/*\
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;


function FileSystemAdaptor(syncer) {
	var self = this;
	this.syncer = syncer;
	this.watchers = {};
	this.pending = {};

	this.setwatcher = function(filename, title) {
		return this.watchers[filename] = this.watchers[filename] ||
			fs.watch(filename, {persistent: false}, function(e) {
				console.log("Filesystem:", e, filename);
				if(e === "change") {
					var tiddlers = $tw.loadTiddlersFromFile(filename).tiddlers;
					for(var t in tiddlers) {
						if(tiddlers[t].title) {
							$tw.wiki.addTiddler(tiddlers[t]);
						}
					}
				}
			});
	}


	for(var f in $tw.boot.files) {
		var fileInfo = $tw.boot.files[f];
		this.setwatcher(fileInfo.filepath, f);
	}
}

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 + "/" + 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;
			self.pending[fileInfo.filepath] = title;
			// 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;
		function _finish() {
			if(self.pending[fileInfo.filepath]) {
				self.setwatcher(fileInfo.filepath, tiddler.fields.title);
				delete self.pending[fileInfo.filepath];
			}
			callback(null, {}, 0);
		}
		if(err) {
			return callback(err);
		}
		if($tw.boot.wikiInfo.doNotSave && $tw.boot.wikiInfo.doNotSave.indexOf(tiddler.fields.title) !== -1) {
			// Don't save the tiddler if it is on the blacklist
			return callback(null,{},0);
		}
		if(self.watchers[fileInfo.filepath]) {
			self.watchers[fileInfo.filepath].close();
			delete self.watchers[fileInfo.filepath];
			self.pending[fileInfo.filepath] = tiddler.fields.title;
		}
		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 = $tw.wiki.renderTiddler("text/plain","$:/core/templates/tiddler-metadata",{tiddlerTitle: tiddler.fields.title});
				fs.writeFile(fileInfo.filepath + ".meta",content,{encoding: "utf8"},function (err) {
					if(err) {
						return callback(err);
					}
console.log("FileSystem: Saved file",fileInfo.filepath);
					_finish();
				});
			});
		} else {
			// Save the tiddler as a self contained templated file
			template = $tw.config.typeTemplates[fileInfo.type];
			content = $tw.wiki.renderTiddler("text/plain",template,{tiddlerTitle: tiddler.fields.title});
			fs.writeFile(fileInfo.filepath,content,{encoding: "utf8"},function (err) {
				if(err) {
					return callback(err);
				}
console.log("FileSystem: Saved file",fileInfo.filepath);
				_finish();
			});
		}
	});
};

/*
Load a tiddler and invoke the callback with (err,tiddlerFields)
*/
FileSystemAdaptor.prototype.loadTiddler = function(title,callback) {
console.log("FileSystem: Loading",title);
	callback(null,{title: title, text: "Fake tiddler: " + title});
};

/*
Delete a tiddler and invoke the callback with (err)
*/
FileSystemAdaptor.prototype.deleteTiddler = function(title,callback) {
	var self = this,
		fileInfo = $tw.boot.files[title];
	// Only delete the tiddler if we have writable information for the file
	if(fileInfo) {
		if($tw.boot.wikiInfo.doNotSave && $tw.boot.wikiInfo.doNotSave.indexOf(title) !== -1) {
			// Don't delete the tiddler if it is on the blacklist
			callback(null);
		} else {
			if(this.watchers[fileInfo.filepath]) {
				this.watchers[fileInfo.filepath].close();
				delete this.watchers[fileInfo.filepath];
			}
			delete this.pending[fileInfo.filepath];
			// Delete the file
			fs.unlink(fileInfo.filepath,function(err) {
				if(err) {
					return callback(err);
				}
console.log("FileSystem: 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;
}

})();