Persist comment source monitoring

src/database/comment-source-watch-repository.ts

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+import { createHash } from 'node:crypto';
+import type Database from 'better-sqlite3';
+import { z } from 'zod';
+import type { CommentReactionVerdict } from '../ai/openrouter.js';
+import type { BrowsingThing, RedditPost } from '../reddit/api.js';
+
+const StoredVerdictSchema = z.object({
+  id: z.string(),
+  qualifies: z.boolean(),
+  expressedGender: z.enum(['male', 'female', 'other', 'unknown']),
+  confidence: z.number().min(0).max(1),
+  evidence: z.string(),
+});
+
+export interface CommentWatchRefreshResult {
+  added: number;
+  active: number;
+  expired: number;
+}
+
+/** Durable source-post rotation and prompt-free comment classification cache. */
+export class CommentSourceWatchRepository {
+  constructor(private readonly db: Database.Database) {}
+
+  refreshSources(posts: readonly RedditPost[], watchWindowMs: number, now = Date.now()): CommentWatchRefreshResult {
+    const expired = this.db.prepare('DELETE FROM comment_source_watches WHERE expires_at <= ?').run(now).changes;
+    const existing = this.db.prepare('SELECT 1 FROM comment_source_watches WHERE source_post_id = ?');
+    const upsert = this.db.prepare(`
+      INSERT INTO comment_source_watches (
+        source_post_id, subreddit, payload_json, post_created_at,
+        discovered_at, updated_at, expires_at
+      ) VALUES (?, ?, ?, ?, ?, ?, ?)
+      ON CONFLICT(source_post_id) DO UPDATE SET
+        subreddit = excluded.subreddit,
+        payload_json = excluded.payload_json,
+        updated_at = excluded.updated_at,
+        expires_at = MAX(comment_source_watches.expires_at, excluded.expires_at)
+    `);
+    let added = 0;
+    this.db.transaction(() => {
+      for (const post of posts) {
+        const createdAt = Math.round(post.created_utc * 1_000);
+        const expiresAt = createdAt + watchWindowMs;
+        if (expiresAt <= now) continue;
+        if (!existing.get(post.id)) added += 1;
+        upsert.run(post.id, post.subreddit, JSON.stringify(post), createdAt, now, now, expiresAt);
+      }
+    })();
+    const active = Number((this.db.prepare(`
+      SELECT COUNT(*) AS count FROM comment_source_watches WHERE expires_at > ?
+    `).get(now) as { count: number }).count);
+    return { added, active, expired };
+  }
+
+  nextSource(subreddit: string, now = Date.now()): RedditPost | null {
+    const row = this.db.prepare(`
+      SELECT payload_json FROM comment_source_watches
+      WHERE subreddit = ? COLLATE NOCASE AND expires_at > ?
+      ORDER BY COALESCE(last_checked_at, 0) ASC, post_created_at DESC
+      LIMIT 1
+    `).get(subreddit, now) as { payload_json: string } | undefined;
+    if (!row) return null;
+    return JSON.parse(row.payload_json) as RedditPost;
+  }
+
+  markChecked(sourcePostId: string, now = Date.now()): void {
+    this.db.prepare(`
+      UPDATE comment_source_watches SET last_checked_at = ?, updated_at = ?
+      WHERE source_post_id = ?
+    `).run(now, now, sourcePostId);
+  }
+
+  getVerdict(comment: Pick<BrowsingThing, 'fullname' | 'text'>): CommentReactionVerdict | null {
+    const row = this.db.prepare(`
+      SELECT body_sha256, verdict_json FROM comment_source_comment_observations
+      WHERE comment_id = ?
+    `).get(comment.fullname) as { body_sha256: string; verdict_json: string } | undefined;
+    if (!row || row.body_sha256 !== hashBody(comment.text)) return null;
+    try {
+      const parsed = StoredVerdictSchema.safeParse(JSON.parse(row.verdict_json));
+      return parsed.success ? parsed.data : null;
+    } catch {
+      return null;
+    }
+  }
+
+  recordVerdict(comment: BrowsingThing, verdict: CommentReactionVerdict, now = Date.now()): void {
+    this.db.prepare(`
+      INSERT INTO comment_source_comment_observations (
+        comment_id, source_post_id, body_sha256, verdict_json, first_seen_at, updated_at
+      ) VALUES (?, ?, ?, ?, ?, ?)
+      ON CONFLICT(comment_id) DO UPDATE SET
+        source_post_id = excluded.source_post_id,
+        body_sha256 = excluded.body_sha256,
+        verdict_json = excluded.verdict_json,
+        updated_at = excluded.updated_at
+    `).run(
+      comment.fullname,
+      comment.parentPostId,
+      hashBody(comment.text),
+      JSON.stringify({ ...verdict, evidence: '' }),
+      now,
+      now,
+    );
+  }
+}
+
+function hashBody(body: string): string {
+  return createHash('sha256').update(body).digest('hex');
+}