using System;
using System.Collections.Generic;
using System.Threading;

namespace OpenNest;

/// <summary>
/// A fresh private legacy plate/drawing/item graph for each call. Only returned poses cross the boundary;
/// legacy quantity mutations are deliberately ignored. Does not certify geometric safety or rotation compliance.
/// </summary>
public sealed class LegacyPlateNesterAdapter : IPlateNester
{
    private readonly Func<Plate, NestEngineBase> engineFactory;

    public LegacyPlateNesterAdapter(Func<Plate, NestEngineBase> engineFactory)
    {
        ArgumentNullException.ThrowIfNull(engineFactory);
        this.engineFactory = engineFactory;
    }

    /// <summary>Convenience overload delegating to <see cref="PlateNesterFactory"/> so strategy
    /// resolution has a single source of truth; rejects unknown keys. Never reads or changes the
    /// process-global NestEngineRegistry.</summary>
    public static IPlateNester Create(string strategy) => PlateNesterFactory.Create(strategy);

    public PlateCandidate Place(PlatePlacementRequest request, IProgress<NestJobProgress> progress = null,
        CancellationToken token = default)
    {
        ArgumentNullException.ThrowIfNull(request);
        token.ThrowIfCancellationRequested();
        var plate = DrawingJobMapper.CreatePlate(request.Stock);
        var items = new List<NestItem>();
        var identities = new Dictionary<Drawing, string>(ReferenceEqualityComparer.Instance);
        foreach (var requirement in request.Parts)
        {
            var drawing = DrawingJobMapper.CreateDrawing(requirement);
            identities.Add(drawing, requirement.Id);
            items.Add(new NestItem
            {
                Drawing = drawing,
                Quantity = requirement.Quantity,
                Priority = requirement.Priority,
                StepAngle = DrawingJobMapper.LegacyStep(requirement.Rotation),
                RotationStart = requirement.Rotation.Start,
                RotationEnd = requirement.Rotation.End
            });
        }
        var engine = engineFactory(plate) ?? throw new InvalidOperationException("Legacy engine factory returned null.");
        var parts = engine.Nest(items, null, token);
        token.ThrowIfCancellationRequested();
        if (parts == null) throw new InvalidOperationException("Legacy engine returned null placements.");
        var placements = new List<NestJobPlacement>();
        foreach (var part in parts)
        {
            if (part?.BaseDrawing == null || !identities.TryGetValue(part.BaseDrawing, out var id))
                throw new InvalidOperationException("Legacy placement does not reference a private requirement drawing.");
            placements.Add(new NestJobPlacement(id, 0, part.Location.X, part.Location.Y, part.Rotation));
        }
        return new PlateCandidate(placements);
    }
}