[WIP] lintcode plugin.

Signed-off-by: Eric Wang <skygragon@gmail.com>

Author: skygragon

lintcode.js

@@ -0,0 +1,344 @@
+var _ = require('underscore');
+var cheerio = require('cheerio');
+var request = require('request');
+var util = require('util');
+
+var h = require('../helper');
+var log = require('../log');
+var Plugin = require('../plugin');
+var queue = require('../queue');
+var session = require('../session');
+
+// Still working in progress!
+//
+// TODO: star/submissions/submission
+// FIXME: why [ERROR] Error: read ECONNRESET [0]??
+//
+var plugin = new Plugin(15, 'lintcode', '2017.08.04',
+    'Plugin to talk with lintcode APIs.');
+
+var config = {
+  URL_BASE:          'http://www.lintcode.com/en',
+  URL_PROBLEMS:      'http://www.lintcode.com/en/problem?page=$page',
+  URL_PROBLEM:       'http://www.lintcode.com/en/problem/$slug/',
+  URL_PROBLEM_CODE:  'http://www.lintcode.com/en/problem/api/code/?problem_id=$id&language=$lang',
+  URL_TEST:          'http://www.lintcode.com/submission/api/submit/',
+  URL_TEST_VERIFY:   'http://www.lintcode.com/submission/api/refresh/?id=$id&waiting_time=0&is_test_submission=true',
+  URL_SUBMIT_VERIFY: 'http://www.lintcode.com/submission/api/refresh/?id=$id&waiting_time=0',
+  URL_LOGIN:         'http://www.lintcode.com/en/accounts/signin/'
+};
+
+var LANGS = [
+  {value: 'cpp', text: 'C++'},
+  {value: 'java', text: 'Java'},
+  {value: 'python', text: 'Python'}
+];
+
+function signOpts(opts, user) {
+  opts.headers.Cookie = 'sessionid=' + user.sessionId +
+                        ';csrftoken=' + user.sessionCSRF + ';';
+}
+
+function makeOpts(url) {
+  var opts = {};
+  opts.url = url;
+  opts.headers = {};
+
+  if (session.isLogin())
+    signOpts(opts, session.getUser());
+  return opts;
+}
+
+function checkError(e, resp, expectedStatus) {
+  if (!e && resp && resp.statusCode !== expectedStatus) {
+    var code = resp.statusCode;
+    log.debug('http error: ' + code);
+
+    if (code === 403 || code === 401) {
+      e = session.errors.EXPIRED;
+    } else {
+      e = {msg: 'http error', statusCode: code};
+    }
+  }
+  return e;
+}
+
+function _split(s, delim) {
+  return (s || '').split(delim).map(function(x) {
+    return x.trim();
+  }).filter(function(x) {
+    return x.length > 0;
+  });
+}
+
+function _strip(s) {
+  s = s.replace(/^<pre><code>/, '').replace(/<\/code><\/pre>$/, '');
+  return util.inspect(s.trim());
+}
+
+plugin.getProblems = function(cb) {
+  log.debug('running lintcode.getProblems');
+
+  var problems = [];
+  var doTask = function(page, taskDone) {
+    plugin.getPageProblems(page, function(e, _problems) {
+      if (!e) problems = problems.concat(_problems);
+      return taskDone(e);
+    });
+  };
+
+  // FIXME: remove this hardcoded range!
+  var pages = [0, 1, 2, 3, 4];
+  queue.run(pages, doTask, function(e) {
+    problems = _.sortBy(problems, function(x) {
+      return -x.id;
+    });
+    return cb(e, problems);
+  });
+};
+
+plugin.getPageProblems = function(page, cb) {
+  log.debug('running lintcode.getPageProblems: ' +  page);
+  var opts = makeOpts(config.URL_PROBLEMS.replace('$page', page));
+
+  request(opts, function(e, resp, body) {
+    e = checkError(e, resp, 200);
+    if (e) return cb(e);
+
+    var $ = cheerio.load(body);
+    var problems = $('div[id=problem_list_pagination] a').map(function(i, a) {
+      var problem = {
+        locked:    false,
+        category:  'lintcode',
+        state:     'None',
+        starred:   false,
+        companies: [],
+        tags:      []
+      };
+      problem.slug = $(a).attr('href').split('/').pop();
+      problem.link = config.URL_PROBLEM.replace('$slug', problem.slug);
+
+      $(a).children('span').each(function(i, span) {
+        var text = $(span).text().trim();
+        var type = _split($(span).attr('class'), ' ');
+        type = type.concat(_split($(span).find('i').attr('class'), ' '));
+
+        if (type.indexOf('title') >= 0) {
+          problem.id = Number(text.split('.')[0]);
+          problem.name = text.split('.')[1].trim();
+        } else if (type.indexOf('difficulty') >= 0) problem.level = text;
+        else if (type.indexOf('rate') >= 0) problem.percent = parseInt(text, 10);
+        else if (type.indexOf('fa-star') >= 0) problem.starred = true;
+        else if (type.indexOf('fa-check') >= 0) problem.state = 'ac';
+        else if (type.indexOf('fa-minus') >= 0) problem.state = 'notac';
+        else if (type.indexOf('fa-briefcase') >= 0) problem.companies = _split($(span).attr('title'), ',');
+      });
+
+      return problem;
+    }).get();
+
+    return cb(null, problems);
+  });
+};
+
+plugin.getProblem = function(problem, cb) {
+  log.debug('running lintcode.getProblem');
+  var opts = makeOpts(problem.link);
+
+  request(opts, function(e, resp, body) {
+    e = checkError(e, resp, 200);
+    if (e) return cb(e);
+
+    var $ = cheerio.load(body);
+    problem.testcase = $('textarea[id=input-testcase]').text();
+    problem.testable = problem.testcase.length > 0;
+
+    var lines = [];
+    $('div[id=description] > div').each(function(i, div) {
+      if (i === 0) {
+        div = $(div).find('div')[0];
+        lines.push($(div).text().trim());
+        return;
+      }
+
+      var text = $(div).text().trim();
+      var type = $(div).find('b').text().trim();
+
+      if (type === 'Tags') {
+        problem.tags = _split(text, '\n');
+        problem.tags.shift();
+      } else if (type === 'Related Problems') return;
+      else lines.push(text);
+    });
+    problem.desc = lines.join('\n').replace(/\n{2,}/g, '\n');
+    problem.totalAC = '';
+    problem.totalSubmit = '';
+    problem.templates = [];
+
+    var doTask = function(lang, taskDone) {
+      plugin.getProblemCode(problem, lang, function(e, code) {
+        if (e) return taskDone(e);
+
+        lang = _.clone(lang);
+        lang.defaultCode = code;
+        problem.templates.push(lang);
+        return taskDone();
+      });
+    };
+
+    queue.run(LANGS, doTask, function(e) {
+      return cb(e, problem);
+    });
+  });
+};
+
+plugin.getProblemCode = function(problem, lang, cb) {
+  log.debug('running lintcode.getProblemCode:' + lang.value);
+  var url = config.URL_PROBLEM_CODE
+    .replace('$id', problem.id)
+    .replace('$lang', lang.text.replace(/\+/g, '%2b'));
+  var opts = makeOpts(url);
+
+  request(opts, function(e, resp, body) {
+    e = checkError(e, resp, 200);
+    if (e) return cb(e);
+
+    var json = JSON.parse(body);
+    return cb(null, json.code);
+  });
+};
+
+function runCode(problem, isTest, cb) {
+  var lang = _.find(LANGS, function(x) {
+    return x.value === h.extToLang(problem.file);
+  });
+
+  var opts = makeOpts(config.URL_TEST);
+  opts.form = {
+    problem_id:          problem.id,
+    code:                h.getFileData(problem.file),
+    language:            lang.text,
+    csrfmiddlewaretoken: session.getUser().sessionCSRF
+  };
+  if (isTest) {
+    opts.form.input = problem.testcase;
+    opts.form.is_test_submission = true;
+  }
+
+  request.post(opts, function(e, resp, body) {
+    e = checkError(e, resp, 200);
+    if (e) return cb(e);
+
+    var json = JSON.parse(body);
+    if (!json.id || !json.success) return cb(json.message);
+
+    verifyResult(json.id, isTest, cb);
+  });
+}
+
+function verifyResult(id, isTest, cb) {
+  log.debug('running verifyResult:' + id);
+  var url = isTest ? config.URL_TEST_VERIFY : config.URL_SUBMIT_VERIFY;
+  var opts = makeOpts(url.replace('$id', id));
+
+  request(opts, function(e, resp, body) {
+    e = checkError(e, resp, 200);
+    if (e) return cb(e);
+
+    var result = JSON.parse(body);
+    if (result.status === 'Compiling' || result.status === 'Running')
+      return setTimeout(verifyResult, 1000, id, isTest, cb);
+
+    return cb(null, formatResult(result));
+  });
+}
+
+function formatResult(result) {
+  var x = {
+    ok:              result.status === 'Accepted',
+    type:            'Actual',
+    state:           result.status,
+    runtime:         result.time_cost + ' ms',
+    answer:          _strip(result.output),
+    stdout:          _strip(result.stdout),
+    expected_answer: _strip(result.expected),
+    testcase:        _strip(result.input),
+    passed:          result.data_accepted_count || 0,
+    total:           result.data_total_count || 0
+  };
+
+  var error = [];
+  if (result.compile_info.length > 0)
+    error = error.concat(_split(result.compile_info, '<br>'));
+  if (result.error_message.length > 0)
+    error = error.concat(_split(result.error_message, '<br>'));
+  x.error = error;
+
+  // make sure everything is ok
+  if (error.length > 0) x.ok = false;
+  if (x.passed !== x.total) x.ok = false;
+
+  return x;
+}
+
+plugin.testProblem = function(problem, cb) {
+  log.debug('running lintcode.testProblem');
+  runCode(problem, true, function(e, result) {
+    if (e) return cb(e);
+
+    var expected = {
+      ok:     true,
+      type:   'Expected',
+      answer: result.expected_answer,
+      stdout: "''"
+    };
+    return cb(null, [result, expected]);
+  });
+};
+
+plugin.submitProblem = function(problem, cb) {
+  log.debug('running lintcode.submitProblem');
+  runCode(problem, false, function(e, result) {
+    if (e) return cb(e);
+    return cb(null, [result]);
+  });
+};
+
+plugin.getSubmission = function(submission, cb) {
+  // FIXME
+  return cb('Not implemented');
+};
+
+plugin.login = function(user, cb) {
+  log.debug('running lintcode.login');
+  request(config.URL_LOGIN, function(e, resp, body) {
+    e = checkError(e, resp, 200);
+    if (e) return cb(e);
+
+    user.loginCSRF = h.getSetCookieValue(resp, 'csrftoken');
+
+    var opts = {
+      url:     config.URL_LOGIN,
+      headers: {
+        Cookie: 'csrftoken=' + user.loginCSRF + ';'
+      },
+      form: {
+        csrfmiddlewaretoken: user.loginCSRF,
+        username_or_email:   user.login,
+        password:            user.pass
+      }
+    };
+    request.post(opts, function(e, resp, body) {
+      if (e) return cb(e);
+      if (resp.statusCode !== 302) return cb('invalid password?');
+
+      user.sessionCSRF = h.getSetCookieValue(resp, 'csrftoken');
+      user.sessionId = h.getSetCookieValue(resp, 'sessionid');
+      user.name = user.login; // FIXME
+
+      return cb(null, user);
+    });
+  });
+};
+
+module.exports = plugin;