1 files changed, 59 insertions, 0 deletions
diff --git a/internal/suppress.go b/internal/suppress.go
new file mode 100644
index 0000000..a270656
--- /dev/null
+++ b/internal/suppress.go
@@ -0,0 +1,59 @@
+package internal
+
+import (
+	"log"
+	"os"
+	"strings"
+	"time"
+)
+
+// isSuppressed checks if alerts should be suppressed based on a file's existence and age.
+// Returns true if the file exists AND its modification time is within maxAgeS seconds of now.
+// Returns false if filePath is empty, file doesn't exist, or file is too old.
+func isSuppressed(filePath string, maxAgeS int) bool {
+	if filePath == "" {
+		return false
+	}
+	info, err := os.Stat(filePath)
+	if err != nil {
+		return false // file doesn't exist or other error
+	}
+	age := time.Since(info.ModTime())
+	return age <= time.Duration(maxAgeS)*time.Second
+}
+
+// isCheckSuppressed determines if a check should be suppressed from email reports.
+// For Prometheus checks (name starts with "Prometheus"): uses PrometheusOnlyIfNotExists config.
+// For regular checks: uses per-check OnlyIfNotExists config if set.
+func isCheckSuppressed(name string, conf config) bool {
+	// Check if this is a Prometheus alert (name starts with "Prometheus")
+	if strings.HasPrefix(name, "Prometheus") {
+		if isSuppressed(conf.PrometheusOnlyIfNotExists, conf.PrometheusOnlyIfNotExistsMaxS) {
+			log.Printf("Suppressing %s: file %s exists and is recent", name, conf.PrometheusOnlyIfNotExists)
+			return true
+		}
+		return false
+	}
+
+	// For regular checks, look up the check config
+	chk, ok := conf.Checks[name]
+	if !ok {
+		return false // check not found in config (e.g., federated)
+	}
+
+	if chk.OnlyIfNotExists == "" {
+		return false
+	}
+
+	// Use per-check max age if set, otherwise use global Prometheus default
+	maxAgeS := chk.OnlyIfNotExistsMaxS
+	if maxAgeS == 0 {
+		maxAgeS = conf.PrometheusOnlyIfNotExistsMaxS
+	}
+
+	if isSuppressed(chk.OnlyIfNotExists, maxAgeS) {
+		log.Printf("Suppressing %s: file %s exists and is recent", name, chk.OnlyIfNotExists)
+		return true
+	}
+	return false
+}