using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using System.Runtime.InteropServices;
namespace PriFileFormat
{
	public class ReverseMapSection: Section
	{
		public uint [] Mapping { get; private set; }
		public IReadOnlyList<ResourceMapScope> Scopes { get; private set; }
		public IReadOnlyList<ResourceMapItem> Items { get; private set; }

		internal const string Identifier = "[mrm_rev_map]  \0";

		internal ReverseMapSection (PriFile priFile) : base (Identifier, priFile)
		{
		}

		protected override bool ParseSectionContent (BinaryReader binaryReader)
		{
			uint numItems = binaryReader.ReadUInt32 ();
			binaryReader.ExpectUInt32 ((uint)(binaryReader.BaseStream.Length - 8));

			uint [] mapping = new uint [numItems];
			for (int i = 0; i < numItems; i++)
				mapping [i] = binaryReader.ReadUInt32 ();
			Mapping = mapping;

			ushort maxFullPathLength = binaryReader.ReadUInt16 ();
			binaryReader.ExpectUInt16 (0);
			uint numEntries = binaryReader.ReadUInt32 ();
			uint numScopes = binaryReader.ReadUInt32 ();
			binaryReader.ExpectUInt32 (numItems);
			uint unicodeDataLength = binaryReader.ReadUInt32 ();
			binaryReader.ReadUInt32 ();

			List<Tuple<ushort, ushort, uint, uint, ushort>> scopeAndItemInfo = new List<Tuple<ushort, ushort, uint, uint, ushort>> ();

			for (int i = 0; i < numScopes + numItems; i++)
			{
				ushort parent = binaryReader.ReadUInt16 ();
				ushort fullPathLength = binaryReader.ReadUInt16 ();
				uint hashCode = binaryReader.ReadUInt32 ();
				uint nameOffset = binaryReader.ReadUInt16 () | (((hashCode >> 24) & 0xF) << 16);
				ushort index = binaryReader.ReadUInt16 ();
				scopeAndItemInfo.Add (new Tuple<ushort, ushort, uint, uint, ushort> (parent, fullPathLength, hashCode, nameOffset, index));
			}

			List<Tuple<ushort, ushort, ushort>> scopeExInfo = new List<Tuple<ushort, ushort, ushort>> ();

			for (int i = 0; i < numScopes; i++)
			{
				ushort scopeIndex = binaryReader.ReadUInt16 ();
				ushort childCount = binaryReader.ReadUInt16 ();
				ushort firstChildIndex = binaryReader.ReadUInt16 ();
				binaryReader.ExpectUInt16 (0);
				scopeExInfo.Add (new Tuple<ushort, ushort, ushort> (scopeIndex, childCount, firstChildIndex));
			}

			ushort [] itemIndexPropertyToIndex = new ushort [numItems];
			for (int i = 0; i < numItems; i++)
			{
				itemIndexPropertyToIndex [i] = binaryReader.ReadUInt16 ();
			}

			long unicodeDataOffset = binaryReader.BaseStream.Position;
			long asciiDataOffset = binaryReader.BaseStream.Position + unicodeDataLength * 2;

			ResourceMapScope [] scopes = new ResourceMapScope [numScopes];
			ResourceMapItem [] items = new ResourceMapItem [numItems];

			for (int i = 0; i < numScopes + numItems; i++)
			{
				bool nameInAscii = (scopeAndItemInfo [i].Item3 & 0x20000000) != 0;
				long pos = (nameInAscii ? asciiDataOffset : unicodeDataOffset) + (scopeAndItemInfo [i].Item4 * (nameInAscii ? 1 : 2));

				binaryReader.BaseStream.Seek (pos, SeekOrigin.Begin);

				string name;

				if (scopeAndItemInfo [i].Item2 != 0)
					name = binaryReader.ReadNullTerminatedString (nameInAscii ? Encoding.ASCII : Encoding.Unicode);
				else
					name = string.Empty;

				ushort index = scopeAndItemInfo [i].Item5;

				bool isScope = (scopeAndItemInfo [i].Item3 & 0x10000000) != 0;

				if (isScope)
				{
					if (scopes [index] != null)
						throw new InvalidDataException ();

					scopes [index] = new ResourceMapScope (index, null, name);
				}
				else
				{
					if (items [index] != null)
						throw new InvalidDataException ();

					items [index] = new ResourceMapItem (index, null, name);
				}
			}

			for (int i = 0; i < numScopes + numItems; i++)
			{
				ushort index = scopeAndItemInfo [i].Item5;

				bool isScope = (scopeAndItemInfo [i].Item3 & 0x10000000) != 0;

				ushort parent = scopeAndItemInfo [i].Item1;

				parent = scopeAndItemInfo [parent].Item5;

				if (parent != 0xFFFF)
					if (isScope)
					{
						if (parent != index)
							scopes [index].Parent = scopes [parent];
					}
					else
						items [index].Parent = scopes [parent];
			}

			for (int i = 0; i < numScopes; i++)
			{
				ResourceMapEntry [] children = new ResourceMapEntry [scopeExInfo [i].Item2];

				for (int j = 0; j < children.Length; j++)
				{
					var saiInfo = scopeAndItemInfo [scopeExInfo [i].Item3 + j];

					bool isScope = (saiInfo.Item3 & 0x10000000) != 0;

					if (isScope)
						children [j] = scopes [saiInfo.Item5];
					else
						children [j] = items [saiInfo.Item5];
				}

				scopes [i].Children = children;
			}

			Scopes = scopes;
			Items = items;

			return true;
		}
		~ReverseMapSection ()
		{
			Mapping = null;
			Scopes = null;
			Items = null;
		}
	}

}
