"use strict";
var streams = require('streamroller')
, path = require('path')
, os = require('os')
, eol = os.EOL || '\n'
, openFiles = [];

//close open files on process exit.
process.on('exit', function() {
  openFiles.forEach(function (file) {
    file.end();
  });
});

module.exports = function(layouts, levels) {
  /**
   * File appender that rolls files according to a date pattern.
   * @filename base filename.
   * @pattern the format that will be added to the end of filename when rolling,
   *          also used to check when to roll files - defaults to '.yyyy-MM-dd'
   * @layout layout function for log messages - defaults to basicLayout
   */
  function appender(filename, pattern, alwaysIncludePattern, layout) {
    layout = layout || layouts.basicLayout;
    
    var logFile = new streams.DateRollingFileStream(
      filename, 
      pattern, 
      { alwaysIncludePattern: alwaysIncludePattern }
    );
    openFiles.push(logFile);
    
    return function(logEvent) {
      logFile.write(layout(logEvent) + eol, "utf8");
    };

  }

  return function configure(config) {
    var layout;
  
    if (config.layout) {
      layout = layouts.layout(config.layout.type, config.layout);
    }
  
    if (!config.alwaysIncludePattern) {
      config.alwaysIncludePattern = false;
    }
  
    return appender(config.filename, config.pattern, config.alwaysIncludePattern, layout);
  };

};