using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using PhilLibX.IO;

namespace TyrantLib
{
    public partial class ResidentEvil2
    {
        public class Material
        {
            #region Constants
            /// <summary>
            /// PFB Magic Number/FourCC
            /// </summary>
            public const int Magic = 0x46444D;
            #endregion

            /// <summary>
            /// Material File Header
            /// </summary>
            [StructLayout(LayoutKind.Sequential, Pack = 1)]
            public struct Header
            {
                /// <summary>
                /// Magic
                /// </summary>
                public uint Magic { get; set; }

                /// <summary>
                /// Unknown, probably version
                /// </summary>
                public ushort Unknown { get; set; }

                /// <summary>
                /// Number of Materials
                /// </summary>
                public int MaterialCount { get; set; }

                /// <summary>
                /// Null Padding
                /// </summary>
                [MarshalAs(UnmanagedType.ByValArray, SizeConst = 6)]
                public byte[] Padding;
            }

            /// <summary>
            /// Material Entry
            /// </summary>
            [StructLayout(LayoutKind.Sequential, Pack = 1)]
            public struct MaterialEntry
            {
                /// <summary>
                /// Offsets to the name of the Material
                /// </summary>
                public long NameOffset { get; set; }

                /// <summary>
                /// Unknown bytes (What looks like a hash and some constants)
                /// </summary>
                [MarshalAs(UnmanagedType.ByValArray, SizeConst = 20)]
                public byte[] Unknown;

                /// <summary>
                /// Number of Textures
                /// </summary>
                public int TextureCount { get; set; }

                /// <summary>
                /// Null Padding
                /// </summary>
                private long Padding { get; set; }

                /// <summary>
                /// Unknown Offset
                /// </summary>
                public long UnknownOffset { get; set; }

                /// <summary>
                /// Pointer to the Texture Entries
                /// </summary>
                public long TexturesOffset { get; set; }

                /// <summary>
                /// Unknown Offsets
                /// </summary>
                [MarshalAs(UnmanagedType.ByValArray, SizeConst = 16)]
                public byte[] UnknownOffsets;
            }

            /// <summary>
            /// Texture File Entry
            /// </summary>
            public struct TextureEntry
            {
                /// <summary>
                /// Offset to Texture Type String (BaseColor, etc.)
                /// </summary>
                public long TextureTypeOffset { get; set; }

                /// <summary>
                /// Hash of some kind, doesn't match MurMur results
                /// </summary>
                public long Hash { get; set; }

                /// <summary>
                /// Texture Name Offset
                /// </summary>
                public long TextureNameOffset { get; set; }
            }

            /// <summary>
            /// Loads Materials from the Material File
            /// </summary>
            public static Dictionary<string, Dictionary<string, string>> LoadMaterialsFromFile(Stream stream)
            {
                // Create reader
                using (var reader = new BinaryReader(stream))
                {
                    var results = new Dictionary<string, Dictionary<string, string>>();
                    // Read Header
                    var header = reader.ReadStruct<Header>();
                    // Read Materials
                    var materials = reader.ReadArray<MaterialEntry>(header.MaterialCount);
                    // Loop through them
                    foreach(var material in materials)
                    {
                        // Read Material Name
                        reader.Seek(material.NameOffset, SeekOrigin.Begin);
                        string materialName = reader.ReadUTF16NullTerminatedString();
                        // Set texture list
                        results[materialName] = new Dictionary<string, string>();
                        // Read Textures
                        reader.Seek(material.TexturesOffset, SeekOrigin.Begin);
                        var textures = reader.ReadArray<TextureEntry>(material.TextureCount);
                        // Loop through them
                        foreach(var texture in textures)
                        {
                            // Read Texture Type
                            reader.Seek(texture.TextureTypeOffset, SeekOrigin.Begin);
                            string textureType = reader.ReadUTF16NullTerminatedString();
                            // Read Name
                            reader.Seek(texture.TextureNameOffset, SeekOrigin.Begin);
                            string textureName = reader.ReadUTF16NullTerminatedString();
                            // Set it
                            results[materialName][textureType] = textureName;
                        }
                    }
                    // Done
                    return results;
                }
            }
        }
    }
}