refactor: clean up solution to part 1 on day 2

cmd/02/main.go

@@ -1,57 +1,24 @@
 package main
 
 import (
-	"strconv"
 	"strings"
 
+	"github.com/StevanFreeborn/advent-of-code-2025/cmd/02/rnge"
 	"github.com/StevanFreeborn/advent-of-code-2025/internal/file"
 )
 
 const SeparatorCharacter = ","
-const RangeSeparatorCharacter = "-"
-
-type Range struct {
-	Start int64
-	End   int64
-}
 
 func SolvePartOne(filePath string) int64 {
 	input := file.ReadAllText(filePath)
 	strRanges := strings.SplitSeq(input, SeparatorCharacter)
 
-	rngs := []Range{}
-
-	for r := range strRanges {
-		parts := strings.Split(strings.TrimSpace(r), "-")
-		start, _ := strconv.ParseInt(parts[0], 10, 64)
-		end, _ := strconv.ParseInt(parts[1], 10, 64)
-		rng := Range{
-			Start: start,
-			End:   end,
-		}
-		rngs = append(rngs, rng)
-	}
-
 	total := int64(0)
 
-	for _, rng := range rngs {
-		for id := rng.Start; id <= rng.End; id++ {
-			idStr := strconv.FormatInt(id, 10)
-			idLength := len(idStr)
-
-			if idLength%2 != 0 {
-				continue
-			}
-
-			midpoint := idLength / 2
-
-			firstHalf := idStr[:midpoint]
-			secondHalf := idStr[midpoint:]
-
-			if firstHalf != secondHalf {
-				continue
-			}
+	for r := range strRanges {
+		rng := rnge.From(r)
 
+		for id := range rng.InvalidIds() {
 			total += id
 		}
 	}