var fs = require('fs');
var path = require('path');
var glob = require('glob');
var stringify = require('json-to-html');
var LiquidEngine = require('liquid-node').Engine;
var liquid = new LiquidEngine();

/**
 * Add any custom liquid filters here.
 */
liquid.registerFilters({

  /**
   * Return a string formatted version of a JSON object.
   * Useful for quick debugging of template data.
   */
  stringify: function(obj) {
    try {
      return '<pre>' + stringify(obj) + '</pre>';
    } catch (e) {
      return '';
    }
  }

});

/**
 * Manages templates. Only supports Mustache currently/
 */
function OKTemplateRepo(options) {
  options = options || {};
  this._root = options.root || 'templates';
  this._extPattern = options.ext || '.+(liquid|html)';
  this._cache = {};
  this._populateCache(this._cache);
}

OKTemplateRepo.prototype.getTemplate = function getTemplate(name) {
  return this._cache[name];
}

/**
 * Go through our template dir and read the template files
 * into memory as strings.
 * Assumes all templates fit into memory.
 */
OKTemplateRepo.prototype._populateCache = function _populateCache(cache) {
  var self = this;
  var files = glob.sync(this._root + '/*' + this._extPattern);
  files.forEach(function eachFile(file) {
    var ext = path.extname(file);
    var name = path.basename(file, ext);
    var templateString = fs.readFileSync(file, {encoding: 'UTF8'});
    cache[name] = {
      name: name,
      templateString: templateString,
      render: function(data) {
        // TODO Not sure if this caches parsed templates behind the scenes?
        return liquid.parseAndRender(templateString, data);
      }
    }
  });
}

module.exports = OKTemplateRepo;