text: /*\
  title: $:/plugins/tiddlywiki/filesystem/filesystemadaptor.js
  type: application/javascript
  module-type: syncadaptor
  
  A sync adaptor module for synchronising with the local filesystem via node.js APIs
  
  \*/
  (function(){
  
  /*jslint node: true, browser: true */
  /*global $tw: false */
  "use strict";
  
  // Get a reference to the file system
  var fs = !$tw.browser ? require("fs") : null,
  	path = !$tw.browser ? require("path") : null;
  
  function FileSystemAdaptor(options) {
  	var self = this;
  	this.wiki = options.wiki;
  	this.logger = new $tw.utils.Logger("FileSystem");
  	// Create the <wiki>/tiddlers folder if it doesn't exist
  	$tw.utils.createDirectory($tw.boot.wikiTiddlersPath);
  }
  
  FileSystemAdaptor.prototype.getTiddlerInfo = function(tiddler) {
  	return {};
  };
  
  $tw.config.typeInfo = {
  	"text/vnd.tiddlywiki": {
  		fileType: "application/x-tiddler",
  		extension: ".tid"
  	},
  	"image/jpeg" : {
  		hasMetaFile: true
  	}
  };
  
  $tw.config.typeTemplates = {
  	"application/x-tiddler": "$:/core/templates/tid-tiddler"
  };
  
  FileSystemAdaptor.prototype.getTiddlerFileInfo = function(tiddler,callback) {
  	// See if we've already got information about this file
  	var self = this,
  		title = tiddler.fields.title,
  		fileInfo = $tw.boot.files[title];
  	// Get information about how to save tiddlers of this type
  	var type = tiddler.fields.type || "text/vnd.tiddlywiki",
  		typeInfo = $tw.config.typeInfo[type];
  	if(!typeInfo) {
  		typeInfo = $tw.config.typeInfo["text/vnd.tiddlywiki"];
  	}
  	var extension = typeInfo.extension || "";
  	if(!fileInfo) {
  		// If not, we'll need to generate it
  		// Start by getting a list of the existing files in the directory
  		fs.readdir($tw.boot.wikiTiddlersPath,function(err,files) {
  			if(err) {
  				return callback(err);
  			}
  			// Assemble the new fileInfo
  			fileInfo = {};
  			fileInfo.filepath = $tw.boot.wikiTiddlersPath + path.sep + self.generateTiddlerFilename(title,extension,files);
  			fileInfo.type = typeInfo.fileType || tiddler.fields.type;
  			fileInfo.hasMetaFile = typeInfo.hasMetaFile;
  			// Save the newly created fileInfo
  			$tw.boot.files[title] = fileInfo;
  			// Pass it to the callback
  			callback(null,fileInfo);
  		});
  	} else {
  		// Otherwise just invoke the callback
  		callback(null,fileInfo);
  	}
  };
  
  /*
  Given a tiddler title and an array of existing filenames, generate a new legal filename for the title, case insensitively avoiding the array of existing filenames
  */
  FileSystemAdaptor.prototype.generateTiddlerFilename = function(title,extension,existingFilenames) {
  	// First remove any of the characters that are illegal in Windows filenames
  	var baseFilename = title.replace(/<|>|\:|\"|\/|\\|\||\?|\*|\^/g,"_");
  	// Truncate the filename if it is too long
  	if(baseFilename.length > 200) {
  		baseFilename = baseFilename.substr(0,200) + extension;
  	}
  	// Start with the base filename plus the extension
  	var filename = baseFilename + extension,
  		count = 1;
  	// Add a discriminator if we're clashing with an existing filename
  	while(existingFilenames.indexOf(filename) !== -1) {
  		filename = baseFilename + " " + (count++) + extension;
  	}
  	return filename;
  };
  
  /*
  Save a tiddler and invoke the callback with (err,adaptorInfo,revision)
  */
  FileSystemAdaptor.prototype.saveTiddler = function(tiddler,callback) {
  	var self = this;
  	this.getTiddlerFileInfo(tiddler,function(err,fileInfo) {
  		var template, content, encoding,
  			_finish = function() {
  				callback(null, {}, 0);
  			};
  		if(err) {
  			return callback(err);
  		}
  		if(fileInfo.hasMetaFile) {
  			// Save the tiddler as a separate body and meta file
  			var typeInfo = $tw.config.contentTypeInfo[fileInfo.type];
  			fs.writeFile(fileInfo.filepath,tiddler.fields.text,{encoding: typeInfo.encoding},function(err) {
  				if(err) {
  					return callback(err);
  				}
  				content = self.wiki.renderTiddler("text/plain","$:/core/templates/tiddler-metadata",{variables: {currentTiddler: tiddler.fields.title}});
  				fs.writeFile(fileInfo.filepath + ".meta",content,{encoding: "utf8"},function (err) {
  					if(err) {
  						return callback(err);
  					}
  					self.logger.log("Saved file",fileInfo.filepath);
  					_finish();
  				});
  			});
  		} else {
  			// Save the tiddler as a self contained templated file
  			template = $tw.config.typeTemplates[fileInfo.type];
  			content = self.wiki.renderTiddler("text/plain",template,{variables: {currentTiddler: tiddler.fields.title}});
  			fs.writeFile(fileInfo.filepath,content,{encoding: "utf8"},function (err) {
  				if(err) {
  					return callback(err);
  				}
  				self.logger.log("Saved file",fileInfo.filepath);
  				_finish();
  			});
  		}
  	});
  };
  
  /*
  Load a tiddler and invoke the callback with (err,tiddlerFields)
  
  We don't need to implement loading for the file system adaptor, because all the tiddler files will have been loaded during the boot process.
  */
  FileSystemAdaptor.prototype.loadTiddler = function(title,callback) {
  	callback(null,null);
  };
  
  /*
  Delete a tiddler and invoke the callback with (err)
  */
  FileSystemAdaptor.prototype.deleteTiddler = function(title,callback,options) {
  	var self = this,
  		fileInfo = $tw.boot.files[title];
  	// Only delete the tiddler if we have writable information for the file
  	if(fileInfo) {
  		// Delete the file
  		fs.unlink(fileInfo.filepath,function(err) {
  			if(err) {
  				return callback(err);
  			}
  			self.logger.log("Deleted file",fileInfo.filepath);
  			// Delete the metafile if present
  			if(fileInfo.hasMetaFile) {
  				fs.unlink(fileInfo.filepath + ".meta",function(err) {
  					if(err) {
  						return callback(err);
  					}
  					callback(null);
  				});
  			} else {
  				callback(null);
  			}
  		});
  	} else {
  		callback(null);
  	}
  };
  
  if(fs) {
  	exports.adaptorClass = FileSystemAdaptor;
  }
  
  })();
  