using System.IO;
using System.Text;
using System.Threading.Tasks;

namespace MAX.Core.Helpers;

/// <summary>
/// 文件和流操作
/// </summary>
public static partial class FileHelper
{
	/// <summary>
	/// 流转换为字节流
	/// </summary>
	/// <param name="stream">流</param>
	public static async Task<byte[]> ToBytesAsync(Stream stream)
	{
		stream.Seek(0, SeekOrigin.Begin);
		byte[] buffer = new byte[stream.Length];
		await stream.ReadAsync(buffer, 0, buffer.Length);
		return buffer;
	}

	/// <summary>
	/// 流转换为字节流
	/// </summary>
	/// <param name="stream">流</param>
	public static byte[] ToBytes(Stream stream)
	{
		stream.Seek(0, SeekOrigin.Begin);
		byte[] buffer = new byte[stream.Length];
		stream.Read(buffer, 0, buffer.Length);
		return buffer;
	}

	/// <summary>
	/// 字符串转换成字节数组
	/// </summary>
	/// <param name="data">数据,默认字符编码utf-8</param>        
	public static byte[] ToBytes(string data)
	{
		return ToBytes(data, Encoding.UTF8);
	}

	/// <summary>
	/// 字符串转换成字节数组
	/// </summary>
	/// <param name="data">数据</param>
	/// <param name="encoding">字符编码</param>
	public static byte[] ToBytes(string data, Encoding encoding)
	{
		if (string.IsNullOrWhiteSpace(data))
		{
			return new byte[] { };
		}

		return encoding.GetBytes(data);
	}

	/// <summary>
	/// 将文件读取到字节流中
	/// </summary>
	/// <param name="filePath">文件的绝对路径</param>
	public static byte[] Read(string filePath)
	{
		if (!File.Exists(filePath))
		{
			return null;
		}

		FileInfo fileInfo = new(filePath);
		using BinaryReader reader = new(fileInfo.Open(FileMode.Open));
		return reader.ReadBytes((int)fileInfo.Length);
	}

	/// <summary>
	/// 流转换成字符串
	/// </summary>
	/// <param name="stream">流</param>
	/// <param name="encoding">字符编码</param>
	/// <param name="bufferSize">缓冲区大小</param>
	/// <param name="isCloseStream">读取完成是否释放流，默认为true</param>
	public static string ToString(Stream stream, Encoding encoding = null, int bufferSize = 1024 * 2, bool isCloseStream = true)
	{
		if (stream == null)
		{
			return string.Empty;
		}

		encoding ??= Encoding.UTF8;

		if (stream.CanRead == false)
		{
			return string.Empty;
		}

		using StreamReader reader = new(stream, encoding, true, bufferSize, !isCloseStream);
		if (stream.CanSeek)
		{
			stream.Seek(0, SeekOrigin.Begin);
		}

		string result = reader.ReadToEnd();
		if (stream.CanSeek)
		{
			stream.Seek(0, SeekOrigin.Begin);
		}

		return result;
	}

	/// <summary>
	/// 流转换成字符串
	/// </summary>
	/// <param name="stream">流</param>
	/// <param name="encoding">字符编码</param>
	/// <param name="bufferSize">缓冲区大小</param>
	/// <param name="isCloseStream">读取完成是否释放流，默认为true</param>
	public static async Task<string> ToStringAsync(Stream stream, Encoding encoding = null, int bufferSize = 1024 * 2, bool isCloseStream = true)
	{
		if (stream == null)
		{
			return string.Empty;
		}

		encoding ??= Encoding.UTF8;

		if (stream.CanRead == false)
		{
			return string.Empty;
		}

		using StreamReader reader = new(stream, encoding, true, bufferSize, !isCloseStream);
		if (stream.CanSeek)
		{
			stream.Seek(0, SeekOrigin.Begin);
		}

		string result = await reader.ReadToEndAsync();
		if (stream.CanSeek)
		{
			stream.Seek(0, SeekOrigin.Begin);
		}

		return result;
	}

	/// <summary>
	/// 复制流并转换成字符串
	/// </summary>
	/// <param name="stream">流</param>
	/// <param name="encoding">字符编码</param>
	public static async Task<string> CopyToStringAsync(Stream stream, Encoding encoding = null)
	{
		if (stream == null)
		{
			return string.Empty;
		}

		encoding ??= Encoding.UTF8;

		if (stream.CanRead == false)
		{
			return string.Empty;
		}

		using MemoryStream memoryStream = new();
		using StreamReader reader = new(memoryStream, encoding);
		if (stream.CanSeek)
		{
			stream.Seek(0, SeekOrigin.Begin);
		}

		stream.CopyTo(memoryStream);
		if (memoryStream.CanSeek)
		{
			memoryStream.Seek(0, SeekOrigin.Begin);
		}

		string result = await reader.ReadToEndAsync();
		if (stream.CanSeek)
		{
			stream.Seek(0, SeekOrigin.Begin);
		}

		return result;
	}
}