using Sharp.Augeas;

namespace CodeLiturgy.Views.Augeas
{
    /// <summary>
    /// Manager class for Augeas. 
    /// </summary>
    public class AugeasManager
    {
        private readonly Sharp.Augeas.Augeas _augeas;
        
        private AugSettings _augSettings;

        /// <summary>
        /// Cached List with the current apache configurations.
        /// </summary>
        public List<string> CurrentApacheConfigurations => _currentApacheConfigurations;

        private List<string> _currentApacheConfigurations;

        private const string ApachePath = "/etc/apache2/sites-available";
        

        /// <summary>
        /// Augeas Manager constructor. 
        /// </summary>
        public AugeasManager()
        {
            _augSettings = AugeasExtensions.GetSettings();
            _augeas = new Sharp.Augeas.Augeas(_augSettings);
            RefreshApacheConfigurations();
        }

        /// <summary>
        /// Write Changes to the disk
        /// </summary>
        /// <returns>Returns true if the save was successful.</returns>
        public bool Save()
        {
            return _augeas.Save();
        }
        
        /// <summary>
        /// Gets a preview of the configuration.
        /// </summary>
        /// <param name="site"></param>
        /// <returns></returns>
        public string GetPreview(string site) 
        {
            
            if (!_currentApacheConfigurations.Contains(site))
            {
                return string.Empty;
            }

            var siteFullPath = $"{ApachePath}/{site}";
            _augeas.LoadFile(siteFullPath);
            var preview = _augeas.GetPreview($"/files{siteFullPath}");
            return preview;
        }

        /// <summary>
        /// Gets available Apache configurations.
        /// </summary>
        /// <param name="skip"></param>
        /// <param name="take"></param>
        /// <returns></returns>
        public List<string> GetApacheAvailableConfigurations(int skip, int take)
        {
            var result =  _currentApacheConfigurations
                .Skip(skip)
                .Take(take)
                .ToList();
            
            return _currentApacheConfigurations;

        }

        /// <summary>
        /// Gets virtual host tree of a site. 
        /// </summary>
        /// <param name="site">Name of the site.</param>
        /// <returns></returns>
        public SuperNode GetVirtualHostTree(string site)
        {
            if (!_currentApacheConfigurations.Contains(site))
            {
                return null;
            }
            
            var siteFullPath = $"{ApachePath}/{site}";
            _augeas.LoadFile(siteFullPath);
            var tree = _augeas.GetTree("VirtualHost",$"/files{siteFullPath}/VirtualHost/*");
            return tree;
        }
        
        
        private void RefreshApacheConfigurations()
        {
            var apacheDir = _augSettings.root + ApachePath;
            DirectoryInfo d = new DirectoryInfo(apacheDir);

            FileInfo[] files = d.GetFiles("*.conf");

            var result =  files
                .Select(x => x.Name)
                .ToList();

            _currentApacheConfigurations = result;
        }

        /// <summary>
        /// Gets a directive.
        /// </summary>
        /// <param name="siteName"></param>
        /// <param name="directiveName"></param>
        /// <returns></returns>
        public Directive GetDirective(string siteName, string directiveName)
        {
            var tree = GetVirtualHostTree(siteName);
            var directive = tree.GetDirective(directiveName);
            return directive;
        }
    }
}