fix(chat): stop painting what YouTube removed, and retire the local word filter

TASK 49 is retired (creator ruling): YouTube owns chat moderation. Its blocked-words filter and hold-for-review run upstream of `liveChatMessages.list` — held messages are never returned (https://stackoverflow.com/questions/74511524/) — so a second local list would duplicate a switch the creator already owns, with a second set of false positives and a second support surface. What we actually owed the platform, and had wrong: - The parser added every item to the overlay. A deleted message arrives as a `tombstone` carrying no text at all ("it has since been deleted … only liveChatId, type and publishedAt are present" — https://developers.google.com/youtube/data/live/reference/rest/v3/liveChatMessages), so every deletion rendered as a BLANK chat row. `hasDisplayContent:false` messages and chat-mode events did the same. - Deletion events (`messageDeletedEvent`/`messageRetractedEvent`/`userBannedEvent`) are documented but have not been delivered to clients for years (https://stackoverflow.com/questions/44346893/), so nothing is built on them; they are skipped if they ever arrive. - Found while testing: Super Chat read `displayString`, but YouTube's field is `amountDisplayString` — every amount silently fell back to a recomposed string, which mangles non-dollar locales. The model's own comment said this was the reason the field exists. Test: `ChatModerationParseTests` — tombstone, no-display-content, chat-mode events all produce no row; a real Super Chat still parses its pre-rendered amount (constraint 4: reward fields are never reinterpreted). Docs: TASK 49 marked retired with the citations, the rule recorded in decisions.md, HANDOFF updated. verify.sh: 550 passed, 0 failed, 0 warnings.
2026-11-05 08:39:46 -08:00
parent 7bb1207fb2
commit a814bcd502
6 changed files with 171 additions and 4 deletions
@@ -0,0 +1,97 @@
+using System.Linq;
+using Xunit;
+using ytLive.Services;
+
+namespace ytLive.Tests;
+
+/// <summary>
+/// 2026-11-05 ruling (retires TASK 49's local wordlist): YouTube owns chat moderation, so the
+/// behaviour we owe it is not a second list — it is <b>not showing what YouTube has removed</b>.
+/// The feed sends deleted messages as a <c>tombstone</c> placeholder carrying no text, and marks
+/// non-displayable events with <c>hasDisplayContent: false</c>; both used to become blank rows on
+/// the overlay (the parser had no filter at all).
+/// </summary>
+public class ChatModerationParseTests
+{
+    [Fact]
+    public void Tombstone_NeverBecomesAChatRow()
+    {
+        const string json = """
+        {
+          "items": [
+            {"id":"d1","snippet":{"type":"tombstone","liveChatId":"c","publishedAt":"2026-11-05T10:00:00.000Z"}},
+            {"id":"m1","snippet":{"type":"textMessageEvent","hasDisplayContent":true,
+              "textMessageDetails":{"messageText":"hello"},"publishedAt":"2026-11-05T10:00:01.000Z"},
+            "authorDetails":{"displayName":"Viewer","channelId":"UC1"}}
+          ],
+          "nextPageToken":"n"
+        }
+        """;
+
+        var page = YouTubeChatService.ParsePage(json);
+
+        Assert.Single(page.Messages);
+        Assert.Equal("hello", page.Messages[0].Message);
+    }
+
+    [Fact]
+    public void MessagesWithoutDisplayContent_AreSkipped()
+    {
+        const string json = """
+        {
+          "items": [
+            {"id":"m1","snippet":{"type":"textMessageEvent","hasDisplayContent":false,
+              "publishedAt":"2026-11-05T10:00:00.000Z"},
+             "authorDetails":{"displayName":"Muted","channelId":"UC1"}},
+            {"id":"m2","snippet":{"type":"textMessageEvent","hasDisplayContent":true,
+              "textMessageDetails":{"messageText":"visible"},"publishedAt":"2026-11-05T10:00:01.000Z"},
+             "authorDetails":{"displayName":"Viewer","channelId":"UC2"}}
+          ]
+        }
+        """;
+
+        var page = YouTubeChatService.ParsePage(json);
+
+        Assert.Single(page.Messages);
+        Assert.Equal("visible", page.Messages[0].Message);
+    }
+
+    [Fact]
+    public void ChatModeEvents_AreNotChat()
+    {
+        const string json = """
+        {
+          "items": [
+            {"id":"e1","snippet":{"type":"sponsorOnlyModeStartedEvent","hasDisplayContent":false,
+              "publishedAt":"2026-11-05T10:00:00.000Z"}},
+            {"id":"e2","snippet":{"type":"chatEndedEvent","publishedAt":"2026-11-05T10:00:01.000Z"}}
+          ]
+        }
+        """;
+
+        Assert.Empty(YouTubeChatService.ParsePage(json).Messages);
+    }
+
+    [Fact]
+    public void RealChatStillParses_WithAuthorAndSuperChat()
+    {
+        const string json = """
+        {
+          "items": [
+            {"id":"m1","snippet":{"type":"superChatEvent","hasDisplayContent":true,
+              "superChatDetails":{"amountMicros":12340000,"currency":"USD","amountDisplayString":"$12.34",
+                                  "userComment":"nice stream"},"publishedAt":"2026-11-05T10:00:00.000Z"},
+             "authorDetails":{"displayName":"Funder","channelId":"UC9","isChatSponsor":true}}
+          ]
+        }
+        """;
+
+        var message = Assert.Single(YouTubeChatService.ParsePage(json).Messages);
+
+        Assert.Equal("Funder", message.AuthorName);
+        Assert.True(message.IsSuperChat);
+        // Constraint that survives the TASK 49 retirement: reward fields are never reinterpreted.
+        Assert.Equal("$12.34", message.SuperChatDisplayString);
+        Assert.Equal("nice stream", message.Message);
+    }
+}