using Autodesk.AutoCAD.Colors;
using Autodesk.AutoCAD.DatabaseServices;

namespace CadParamPluging.Cad
{
    internal sealed class DrawingStyleManager
    {
        private const string BreakLineLinetypeName = "BREAK_THREE_SHORT_V2";

        public enum Role
        {
            OutlineBold,
            OutlineThin,
            PartContour,
            BreakLine,      // 截断线（白色双点划线）
            Centerline,
            Hidden,
            Hatch,
            Dimension,
            Text
        }

        private readonly Database _db;
        private readonly Transaction _tr;

        public DrawingStyleManager(Database db, Transaction tr)
        {
            _db = db;
            _tr = tr;
        }

        public void Apply(Entity ent, Role role)
        {
            if (ent == null || _db == null || _tr == null)
            {
                return;
            }

            var spec = GetSpec(role);
            EnsureLayer(spec.LayerName, spec.DefaultLinetypeName, spec.DefaultLineWeight, spec.DefaultColorIndex);

            try { ent.Layer = spec.LayerName; } catch { }
            try { ent.ColorIndex = 256; } catch { } // ByLayer
            try { ent.Linetype = "ByLayer"; } catch { }
            if (role == Role.BreakLine)
            {
                try { ent.Linetype = BreakLineLinetypeName; } catch { }
            }
            try { ent.LineWeight = LineWeight.ByLayer; } catch { }
        }

        private sealed class LayerSpec
        {
            public string LayerName { get; set; }
            public string DefaultLinetypeName { get; set; }
            public LineWeight DefaultLineWeight { get; set; }
            public short DefaultColorIndex { get; set; }
        }

        private static LayerSpec GetSpec(Role role)
        {
            switch (role)
            {
                case Role.OutlineBold:
                    return new LayerSpec { LayerName = "粗实线", DefaultLinetypeName = "Continuous", DefaultLineWeight = LineWeight.LineWeight050, DefaultColorIndex = 7 };
                case Role.PartContour:
                    return new LayerSpec { LayerName = "双点划线", DefaultLinetypeName = "PHANTOM", DefaultLineWeight = LineWeight.LineWeight015, DefaultColorIndex = 7 };
                case Role.BreakLine:
                    return new LayerSpec { LayerName = "截断线", DefaultLinetypeName = BreakLineLinetypeName, DefaultLineWeight = LineWeight.LineWeight015, DefaultColorIndex = 7 };
                case Role.Centerline:
                    return new LayerSpec { LayerName = "中心线", DefaultLinetypeName = "CENTER", DefaultLineWeight = LineWeight.LineWeight015, DefaultColorIndex = 7 };
                case Role.Hidden:
                    return new LayerSpec { LayerName = "虚线", DefaultLinetypeName = "DASHED", DefaultLineWeight = LineWeight.LineWeight025, DefaultColorIndex = 7 };
                case Role.Hatch:
                    return new LayerSpec { LayerName = "剖面线", DefaultLinetypeName = "Continuous", DefaultLineWeight = LineWeight.LineWeight015, DefaultColorIndex = 4 };
                case Role.Dimension:
                    return new LayerSpec { LayerName = "尺寸标注", DefaultLinetypeName = "Continuous", DefaultLineWeight = LineWeight.LineWeight018, DefaultColorIndex = 3 };
                case Role.Text:
                    return new LayerSpec { LayerName = "文字", DefaultLinetypeName = "Continuous", DefaultLineWeight = LineWeight.LineWeight018, DefaultColorIndex = 7 };
                case Role.OutlineThin:
                default:
                    return new LayerSpec { LayerName = "细实线", DefaultLinetypeName = "Continuous", DefaultLineWeight = LineWeight.LineWeight025, DefaultColorIndex = 7 };
            }
        }

        private void EnsureLayer(string layerName, string linetypeName, LineWeight lineWeight, short colorIndex)
        {
            if (string.IsNullOrWhiteSpace(layerName) || _db == null || _tr == null)
            {
                return;
            }

            try
            {
                EnsureLinetype(linetypeName);

                var layerTbl = (LayerTable)_tr.GetObject(_db.LayerTableId, OpenMode.ForRead);
                if (layerTbl.Has(layerName))
                {
                    try
                    {
                        var layerId = layerTbl[layerName];
                        var existingLayer = (LayerTableRecord)_tr.GetObject(layerId, OpenMode.ForWrite);
                        if (existingLayer != null)
                        {
                            // Make sure the layer is visible in the template.
                            existingLayer.IsOff = false;
                            existingLayer.IsFrozen = false;
                            existingLayer.IsLocked = false;

                            existingLayer.Color = Color.FromColorIndex(ColorMethod.ByAci, colorIndex);
                            existingLayer.LineWeight = lineWeight;

                            if (!string.IsNullOrWhiteSpace(linetypeName))
                            {
                                var lt = (LinetypeTable)_tr.GetObject(_db.LinetypeTableId, OpenMode.ForRead);
                                if (lt.Has(linetypeName))
                                {
                                    existingLayer.LinetypeObjectId = lt[linetypeName];
                                }
                            }
                        }
                    }
                    catch
                    {
                        // ignore
                    }
                    return;
                }

                layerTbl.UpgradeOpen();

                var ltr = new LayerTableRecord
                {
                    Name = layerName,
                    Color = Color.FromColorIndex(ColorMethod.ByAci, colorIndex),
                    LineWeight = lineWeight
                };

                try
                {
                    if (!string.IsNullOrWhiteSpace(linetypeName))
                    {
                        var lt = (LinetypeTable)_tr.GetObject(_db.LinetypeTableId, OpenMode.ForRead);
                        if (lt.Has(linetypeName))
                        {
                            ltr.LinetypeObjectId = lt[linetypeName];
                        }
                    }
                }
                catch
                {
                    // ignore
                }

                layerTbl.Add(ltr);
                _tr.AddNewlyCreatedDBObject(ltr, true);
            }
            catch
            {
                // ignore
            }
        }

        private void EnsureLinetype(string linetypeName)
        {
            if (string.IsNullOrWhiteSpace(linetypeName) || _db == null || _tr == null)
            {
                return;
            }

            try
            {
                var lt = (LinetypeTable)_tr.GetObject(_db.LinetypeTableId, OpenMode.ForRead);
                if (lt.Has(linetypeName))
                {
                    return;
                }

                if (linetypeName == BreakLineLinetypeName)
                {
                    lt.UpgradeOpen();
                    var record = new LinetypeTableRecord
                    {
                        Name = BreakLineLinetypeName,
                        AsciiDescription = "Long dash, three short dashes",
                        PatternLength = 1.68,
                        NumDashes = 8
                    };
                    record.SetDashLengthAt(0, 0.6);
                    record.SetDashLengthAt(1, -0.18);
                    record.SetDashLengthAt(2, 0.12);
                    record.SetDashLengthAt(3, -0.18);
                    record.SetDashLengthAt(4, 0.12);
                    record.SetDashLengthAt(5, -0.18);
                    record.SetDashLengthAt(6, 0.12);
                    record.SetDashLengthAt(7, -0.18);
                    lt.Add(record);
                    _tr.AddNewlyCreatedDBObject(record, true);
                    return;
                }

                try
                {
                    _db.LoadLineTypeFile(linetypeName, "acad.lin");
                }
                catch
                {
                    // Some linetypes may not exist in acad.lin; ignore.
                }
            }
            catch
            {
                // ignore
            }
        }
    }
}