namespace Explorer.Domain;

public static class VolumeIdentityMatcher
{
    public sealed record MatchResult(Source? Source, MatchStrength Strength, bool Ambiguous);

    public enum MatchStrength
    {
        None,
        Weak,
        SerialCapacity,
        Guid
    }

    public static MatchResult Match(VolumeFingerprint fingerprint, IReadOnlyList<Source> known)
    {
        if (!string.IsNullOrWhiteSpace(fingerprint.VolumeGuid))
        {
            var guidHits = known
                .Where(s => !string.IsNullOrEmpty(s.VolumeGuid)
                            && string.Equals(s.VolumeGuid, fingerprint.VolumeGuid, StringComparison.OrdinalIgnoreCase))
                .ToList();
            if (guidHits.Count == 1)
            {
                return new MatchResult(guidHits[0], MatchStrength.Guid, false);
            }

            if (guidHits.Count > 1)
            {
                return new MatchResult(guidHits[0], MatchStrength.Guid, true);
            }
        }

        if (fingerprint.VolumeSerial is > 0)
        {
            var serialHits = known.Where(s =>
                    s.VolumeSerial == fingerprint.VolumeSerial
                    && string.Equals(s.Filesystem, fingerprint.Filesystem, StringComparison.OrdinalIgnoreCase)
                    && s.CapacityBytes == fingerprint.CapacityBytes)
                .ToList();
            if (serialHits.Count == 1)
            {
                return new MatchResult(serialHits[0], MatchStrength.SerialCapacity, false);
            }

            if (serialHits.Count == 0 && !string.IsNullOrEmpty(fingerprint.Label))
            {
                serialHits = known.Where(s =>
                        s.VolumeSerial == fingerprint.VolumeSerial
                        && string.Equals(s.Label, fingerprint.Label, StringComparison.OrdinalIgnoreCase)
                        && s.CapacityBytes == fingerprint.CapacityBytes)
                    .ToList();
            }

            if (serialHits.Count == 1)
            {
                return new MatchResult(serialHits[0], MatchStrength.Weak, false);
            }

            if (serialHits.Count > 1)
            {
                return new MatchResult(serialHits[0], MatchStrength.Weak, true);
            }
        }

        if (fingerprint.Kind is SourceKind.Smb or SourceKind.Nfs)
        {
            var unc = PathRules.CanonicalUncRoot(fingerprint.RootPath);
            var uncHits = known.Where(s =>
                    s.Kind == fingerprint.Kind
                    && s.LastRootPath is not null
                    && string.Equals(PathRules.CanonicalUncRoot(s.LastRootPath), unc, StringComparison.OrdinalIgnoreCase))
                .ToList();
            if (uncHits.Count == 1)
            {
                return new MatchResult(uncHits[0], MatchStrength.SerialCapacity, false);
            }
        }

        return new MatchResult(null, MatchStrength.None, false);
    }
}