'use strict';

function eggSend(obj) {
  /*jslint validthis: true*/
  var me = this;
  if (!me.getHeader('content-type')) {
    me.setHeader('Content-Type', 'application/json');
  }
  me.end(JSON.stringify(obj));
}

module.exports = function eggspress() {
  //var patternsMap = {};
  var allPatterns = [];
  var app = function (req, res) {
    var patterns = allPatterns.slice(0).reverse();
    function next(err) {
      if (err) {
        req.end(err.message);
        return;
      }
      var todo = patterns.pop();
      if (!todo) {
        console.log('[eggspress] Did not match any patterns', req.url);
        require('finalhandler')(req, res)();
        return;
      }

      // '', GET, POST, DELETE
      if (todo[2] && req.method.toLowerCase() !== todo[2]) {
        //console.log("[eggspress] HTTP method doesn't match", req.url);
        next();
        return;
      }

      var urlstr = (req.url.replace(/\/$/, '') + '/');
      var match = urlstr.match(todo[0]);
      if (!match) {
        //console.log("[eggspress] pattern doesn't match", todo[0], req.url);
        next();
        return;
      } else if ('string' === typeof todo[0] && 0 !== match.index) {
        //console.log("[eggspress] string pattern is not the start", todo[0], req.url);
        next();
        return;
      }

      function fail(e) {
        console.error("[eggspress] error", todo[2], todo[0], req.url);
        console.error(e);
        // TODO make a nice error message
        res.end(e.message);
      }

      console.log("[eggspress] matched pattern", todo[0], req.url);
      if ('function' === typeof todo[1]) {
        // TODO this is prep-work
        todo[1] = [todo[1]];
      }

      var fns = todo[1].slice(0);
      req.params = match.slice(1);

      function nextTodo(err) {
        if (err) { fail(err); return; }
        var fn = fns.shift();
        if (!fn) { next(err); return; }
        try {
          var p = fn(req, res, nextTodo);
          if (p && p.catch) {
            p.catch(fail);
          }
        } catch(e) {
          fail(e);
          return;
        }
      }
      nextTodo();
    }

    res.send = eggSend;

    next();
  };

  app.use = function (pattern) {
    var fns = Array.prototype.slice.call(arguments, 1);
    return app._use('', pattern, fns);
  };
  [ 'HEAD', 'GET', 'POST', 'DELETE' ].forEach(function (method) {
    app[method.toLowerCase()] = function (pattern) {
      var fns = Array.prototype.slice.call(arguments, 1);
      return app._use(method, pattern, fns);
    };
  });

  app.post = function (pattern) {
    var fns = Array.prototype.slice.call(arguments, 1);
    return app._use('POST', pattern, fns);
  };
  app._use = function (method, pattern, fns) {
    // always end in a slash, for now
    if ('string' === typeof pattern) {
      pattern = pattern.replace(/\/$/, '')  + '/';
    }
    /*
    if (!patternsMap[pattern]) {
      patternsMap[pattern] = [];
    }
    patternsMap[pattern].push(fn);
    patterns = Object.keys(patternsMap).sort(function (a, b) {
      return b.length - a.length;
    });
    */
    allPatterns.push([pattern, fns, method.toLowerCase()]);
    return app;
  };

  return app;
};