/////////////////////////////////////////////////////////////////////////////////
//
// Photoshop PSD FileType Plugin for Paint.NET
// http://psdplugin.codeplex.com/
//
// This software is provided under the MIT License:
//   Copyright (c) 2006-2007 Frank Blumenberg
//   Copyright (c) 2010-2016 Tao Yue
//
// Portions of this file are provided under the BSD 3-clause License:
//   Copyright (c) 2006, Jonas Beckeman
//
// See LICENSE.txt for complete licensing and attribution information.
//
/////////////////////////////////////////////////////////////////////////////////

using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Diagnostics;
using PDNWrapper;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Threading;
using Unity.Collections;
using Unity.Collections.LowLevel.Unsafe;

namespace PhotoshopFile
{
    [DebuggerDisplay("Name = {Name}")]
    internal class Layer
    {
        internal PsdFile PsdFile { get; private set; }

        /// <summary>
        /// The rectangle containing the contents of the layer.
        /// </summary>
        public Rectangle Rect { get; set; }

        public bool IsGroup { get; set; }
        public bool IsEndGroupMarker { get; set; }
        public Layer ParentLayer {get; set; }
        // ID from Key "lyid"
        public int LayerID { get; set; }

        /// <summary>
        /// Image channels.
        /// </summary>
        public ChannelList Channels { get; private set; }

        /// <summary>
        /// Returns alpha channel if it exists, otherwise null.
        /// </summary>
        public Channel AlphaChannel
        {
            get
            {
                if (Channels.ContainsId(-1))
                    return Channels.GetId(-1);
                else
                    return null;
            }
        }

        private string blendModeKey;
        /// <summary>
        /// Photoshop blend mode key for the layer
        /// </summary>
        public string BlendModeKey
        {
            get { return blendModeKey; }
            set
            {
                if (value.Length != 4)
                {
                    throw new ArgumentException(
                        "BlendModeKey must be 4 characters in length.");
                }
                blendModeKey = value;
            }
        }

        /// <summary>
        /// 0 = transparent ... 255 = opaque
        /// </summary>
        public byte Opacity { get; set; }

        /// <summary>
        /// false = base, true = non-base
        /// </summary>
        public bool Clipping { get; set; }

        private static int protectTransBit = BitVector32.CreateMask();
        private static int visibleBit = BitVector32.CreateMask(protectTransBit);
        BitVector32 flags = new BitVector32();

        /// <summary>
        /// If true, the layer is visible.
        /// </summary>
        public bool Visible
        {
            get { return !flags[visibleBit]; }
            set { flags[visibleBit] = !value; }
        }

        /// <summary>
        /// Protect the transparency
        /// </summary>
        public bool ProtectTrans
        {
            get { return flags[protectTransBit]; }
            set { flags[protectTransBit] = value; }
        }

        /// <summary>
        /// The descriptive layer name
        /// </summary>
        public string Name { get; set; }

        public BlendingRanges BlendingRangesData { get; set; }

        public MaskInfo Masks { get; set; }

        public List<LayerInfo> AdditionalInfo { get; set; }

        ///////////////////////////////////////////////////////////////////////////

        public Layer(PsdFile psdFile)
        {
            PsdFile = psdFile;
            Rect = Rectangle.Empty;
            Channels = new ChannelList();
            BlendModeKey = PsdBlendMode.Normal;
            AdditionalInfo = new List<LayerInfo>();
            IsGroup = false;
            ParentLayer = null;
            IsEndGroupMarker = false;
        }

        public Layer(PsdBinaryReader reader, PsdFile psdFile)
            : this(psdFile)
        {
            Util.DebugMessage(reader.BaseStream, "Load, Begin, Layer");

            Rect = reader.ReadRectangle();

            //-----------------------------------------------------------------------
            // Read channel headers.  Image data comes later, after the layer header.

            int numberOfChannels = reader.ReadUInt16();
            for (int channel = 0; channel < numberOfChannels; channel++)
            {
                var ch = new Channel(reader, this);
                Channels.Add(ch);
            }

            //-----------------------------------------------------------------------
            //

            var signature = reader.ReadAsciiChars(4);
            if (signature != "8BIM")
                throw (new PsdInvalidException("Invalid signature in layer header."));

            BlendModeKey = reader.ReadAsciiChars(4);
            Opacity = reader.ReadByte();
            Clipping = reader.ReadBoolean();

            var flagsByte = reader.ReadByte();
            flags = new BitVector32(flagsByte);
            reader.ReadByte(); //padding

            //-----------------------------------------------------------------------

            // This is the total size of the MaskData, the BlendingRangesData, the
            // Name and the AdjustmentLayerInfo.
            var extraDataSize = reader.ReadUInt32();
            var extraDataStartPosition = reader.BaseStream.Position;

            Masks = new MaskInfo(reader, this);
            BlendingRangesData = new BlendingRanges(reader, this);
            Name = reader.ReadPascalString(4);

            //-----------------------------------------------------------------------
            // Process Additional Layer Information

            long adjustmentLayerEndPos = extraDataStartPosition + extraDataSize;
            while (reader.BaseStream.Position < adjustmentLayerEndPos)
            {
                var layerInfo = LayerInfoFactory.Load(reader, this.PsdFile, false, adjustmentLayerEndPos);
                AdditionalInfo.Add(layerInfo);
            }

            foreach (var adjustmentInfo in AdditionalInfo)
            {
                switch (adjustmentInfo.Key)
                {
                    case "luni":
                        Name = ((LayerUnicodeName)adjustmentInfo).Name;
                        break;
                    case "lyid":
                        LayerID = ((LayerId)adjustmentInfo).ID;
                        break;
                }
            }

            Util.DebugMessage(reader.BaseStream, "Load, End, Layer, {0}", Name);

            PsdFile.LoadContext.OnLoadLayerHeader(this);
        }

        ///////////////////////////////////////////////////////////////////////////

        /// <summary>
        /// Create ImageData for any missing channels.
        /// </summary>
        public void CreateMissingChannels()
        {
            var channelCount = this.PsdFile.ColorMode.MinChannelCount();
            for (short id = 0; id < channelCount; id++)
            {
                if (!this.Channels.ContainsId(id))
                {
                    var size = this.Rect.Height * this.Rect.Width;

                    var ch = new Channel(id, this);
                    ch.ImageData = new NativeArray<byte>(size, Allocator.TempJob);
                    unsafe
                    {
                        UnsafeUtility.MemSet(ch.ImageData.GetUnsafePtr(), (byte)255, size);
                    }
                    this.Channels.Add(ch);
                }
            }
        }

        ///////////////////////////////////////////////////////////////////////////
        
    }
}