using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Text.RegularExpressions;
using UnityEngine;

namespace UnityGLTF
{
	public static class URIHelper
	{
		private const string Base64StringInitializer = "^data:[a-z-]+/[a-z-]+;base64,";

		/// <summary>
		///  Get the absolute path to a gltf uri reference.
		/// </summary>
		/// <param name="uri">The path to the gltf file</param>
		/// <returns>A path without the filename or extension</returns>
		public static string AbsoluteUriPath(Uri uri)
		{
			var partialPath = uri.AbsoluteUri.Remove(uri.AbsoluteUri.Length - uri.Segments[uri.Segments.Length - 1].Length);
			return partialPath;
		}

		public static string GetFileFromUri(Uri uri)
		{
			return uri.Segments[uri.Segments.Length - 1];
		}

		/// <summary>
		/// Gets a directory name from a file path
		/// </summary>
		/// <param name="fullPath">Full path of a file</param>
		/// <returns>The name of directory file is in</returns>
		public static string GetDirectoryName(string fullPath)
		{
			var fileName = Path.GetFileName(fullPath);
			return fullPath.Substring(0, fullPath.Length - fileName.Length);
		}

		/// <summary>
		/// Tries to parse the uri as a base 64 encoded string
		/// </summary>
		/// <param name="uri">The string that represents the data</param>
		/// <param name="bufferData">Returns the deencoded bytes</param>
		public static void TryParseBase64(string uri, out byte[] bufferData)
		{
			Regex regex = new Regex(Base64StringInitializer);
			Match match = regex.Match(uri);
			bufferData = null;
			if (match.Success)
			{
				var base64Data = uri.Substring(match.Length);
				bufferData = Convert.FromBase64String(base64Data);
			}
		}

		/// <summary>
		/// Returns whether the input uri is base64 encoded
		/// </summary>
		/// <param name="uri">The uri data</param>
		/// <returns>Whether the uri is base64</returns>
		public static bool IsBase64Uri(string uri)
		{
			Regex regex = new Regex(Base64StringInitializer);
			Match match = regex.Match(uri);
			return match.Success;
		}
	}
}