var pug = require('pug');
var FeedParser = require('feedparser');
var ejs = require('ejs');
var fs = require('fs');
var template = ejs.compile(fs.readFileSync('./lib/template.ejs','utf8'));
var timeAgo = require('timeago.js');

function isArray(a){
  return Array.isArray(a);
}

// accumulate a stream of XML into a html file

module.exports = function(stream,opts,callback){
  var callback = callback;
  var opts = opts;
  if (typeof opts == 'function'){
  	callback = opts;
  	opts = {};
  }

  // convert s from atom feed to a full html page for rendering
  breakDown(stream,function(er,data){
    if (er) {
      return callback(er);
    }
    // try and build up
    try{
      var result = buildUp(data,opts)
    }catch(e){
      return callback(e);
    }
    return callback(null,result);
  });

}

// break the xml into json
function breakDown(stream,callback){

  var spent = false;
  function cbOnce(er,data){
    if (!spent){
      callback(er,data);
      spent = true;
    }
  }

  stream.on('error',cbOnce);
  var feedparser = new FeedParser();
  feedparser.on('error', cbOnce);
  stream.pipe(feedparser)


  feedparser.items = [];
  feedparser.on('readable', function () {
    // This is where the action is!
    var stream = this; // `this` is `feedparser`, which is a stream
    var items = [];
    var item;

    while (item = stream.read()) {
      feedparser.items.push(item);
    }


  });

  feedparser.on('end',function(er){cbOnce(null,feedparser)});

}

// hydrate the json to html
function buildUp(jsonObj,opts){

  // assign opts to the obj
  jsonObj.opts = opts||{};

  // iterate through the items
  jsonObj.items = jsonObj.items.filter(function(item){

  	// get date
  	item.stringDate = getTimeDisplay(item.date);

  	item.content = getH(item,'atom:content');
    if (!item.content ){// item was deleted
      return false;
    }

    // make anchor tags have the "_top" target
    item.content = item.content.replace(/\<\s*a\s*/ig,'<a target="_top"');

  	// get enclosures
  	item.enclosures = [];

    function findEnclosure(link){
      if (!link['@']){return;} // avoid keyerror
      var rel = link['@'].rel;
      var href = link['@'].href;
      if (rel == 'enclosure'){
        item.enclosures.push({
          url:href,
          type:link['@'].type||''
        });
      }
    }

    // find them in the item's links
    if (item['atom:link']){
      var links = item['atom:link'];
      if (!isArray(links) && typeof links == 'object'){
        links = [links];
      }else if (!isArray(links)){
        links = [];
      }
      links.forEach(findEnclosure);
    }

    // find them in activity:object
    if (item["activity:object"] && item["activity:object"].link){
      var enclosureLinks = item["activity:object"].link;
      if (!isArray(enclosureLinks) && typeof enclosureLinks == 'object'){
        enclosureLinks = [enclosureLinks];
      }else if (!isArray(enclosureLinks)){
        enclosureLinks = [];// not an object or array.
      }
      enclosureLinks.forEach(findEnclosure);
    }


  	// get author info

  	item.author = {};
  	var _author = item.meta['atom:author'];
  	if ( item['activity:object'] && item['activity:object'].author){
  	  _author = item['activity:object'].author;
  	}

  	item.author.name = getH(_author,'name');
  	item.author.uri = getH(_author,'uri');
  	item.author.fullName = getH(_author,'email');
  	item.author.displayName = getH(_author,'poco:displayname')||getH(_author,'poco:preferredUsername')||item.author.name;

  	var authorLinks = _author.link || [];

    if (!isArray(authorLinks) && typeof authorLinks == 'object'){
      authorLinks = [authorLinks];
    }else if ( !isArray(authorLinks) ){
      authorLinks = [];// not an object or string.
    }

  	authorLinks.forEach(function(link){// todo: guard against authorLinks not being an array
  	  if (!link['@']){return;} // avoid keyerror
  	  var rel = link['@'].rel;
  	  var href = link['@'].href;
  	  if (rel == 'avatar'){
  	    item.author.avatar = href;
  	  }else if(rel == 'alternate'){
  	    item.author.alternate = href;
  	  }
  	});

    return true;

  });

  return template(jsonObj);
}


// get obj[key]['#'] or ''
function getH(obj,key){
 if (!obj[key]){return ''}
 return obj[key]['#']||'';
}

function getTimeDisplay(d){
  var d = d;
  if (typeof d !== 'object'){
     d = new Date(d);
  }
  // convert to number
  dt = d.getTime();
  var now = Date.now();

  var delta = now - dt;

  // over 6 days ago
  if (delta > 1000*60*60*24*6){
    return isoDateToEnglish(d.toISOString());
  }else{
    return timeAgo().format(dt);
  }

}

function isoDateToEnglish(d){

  var dt = d.split(/[t\-]/ig);
  var months = [ "January", "February", "March", "April", "May", "June",
    "July", "August", "September", "October", "November", "December" ];

  return months[Number(dt[1])-1] +' '+dt[2]+ ', '+dt[0];
}