feat(ypp): session report derived from YouTube — no ledger, money off by default (TASK 3·20)

The task asked for a `RewardEvents` table plus a backfill. That would have contradicted the published promise that no viewer, member or donor information is retained after the session ends, and it would have meant owning a ledger that YouTube already keeps. So the report is DERIVED on demand instead: - `Services/SuperChatEventService.cs` — `superChatEvents.list`, parsed for both event types (a sticker must not be dropped), authorised by the existing `auth/youtube` scope, so no re-consent. - `Models/SessionRewardSummary.cs` — rolls events up for the session window with **per-currency totals that are never summed together** (a $5 and a €5 are not $10). Nothing is written down. - The YPP drawer gains a **THIS SESSION** section: counts are neutral and always shown when there were events; money appears only when the creator asks for it. `Show monetary metrics` is a drawer toggle, persisted, **off by default** — a creator who never monetized is never shown a $0.00. Also: money is labelled as estimates (removed/refunded events are excluded and totals can be restated for weeks, not days). Tests: `SessionRewardReportTests` — both reward types parse, the window makes it a session rather than a channel report, currencies stay separate, an empty session shows nothing, a sticker-only session still counts. `BackOnAirTests` moves into the serialised `MainViewModelLayoutPath` collection: it builds a MainViewModel directly and was flaking against parallel tests that swap the static layout path. FAST gate: 557 passed, 0 failed, 0 warnings.
2026-11-05 15:38:32 -08:00
parent 27f655c8de
commit 0fade9702b
13 changed files with 488 additions and 7 deletions
@@ -0,0 +1,94 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+
+namespace ytLive.Models;
+
+/// <summary>One Super Chat or Super Sticker event, as YouTube reports it.</summary>
+public sealed record SuperChatEvent(
+    string Id,
+    ChatEventKind Kind,
+    long AmountMicros,
+    string Currency,
+    string? DisplayAmount,
+    DateTime PublishedAt);
+
+/// <summary>
+/// TASK 3·20: what this session's rewards added up to — <b>in memory only</b>.
+/// <para>Derived on demand from <c>superChatEvents.list</c> rather than persisted: YouTube is the system
+/// of record for money, and keeping a local ledger would contradict the published promise that no
+/// viewer, member or donor information is retained after the session ends.</para>
+/// <para>Totals are kept <b>per currency</b> and never summed across currencies — a $5 and a €5 are not
+/// $10, and a single blended number would be a lie.</para>
+/// </summary>
+public sealed record SessionRewardSummary(
+    int SuperChatCount,
+    int SuperStickerCount,
+    IReadOnlyDictionary<string, long> MicrosByCurrency,
+    DateTime? FirstEventAt,
+    DateTime? LastEventAt)
+{
+    public static readonly SessionRewardSummary Empty = new(
+        0, 0, new Dictionary<string, long>(), null, null);
+
+    public int TotalEvents => SuperChatCount + SuperStickerCount;
+
+    public bool HasEvents => TotalEvents > 0;
+
+    /// <summary>Filters to a session window and rolls the events up. Events outside
+    /// [<paramref name="sinceUtc"/>, <paramref name="untilUtc"/>] are ignored, which is what makes a
+    /// report "this session" rather than "this channel".</summary>
+    public static SessionRewardSummary From(
+        IEnumerable<SuperChatEvent> events, DateTime sinceUtc, DateTime? untilUtc = null)
+    {
+        var until = untilUtc ?? DateTime.MaxValue;
+        var inWindow = events
+            .Where(e => e.PublishedAt >= sinceUtc && e.PublishedAt <= until)
+            .OrderBy(e => e.PublishedAt)
+            .ToList();
+
+        if (inWindow.Count == 0) return Empty;
+
+        var byCurrency = new Dictionary<string, long>(StringComparer.OrdinalIgnoreCase);
+        foreach (var e in inWindow)
+        {
+            var currency = string.IsNullOrWhiteSpace(e.Currency) ? "?" : e.Currency.ToUpperInvariant();
+            byCurrency.TryGetValue(currency, out var total);
+            byCurrency[currency] = total + Math.Max(0, e.AmountMicros);
+        }
+
+        return new SessionRewardSummary(
+            inWindow.Count(e => e.Kind == ChatEventKind.SuperChat),
+            inWindow.Count(e => e.Kind == ChatEventKind.SuperSticker),
+            byCurrency,
+            inWindow[0].PublishedAt,
+            inWindow[^1].PublishedAt);
+    }
+
+    /// <summary>Money lines for display, e.g. "USD $12.34 · EUR €4.00". Empty when there is nothing to
+    /// show — a creator who never monetized must never be shown a zero.</summary>
+    public IReadOnlyList<string> MoneyLines()
+        => MicrosByCurrency
+            .Where(pair => pair.Value > 0)
+            .OrderByDescending(pair => pair.Value)
+            .Select(pair => $"{pair.Key} {Format(pair.Key, pair.Value)}")
+            .ToList();
+
+    private static string Format(string currency, long micros)
+    {
+        var amount = micros / 1_000_000m;
+        var symbol = currency switch
+        {
+            "USD" => "$",
+            "EUR" => "€",
+            "GBP" => "£",
+            "CAD" => "CA$",
+            "AUD" => "A$",
+            _ => string.Empty,
+        };
+        return symbol.Length > 0
+            ? symbol + amount.ToString("0.00", CultureInfo.InvariantCulture)
+            : amount.ToString("0.00", CultureInfo.InvariantCulture) + " " + currency;
+    }
+}