using System.Security.Cryptography;
using System.Text.Json;

namespace PRecAnnot.Plant3D2026;

internal sealed record CompositeAssemblyManifest(string Name, string Sha256, bool Required);
internal sealed record CompositeManifest(int SchemaVersion, string Package, string Version, IReadOnlyList<string> Modules, IReadOnlyList<CompositeAssemblyManifest> Assemblies);

internal static class CompositeModuleManifest
{
    public static CompositeManifest Validate()
    {
        var assemblyPath = typeof(EntryPoint).Assembly.Location;
        var path = Path.GetFullPath(Path.Combine(Path.GetDirectoryName(assemblyPath)!, "..", "module-manifest.json"));
        if (!File.Exists(path)) throw new InvalidOperationException("COMPOSITE_MODULE_MANIFEST_MISSING");
        var manifest = JsonSerializer.Deserialize<CompositeManifest>(File.ReadAllText(path), new JsonSerializerOptions { PropertyNameCaseInsensitive = true }) ?? throw new InvalidOperationException("COMPOSITE_MODULE_MANIFEST_INVALID");
        if (manifest.SchemaVersion != 1 || !string.Equals(manifest.Package, "P_Rec_Annot", StringComparison.Ordinal) || manifest.Modules.Count == 0) throw new InvalidOperationException("COMPOSITE_MODULE_MANIFEST_INVALID");
        foreach (var item in manifest.Assemblies.Where(value => value.Required))
        {
            var file = Path.Combine(Path.GetDirectoryName(assemblyPath)!, item.Name);
            if (!File.Exists(file)) throw new InvalidOperationException($"COMPOSITE_MODULE_ASSEMBLY_MISSING:{item.Name}");
            var hash = Convert.ToHexString(SHA256.HashData(File.ReadAllBytes(file))).ToLowerInvariant();
            if (!string.Equals(hash, item.Sha256, StringComparison.OrdinalIgnoreCase)) throw new InvalidOperationException($"COMPOSITE_MODULE_HASH_MISMATCH:{item.Name}");
        }
        return manifest;
    }
}