// Generated from executable documentation examples. Edit the source region, then regenerate.
using System;
using System.IO;
using System.IO.Pipelines;
using System.Linq;
using System.Buffers;
using System.Collections.Generic;
using System.Dynamic;
using System.Globalization;
using System.Numerics;
using System.Runtime.CompilerServices;
using System.Threading;
using System.Threading.Tasks;
using CStructSharp;
using CStructSharp.Codecs;
using CStructSharp.Diagnostics;
using CStructSharp.Introspection;
using CStructSharp.Values;

internal static partial class Program
{
    public static void Main()
    {
        LayoutIntrospection();
        Console.WriteLine("PASS layout-introspection");
    }

    private static void LayoutIntrospection()
    {
        // `Layout` describes the compiled declarations with sizes, offsets, and members; `ToDefinition` renders
        // them back; `WithEndianness` compiles the sibling layout a byte-order-switching format needs.
        var layout = new CStruct("enum kind : uint8 { NONE, DATA = 2 }; struct root { kind type; uint16 length; char name[4]; };");
        LayoutDeclarationInfo root = layout.Layout.Declarations.Single(item => item.Name == "root");
        Equal(7, root.Size!.Value);
        Equal(1, root.Fields[1].Offset!.Value);
        Equal("uint16", root.Fields[1].TypeName);
        Equal(LayoutArrayKind.Fixed, root.Fields[2].ArrayKind);
        LayoutDeclarationInfo kind = layout.Layout.Declarations.Single(item => item.Name == "kind");
        Equal(new BigInteger(2), kind.Members[1].Value);

        string definition = layout.ToDefinition();
        True(definition.Contains("enum kind : uint8 {", StringComparison.Ordinal), "the rendered definition names the enum");
        Equal(7, new CStruct(definition).GetStructSizeInBytes("root"));

        byte[] bigEndian = [2, 0x01, 0x02, (byte)'a', (byte)'b', 0, 0];
        Equal((ushort)0x0102, layout.WithEndianness(isLittleEndian: false).Parse(bigEndian, "root").Get<ushort>("length"));
        True(ReferenceEquals(layout, layout.WithEndianness(isLittleEndian: true)), "the same byte order returns the same instance");
    }

    private static void Equal<T>(T expected, T actual)
    {
        if (!EqualityComparer<T>.Default.Equals(expected, actual))
        {
            throw new InvalidOperationException($"Expected '{expected}', received '{actual}'.");
        }
    }

    private static void True(bool condition, string message)
    {
        if (!condition)
        {
            throw new InvalidOperationException(message);
        }
    }
}