Add an option -l for submission command which allows user to retrive recent submission in requried programming language, if no submissino in required language, an error will be printed. If no language is specified, program will retrive retrive most recent accepted submission.

Author: Jiati Le

lib/commands/submission.js

@@ -30,6 +30,12 @@ var cmd = {
       type:     'boolean',
       default:  false,
       describe: 'Provide extra problem details in submission file'
+    },
+    lang: {
+      alias:    'l',
+      type:     'string',
+      default:  'all',
+      describe: 'Programming language used for previous submission'
     }
   }
 };
@@ -68,9 +74,17 @@ function exportSubmission(argv, problem, cb) {
     if (e) return cb(e);
     if (submissions.length === 0) return cb('no submissions?');
 
-    // find the latest accepted one
-    var submission = _.find(submissions, function(x) {
-      // TODO: select by lang?
+    // get obj list contain required filetype
+    var submissionInTargetType = _.filter(submissions, function(x) {
+      if (argv.lang === 'all') {
+        return true;
+      }
+      return argv.lang === x.lang;
+    });
+    if (submissionInTargetType.length === 0) {
+      return cb("No previous submission in required language.");
+    }
+    var submission = _.find(submissionInTargetType, function(x) {
       return x.status_display === 'Accepted';
     });