package core

import (
	"strconv"
	"strings"
)

// CompareVersions compares two semver strings (e.g. "v1.4.0", "1.2.3").
// Returns -1 if a < b, 0 if equal, 1 if a > b.
func CompareVersions(a, b string) int {
	pa := parseVersionParts(a)
	pb := parseVersionParts(b)
	for i := 0; i < 3; i++ {
		if pa[i] < pb[i] {
			return -1
		}
		if pa[i] > pb[i] {
			return 1
		}
	}
	return 0
}

func parseVersionParts(v string) [3]int {
	v = strings.TrimPrefix(v, "v")
	parts := strings.SplitN(v, ".", 3)
	var nums [3]int
	for i, p := range parts {
		if i >= 3 {
			break
		}
		n, _ := strconv.Atoi(p)
		nums[i] = n
	}
	return nums
}