[ProblemSet] Refactor stat command.

* '-t': show statistics by tag.
* '-g': fixes graph display bug.

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

Author: skygragon

lib/commands/stat.js

@@ -1,6 +1,7 @@
 var sprintf = require('sprintf-js').sprintf;
 var _ = require('underscore');
 
+var config = require('../config');
 var chalk = require('../chalk');
 var log = require('../log');
 var core = require('../core');
@@ -14,6 +15,13 @@ var cmd = {
       type:     'boolean',
       default:  false,
       describe: 'Show graphic statistics'
+    },
+    tag: {
+      alias:    't',
+      type:     'string',
+      default:  'all',
+      describe: 'Show statistics on given tag',
+      choices:  ['all'].concat(config.CATEGORIES)
     }
   }
 };
@@ -27,40 +35,49 @@ function bar(c, n) {
 }
 
 function prettyLine(key, done, all) {
-  done = done || 0;
   var n = 30;
-  var x = Math.ceil(n * done / all);
+  var percent = (all > 0) ? done / all : 0;
+  var x = Math.ceil(n * percent);
   return sprintf(' %-8s %3d/%-3d (%.2f%%)\t%s%s',
-      key, done, all, done * 100 / all,
+      key, done, all, 100 * percent,
       chalk.green(bar('█', x)),
       chalk.red(bar('░', n - x)));
 }
 
 function showSummary(problems) {
-  var stats = {};
-  var statsNoLock = {};
+  var stats = {
+    easy:   {all: 0, ac: 0},
+    medium: {all: 0, ac: 0},
+    hard:   {all: 0, ac: 0}
+  };
+  var statsNoLock = {
+    easy:   {all: 0, ac: 0},
+    medium: {all: 0, ac: 0},
+    hard:   {all: 0, ac: 0}
+  };
 
   problems.forEach(function(problem) {
-    var keyAll = 'all' + problem.level;
-    var keyAC = problem.state + problem.level;
-    stats[keyAll] = (stats[keyAll] || 0) + 1;
-    stats[keyAC] = (stats[keyAC] || 0) + 1;
-
-    if (!problem.locked) {
-      statsNoLock[keyAll] = (statsNoLock[keyAll] || 0) + 1;
-      statsNoLock[keyAC] = (statsNoLock[keyAC] || 0) + 1;
-    }
+    var level = problem.level.toLowerCase();
+    var state = problem.state.toLowerCase();
+
+    if (!(level in stats)) return;
+    ++stats[level].all;
+    if (!problem.locked) ++statsNoLock[level].all;
+
+    if (!(state in stats[level])) return;
+    ++stats[level][state];
+    if (!problem.locked) ++statsNoLock[level][state];
   });
 
-  log.info(prettyLine('Easy', stats.acEasy, stats.allEasy));
-  log.info(prettyLine('Medium', stats.acMedium, stats.allMedium));
-  log.info(prettyLine('Hard', stats.acHard, stats.allHard));
+  log.info(prettyLine('Easy', stats.easy.ac, stats.easy.all));
+  log.info(prettyLine('Medium', stats.medium.ac, stats.medium.all));
+  log.info(prettyLine('Hard', stats.hard.ac, stats.hard.all));
 
   log.info();
   log.info('Without Locked:');
-  log.info(prettyLine('Easy', statsNoLock.acEasy, statsNoLock.allEasy));
-  log.info(prettyLine('Medium', statsNoLock.acMedium, statsNoLock.allMedium));
-  log.info(prettyLine('Hard', statsNoLock.acHard, statsNoLock.allHard));
+  log.info(prettyLine('Easy', statsNoLock.easy.ac, statsNoLock.easy.all));
+  log.info(prettyLine('Medium', statsNoLock.medium.ac, statsNoLock.medium.all));
+  log.info(prettyLine('Hard', statsNoLock.hard.ac, statsNoLock.hard.all));
 }
 
 function showGraph(problems) {
@@ -83,7 +100,7 @@ function showGraph(problems) {
         1, 10, 11, 20, 21, 30, 31, 40, 41, 50));
 
   var line = [sprintf(' %03d   ', 1)];
-  for (var i = 1, n = graph.length; i < n; ++i) {
+  for (var i = 1, n = graph.length; i <= n; ++i) {
     line.push(graph[i] || ' ');
     if (i % 10 === 0) line.push('   ');
     if (i % 50 === 0 || i === n) {
@@ -104,6 +121,12 @@ cmd.handler = function(argv) {
   core.getProblems(function(e, problems) {
     if (e) return log.fail(e);
 
+    if (argv.tag !== 'all') {
+      problems = _.filter(problems, function(x) {
+        return x.category === argv.tag;
+      });
+    }
+
     if (argv.graph) {
       showGraph(problems);
     } else {