using System;
using System.Collections.Generic;
using System.IO;

using ACE.DatLoader.Entity;
using ACE.Entity.Enum;

namespace ACE.DatLoader.FileTypes
{
    /// <summary>
    /// This reads an "indoor" cell from the client_cell.dat. This is mostly dungeons, but can also be a building interior.
    /// An EnvCell is designated by starting 0x0100 (whereas all landcells are in the 0x0001 - 0x0040 range.
    /// <para />
    /// The fileId is the full int32/dword landblock value as reported by the @loc command (e.g. 0x12345678)
    /// </summary>
    /// <remarks>
    /// Very special thanks again to David Simpson for his early work on reading the cell.dat. Even bigger thanks for his documentation of it!
    /// </remarks>
    [DatFileType(DatFileType.EnvCell)]
    public class EnvCell : FileType
    {
        public EnvCellFlags Flags { get; private set; }
        // 0x08000000 surfaces (which contains degrade/quality info to reference the specific 0x06000000 graphics)
        public List<uint> Surfaces { get; } = new List<uint>();
        // the 0x0D000000 model of the pre-fab dungeon block
        public uint EnvironmentId { get; private set; }
        public ushort CellStructure { get; private set; }
        public Frame Position { get; } = new Frame();
        public List<CellPortal> CellPortals { get; } = new List<CellPortal>();
        public List<ushort> VisibleCells { get; } = new List<ushort>();
        public List<Stab> StaticObjects { get; } = new List<Stab>();
        public uint RestrictionObj { get; private set; }

        public bool SeenOutside => Flags.HasFlag(EnvCellFlags.SeenOutside);

        public override void Unpack(BinaryReader reader)
        {
            Id = reader.ReadUInt32();

            Flags = (EnvCellFlags)reader.ReadUInt32();

            reader.BaseStream.Position += 4; // Skip ahead 4 bytes, because this is the CellId. Again. Twice.

            byte numSurfaces    = reader.ReadByte();
            byte numPortals     = reader.ReadByte();    // Note that "portal" in this context does not refer to the swirly pink/purple thing, its basically connecting cells
            ushort numStabs     = reader.ReadUInt16();  // I believe this is what cells can be seen from this one. So the engine knows what else it needs to load/draw.

            // Read what surfaces are used in this cell
            for (uint i = 0; i < numSurfaces; i++)
                Surfaces.Add(0x08000000u | reader.ReadUInt16()); // these are stored in the dat as short values, so we'll make them a full dword

            EnvironmentId = (0x0D000000u | reader.ReadUInt16());

            CellStructure = reader.ReadUInt16();

            Position.Unpack(reader);

            CellPortals.Unpack(reader, numPortals);

            for (uint i = 0; i < numStabs; i++)
                VisibleCells.Add(reader.ReadUInt16());

            if ((Flags & EnvCellFlags.HasStaticObjs) != 0)
                StaticObjects.Unpack(reader);

            if ((Flags & EnvCellFlags.HasRestrictionObj) != 0)
                RestrictionObj = reader.ReadUInt32();
        }
    }
}