var util = require('util');
var path = require('path');
var fs = require('fs');
var mkdirp = require('mkdirp');

// Default to the global app root, otherwise fallback on the cwd.
var FINAL_SCREEN_SHOT_DIR = path.join(global.appRoot || '.',
    '/../screen_shots/');
mkdirp.sync(FINAL_SCREEN_SHOT_DIR);

function FrameStore() {
  this.sessionImgCountMap = {};
}

FrameStore.prototype.storeFrame = function(frame, sessionId) {
  if (this.sessionImgCountMap[sessionId]) {
    this.sessionImgCountMap[sessionId] += 1;
  } else {
    this.sessionImgCountMap[sessionId] = 1;
  }

  var sessionImgNumber = this.sessionImgCountMap[sessionId];
  var fileName = util.format('%s_%s_%d.jpg', sessionId, sessionImgNumber,
      Date.now());
  var filePath = path.join(FINAL_SCREEN_SHOT_DIR, fileName);

  fs.writeFile(filePath, frame, function(err) {
    if (err) {
      console.log(err);
    }
  });

  return fileName;
};

module.exports = FrameStore;