feat: integrate git repository diff handling into common route

- Added functions to check if a path is a git repository and to parse git status output into a structured format.
- Refactored diff handling in both git and worktree routes to utilize the new common functions, improving code reuse and maintainability.
- Enhanced error logging for better debugging during git operations.

This update streamlines the process of retrieving diffs for both git and non-git directories, ensuring a consistent approach across the application.

apps/server/src/routes/git/routes/diffs.ts

@@ -3,24 +3,8 @@
  */
 
 import type { Request, Response } from "express";
-import { exec } from "child_process";
-import { promisify } from "util";
 import { getErrorMessage, logError } from "../common.js";
-import { appendUntrackedFileDiffs, generateDiffsForNonGitDirectory } from "../../common.js";
-
-const execAsync = promisify(exec);
-
-/**
- * Check if a path is a git repository
- */
-async function isGitRepo(repoPath: string): Promise<boolean> {
-  try {
-    await execAsync("git rev-parse --is-inside-work-tree", { cwd: repoPath });
-    return true;
-  } catch {
-    return false;
-  }
-}
+import { getGitRepositoryDiffs } from "../../common.js";
 
 export function createDiffsHandler() {
   return async (req: Request, res: Response): Promise<void> => {
@@ -32,70 +16,16 @@ export function createDiffsHandler() {
         return;
       }
 
-      // Check if it's a git repository
-      const isRepo = await isGitRepo(projectPath);
-
-      if (!isRepo) {
-        // Not a git repo - list all files and treat them as new
-        try {
-          const result = await generateDiffsForNonGitDirectory(projectPath);
-          res.json({
-            success: true,
-            diff: result.diff,
-            files: result.files,
-            hasChanges: result.files.length > 0,
-          });
-        } catch (error) {
-          logError(error, "Failed to list files in non-git directory");
-          res.json({ success: true, diff: "", files: [], hasChanges: false });
-        }
-        return;
-      }
-
       try {
-        const { stdout: diff } = await execAsync("git diff HEAD", {
-          cwd: projectPath,
-          maxBuffer: 10 * 1024 * 1024,
-        });
-        const { stdout: status } = await execAsync("git status --porcelain", {
-          cwd: projectPath,
-        });
-
-        const files = status
-          .split("\n")
-          .filter(Boolean)
-          .map((line) => {
-            const statusChar = line[0];
-            const filePath = line.slice(3);
-            const statusMap: Record<string, string> = {
-              M: "Modified",
-              A: "Added",
-              D: "Deleted",
-              R: "Renamed",
-              C: "Copied",
-              U: "Updated",
-              "?": "Untracked",
-            };
-            return {
-              status: statusChar,
-              path: filePath,
-              statusText: statusMap[statusChar] || "Unknown",
-            };
-          });
-
-        // Generate synthetic diffs for untracked (new) files
-        // git diff HEAD doesn't include untracked files, so we need to generate them
-        const combinedDiff = await appendUntrackedFileDiffs(projectPath, diff, files);
-
+        const result = await getGitRepositoryDiffs(projectPath);
         res.json({
           success: true,
-          diff: combinedDiff,
-          files,
-          hasChanges: files.length > 0,
+          diff: result.diff,
+          files: result.files,
+          hasChanges: result.hasChanges,
         });
       } catch (innerError) {
-        // Log the error for debugging instead of silently swallowing it
-        logError(innerError, "Git command failed");
+        logError(innerError, "Git diff failed");
         res.json({ success: true, diff: "", files: [], hasChanges: false });
       }
     } catch (error) {