using PeNet;

namespace PdbFind.Lib
{
    public class Locator
    {
        public static (string? pdbName, string? checksum) GetPdbChecksum(string path)
        {
            if (!File.Exists(path))
            {
                throw new FileNotFoundException("PE File not found", path);
            }

            var peFile = new PeFile(path);

            var pdb70 = peFile.ImageDebugDirectory?.Where(d => d.CvInfoPdb70 != null).Select(d => d.CvInfoPdb70).FirstOrDefault();

            var pdbName = (pdb70?.PdbFileName != null) ? Path.GetFileName(pdb70.PdbFileName) : null;

            var checksum = pdb70?.Signature != null ? $"{pdb70.Signature:N}{pdb70.Age}" : null;

            return (pdbName, checksum);
        }

        public static string LocatePdbInStore(string path, string store)
        {
            if (!Directory.Exists(store))
            {
                throw new DirectoryNotFoundException($"Directory \"{store}\" not found.");
            }

            var (pdbName, checksum) = GetPdbChecksum(path);

            _ = pdbName ?? throw new InvalidOperationException("PDB name not found in PE header.");
            _ = checksum ?? throw new InvalidOperationException("Checksum not found in PE header.");

            var isIndex2 = File.Exists(Path.Combine(store, "index2.txt"));

            var pdbPath = Path.Combine(pdbName, checksum, pdbName);
            if (isIndex2)
            {
                pdbPath = Path.Combine(pdbName.Substring(0, 2), pdbName, checksum, pdbName);
            }

            return Path.Combine(store, pdbPath);
        }
    }
}