/**
 * Handles logging messages to different sources. Creates log in hosts/log/ directory.
 * @see https://github.com/sidpalas/extendscript-logging
 *
 * var logger = new Logger('~/mylog.log','DEBUG');
 *
 * Wrap definition to allow testing with jasminejsx which depends on this library.
 */
var Logger = Logger || (function Logger(givenLogPath, givenLevel){
	var _private = {
		logPath: givenLogPath || '/tmp/'+moment().format('YYYYMMDDHms')+'.log',
		level: givenLevel || 'DEBUG',
		levels: [
			'DEBUG',
			'INFO',
			'NOTICE',
			'VALID',
			'WARN',
			'ERROR',
			'CRITICAL',
		],
	};
	
	/**
	 * The last log is written to this variable for easy access.
	 */
	this.lastLog = null;
	
	/**
	 * @type {String}
	 */
	this.separator = '|';
	
	/**
	 * @return {String} Path to log file
	 */
	this.logPath = function() {
		return _private.logPath;
	}
	
	this.levels = function() {
		return _private.levels;
	}
	
	this.level = function() {
		return _private.level;
	}
	
	this.debug = function(message) {
		return this.log(message, 'DEBUG');
	}
	this.info = function(message) {
		return this.log(message, 'INFO');
	}
	this.notice = function(message) {
		return this.log(message, 'NOTICE');
	}
	this.notice = function(message) {
		return this.log(message, 'VALID');
	}
	this.warn = function(message) {
		return this.log(message, 'WARN');
	}
	this.error = function(message) {
		return this.log(message, 'ERROR');
	}
	this.critical = function(message) {
		return this.log(message, 'CRITICAL');
	}
	
	/**
	 * Convenience function to log exceptions from try-catch blocks.
	 * Usually called as `catch(e){ logger.exception(e); }`
	 * @param  Exception exception
	 * @param  string fileName Originating file path
	 * @return boolean
	 */
	this.exception = function(error, level) {
		//Undocumented error properties. This code borrowed from Jasmine's ExceptionFormatter
		var msg = error.name + ': ' + error.message;
		if (error.fileName || error.sourceURL) {
			msg += ' in ' + (error.fileName || error.sourceURL);
		}
		if (error.line || error.lineNumber) {
			msg += ' (line ' + (error.line || error.lineNumber) + ')';
		}
		return this.log(msg, level || 'WARN');
	}
	
	this.messageString = function(message, level){
		var msg = moment().format('YYYY-MM-DDTHH:mm:ss');
		msg += this.separator + level;
	
		if(typeof(message) == 'object') {
			try {
				msg += this.separator + JSON.stringify(message);
			} catch(e){
				//attempt to display ExtendScript object
				if (e instanceof InternalError && message.properties) {
					msg += this.separator + JSON.stringify(message.properties.toSource());
				} else {
					throw e;
				}
			}
		} else {
			msg += this.separator + message
		}
	
		return msg;
	}
	
	/**
	 * Ensure file folder exists so we can create the log file.
	 */
	this.file = function() {
		var logFile = new File(this.logPath())
		if (!logFile.parent.exists){
			logFile.parent.create();
		}
		return logFile;
	}
	
	/**
	 * Compares two levels.
	 * @param {String} comparisionLevel
	 * @param {String} baseLevel
	 * @return boolean
	 */
	this.meetsLevel = function(comparisionLevel, baseLevel) {
		return _private.levels.indexOf(comparisionLevel) >= _private.levels.indexOf(baseLevel);
	}
	
	this.log = function(message, level) {
		if(_private.levels.indexOf(level) == -1) {
			throw new TypeError('Level '+level+' is not valid level');
		}
	
		if(!this.meetsLevel(level, this.level())) {
			return false;
		}
	
		var file = this.file();
		file.open('a+');
		file.encoding = 'UTF-8';
		file.lineFeed = 'Unix';
		this.lastLog = this.messageString(message,level);
		file.writeln(this.lastLog);
		file.close();
		return true;
	}
	
	/**
	 * Deletes this log immediately. Useful in testing.
	 * @return boolean
	 */
	this.delete = function() {
		return this.file().remove();
	}
	
	return this;
}());