'use strict';

var express = require('express');
var _ = require('lodash');
var compress = require('compression');
var resourceParser = require('./resource-parser');
var DatabaseResourceRepository = require('./data');
var MemoryCacheResourceRepository = require('./memory');

var dbHost = '---';
var dbName = '---';
var dbUser = '---';
var dbPassword = '---';
var host = '---';

var resourceRepository = new MemoryCacheResourceRepository(new DatabaseResourceRepository(dbHost,
  dbName, dbUser, dbPassword));

var app = express();
app.disable('x-powered-by');
app.use(compress());

app.get('/:lib/releases', function(req, res) {
  var releases = resourceRepository.getAllReleasesByLib(req.params.lib);
  res.type('application/json');
  res.send(JSON.stringify(releases, null, 2));
});

app.get('/list/:type', function(req, res) {
  var libs = resourceRepository.getAllReleasesByType(req.params.type);
  res.type('application/json');
  res.send(JSON.stringify(libs, null, 2));
});

app.get(/\/([^/]+)\/(.+)\/*/, function(req, res) {
  var domain = req.params[0];
  var resourcePath = req.params[1];
  var resourceStrings = _.without(resourcePath.split('/'), ''); // Ignore empty parts

  var releaseRequests = resourceStrings.map(function(resourceString) {
    var match = resourceParser(resourceString);
    if (!match) {
      throw new Error('There is something wrong with the structure of this request. ' +
      'Try requesting with the form \'http://abcdn.io/<lib>~<version>-<type>\'. ' +
      'For example abcdn.io/bootstrap~3.0.0.js. ' +
      'Remember though, both version and type are optional.');
    }

    match.fullName = resourceString;
    return match;
  });

  Promise.all(releaseRequests.map(function(releaseRequest) {
    var releases = resourceRepository.getReleases(releaseRequest);
    if (!releases) {
      res.status(404);
      throw new Error('ABCDN could not find a resource with the name \'' + releaseRequest.fullName + '\'. ' +
      'Try requesting with the form \'http://abcdn.io/<lib>~<version>-<type>\'. ' +
      'For example abcdn.io/bootstrap~3.0.0.js. ' +
      'Remember though, both version and type are optional.');
    }

    return releases;
  })).then(function(releases) {
    return _.flatten(releases);
  }).then(function(releases) {
    var thePackage = createPackage(releases, domain);

    res.setHeader('Cache-Control', 'public, max-age=2592000'); // 30 days
    res.type(thePackage.contentType);
    res.send(thePackage.content);
  });
});

resourceRepository.initialise().then(function() {
  var server = app.listen(8081, function() {
    var host = server.address().address;
    var port = server.address().port;

    console.log('ABCDN Resource Server listening at http://%s:%s', host, port);
  });
});

module.exports = app;

function createPackage(releases, domain) {
  var groupedReleases = _.groupBy(releases, 'resourceType');
  if (groupedReleases.js) {
    return createJSPackage(groupedReleases.js, groupedReleases.css, domain);
  } else {
    return createCSSPackage(groupedReleases.css);
  }
}

function createJSPackage(jsReleases, cssReleases, domain) {
  var releaseContents = _.map(jsReleases, 'content');
  var thePackage = generateClientValidator(domain) +
    generateCssHeadAdder(cssReleases, domain) + releaseContents.join('\n');

  return {contentType: 'text/javascript', content: thePackage};
}

function createCSSPackage(cssReleases) {
  var releaseContents = _.map(cssReleases, 'content');
  var thePackage = releaseContents.join('\n');

  return {contentType: 'text/css', content: thePackage};
}

function generateCssHeadAdder(cssReleases, domain) {
  if (!cssReleases) {
    return '';
  }

  var cssUrl = '//' + host + '/' + domain + '/' + _.map(cssReleases, function(release) { return release.fullName + '.css' }).join('/');

  function cssHeadAdder(cssUrl) {
    var headHTML = document.getElementsByTagName('head')[0].innerHTML;
    headHTML += '<link type="text/css" rel="stylesheet" href="' + cssUrl + '">';
    document.getElementsByTagName('head')[0].innerHTML = headHTML;
  }

  return '(' + cssHeadAdder.toString() + ')(\'' + cssUrl + '\');\n';
}

function generateClientValidator(domain) {
  function validator(domain) {
    if (window.location.host != domain) {
      alert('This package from ABCDN.io is permitted to be used on ' + domain +
        ' only. But don\'t worry, you too can use ABCDN.io for free like this: http://www.abcdn.io/mywebsite.com/jquery/angular/bootstrap');
    }
  }

  return '(' + validator.toString() + ')(\'' + domain + '\');\n';
}