using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Text;

namespace NcProgramManager.Cnc.Mazak
{
    /// <summary>Client FTP per trasferimento programmi Mazak CNC.</summary>
    internal sealed class MazakFtpClient : IMazakFtpClient
    {
        private readonly MazakConnectionConfig _config;

        public MazakFtpClient(MazakConnectionConfig config)
        {
            _config = config ?? throw new ArgumentNullException("config");
        }

        /// <summary>Verifica raggiungibilita server FTP listando la directory programmi.</summary>
        public bool Ping()
        {
            try
            {
                var req = CreateRequest(_config.ProgramDirectory, WebRequestMethods.Ftp.ListDirectory);
                using (var resp = (FtpWebResponse)req.GetResponse())
                    return resp.StatusCode == FtpStatusCode.DataAlreadyOpen
                        || resp.StatusCode == FtpStatusCode.OpeningData
                        || (int)resp.StatusCode / 100 == 2;
            }
            catch { return false; }
        }

        /// <summary>
        /// Lista una directory FTP (LIST/ListDirectoryDetails). Ritorna file e
        /// sotto-cartelle con nome, path completo, flag directory e dimensione.
        /// Parsa sia il formato Unix (drwx...) sia quello DOS/IIS (MM-DD-YY ... &lt;DIR&gt;),
        /// cioe' i due layout esposti dai controlli Mazak Smooth/Matrix.
        /// </summary>
        public IReadOnlyList<FtpEntry> ListDirectory(string path)
        {
            string dir = FtpListParser.NormalizeDir(path);
            var req = CreateRequest(dir, WebRequestMethods.Ftp.ListDirectoryDetails);
            var entries = new List<FtpEntry>();
            using (var resp = (FtpWebResponse)req.GetResponse())
            using (var reader = new StreamReader(resp.GetResponseStream(), Encoding.ASCII))
            {
                string line;
                while ((line = reader.ReadLine()) != null)
                {
                    var entry = FtpListParser.Parse(line, dir);
                    if (entry != null)
                        entries.Add(entry);
                }
            }
            return entries;
        }

        /// <summary>Scarica file dal Mazak in stringa.</summary>
        public string DownloadFile(string ncPath)
        {
            var req = CreateRequest(ncPath, WebRequestMethods.Ftp.DownloadFile);
            using (var resp = (FtpWebResponse)req.GetResponse())
            using (var reader = new StreamReader(resp.GetResponseStream(), Encoding.ASCII))
                return reader.ReadToEnd();
        }

        /// <summary>Carica contenuto stringa su Mazak.</summary>
        public void UploadFile(string ncPath, string content)
        {
            var req = CreateRequest(ncPath, WebRequestMethods.Ftp.UploadFile);
            byte[] data = Encoding.ASCII.GetBytes(content);
            req.ContentLength = data.Length;
            using (var stream = req.GetRequestStream())
                stream.Write(data, 0, data.Length);
            using ((FtpWebResponse)req.GetResponse()) { }
        }

        public void DeleteFile(string ncPath)
        {
            var req = CreateRequest(ncPath, WebRequestMethods.Ftp.DeleteFile);
            using ((FtpWebResponse)req.GetResponse()) { }
        }

        private FtpWebRequest CreateRequest(string path, string method)
        {
            string uri = string.Format("ftp://{0}:{1}{2}", _config.IpAddress, _config.Port, path);
            var req = (FtpWebRequest)WebRequest.Create(uri);
            req.Method = method;
            req.Credentials = new NetworkCredential(_config.Username, _config.Password);
            req.Timeout = (int)_config.RequestTimeout.TotalMilliseconds;
            req.KeepAlive = false;
            req.UseBinary = false;
            req.UsePassive = true;
            return req;
        }
    }
}