using System.IO;
using System.Text;
using Syroot.IO;
using Syroot.Maths;
using Syroot.Worms.Core;

namespace Syroot.Worms.Gen2.Worms2
{
    /// <summary>
    /// Represents map configuration stored by the land generator in LAND.DAT files.
    /// Used by W2. S. https://worms2d.info/Land_Data_file.
    /// </summary>
    public class LandData : ILoadableFile
    {
        // ---- CONSTANTS ----------------------------------------------------------------------------------------------

        private const int _signature = 0x1A444E4C; // "LND", 0x1A

        // ---- CONSTRUCTORS & DESTRUCTOR ------------------------------------------------------------------------------

        /// <summary>
        /// Initializes a new instance of the <see cref="LandData"/> class.
        /// </summary>
        public LandData()
        {
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="LandData"/> class, loading the data from the given
        /// <see cref="Stream"/>.
        /// </summary>
        /// <param name="stream">The <see cref="Stream"/> to load the data from.</param>
        public LandData(Stream stream)
        {
            Load(stream);
        }

        /// <summary>
        /// Initializes a new instance of the <see cref="LandData"/> class, loading the data from the given file.
        /// </summary>
        /// <param name="fileName">The name of the file to load the data from.</param>
        public LandData(string fileName)
        {
            Load(fileName);
        }

        // ---- PROPERTIES ---------------------------------------------------------------------------------------------

        /// <summary>
        /// Gets or sets the size of the landscape in pixels.
        /// </summary>
        public Vector2 Size { get; set; }

        /// <summary>
        /// Gets or sets a value indicating whether an indestructible top border will be enabled.
        /// </summary>
        public bool TopBorder { get; set; }
        
        /// <summary>
        /// Gets or sets an array of coordinates at which objects can be placed.
        /// </summary>
        public Vector2[] ObjectLocations { get; set; }

        /// <summary>
        /// Gets or sets the visual foreground image.
        /// </summary>
        public Image Foreground { get; set; }

        /// <summary>
        /// Gets or sets the collision mask of the landscape.
        /// </summary>
        public Image CollisionMask { get; set; }

        /// <summary>
        /// Gets or sets the visual background image.
        /// </summary>
        public Image Background { get; set; }

        /// <summary>
        /// Gets or sets an image of unknown use.
        /// </summary>
        public Image UnknownImage { get; set; }

        /// <summary>
        /// Gets or sets the path to the land image file.
        /// </summary>
        public string LandTexturePath { get; set; }

        /// <summary>
        /// Gets or sets the path to the Water.dir file.
        /// </summary>
        public string WaterDirPath { get; set; }
        
        // ---- METHODS (PUBLIC) ---------------------------------------------------------------------------------------

        /// <summary>
        /// Loads the data from the given <see cref="Stream"/>.
        /// </summary>
        /// <param name="stream">The <see cref="Stream"/> to load the data from.</param>
        public void Load(Stream stream)
        {
            using (BinaryDataReader reader = new BinaryDataReader(stream, Encoding.ASCII, true))
            {
                // Read the header.
                if (reader.ReadInt32() != _signature)
                {
                    throw new InvalidDataException("Invalid LND file signature.");
                }
                int fileLength = reader.ReadInt32();

                // Read the data.
                Size = reader.ReadStruct<Vector2>();
                TopBorder = reader.ReadBoolean(BinaryBooleanFormat.NonZeroDword);

                // Read the possible object coordinate array.
                ObjectLocations = new Vector2[reader.ReadInt32()];
                for (int i = 0; i < ObjectLocations.Length; i++)
                {
                    ObjectLocations[i] = reader.ReadStruct<Vector2>();
                }
                int unknown = reader.ReadInt32(); // Seems 0.

                // Read the image data.
                Foreground = new Image(stream);
                CollisionMask = new Image(stream);
                Background = new Image(stream);
                UnknownImage = new Image(stream);

                // Read the file paths.
                LandTexturePath = reader.ReadString(BinaryStringFormat.ByteLengthPrefix);
                WaterDirPath = reader.ReadString(BinaryStringFormat.ByteLengthPrefix);
            }
        }

        /// <summary>
        /// Loads the data from the given file.
        /// </summary>
        /// <param name="fileName">The name of the file to load the data from.</param>
        public void Load(string fileName)
        {
            using (FileStream stream = new FileStream(fileName, FileMode.Open, FileAccess.Read, FileShare.Read))
            {
                Load(stream);
            }
        }
    }
}