using System;
using System.Runtime.InteropServices;
using CeresSharp.Native;

namespace CeresSharp.Native.SafeHandles;

/// <summary>
/// Safe handle for Ceres Problem.
/// Note: Uses official C API (ceres_create_problem/ceres_free_problem).
/// </summary>
internal sealed class ProblemHandle : BaseSafeHandle
{
    private ProblemHandle() : base()
    {
    }

    private ProblemHandle(IntPtr handle, bool ownsHandle) : base(handle, ownsHandle)
    {
    }

    public static ProblemHandle Create()
    {
        // Note: ceres_create_problem is from official C API, not wrapper
        // We'll need to import it separately or use wrapper function if available
        var handle = CeresNative.ceres_create_problem();
        if (handle == IntPtr.Zero)
        {
            throw new Exceptions.CeresException(Exceptions.CeresErrorCode.OutOfMemory, "Failed to create problem");
        }
        return new ProblemHandle(handle, true);
    }

    public static ProblemHandle CreateWithOptions(IntPtr problemOptions)
    {
        var handle = CeresNative.ceres_wrapper_create_problem_with_options(problemOptions);
        if (handle == IntPtr.Zero)
        {
            throw new Exceptions.CeresException(Exceptions.CeresErrorCode.OutOfMemory, "Failed to create problem with options");
        }
        return new ProblemHandle(handle, true);
    }

    protected override void ReleaseNativeHandle(IntPtr handle)
    {
        // Note: ceres_free_problem is from official C API
        // Add null check to prevent crash if handle is invalid
        if (handle != IntPtr.Zero)
        {
            try
            {
                CeresNative.ceres_free_problem(handle);
            }
            catch
            {
                // Ignore errors - handle may already be freed or invalid
                // This can happen in finalizer thread
            }
        }
    }
}