using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using BurnOutSharp.Matching;

namespace BurnOutSharp.Tools
{
    internal static class Extensions
    {
        // TODO: Add extensions for BitConverter.ToX(); offset += x;
        #region Byte Arrays

        /// <summary>
        /// Find all positions of one array in another, if possible, if possible
        /// </summary>
        public static List<int> FindAllPositions(this byte[] stack, byte?[] needle, int start = 0, int end = -1)
        {
            // Get the outgoing list
            List<int> positions = new List<int>();

            // Initialize the loop variables
            bool found = true;
            int lastPosition = start;
            var matcher = new ContentMatch(needle, end: end);

            // Loop over and get all positions
            while (found)
            {
                matcher.Start = lastPosition;
                (found, lastPosition) = matcher.Match(stack, false);
                if (found)
                    positions.Add(lastPosition);
            }

            return positions;
        }

        /// <summary>
        /// Find the first position of one array in another, if possible
        /// </summary>
        public static bool FirstPosition(this byte[] stack, byte?[] needle, out int position, int start = 0, int end = -1)
        {
            var matcher = new ContentMatch(needle, start, end);
            (bool found, int foundPosition) = matcher.Match(stack, false);
            position = foundPosition;
            return found;
        }

        /// <summary>
        /// Find the last position of one array in another, if possible
        /// </summary>
        public static bool LastPosition(this byte[] stack, byte?[] needle, out int position, int start = 0, int end = -1)
        {
            var matcher = new ContentMatch(needle, start, end);
            (bool found, int foundPosition) = matcher.Match(stack, true);
            position = foundPosition;
            return found;
        }

        /// <summary>
        /// See if a byte array starts with another
        /// </summary>
        public static bool StartsWith(this byte[] stack, byte?[] needle)
        {
            return stack.FirstPosition(needle, out int _, start: 0, end: 1);
        }

        /// <summary>
        /// See if a byte array ends with another
        /// </summary>
        public static bool EndsWith(this byte[] stack, byte?[] needle)
        {
            return stack.FirstPosition(needle, out int _, start: stack.Length - needle.Length);
        }

        #endregion

        #region Streams

        /// <summary>
        /// Read a byte from the stream
        /// </summary>
        public static byte ReadByteValue(this Stream stream)
        {
            byte[] buffer = new byte[1];
            stream.Read(buffer, 0, 1);
            return buffer[0];
        }

        /// <summary>
        /// Read a byte array from the stream
        /// </summary>
        public static byte[] ReadBytes(this Stream stream, int count)
        {
            byte[] buffer = new byte[count];
            stream.Read(buffer, 0, count);
            return buffer;
        }

        /// <summary>
        /// Read a character from the stream
        /// </summary>
        public static char ReadChar(this Stream stream)
        {
            byte[] buffer = new byte[1];
            stream.Read(buffer, 0, 1);
            return (char)buffer[0];
        }

        /// <summary>
        /// Read a character array from the stream
        /// </summary>
        public static char[] ReadChars(this Stream stream, int count) => stream.ReadChars(count, Encoding.Default);

        /// <summary>
        /// Read a character array from the stream
        /// </summary>
        public static char[] ReadChars(this Stream stream, int count, Encoding encoding)
        {
            byte[] buffer = new byte[count];
            stream.Read(buffer, 0, count);
            return encoding.GetString(buffer).ToCharArray();
        }

        /// <summary>
        /// Read a short from the stream
        /// </summary>
        public static short ReadInt16(this Stream stream)
        {
            byte[] buffer = new byte[2];
            stream.Read(buffer, 0, 2);
            return BitConverter.ToInt16(buffer, 0);
        }

        /// <summary>
        /// Read a ushort from the stream
        /// </summary>
        public static ushort ReadUInt16(this Stream stream)
        {
            byte[] buffer = new byte[2];
            stream.Read(buffer, 0, 2);
            return BitConverter.ToUInt16(buffer, 0);
        }

        /// <summary>
        /// Read an int from the stream
        /// </summary>
        public static int ReadInt32(this Stream stream)
        {
            byte[] buffer = new byte[4];
            stream.Read(buffer, 0, 4);
            return BitConverter.ToInt32(buffer, 0);
        }

        /// <summary>
        /// Read a uint from the stream
        /// </summary>
        public static uint ReadUInt32(this Stream stream)
        {
            byte[] buffer = new byte[4];
            stream.Read(buffer, 0, 4);
            return BitConverter.ToUInt32(buffer, 0);
        }

        /// <summary>
        /// Read a long from the stream
        /// </summary>
        public static long ReadInt64(this Stream stream)
        {
            byte[] buffer = new byte[8];
            stream.Read(buffer, 0, 8);
            return BitConverter.ToInt64(buffer, 0);
        }

        /// <summary>
        /// Read a ulong from the stream
        /// </summary>
        public static ulong ReadUInt64(this Stream stream)
        {
            byte[] buffer = new byte[8];
            stream.Read(buffer, 0, 8);
            return BitConverter.ToUInt64(buffer, 0);
        }

        /// <summary>
        /// Read a null-terminated string from the stream
        /// </summary>
        public static string ReadString(this Stream stream) => stream.ReadString(Encoding.Default);

        /// <summary>
        /// Read a null-terminated string from the stream
        /// </summary>
        public static string ReadString(this Stream stream, Encoding encoding)
        {
            byte[] nullTerminator = encoding.GetBytes(new char[] { '\0' });
            int charWidth = nullTerminator.Length;

            List<byte> tempBuffer = new List<byte>();

            byte[] buffer = new byte[charWidth];
            while (stream.Read(buffer, 0, charWidth) != 0 && buffer.SequenceEqual(nullTerminator))
            {
                tempBuffer.AddRange(buffer);
            }

            return encoding.GetString(tempBuffer.ToArray());
        }

        #endregion
    }
}