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

namespace ImageSorter
{
    public class ImageCollection : IEnumerable<ImageInfo>
    {
        private List<ImageInfo> _images;
        private static Regex _imageFileNameRE = new Regex(@"\.(?:jpg|png|bmp)", RegexOptions.IgnoreCase | RegexOptions.Compiled);
        private TagCollection _tags;

        public ImageCollection(string dir)
        {
            LoadFromDirectory(dir);

            BuildTagCollection();
        }

        /// <summary>
        /// Construct from an XML save file
        /// </summary>
        public ImageCollection(TextReader xml)
        {
            readXMLFile(xml);
            BuildTagCollection();
        }

        private void readXMLFile(TextReader xml)
        {
            XmlDocument doc = new XmlDocument();
            doc.Load(xml);

            _images = new List<ImageInfo>();

            foreach (XmlNode imageNode in doc.SelectNodes("/images/image"))
            {
                string file = imageNode.Attributes.GetNamedItem("file").Value;
                ImageInfo image = new ImageInfo(file);
                foreach (XmlNode tag in imageNode.SelectNodes("*"))
                {
                    image.SetTag(tag.Name, true);
                }
                _images.Add(image);
            }
        }
        private void LoadFromDirectory(string dir)
        {
            _images = new List<ImageInfo>();
            foreach (string file in Directory.GetFiles(dir))
            {
                if (_imageFileNameRE.Match(file).Success)
                {
                    _images.Add(new ImageInfo(file));
                }
            }
        }

        private void BuildTagCollection()
        {
            Dictionary<string, bool> tagSet = new Dictionary<string, bool>();
            foreach (ImageInfo image in _images)
            {
                foreach (string tag in image.Tags)
                {
                    tagSet[tag] = true;
                }
            }
            _tags = new TagCollection(tagSet.Keys);
        }

        public ImageInfo this[int imageNum]
        {
            get
            {
                return _images[imageNum];
            }
        }

        public int Count
        {
            get
            {
                return _images.Count;
            }
        }

        public TagCollection Tags
        {
            get
            {
                return _tags;
            }
        }
        internal int UsesOfTag(string tag)
        {
            int uses = 0;
            foreach (ImageInfo image in _images)
            {
                if (image.HasTag(tag))
                {
                    ++uses;
                }
            }
            return uses;
        }

        public void WriteTo(TextWriter outstr)
        {
            using (XmlWriter wrt = XmlWriter.Create(outstr))
            {
                wrt.WriteStartDocument();
                wrt.WriteStartElement("images");
                foreach (ImageInfo image in this)
                {
                    WriteImageTo(image, wrt);
                }
                wrt.WriteEndElement();
            }
        }

        private void WriteImageTo(ImageInfo image, XmlWriter wrt)
        {
            wrt.WriteStartElement("image");
            wrt.WriteAttributeString("file", image.Filename);

            foreach (string tag in image.Tags)
            {
                wrt.WriteStartElement(tag);
                wrt.WriteEndElement();
            }

            wrt.WriteEndElement();
        }

        #region IEnumerable<ImageInfo> Members

        public IEnumerator<ImageInfo> GetEnumerator()
        {
            return _images.GetEnumerator();
        }

        #endregion

        #region IEnumerable Members

        System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
        {
            return _images.GetEnumerator();
        }

        #endregion

        internal void Exclude(int image)
        {
            _images.RemoveAt(image);
        }

        internal void Insert(int index, ImageInfo image)
        {
            _images.Insert(index, image);
        }
    }
}