using System.ComponentModel;
using System.Reflection;
using Microsoft.Data.SqlClient;

namespace ZB.MOM.WW.OtOpcUa.ControlPlane.Tests.Harness;

/// <summary>
///     Builds real <see cref="SqlException"/>s for tests. The type has no public constructor, so this goes through its
///     internal factory by reflection — the same objects SQL Server failures produce, carrying a real error number.
/// </summary>
public static class SqlExceptionFactory
{
    private const BindingFlags NonPublic = BindingFlags.NonPublic | BindingFlags.Instance;

    /// <summary>A <see cref="SqlException"/> with one error of the given number.</summary>
    /// <param name="number">The SQL Server error number (e.g. 2628, 1205, -2).</param>
    /// <param name="message">The error text.</param>
    /// <param name="inner">An inner exception (e.g. a <see cref="Win32Exception"/> for a timeout).</param>
    /// <returns>The exception.</returns>
    public static SqlException Create(int number, string message, Exception? inner = null)
    {
        var errorCtor = typeof(SqlError).GetConstructors(NonPublic)
            .OrderByDescending(c => c.GetParameters().Length)
            .First();
        var args = errorCtor.GetParameters().Select(p => p.Name switch
        {
            "infoNumber" => (object?)number,
            "errorMessage" => message,
            "server" => "test-sql",
            "procedure" => string.Empty,
            "exception" => inner,
            "errorClass" => (byte)16,
            _ => p.ParameterType == typeof(string) ? string.Empty
                : p.ParameterType.IsValueType ? Activator.CreateInstance(p.ParameterType) : null,
        }).ToArray();
        var error = (SqlError)errorCtor.Invoke(args);

        var collection = (SqlErrorCollection)Activator.CreateInstance(typeof(SqlErrorCollection), nonPublic: true)!;
        typeof(SqlErrorCollection).GetMethod("Add", NonPublic)!.Invoke(collection, [error]);

        var create = typeof(SqlException)
            .GetMethods(BindingFlags.NonPublic | BindingFlags.Static)
            .Where(m => m.Name == "CreateException")
            .Select(m => (Method: m, Params: m.GetParameters()))
            .Where(x => x.Params.Length >= 2 && x.Params[0].ParameterType == typeof(SqlErrorCollection)
                && x.Params[1].ParameterType == typeof(string))
            .OrderBy(x => x.Params.Length)
            .First();
        var createArgs = create.Params.Select((p, i) => i switch
        {
            0 => collection,
            1 => (object?)"16.0.0",
            _ => p.ParameterType == typeof(Exception) ? inner
                : p.ParameterType.IsValueType ? Activator.CreateInstance(p.ParameterType) : null,
        }).ToArray();
        return (SqlException)create.Method.Invoke(null, createArgs)!;
    }

    /// <summary>A command timeout as SQL Server reports it: number -2 over a Win32 258 (WAIT_TIMEOUT).</summary>
    /// <returns>The exception.</returns>
    public static SqlException Timeout() =>
        Create(-2, "Execution Timeout Expired.", new Win32Exception(258, "The wait operation timed out."));
}