitted, Critical+Warning expanded / Info collapsed), the RecommendationsState enum, and RecommendationCardViewModel / RecommendationSectionViewModel DTOs carrying the display flags + ShowApply/ShowMute predicates.
• Dashboard/Controls/RecommendationsContent.xaml — the card-list-grouped-by-severity UI (Expander per section, Expander per card for "Show T-SQL"), header bar, and the four mutually-exclusive state regions. All theme DynamicResource brushes; no hardcoded colors (badge text uses a fixed dark glyph color over the colored badge, matching badge-on-status-color convention).
• Dashboard/Controls/RecommendationsContent.xaml.cs — Initialize(DatabaseService, ServerConnection, ICredentialService), SetTimeRange(hoursBack), RefreshDataAsync(), GenerateNowButton_Click (live), CopySql_Click (live), and ApplyViewModel state-swap.
• Dashboard.Tests/RecommendationsViewModelTests.cs — 23 VM unit tests (xUnit v3).

Modified

• Dashboard/ServerTab.xaml:283-286 — <TabItem Header="Critical Issues"><controls:CriticalIssuesContent .../> → <TabItem Header="Recommendations"><controls:RecommendationsContent x:Name="RecommendationsTab"/>.
• Dashboard/ServerTab.xaml.cs:99 — RecommendationsTab.Initialize(_databaseService, _serverConnection, _credentialService) (dropped the obsolete InvestigateRequested subscribe/unsubscribe at old :100/:238); :124,:384 — RecommendationsTab.SetTimeRange(...).
• Dashboard/ServerTab.Refresh.cs:195 — RefreshOverviewTabAsync now awaits RecommendationsTab.RefreshDataAsync() (same Overview-tab refresh slot the Critical Issues sub-tab used).
• Dashboard/ServerTab.TimeRange.cs:233,536,540 — global-time-range + Overview paths now call RecommendationsTab.SetTimeRange(...) / RefreshDataAsync().

CriticalIssuesContent.xaml(.cs) is left intact (unused) per the task. The now-unreferenced OnInvestigateCriticalIssue (in ServerTab.DrillDown.cs) is harmless — no compiler warning, build clean.

Test counts (real)

• dotnet build PerformanceMonitor.sln -c Debug → 0 errors (1 pre-existing warning in RemediationTests.cs, unrelated).
• dotnet test Dashboard.Tests --no-build → 302 passed, 0 failed (279 baseline + 23 new).
• dotnet test Lite.Tests → 360 passed, 0 failed (Lite untouched).
• New RecommendationsViewModelTests in isolation → 23 passed: grouping into severity sections (order, empty-section omission, intra-band order preserved, expand defaults, header count); state selection (loading / empty / loaded / insufficient-data with engine message + blank-fallback); Apply visibility (only when Remediation != null, false for legacy); Mute visibility (only when Source == Engine); card display flags (HasSql, DatabaseBracketed, SeverityLabel, disabled-tooltip).

Deferred to WS1b-2

• Apply action wiring + the two-sided informed-consent (RemediationConfirmWindow) gate.
• Mute action wiring.
• (Both buttons are present-but-disabled now.)

Needs visual verification (launch the Dashboard)

WPF rendering is not unit-testable. Please launch the Dashboard and confirm: the Recommendations sub-tab (under Overview) renders the grouped collapsible sections; severity badges/colors; the "Show T-SQL" expander + Copy; Apply/Mute appear disabled with the tooltip and per the visibility rules; Refresh and Generate now behave; and the loading / empty / insufficient-data states display correctly.

🤖 Generated with Claude Code