using Microsoft.Xna.Framework;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;

namespace OpenVIII.Battle
{
    /// <summary>
    /// Magic Obj Reader
    /// </summary>
    /// <see cref="http://forums.qhimm.com/index.php?topic=15056.msg211220"/>
    /// <seealso cref="http://forums.qhimm.com/index.php?topic=16283.0"/>
    /// <seealso cref="http://forums.qhimm.com/index.php?topic=15906.0"/>
    /// <seealso cref="http://wiki.ffrtt.ru/index.php?title=FF8/FileFormat_magfiles"/>
    /// <seealso cref="https://github.com/MaKiPL/FF8-Rinoa-s-Toolset/blob/master/SerahToolkit_SharpGL/GF_AlternativeTexture.cs"/>
    /// <seealso cref="https://github.com/MaKiPL/FF8-Rinoa-s-Toolset/blob/master/SerahToolkit_SharpGL/GfEnviro.cs"/>
    public partial class Mag
    {
        #region Fields

        public uint
            pBones,
            pTextureLimit,
            pGeometry,
            pSCOT,
            pTexture;

        private static readonly ushort[] _knownPolygons = new ushort[]
        {
            0x2,
            0x6,
            0x7,
            0x8,
            0x9,
            0xC,
            0x10,
            0x12,
            0x11,
            0x13,
        };

        public List<Geometry> Geometries;

        #endregion Fields

        #region Constructors

        public static IEnumerable<Battle.Mag> WithGeometries => All?.Where(x => (x.Geometries?.Count ?? 0) > 0) ?? null;

        public static IEnumerable<Battle.Mag> Packed => All?.Where(x => x.isPackedMag) ?? null;

        public static IEnumerable<Battle.Mag> MagTim => All?.Where(x => x.isTIM) ?? null;

        public static IEnumerable<int> Unknown => All?.Where(x => x.UnknownType > 0).Select(x => x.UnknownType) ?? null;
        public static List<Mag> All;

        public static void Init()
        {
            return;
            //All = new List<Mag>();
            //ArchiveBase aw = ArchiveWorker.Load(Memory.Archives.A_MAGIC);
            ////aw.CacheFS();
            //IEnumerable<string> magFiles = aw.GetListOfFiles().Where(x => Path.GetFileName(Path.GetDirectoryName(x)).IndexOf("magic", System.StringComparison.OrdinalIgnoreCase) >= 0 || Path.GetFileName(Path.GetDirectoryName(x)).IndexOf("battle", System.StringComparison.OrdinalIgnoreCase) >= 0 && Path.GetFileName(x).StartsWith("mag", System.StringComparison.OrdinalIgnoreCase)).Distinct();
            //var v  = magFiles.ToList();

            //foreach (KeyValuePair<string, byte[]> i in magFiles.ToDictionary(x => x, x => aw.GetBinaryFile(x)))
            //{
            //    All.Add(Mag.Load(i.Key, i.Value));
            //}
        }

        public static Mag Load(string filename, byte[] buffer)
        {
            using (var br = new BinaryReader(new MemoryStream(buffer, false)))
                return Load(filename, br);
        }

        public static Mag Load(string filename, BinaryReader br)
        {
            br.BaseStream.Seek(0, SeekOrigin.Begin);
            var m = new Mag
            {
                FileName = filename
            };

            if (m.TryReadTIM(br) != null) return m;
            m.isTIM = false;
            br.BaseStream.Seek(0, SeekOrigin.Begin);
            //Offset Description
            //0x00    Probably always null
            if (!br.Read(out uint pPadding)) return null;
            if (pPadding != 0)
                return m;
            //0x04    Probably bones/ animation data, might be 0x00
            if (!br.Read(out m.pBones)) return null;
            //0x08    Unknown(used to determinate texture size *), might be 0x64
            if (!br.Read(out m.pTextureLimit)) return null;
            //0x0C    Geometry pointer, might be 0xAC
            if (!br.Read(out m.pGeometry)) return null;
            //0x10    SCOT pointer, might be 0x00
            if (!br.Read(out m.pSCOT)) return null;
            //0x14    Texture pointer, might be 0x30
            if (!br.Read(out m.pTexture)) return null;
            //0x18 == 0x98
            //0x1C == 0xAC
            if (m.pBones > br.BaseStream.Length ||
                m.pTextureLimit > br.BaseStream.Length ||
                m.pGeometry > br.BaseStream.Length ||
                m.pSCOT > br.BaseStream.Length ||
                m.pTexture > br.BaseStream.Length)
            {
                return m;
            }
            if (m.FileName == "c:\\ff8\\data\\eng\\battle\\mag201_b.19")
            {
            }
            else if (m.FileName == "c:\\ff8\\data\\eng\\battle\\mag204_b.04")
            {
            }
            m.isPackedMag = true;
            m.ReadGeometry(br);
            m.ReadTextures(br);
            return m;
        }

        #endregion Constructors

        #region Properties

        public byte DataType => getValue(2);

        public string FileName { get; set; }

        public byte IDnumber => getValue(1);

        public bool isPackedMag { get; set; } = false;

        public bool isTIM { get; set; } = false;

        public byte SequenceNumber => getValue(3);

        public TIM2[] TIM { get; set; }

        private bool bFileNameTest => FileName != null && Path.GetExtension(FileName).Trim('.').Length == 3;

        /// <summary>
        /// if quit loop because unknown type.
        /// </summary>
        public int UnknownType { get; set; } = int.MinValue;

        #endregion Properties

        #region Methods

        public TIM2[] TryReadTIM(BinaryReader br)
        {
            try
            {
                var tim = new TIM2(br, noExec: true);
                if (tim.NotTIM)
                    return TIM = null;
                isTIM = true;
                return TIM = new TIM2[] { tim };
            }
            catch (InvalidDataException)
            {
                return TIM = null;
            }
        }

        private byte getValue(int index) => bFileNameTest ? byte.Parse(FileName.Substring(FileName.Length - index, 1),
                                                System.Globalization.NumberStyles.HexNumber) : (byte)0xff;

        private void ReadGeometry(BinaryReader br)
        {
            if (pGeometry == 0) return;
            br.BaseStream.Seek(pGeometry, SeekOrigin.Begin);
            if (!br.Read(out int count)) return;
            //Count = Count > 0x24 ? 0x24 : Count; // unsure why.
            var positions = new List<uint>();
            while (count-- > 0 && br.Read(out uint pos))
            {
                if (pos > 0 && pos + pGeometry < br.BaseStream.Length)
                    positions.Add(pos + pGeometry);
            }
            if (count > 0) return;

            Geometries = new List<Geometry>(positions.Count);

            foreach (var pos in positions)
            {
                var g = new Geometry();
                const int PassFromStart = 24;
                var OnlyVertex = true;
                br.BaseStream.Seek(pos, SeekOrigin.Begin);
                if (!br.Read(out count)) break;

                if (count > 12u)
                    continue;
                if (count != 2u)
                    OnlyVertex = false;
                br.BaseStream.Seek(pos + 8, SeekOrigin.Begin);

                var _relativeJump = br.ReadUInt32() + pos;
                br.BaseStream.Seek(pos + PassFromStart, SeekOrigin.Begin);
                var _vertexCount = br.ReadUInt16() * 8;
                br.BaseStream.Seek(pos + PassFromStart - 4, SeekOrigin.Begin);
                var _verticesOffset = br.ReadUInt16() + pos;
                ReadVertices();
                if (OnlyVertex) { continue; }
                if (_relativeJump > br.BaseStream.Length) return;
                br.BaseStream.Seek(_relativeJump, SeekOrigin.Begin);
                var _polygonType = br.ReadUInt16();
                var polygons = br.ReadUInt16();
                bool _generatefaces;
                bool isknownpolygon() => _knownPolygons.Any(x => x == _polygonType);
                long localoffset = _relativeJump + 4;
                var safeHandle = 0;
                while (!(_generatefaces = !isknownpolygon()))
                {
                    switch (_polygonType)
                    {
                        case 0x2:
                        case 0x7:
                            GetTriangle(20, 0xC);
                            break;

                        case 0x6:
                            GetTriangle(12, 0x4);
                            break;

                        case 0x8:
                            GetTriangle(20, 0xA);
                            break;

                        case 0x9:
                            GetTriangle(28, 0x12);
                            break;

                        case 0xC:
                            GetQuad(28, 0x14);
                            break;

                        case 0x12:
                            GetQuad(24, 0xC);
                            break;

                        case 0x13:
                            GetQuad(36, 0x18);
                            break;

                        case 0x10:
                            GetQuad(12, 0x4);
                            break;

                        case 0x11:
                            GetQuad(24, 0x10);
                            break;
                    }
                    br.BaseStream.Seek(localoffset + safeHandle, SeekOrigin.Begin);
                    if (br.BaseStream.Position + 4 > br.BaseStream.Length) return;
                    if (br.ReadUInt32() == uint.MaxValue)
                        break;
                    localoffset += safeHandle;
                    _polygonType = br.ReadUInt16();
                    polygons = br.ReadUInt16();
                    localoffset += 4;
                    void GetTriangle(int cnt, int off0)
                    {
                        int off1 = off0 + 2, off2 = off0 + 4;
                        var size = polygons * cnt;
                        for (var i = 0; i < size; i += cnt)
                        {
                            g.Triangles.Add(new Vector3(GetPolygonIndex(localoffset + i + off0),
                                GetPolygonIndex(localoffset + i + off1),
                                GetPolygonIndex(localoffset + i + off2)));
                        }
                        safeHandle = size;
                    }
                    void GetQuad(int cnt, int off0)
                    {
                        int off1 = off0 + 2, off2 = off0 + 6, off3 = off0 + 4;
                        var size = polygons * cnt;
                        for (var i = 0; i < size; i += cnt)
                        {
                            g.Quads.Add(new Vector4(GetPolygonIndex(localoffset + i + off0),
                                GetPolygonIndex(localoffset + i + off1),
                                GetPolygonIndex(localoffset + i + off2),
                                GetPolygonIndex(localoffset + i + off3)));
                        }
                        safeHandle = size;
                    }
                    ushort GetPolygonIndex(long offset)
                    {
                        br.BaseStream.Seek(offset, SeekOrigin.Begin);
                        var temp = checked((ushort)(br.ReadUInt16() / 8));
                        Debug.Assert(temp < g.Vertices.Count);
                        //return temp == 0 ? 1 : (temp / 8) + 1;
                        return temp;
                    }
                }
                if (_generatefaces)
                {
                    UnknownType = _polygonType;
                }
                void ReadVertices()
                {
                    br.BaseStream.Seek(_verticesOffset, SeekOrigin.Begin);
                    if (_vertexCount % 8 != 0) return;
                    for (var i = 0; i < _vertexCount / 8; i++)
                    {
                        br.BaseStream.Seek(_verticesOffset + i * 8, SeekOrigin.Begin);
                        g.Vertices.Add(br.ReadVertex());
                    }
                }
                Geometries.Add(g);
            }
        }

        private TIM2[] ReadTextures(BinaryReader br)
        { //this doesn't sound like a tim file per documentation.
            if (pTexture == 0 ||
                pTexture >= pTextureLimit ||
                pTexture + pTextureLimit >= br.BaseStream.Length ||
                (pTextureLimit - pTexture) % 4 != 0
                ) return null;

            br.BaseStream.Seek(pTexture, SeekOrigin.Begin);
            var positions = new List<uint>();
            //Debug.Assert(pTextureSize > 0 && pTextureSize < br.BaseStream.Length);
            while (pTextureLimit > 0 && br.BaseStream.Position < pTextureLimit && br.BaseStream.Position + 4 < br.BaseStream.Length)
            {
                var pos = br.ReadUInt32();
                if (pos != 0)
                    positions.Add(pos + pTexture);
            }
            if (positions.Count > 0)
            {
                //textures here?
                return null;
            }
            else
                return null;
        }
    }

    #endregion Methods
}