first commit

Services/Utilities/CoordinateParser.cs

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+using System.Text.RegularExpressions;
+
+namespace StitcherApi.Services.Utilities;
+
+public static class CoordinateParser
+{
+    private static readonly Regex CoordRegex = new(
+        @"([A-Z]+)(\d+)",
+        RegexOptions.Compiled | RegexOptions.IgnoreCase
+    );
+
+    public static (int MinRow, int MinCol, int MaxRow, int MaxCol) ParseCanvasRect(string rect)
+    {
+        if (string.IsNullOrEmpty(rect))
+        {
+            throw new ArgumentException("canvas_rect cannot be null or empty.");
+        }
+
+        var parts = rect.Split(':');
+        if (parts.Length != 2)
+        {
+            throw new ArgumentException("Invalid canvas_rect format.");
+        }
+
+        var (row1, col1) = ParseSingleCoordinate(parts[0]);
+        var (row2, col2) = ParseSingleCoordinate(parts[1]);
+
+        return (
+            Math.Min(row1, row2),
+            Math.Min(col1, col2),
+            Math.Max(row1, row2),
+            Math.Max(col1, col2)
+        );
+    }
+
+    private static (int Row, int Col) ParseSingleCoordinate(string coord)
+    {
+        var match = CoordRegex.Match(coord);
+        if (!match.Success)
+        {
+            throw new ArgumentException($"Invalid coordinate format: {coord}");
+        }
+
+        var rowStr = match.Groups[1].Value.ToUpper();
+        var colStr = match.Groups[2].Value;
+
+        int row = rowStr.Length == 1 ? rowStr[0] - 'A' : 26 + (rowStr[1] - 'A');
+        int col = int.Parse(colStr) - 1;
+
+        return (row, col);
+    }
+}