var camp = require('camp').start({
  port: process.env.PORT||+process.argv[2]||80
});
var badge = require('./badge.js');
var svg2img = require('./svg-to-img.js');
var serverStartTime = new Date((new Date()).toGMTString());

// Escapes `t` using the format specified in
// <https://github.com/espadrine/gh-badges/issues/12#issuecomment-31518129>
function escapeFormat(t) {
  return t
    // Inline single underscore.
    .replace(/([^_])_([^_])/g, '$1 $2')
    // Leading or trailing underscore.
    .replace(/([^_])_$/, '$1 ').replace(/^_([^_])/, ' $1')
    // Double underscore and double dash.
    .replace(/__/g, '_').replace(/--/g, '-');
}

function sixHex(s) { return /^[0-9a-fA-F]{6}$/.test(s); }

camp.route(/^\/:(([^-]|--)+)-(([^-]|--)+)-(([^-]|--)+).(svg|png|gif|jpg|pdf)$/,
  function(data, match, end, ask) {
    var subject = escapeFormat(match[1]);
    var status = escapeFormat(match[3]);
    var color = escapeFormat(match[5]);
    var format = match[7];

    // Cache management.
    var cacheDuration = (3600*24*1)|0;  // 1 day.
    ask.res.setHeader('Cache-Control', 'public, max-age=' + cacheDuration);
    if (+(new Date(ask.req.headers['if-modified-since'])) >= +serverStartTime) {
      ask.res.statusCode = 304;
      ask.res.end();  // not modified.
      return;
    }
    ask.res.setHeader('Last-Modified', serverStartTime.toGMTString());

    // Badge creation.
    try {
      var badgeData = {text: [subject, status]};
      if (sixHex(color)) {
        badgeData.colorB = '#' + color;
      } else {
        badgeData.colorscheme = color;
      }
      badge(badgeData, makeSend(format, ask.res, end));
    } catch(e) {
      badge({text: ["error", "bad badge"], colorscheme: "red"},
        makeSend(format, ask.res, end));
    }
});

function makeSend(format, askres, end) {
  if (format === 'svg') {
    return function(res) { sendSVG(res, askres, end); };
  } else {
    return function(res) { sendOther(format, res, askres, end); };
  }
}

function sendSVG(res, askres, end) {
  askres.setHeader('Content-Type', 'image/svg+xml');
  end(null, {template: streamFromString(res)});
}

function sendOther(format, res, askres, end) {
  askres.setHeader('Content-Type', 'image/' + format);
  svg2img(res, format, askres);
}

var stream = require('stream');
function streamFromString(str) {
  var newStream = new stream.Readable();
  newStream._read = function() { newStream.push(str); newStream.push(null); };
  return newStream;
}