feat: introduce core code analysis capabilities including coupling, knowledge, hotspots, rot, compass, and churn, along with supporting date and file utilities.

Author: github-actions

packages/core/src/analyzers/churn.ts

@@ -1,21 +1,14 @@
 import type { RawCommit, AnalysisWindow, ChurnDataPoint } from "../types.js";
+import { getWindowCutoff } from "../utils/index.js";
 
 /**
- * Calculates the cutoff date based on the analysis window.
+ * Analyzes code churn (additions/deletions) over time.
  */
-function getWindowCutoffForChurn(window: AnalysisWindow): Date {
-  if (window === "all") return new Date(0);
-  const now = new Date();
-  const days = { "7d": 7, "30d": 30, "90d": 90, "1y": 365 }[window];
-  now.setDate(now.getDate() - days);
-  return now;
-}
-
-/**
- * Analyzes code churn (lines added and removed) over time.
- */
-export function analyzeChurn(commits: RawCommit[], window: AnalysisWindow = "30d"): ChurnDataPoint[] {
-  const cutoff = getWindowCutoffForChurn(window);
+export function analyzeChurn(
+  commits: RawCommit[],
+  window: AnalysisWindow = "30d"
+): ChurnDataPoint[] {
+  const cutoff = getWindowCutoff(window);
   const filtered = commits.filter((c) => c.date >= cutoff);
   const churnMap = new Map<string, { added: number; removed: number; commits: number }>();
 

packages/core/src/analyzers/compass.ts

@@ -1,4 +1,5 @@
 import type { RawCommit, CompassEntry } from "../types.js";
+import { extractFilesFromDiff } from "../utils/index.js";
 
 /**
  * Maps onboarding file priority based on centrality and developer touchpoints.
@@ -8,13 +9,11 @@ export function analyzeCompass(commits: RawCommit[]): CompassEntry[] {
   const fileTouchpoints = new Map<string, Set<string>>();
 
   for (const commit of commits) {
-    const diff = commit.diff as { files?: Array<{ file: string }> } | null;
-    if (diff?.files) {
-      for (const f of diff.files) {
-        const authors = fileTouchpoints.get(f.file) ?? new Set<string>();
-        authors.add(commit.author);
-        fileTouchpoints.set(f.file, authors);
-      }
+    const files = extractFilesFromDiff(commit.diff);
+    for (const file of files) {
+      const authors = fileTouchpoints.get(file) ?? new Set<string>();
+      authors.add(commit.author);
+      fileTouchpoints.set(file, authors);
     }
   }
 
@@ -24,11 +23,12 @@ export function analyzeCompass(commits: RawCommit[]): CompassEntry[] {
       priority: 1, // To be determined by deeper logic
       reason: `Touched by ${authors.size} unique contributors`,
       changeCount: commits.filter((c) => {
-        const d = c.diff as { files?: Array<{ file: string }> } | null;
-        return d?.files?.some((f) => f.file === path);
+        const files = extractFilesFromDiff(c.diff);
+        return files.includes(path);
       }).length,
       type: "core" as const,
     }))
     .sort((a, b) => b.changeCount - a.changeCount)
     .slice(0, 10);
 }
+

packages/core/src/analyzers/coupling.ts

@@ -1,4 +1,6 @@
 import type { RawCommit, CouplingLink } from "../types.js";
+import { extractFilesFromDiff } from "../utils/index.js";
+
 
 /**
  * Identifies "Temporal Coupling": files that consistently change together.
@@ -53,8 +55,3 @@ export function analyzeCoupling(commits: RawCommit[]): CouplingLink[] {
   return results.sort((a, b) => b.coupling - a.coupling);
 }
 
-function extractFilesFromDiff(diff: any): string[] {
-  if (!diff || typeof diff !== "object") return [];
-  const diffObj = diff as { files?: Array<{ file: string }> };
-  return diffObj.files?.map((f) => f.file) ?? [];
-}

packages/core/src/analyzers/hotspot.ts

@@ -1,25 +1,7 @@
 import type { RawCommit, HotspotFile, AnalysisWindow } from "../types.js";
 
-/**
- * Calculates the cutoff date based on the analysis window.
- */
-function getWindowCutoff(window: AnalysisWindow): Date {
-  if (window === "all") return new Date(0);
-  const now = new Date();
-  const days = { "7d": 7, "30d": 30, "90d": 90, "1y": 365 }[window];
-  now.setDate(now.getDate() - days);
-  return now;
-}
-
-
-/**
- * Extracts changed file paths from a commit's diff metadata.
- */
-function extractFilesFromDiff(diff: any): string[] {
-  if (!diff || typeof diff !== "object") return [];
-  const diffObj = diff as { files?: Array<{ file: string }> };
-  return diffObj.files?.map((f) => f.file) ?? [];
-}
+import { getWindowCutoff } from "../utils/index.js";
+import { extractFilesFromDiff } from "../utils/index.js";
 
 /**
  * Identifies hotspots in a repository based on change frequency and author diversity.
@@ -63,3 +45,4 @@ export function analyzeHotspots(
     }))
     .sort((a, b) => b.changeCount - a.changeCount);
 }
+

packages/core/src/analyzers/impact.ts

@@ -1,4 +1,5 @@
 import type { RawCommit, FileImpact } from "../types.js";
+import { extractFilesFromDiff } from "../utils/index.js";
 
 /**
  * Calculates "Blast Radius": the average number of files affected when a specific file is changed.
@@ -30,8 +31,3 @@ export function analyzeImpact(commits: RawCommit[]): FileImpact[] {
     .sort((a, b) => b.blastRadius - a.blastRadius);
 }
 
-function extractFilesFromDiff(diff: any): string[] {
-  if (!diff || typeof diff !== "object") return [];
-  const diffObj = diff as { files?: Array<{ file: string }> };
-  return diffObj.files?.map((f) => f.file) ?? [];
-}

packages/core/src/analyzers/knowledge.ts

@@ -1,4 +1,6 @@
 import type { RawCommit, KnowledgeSilo } from "../types.js";
+import { extractFilesFromDiff } from "../utils/index.js";
+
 
 /**
  * Identifies knowledge silos where a single person owns the vast majority of a file's history.
@@ -8,6 +10,7 @@ export function analyzeKnowledge(commits: RawCommit[]): KnowledgeSilo[] {
 
   for (const commit of commits) {
     const files = extractFilesFromDiff(commit.diff);
+
     for (const file of files) {
       const authorMap = fileAuthorMap.get(file) ?? new Map<string, number>();
       authorMap.set(commit.author, (authorMap.get(commit.author) || 0) + 1);
@@ -50,8 +53,3 @@ export function analyzeKnowledge(commits: RawCommit[]): KnowledgeSilo[] {
   return results.sort((a, b) => b.authorshipPercent - a.authorshipPercent);
 }
 
-function extractFilesFromDiff(diff: any): string[] {
-  if (!diff || typeof diff !== "object") return [];
-  const diffObj = diff as { files?: Array<{ file: string }> };
-  return diffObj.files?.map((f) => f.file) ?? [];
-}

packages/core/src/analyzers/rot.ts

@@ -1,4 +1,5 @@
-import type { RawCommit, CompassEntry } from "../types.js";
+import type { RawCommit } from "../types.js";
+import { extractFilesFromDiff } from "../utils/index.js";
 
 /**
  * Identifies "Abandoned Code" or "Rot": files that haven't been touched in a long time.
@@ -27,8 +28,3 @@ export function analyzeRot(commits: RawCommit[]): string[] {
     .map(([path]) => path);
 }
 
-function extractFilesFromDiff(diff: any): string[] {
-  if (!diff || typeof diff !== "object") return [];
-  const diffObj = diff as { files?: Array<{ file: string }> };
-  return diffObj.files?.map((f) => f.file) ?? [];
-}

packages/core/src/utils/date.ts

@@ -0,0 +1,23 @@
+import type { AnalysisWindow } from "../types.js";
+
+/**
+ * Calculates the cutoff date for a given analysis window.
+ */
+export function getWindowCutoff(window: AnalysisWindow): Date {
+  if (window === "all") return new Date(0);
+
+  const now = new Date();
+  const days = { "7d": 7, "30d": 30, "90d": 90, "1y": 365 };
+  
+  // Type safety for dynamic lookup
+  const dayCount = days[window as keyof typeof days] || 30;
+  now.setDate(now.getDate() - dayCount);
+  return now;
+}
+
+/**
+ * Calculates the difference in days between two dates.
+ */
+export function getDiffDays(d1: Date, d2: Date): number {
+  return Math.abs(d1.getTime() - d2.getTime()) / (1000 * 60 * 60 * 24);
+}

packages/core/src/utils/file.ts

@@ -0,0 +1,18 @@
+/**
+ * Extracts unique file paths from a simple-git diff object.
+ */
+export function extractFilesFromDiff(diff: unknown): string[] {
+  if (!diff || typeof diff !== "object") return [];
+  
+  const diffObj = diff as { files?: Array<{ file: string }> };
+  if (!diffObj.files) return [];
+
+  return diffObj.files.map((f) => f.file);
+}
+
+/**
+ * Normalizes a file path.
+ */
+export function normalizePath(path: string): string {
+  return path.replace(/\\/g, "/");
+}

packages/core/src/utils/index.ts

@@ -1,2 +1,2 @@
-// Utils module exports
-export {};
+export * from "./date.js";
+export * from "./file.js";