using System.Text.RegularExpressions;

namespace Launcher.Next.Core;

public sealed class PackageManifestValidator : IPackageManifestValidator
{
    private static readonly string[] Forbidden = ["acmgd.dll", "acdbmgd.dll", "accoremgd.dll", "adwindows.dll"];
    public ValidationResult Validate(PackageManifest manifest, int productYear, string architecture)
    {
        var issues = new List<ValidationIssue>();
        if (manifest.SchemaVersion != 1) issues.Add(new("schema", "Unsupported schemaVersion."));
        if (string.IsNullOrWhiteSpace(manifest.PackageId) || string.IsNullOrWhiteSpace(manifest.Version)) issues.Add(new("identity", "packageId and version are required."));
        if (string.IsNullOrWhiteSpace(manifest.Product) || manifest.ProductYear != productYear) issues.Add(new("product", "Package product or year is incompatible."));
        if (!string.Equals(manifest.Architecture, architecture, StringComparison.OrdinalIgnoreCase)) issues.Add(new("architecture", "Package architecture is incompatible."));
        var paths = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
        foreach (var file in manifest.Files)
        {
            if (string.IsNullOrWhiteSpace(file.Path) || Path.IsPathRooted(file.Path) || file.Path.Split(['/', '\\']).Any(x => x is ".." or "")) issues.Add(new("path", $"Invalid package path: {file.Path}"));
            if (!paths.Add(file.Path)) issues.Add(new("duplicate", $"Duplicate package path: {file.Path}"));
            var name = Path.GetFileName(file.Path);
            if (Forbidden.Contains(name, StringComparer.OrdinalIgnoreCase) || name.StartsWith("PnP", StringComparison.OrdinalIgnoreCase) || name.StartsWith("Autodesk.ProcessPower", StringComparison.OrdinalIgnoreCase)) issues.Add(new("autodesk", $"Forbidden Autodesk assembly: {name}"));
            if (!Regex.IsMatch(file.Sha256 ?? string.Empty, "^[A-Fa-f0-9]{64}$")) issues.Add(new("hash", $"Invalid SHA-256 for {file.Path}"));
        }
        if (!paths.Contains(manifest.EntryAssembly)) issues.Add(new("entry", "entryAssembly must be listed in files."));
        return issues.Count == 0 ? ValidationResult.Success : new ValidationResult(issues);
    }
}