using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Security.Cryptography;

namespace EFCDesk.Classes
{
    public static class FileUtil
    {
        public static bool IsFileReady(string path)
        {
            try
            {
                using var stream = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.None);
                return stream.Length >= 0; // si abre sin excepción, está listo
            }
            catch
            {
                return false;
            }
        }

        public static bool WaitAllFilesReady(IEnumerable<string> files, int perFileTimeoutSeconds)
        {
            var deadline = DateTime.UtcNow.AddSeconds(perFileTimeoutSeconds);
            var pendientes = new HashSet<string>(files);

            while (pendientes.Count > 0 && DateTime.UtcNow < deadline)
            {
                var listos = new List<string>();
                foreach (var f in pendientes)
                {
                    if (File.Exists(f) && IsFileReady(f))
                        listos.Add(f);
                }
                foreach (var ok in listos)
                    pendientes.Remove(ok);

                if (pendientes.Count == 0) return true;
                Thread.Sleep(500);
            }
            return pendientes.Count == 0;
        }

        public static string? TryGetSHA1(string path)
        {
            try
            {
                using var fs = File.OpenRead(path);
                using var sha1 = SHA1.Create();
                var hash = sha1.ComputeHash(fs);
                return BitConverter.ToString(hash).Replace("-", "");
            }
            catch
            {
                return null;
            }
        }
    }
}