refactor(github): extract insights generation into standalone buildIn… (JhaSourav07#766)

## Description

Fixes JhaSourav07#298

Extracted insight generation logic into a standalone `buildInsights()`
helper.

Added independent tests for:
- streak > 3 path
- streak ≤ 3 path
- missing language fallback

`getFullDashboardData()` now delegates to `buildInsights()`.

## Pillar

- [x] 🛠️ Other (Bug fix, refactoring, docs)

## Visual Preview

N/A — backend refactor only.
## Checklist before requesting a review:

- [x] I have read the CONTRIBUTING.md file.
- [x] I have tested these changes locally.
- [x] I have run npm test locally.
- [x] My commits follow Conventional Commits format.

Author: BinduShree0514

lib/github.test.ts

@@ -9,7 +9,7 @@ import {
   GITHUB_CACHE_TTL_MS,
   validateGitHubUsername,
   cacheKey,
-  buildCommitClock,
+  buildInsights,
   fetchOrgMembers,
   getOrgDashboardData,
   getWrappedData,
@@ -455,8 +455,6 @@ describe('getFullDashboardData', () => {
       { name: 'Rust', percentage: 33, color: '#dea584' },
     ]);
     expect(result.insights).toBeDefined();
-    expect(result.commitClock).toBeDefined();
-    expect(result.commitClock).toHaveLength(7);
   });
 
   it('maps contribution counts to correct intensity levels', async () => {
@@ -670,27 +668,44 @@ describe('cacheKey', () => {
     expect(cacheKey('contributions', 'DeepSikha', '2025')).toBe('contributions:deepsikha:2025');
   });
 });
+describe('buildInsights', () => {
+  it('uses active streak message when current streak > 3', () => {
+    const result = buildInsights(
+      {
+        totalContributions: 120,
+        currentStreak: 7,
+        longestStreak: 20,
+      },
+      [{ name: 'TypeScript' }]
+    );
 
-describe('buildCommitClock', () => {
-  it('aggregates commits correctly by day of week', () => {
-    const allDays = [
-      { date: '2024-06-09', contributionCount: 2 }, // Sun
-      { date: '2024-06-10', contributionCount: 5 }, // Mon
-      { date: '2024-06-10', contributionCount: 3 }, // Mon
-      { date: '2024-06-12', contributionCount: 4 }, // Wed
-    ];
-
-    const result = buildCommitClock(allDays);
-
-    expect(result).toEqual([
-      { day: 'Sun', commits: 2 },
-      { day: 'Mon', commits: 8 },
-      { day: 'Tue', commits: 0 },
-      { day: 'Wed', commits: 4 },
-      { day: 'Thu', commits: 0 },
-      { day: 'Fri', commits: 0 },
-      { day: 'Sat', commits: 0 },
-    ]);
+    expect(result[2].text).toContain('active 7-day streak');
+  });
+
+  it('uses longest streak message when current streak <= 3', () => {
+    const result = buildInsights(
+      {
+        totalContributions: 120,
+        currentStreak: 2,
+        longestStreak: 15,
+      },
+      [{ name: 'Rust' }]
+    );
+
+    expect(result[2].text).toContain('15 days');
+  });
+
+  it('falls back to Unknown when languages list is empty', () => {
+    const result = buildInsights(
+      {
+        totalContributions: 50,
+        currentStreak: 1,
+        longestStreak: 5,
+      },
+      []
+    );
+
+    expect(result[1].text).toContain('Unknown');
   });
 });
 

lib/github.ts

@@ -452,6 +452,46 @@ export function generateAchievements(totalContributions: number, currentStreak:
   }
   return achievements;
 }
+type StreakStats = {
+  totalContributions: number;
+  currentStreak: number;
+  longestStreak: number;
+};
+
+type Language = {
+  name: string;
+};
+
+export function buildInsights(streakStats: StreakStats, languages: Language[]) {
+  const insights = [
+    {
+      id: '1',
+      icon: 'Flame',
+      text: `You have a total of ${streakStats.totalContributions} contributions this year.`,
+    },
+    {
+      id: '2',
+      icon: 'Code',
+      text: `Your primary language is ${languages[0]?.name || 'Unknown'}.`,
+    },
+  ];
+
+  if (streakStats.currentStreak > 3) {
+    insights.push({
+      id: '3',
+      icon: 'Zap',
+      text: `You are currently on an active ${streakStats.currentStreak}-day streak! Keep it going!`,
+    });
+  } else {
+    insights.push({
+      id: '3',
+      icon: 'Star',
+      text: `Your longest coding streak is ${streakStats.longestStreak} days!`,
+    });
+  }
+
+  return insights;
+}
 
 export function buildCommitClock(allDays: ContributionDay[]) {
   const dayNames = ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'];
@@ -553,29 +593,20 @@ export async function getFullDashboardData(username: string, options: FetchOptio
     streakStats.currentStreak
   );
 
-  const insights = [
-    {
-      id: '1',
-      icon: 'Flame',
-      text: `You have a total of ${streakStats.totalContributions} contributions this year.`,
-    },
-    { id: '2', icon: 'Code', text: `Your primary language is ${languages[0]?.name || 'Unknown'}.` },
-  ];
-  if (streakStats.currentStreak > 3) {
-    insights.push({
-      id: '3',
-      icon: 'Zap',
-      text: `You are currently on an active ${streakStats.currentStreak}-day streak! Keep it going!`,
-    });
-  } else {
-    insights.push({
-      id: '3',
-      icon: 'Star',
-      text: `Your longest coding streak is ${streakStats.longestStreak} days!`,
-    });
-  }
+  // 4. Insights Generation
+  const insights = buildInsights(streakStats, languages);
 
-  const commitClock = buildCommitClock(allDays);
+  // Aggregate real contribution data by day of week from the already-fetched calendar
+  const dayNames = ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat'];
+  const dayTotals = new Array(7).fill(0);
+  for (const day of allDays) {
+    const dow = new Date(day.date).getUTCDay();
+    dayTotals[dow] += day.contributionCount;
+  }
+  const commitClock = dayNames.map((name, i) => ({
+    day: name,
+    commits: dayTotals[i],
+  }));
 
   return {
     profile,