using System.Reflection.Metadata;
using System.Reflection.PortableExecutable;
using System.Text;


if (args.Length < 2)
{
    Console.Error.WriteLine("Usage: InteropInspect <assembly.dll> <keyword>... | <assembly.dll> --type <FullName>");
    return 1;
}

var path = args[0];
var detail = false;
string detailType = null;
var keywords = new List<string>();
for (int i = 1; i < args.Length; i++)
{
    if (args[i] == "--type" && i + 1 < args.Length) { detail = true; detailType = args[++i]; }
    else keywords.Add(args[i]);
}

using var fs = File.OpenRead(path);
using var pe = new PEReader(fs);
var md = pe.GetMetadataReader();

string GetString(StringHandle h) => md.GetString(h);
string GetNs(TypeDefinition t)
{
    var ns = GetString(t.Namespace);
    var decl = t.GetDeclaringType();
    if (!decl.IsNil)
    {
        var outer = md.GetTypeDefinition(decl);
        return GetNs(outer) + "+" + GetString(outer.Name);
    }
    return ns;
}

foreach (var tdh in md.TypeDefinitions)
{
    var td = md.GetTypeDefinition(tdh);
    var fullName = GetNs(td) + "." + GetString(td.Name);

    bool match;
    if (detail)
        match = fullName.Equals(detailType, StringComparison.OrdinalIgnoreCase);
    else
        match = keywords.Any(k => fullName.IndexOf(k, StringComparison.OrdinalIgnoreCase) >= 0 ||
            (k.StartsWith("field:") && td.GetFields().Any(f =>
                GetString(md.GetFieldDefinition(f).Name).Contains(k[6..], StringComparison.OrdinalIgnoreCase))));

    if (!match) continue;

    if (!detail)
    {
        Console.WriteLine(fullName);
        continue;
    }

    var sb = new StringBuilder();
    sb.AppendLine($"TYPE {fullName}");
    if (!td.BaseType.IsNil)
    {
        try { sb.AppendLine($"  base: {ResolveName(md, td.BaseType)}"); } catch { }
    }
    foreach (var iih in td.GetInterfaceImplementations())
    {
        var ii = md.GetInterfaceImplementation(iih);
        try { sb.AppendLine($"  impl: {ResolveName(md, ii.Interface)}"); } catch { }
    }
    sb.AppendLine("  fields:");
    foreach (var fh in td.GetFields())
    {
        var f = md.GetFieldDefinition(fh);
        var constantHandle = f.GetDefaultValue();
        var constantValue = "";
        if (!constantHandle.IsNil)
        {
            var constant = md.GetConstant(constantHandle);
            var reader = md.GetBlobReader(constant.Value);
            constantValue = " = " + reader.ReadConstant(constant.TypeCode);
        }
        sb.AppendLine($"    {GetString(f.Name)}{constantValue}");
    }
    sb.AppendLine("  methods:");
    foreach (var mh in td.GetMethods())
    {
        var m = md.GetMethodDefinition(mh);
        var attrs = m.Attributes;
        var prms = m.GetParameters().Select(ph => md.GetParameter(ph))
                     .Select(pp => $"{GetString(pp.Name)}");
        sb.AppendLine($"    {GetString(m.Name)}({string.Join(", ", prms)})  [{attrs}]");
    }
    sb.AppendLine("  properties:");
    foreach (var ph in td.GetProperties())
    {
        var p = md.GetPropertyDefinition(ph);
        sb.AppendLine($"    {GetString(p.Name)}");
    }
    Console.Write(sb.ToString());
}

return 0;

static string ResolveName(MetadataReader md, EntityHandle h)
{
    if (h.Kind == HandleKind.TypeReference)
    {
        var tr = md.GetTypeReference((TypeReferenceHandle)h);
        return $"{md.GetString(tr.Namespace)}.{md.GetString(tr.Name)}";
    }
    if (h.Kind == HandleKind.TypeDefinition)
    {
        var td2 = md.GetTypeDefinition((TypeDefinitionHandle)h);
        return $"{md.GetString(td2.Namespace)}.{md.GetString(td2.Name)}";
    }
    return h.Kind.ToString();
}