// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
//
// 
// Description: The FontSourceCollection class represents a collection of font files.
//
//
 
using System.IO;
 
using Microsoft.Win32;
using MS.Internal.Text.TextInterface;
 
namespace MS.Internal.FontCache
{
    internal class FontSourceCollectionFactory : IFontSourceCollectionFactory
    {
        public FontSourceCollectionFactory() { }
 
        public IFontSourceCollection Create(string uriString)
        {
            return new FontSourceCollection(new Uri(uriString));
        }
    }
 
    /// <summary>
    /// FontSourceCollection class represents a collection of font files.
    /// </summary>
    internal class FontSourceCollection : IFontSourceCollection
    {
        public FontSourceCollection(Uri folderUri)
        {
            Initialize(folderUri, false);
        }
 
        public FontSourceCollection(Uri folderUri, bool tryGetCompositeFontsOnly)
        {
            Initialize(folderUri, tryGetCompositeFontsOnly);
        }
 
        private void Initialize(Uri folderUri, bool tryGetCompositeFontsOnly)
        {
            _uri = folderUri;
            _tryGetCompositeFontsOnly = tryGetCompositeFontsOnly;
 
            bool isComposite = false;
 
            // Check whether the given uri is a font file. In some cases we will construct a DWrite Font Collection by passing
            // a file path and not a directory path. In this case we need to construct a FontCollection that only holds this
            // file.
            bool isSingleSupportedFile = Util.IsSupportedFontExtension(Util.GetUriExtension(_uri), out isComposite);
            if (isSingleSupportedFile || !Util.IsEnumerableFontUriScheme(_uri))
            {
                _fontSources = new List<Text.TextInterface.IFontSource>(1);                
                _fontSources.Add(new FontSource(_uri, isComposite));
            }
            else
            {
                InitializeDirectoryProperties();
            }
        }
 
        private void InitializeDirectoryProperties()
        {
            _isFileSystemFolder = false;
 
            if (_uri.IsFile)
            {
                // Get the local path
                string localPath = _uri.LocalPath;
 
                // Decide if it's a file or folder based on syntax, not contents of file system
                _isFileSystemFolder = localPath[localPath.Length - 1] == Path.DirectorySeparatorChar;
            }
        }
 
        private void SetFontSources()
        {
            if (_fontSources != null)
                return;
 
            lock (this)
            {
                List<Text.TextInterface.IFontSource> fontSources;
                if (_uri.IsFile)
                {
                    ICollection<string> files;
                    bool isOnlyCompositeFontFiles = false;
                    if (_isFileSystemFolder)
                    {
                        if (_tryGetCompositeFontsOnly)
                        {
                            files = Directory.GetFiles(_uri.LocalPath, "*" + Util.CompositeFontExtension);
                            isOnlyCompositeFontFiles = true;                               
                        }
                        else
                        {
                            files = Directory.GetFiles(_uri.LocalPath);
                        }
                    }
                    else
                    {
                        files = new string[1] {_uri.LocalPath};
                    }
 
                    fontSources = new List<Text.TextInterface.IFontSource>(files.Count);
                    if (isOnlyCompositeFontFiles)
                    {
                        foreach (string file in files)
                        {
                            fontSources.Add(new FontSource(new Uri(file, UriKind.Absolute), true));
                        }
                    }
                    else
                    {
                        bool isComposite;
                        foreach (string file in files)
                        {                            
                            if (Util.IsSupportedFontExtension(Path.GetExtension(file), out isComposite))
                                fontSources.Add(new FontSource(new Uri(file, UriKind.Absolute), isComposite));
                        }
                    }
                }
                else
                {
                    List<string> resourceEntries = FontResourceCache.LookupFolder(_uri);
 
                    if (resourceEntries == null)
                        fontSources = new List<Text.TextInterface.IFontSource>(0);
                    else
                    {
                        bool isComposite = false;
 
                        // Enumerate application resources, content files and container structure.
                        fontSources = new List<Text.TextInterface.IFontSource>(resourceEntries.Count);
 
                        foreach (string resourceName in resourceEntries)
                        {
                            // If resourceName is an empty string, this means that the _uri is a full file name;
                            // otherwise resourceName is a file name within a folder.
                            if (String.IsNullOrEmpty(resourceName))
                            {
                                isComposite = Util.IsCompositeFont(Path.GetExtension(_uri.AbsoluteUri));
                                fontSources.Add(new FontSource(_uri, isComposite));
                            }
                            else
                            {
                                isComposite = Util.IsCompositeFont(Path.GetExtension(resourceName));
                                fontSources.Add(new FontSource(new Uri(_uri, resourceName), isComposite));
                            }
                        }
                    }
                }
 
                _fontSources = fontSources;
            }
        }
 
        
        #region IEnumerable<FontSource> Members
 
        IEnumerator<Text.TextInterface.IFontSource> System.Collections.Generic.IEnumerable<Text.TextInterface.IFontSource>.GetEnumerator()
        {
            SetFontSources();
            return (IEnumerator<Text.TextInterface.IFontSource>)_fontSources.GetEnumerator();
        }
 
        #endregion
 
        #region IEnumerable Members
 
        System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
        {
            SetFontSources();
            return _fontSources.GetEnumerator();
        }
 
        #endregion
    
 
        private Uri                         _uri;
 
        // _isFileSystemFolder flag makes sense only when _uri.IsFile is set to true.
        private bool                                           _isFileSystemFolder;
        private volatile IList<Text.TextInterface.IFontSource> _fontSources;
 
        // Flag to indicate that only composite fonts in the provided URI location should be retrieved.        
        private bool                               _tryGetCompositeFontsOnly;
    }
}