feat: expose monitoring tg poll diagnostics

cmd/server/main.go

@@ -135,6 +135,7 @@ type componentProbe struct {
 	Status    string `json:"status"`
 	LatencyMs int64  `json:"latency_ms"`
 	Error     string `json:"error,omitempty"`
+	Details   any    `json:"details,omitempty"`
 }
 
 func main() {
@@ -444,10 +445,22 @@ func (a *app) probePollErrors(ctx context.Context) componentProbe {
 		return componentProbe{Name: "poll_errors", Status: "down", LatencyMs: time.Since(start).Milliseconds(), Error: err.Error()}
 	}
 	if total > 0 {
+		recent, recentErr := a.recentPollErrors(ctx)
 		status := "degraded"
 		if other > 0 {
 			status = "down"
 		}
+		details := map[string]any{
+			"total":       total,
+			"flood_wait":  floodWait,
+			"unavailable": unavailable,
+			"other":       other,
+		}
+		if recentErr != nil {
+			details["recent_error"] = recentErr.Error()
+		} else {
+			details["recent_errors"] = recent
+		}
 		return componentProbe{
 			Name:      "poll_errors",
 			Status:    status,
@@ -456,11 +469,64 @@ func (a *app) probePollErrors(ctx context.Context) componentProbe {
 				" flood_wait=" + strconv.FormatInt(floodWait, 10) +
 				" unavailable=" + strconv.FormatInt(unavailable, 10) +
 				" other=" + strconv.FormatInt(other, 10),
+			Details: details,
 		}
 	}
 	return componentProbe{Name: "poll_errors", Status: "ok", LatencyMs: time.Since(start).Milliseconds()}
 }
 
+func (a *app) recentPollErrors(ctx context.Context) ([]map[string]any, error) {
+	rows, err := a.db.Query(ctx, `
+		SELECT
+			c.id,
+			c.identifier,
+			COALESCE(c.title, '') AS title,
+			s.slug,
+			s.title AS section_title,
+			COALESCE(c.last_poll_error_code, '') AS error_code,
+			COALESCE(c.last_poll_error, '') AS error_text,
+			c.last_poll_error_at
+		FROM channels c
+		LEFT JOIN sections s ON s.id = c.section_id
+		WHERE c.is_active = true
+		  AND c.source_channel_id IS NULL
+		  AND c.last_poll_status = 'error'
+		ORDER BY c.last_poll_error_at DESC NULLS LAST, c.id DESC
+		LIMIT 5`)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	out := make([]map[string]any, 0, 5)
+	for rows.Next() {
+		var (
+			id           int64
+			identifier   string
+			title        string
+			sectionSlug  sql.NullString
+			sectionTitle sql.NullString
+			code         string
+			text         string
+			at           sql.NullTime
+		)
+		if err := rows.Scan(&id, &identifier, &title, &sectionSlug, &sectionTitle, &code, &text, &at); err != nil {
+			return nil, err
+		}
+		out = append(out, map[string]any{
+			"channel_id":    id,
+			"identifier":    identifier,
+			"title":         nullableString(title),
+			"section_slug":  nullString(sectionSlug),
+			"section_title": nullString(sectionTitle),
+			"error_code":    nullableString(code),
+			"error":         nullableString(text),
+			"error_at":      nullTime(at),
+		})
+	}
+	return out, rows.Err()
+}
+
 func (a *app) probeMediaStorage(ctx context.Context) componentProbe {
 	start := time.Now()
 	if a.minio == nil || a.cfg.MinioBucket == "" {