using System;

namespace ShrinkModFramework
{
    internal static class ShrinkVersionUtility
    {
        public static int Compare(string left, string right)
        {
            if (ReferenceEquals(left, right)) return 0;
            if (left == null) return -1;
            if (right == null) return 1;

            var leftParts = left.Split('.');
            var rightParts = right.Split('.');
            var max = Math.Max(leftParts.Length, rightParts.Length);

            for (var i = 0; i < max; i++)
            {
                var leftValue = i < leftParts.Length ? ParseSegment(leftParts[i]) : 0;
                var rightValue = i < rightParts.Length ? ParseSegment(rightParts[i]) : 0;

                if (leftValue != rightValue)
                    return leftValue.CompareTo(rightValue);
            }

            return string.CompareOrdinal(left, right);
        }

        private static int ParseSegment(string segment)
        {
            if (string.IsNullOrEmpty(segment))
                return 0;

            var digits = "";
            for (var i = 0; i < segment.Length; i++)
            {
                if (!char.IsDigit(segment[i]))
                    break;
                digits += segment[i];
            }

            return int.TryParse(digits, out var value) ? value : 0;
        }
    }
}