using System;
using System.IO;

namespace UnityEditor.PackageManager.ValidationSuite.ValidationTests.Standards
{
    internal class FilePathLengthUS0113 : BaseStandardChecker
    {
        public override string StandardCode => "US-0113";
        public override StandardVersion Version => new StandardVersion(1, 0, 0);

        public static int MaxPathLength => 140;

        public void Check(string rootPath)
        {
            CheckPathLengthInFolderRecursively(string.Empty, rootPath);
        }

        private static string CombineAllowingEmpty(string path1, string path2)
        {
            if (string.IsNullOrEmpty(path1))
                return path2;
            if (string.IsNullOrEmpty(path2))
                return path1;
            return Path.Combine(path1, path2);
        }

        private bool IsHiddenDirectory(string path)
        {
            if (path.Length > 0
                && (path[path.Length - 1] == Path.DirectorySeparatorChar
                    || path[path.Length - 1] == Path.AltDirectorySeparatorChar))
                path = path.Substring(0, path.Length - 1);

            string dir = Path.GetFileName(path);

            if (dir.EndsWith("~") || dir.StartsWith("."))
                return true;
            return false;
        }

        void CheckPathLengthInFolderRecursively(string relativeFolder, string absoluteBasePath)
        {
            try
            {
                var fullFolder = CombineAllowingEmpty(absoluteBasePath, relativeFolder);
                if (IsHiddenDirectory(fullFolder))
                    return;

                foreach (string entry in Directory.GetFileSystemEntries(fullFolder))
                {
                    var fullPath = CombineAllowingEmpty(relativeFolder, Path.GetFileName(entry));
                    if (fullPath.Length > MaxPathLength)
                    {
                        AddError($"{fullPath} is {fullPath.Length} characters, which is longer than the limit of {MaxPathLength} characters. You must use shorter names.");
                    }
                }

                foreach (string dir in Directory.GetDirectories(fullFolder))
                {
                    CheckPathLengthInFolderRecursively(CombineAllowingEmpty(relativeFolder, Path.GetFileName(dir)), absoluteBasePath);
                }
            }
            catch (Exception e)
            {
                AddError("Exception " + e.Message);
            }
        }
    }
}