feat: add --time mode for using 24h time format

internal/core/time.go

@@ -0,0 +1,33 @@
+package core
+
+import (
+	"time"
+	"tz-snipe/internal/geodata"
+)
+
+func GetTZsMatchingTime(db geodata.TimezoneMap, targetTime string) ([]string, error) {
+	// another go quirK: for layout it uses a fixed point in time
+	// as reference date Mon, 1/2 03:04:05 PM 2006 -0700
+	// 1 2 3 4 5 6 7
+	if _, err := time.Parse("15:04", targetTime); err != nil {
+		return nil, err
+	}
+
+	now := time.Now().UTC()
+	var matches []string
+
+	for tz := range db {
+		// Parse offset to location
+		zoneTime, err := time.Parse("-0700", tz)
+		if err != nil {
+			continue
+		}
+
+		// Check if the formatted string matches exactly
+		// same minute match
+		if now.In(zoneTime.Location()).Format("15:04") == targetTime {
+			matches = append(matches, tz)
+		}
+	}
+	return matches, nil
+}