Merge pull request #3 from presubmit/dev

Add PR Summary Generation with File Diffs and Messages

src/diff.ts

@@ -0,0 +1,194 @@
+type File = {
+  filename: string;
+  status:
+    | "added"
+    | "removed"
+    | "modified"
+    | "renamed"
+    | "copied"
+    | "changed"
+    | "unchanged";
+  previous_filename?: string;
+  patch?: string;
+};
+
+export type Hunk = {
+  startLine: number;
+  endLine: number;
+  diff: string;
+};
+
+export type FileDiff = File & {
+  hunks: Hunk[];
+};
+
+export function parseFileDiff(file: File): FileDiff {
+  if (!file.patch) {
+    return {
+      ...file,
+      hunks: [],
+    };
+  }
+
+  const hunks: Hunk[] = [];
+
+  let currentHunk: Hunk | null = null;
+  for (const line of file.patch.split("\n")) {
+    const hunkHeader = line.match(/@@ -(\d+),?\d* \+(\d+),?\d* @@/);
+    if (hunkHeader) {
+      if (currentHunk) {
+        hunks.push(currentHunk);
+      }
+      currentHunk = {
+        startLine: parseInt(hunkHeader[2]),
+        endLine: parseInt(hunkHeader[2]),
+        diff: line + "\n",
+      };
+    } else if (currentHunk) {
+      currentHunk.diff += line + "\n";
+      if (line[0] !== "-") {
+        currentHunk.endLine++;
+      }
+    }
+  }
+  if (currentHunk) {
+    hunks.push(currentHunk);
+  }
+
+  return {
+    ...file,
+    hunks,
+  };
+}
+
+function removeDeletedLines(hunk: Hunk): Hunk {
+  return {
+    ...hunk,
+    diff: hunk.diff
+      .split("\n")
+      .filter((line) => !line.startsWith("-"))
+      .join("\n"),
+  };
+}
+
+function removeAddedLines(hunk: Hunk): Hunk {
+  return {
+    ...hunk,
+    diff: hunk.diff
+      .split("\n")
+      .filter((line) => !line.startsWith("+"))
+      .join("\n"),
+  };
+}
+
+function prependLineNumbers(hunk: Hunk): Hunk {
+  const lines = hunk.diff.split("\n");
+  let currentLine = hunk.startLine;
+  const numberedLines = lines.map((line) => {
+    // Skip empty lines at the end of the diff
+    if (!line) return line;
+
+    // Handle different line prefixes
+    if (line.startsWith("@@")) {
+      return line; // Keep hunk headers as is
+    } else if (line.startsWith("-")) {
+      return line; // Don't number removed lines
+    } else if (line.startsWith("+")) {
+      return `${currentLine++} ${line}`;
+    } else {
+      return `${currentLine++} ${line}`;
+    }
+  });
+
+  return {
+    startLine: hunk.startLine,
+    endLine: hunk.endLine,
+    diff: numberedLines.join("\n"),
+  };
+}
+
+function formatDiffHunk(hunk: Hunk): string {
+  const oldHunk = removeAddedLines(hunk);
+  const newHunk = prependLineNumbers(removeDeletedLines(hunk));
+
+  // Extract the @@ header from the first line
+  const lines = hunk.diff.split("\n");
+  const headerLine = lines.find((line) => line.startsWith("@@"));
+
+  // Check if there's content in each hunk after removing lines (excluding @@ header)
+  const hasOldContent = oldHunk.diff
+    .trim()
+    .split("\n")
+    .some((line) => line && !line.startsWith("@@"));
+  const hasNewContent = newHunk.diff
+    .trim()
+    .split("\n")
+    .some((line) => line && !line.startsWith("@@"));
+
+  let output = "";
+
+  // Add header first if we have any content
+  if ((hasOldContent || hasNewContent) && headerLine) {
+    output += `${headerLine}\n`;
+  }
+
+  if (hasNewContent) {
+    // Remove @@ header from new hunk content
+    const newContent = newHunk.diff
+      .split("\n")
+      .filter((line) => !line.startsWith("@@"))
+      .join("\n")
+      .trimEnd();
+    output += `__new hunk__\n${newContent}\n`;
+  }
+
+  if (hasOldContent) {
+    if (hasNewContent) output += "\n";
+    // Remove @@ header from old hunk content
+    const oldContent = oldHunk.diff
+      .split("\n")
+      .filter((line) => !line.startsWith("@@"))
+      .join("\n")
+      .trimEnd();
+    output += `__old hunk__\n${oldContent}\n`;
+  }
+
+  return output || "No changes in this hunk";
+}
+
+export function formatFileDiff(file: File): string {
+  const diff = file.patch || "";
+
+  let header = `## File ${file.status}: `;
+  if (file.previous_filename) {
+    header += `'${file.previous_filename}' → `;
+  }
+  header += `'${file.filename}'`;
+
+  if (diff.length) {
+    header += `\n\n${diff}`;
+  }
+
+  return header;
+}
+
+export function generateFileCodeDiff(
+  fileDiff: FileDiff,
+  simplified: boolean = false
+): string {
+  const hunksText = simplified
+    ? fileDiff.patch || ""
+    : fileDiff.hunks.map((hunk) => formatDiffHunk(hunk)).join("\n\n");
+
+  let header = `## File ${fileDiff.status}: `;
+  if (fileDiff.previous_filename) {
+    header += `'${fileDiff.previous_filename}' → `;
+  }
+  header += `'${fileDiff.filename}'`;
+
+  if (hunksText.length) {
+    header += `\n\n${hunksText}`;
+  }
+
+  return header;
+}

src/messages.ts

@@ -0,0 +1,60 @@
+import { FileDiff } from "./diff";
+import { PullRequestSummary } from "./prompts";
+
+export function buildInitialMessage(
+  baseCommit: string,
+  headCommit: string,
+  fileDiffs: FileDiff[]
+): string {
+  let message = `⏳ **Analyzing changes in this PR...** ⏳\n\n`;
+  message += `_This might take a few minutes, please wait_\n\n`;
+
+  // Group files by operation
+
+  message += `<details>\n<summary>📥 Commits</summary>\n\n`;
+  message += `Analyzing changes from base commit (\`${baseCommit}\`) to head commit (\`${headCommit}\`)\n\n`;
+  message += "\n</details>\n\n";
+
+  message += `<details>\n<summary>📁 Files being considered (${fileDiffs.length})</summary>\n\n`;
+  for (const diff of fileDiffs) {
+    let prefix = "🔄"; // Modified
+    if (diff.status === "added") prefix = "➕";
+    if (diff.status === "removed") prefix = "➖";
+    if (diff.status === "renamed") prefix = "📝";
+
+    let fileText = `${prefix} ${diff.filename}`;
+    if (diff.status === "renamed") {
+      fileText += ` (from ${diff.previous_filename})`;
+    }
+    fileText += ` _(${diff.hunks.length} hunks)_`;
+    message += `${fileText}\n`;
+  }
+  message += "\n</details>\n\n";
+
+  message += "--- \n_autogenerated by presubmit.ai_";
+
+  return message;
+}
+
+export function buildWalkthroughMessage(summary: PullRequestSummary): string {
+  let message = `# 📖 Walkthrough\n\n`;
+
+  // Add description with proper spacing
+  message += `${summary.description.trim()}\n\n`;
+
+  message += `## Changes\n\n`;
+
+  // Create table with proper column alignment and escaping
+  message += `| File | Summary |\n`;
+  message += `|:----------|:---------------|\n`; // Left-align columns
+
+  for (const file of summary.files) {
+    // Escape pipes and wrap paths in backticks for better formatting
+    const escapedPath = file.filename.replace(/\|/g, "\\|");
+    const escapedSummary = file.summary.replace(/\|/g, "\\|");
+
+    message += `| \`${escapedPath}\` | ${escapedSummary} |\n`;
+  }
+
+  return message;
+}

src/octokit.ts

@@ -10,7 +10,7 @@ export const initOctokit = (token?: string) => {
     throw new Error("No github token");
   }
   return new SmartOctokit({
-    auth: `token ${token}`,
+    auth: token,
     throttle: {
       onRateLimit: (
         retryAfter: any,

src/prompts.ts

@@ -1,12 +1,24 @@
 import { runPrompt } from "./ai";
 import { z } from "zod";
+import { formatFileDiff } from "./diff";
 
 type PullRequestSummaryPrompt = {
   prTitle: string;
   prDescription: string;
   commitMessages: string[];
-  files: FileDiff[];
-  diff: string;
+  files: {
+    filename: string;
+    status:
+      | "added"
+      | "removed"
+      | "modified"
+      | "renamed"
+      | "copied"
+      | "changed"
+      | "unchanged";
+    previous_filename?: string;
+    patch?: string;
+  }[];
 };
 
 export type PullRequestSummary = {
@@ -46,11 +58,11 @@ ${pr.commitMessages.join("\n")}
 </Commit Messages>
 
 <Affected Files>
-${pr.files.map((file) => `- ${file.operation}: ${file.fileName}`).join("\n")}
+${pr.files.map((file) => `- ${file.status}: ${file.filename}`).join("\n")}
 </Affected Files>
 
 <File Diffs>
-${pr.diff}
+${pr.files.map((file) => formatFileDiff(file)).join("\n\n")}
 </File Diffs>
 
 Make sure each affected file is summarized and it's part of the returned JSON.

src/pull_request.ts

@@ -1,7 +1,10 @@
-import { warning } from "@actions/core";
+import { info, warning } from "@actions/core";
 import { Config } from "./config";
 import { initOctokit } from "./octokit";
 import { loadContext } from "./context";
+import runSummaryPrompt from "./prompts";
+import { buildInitialMessage, buildWalkthroughMessage } from "./messages";
+import { parseFileDiff } from "./diff";
 
 export async function handlePullRequest(config: Config) {
   const context = await loadContext();
@@ -21,24 +24,55 @@ export async function handlePullRequest(config: Config) {
 
   const octokit = initOctokit(config.githubToken);
 
-  // Get PR files
+  // Get modified files
   const { data: files } = await octokit.rest.pulls.listFiles({
     ...context.repo,
     pull_number: pull_request.number,
   });
+  const fileDiffs = files.map(parseFileDiff);
+  info(`successfully fetched file diffs`);
 
-  console.log("files: ", files);
-  console.log("pull_request: ", pull_request);
-
-  return {
-    title: pull_request.title,
-    description: pull_request.body || "",
-    files: files.map((file) => ({
-      filename: file.filename,
-      status: file.status,
-      additions: file.additions,
-      deletions: file.deletions,
-      patch: file.patch,
-    })),
-  };
+  // Create initial comment with the summary
+  const initialComment = await octokit.rest.issues.createComment({
+    ...context.repo,
+    issue_number: pull_request.number,
+    body: buildInitialMessage(
+      pull_request.base.sha,
+      pull_request.head.sha,
+      fileDiffs
+    ),
+  });
+  info(`posted initial comment`);
+  // Get commit messages
+  const { data: commits } = await octokit.rest.pulls.listCommits({
+    ...context.repo,
+    pull_number: pull_request.number,
+  });
+  info(`successfully fetched commit messages`);
+
+  // Generate PR summary
+  const summary = await runSummaryPrompt({
+    prTitle: pull_request.title,
+    prDescription: pull_request.body || "",
+    commitMessages: commits.map((commit) => commit.commit.message),
+    files: files,
+  });
+  info(`generated pull request summary: ${summary.title}`);
+
+  // Update PR title and description
+  await octokit.rest.pulls.update({
+    ...context.repo,
+    pull_number: pull_request.number,
+    title: summary.title,
+    body: summary.description,
+  });
+  info(`updated pull request title and description`);
+
+  // Update initial comment with the walkthrough
+  await octokit.rest.issues.updateComment({
+    ...context.repo,
+    comment_id: initialComment.data.id,
+    body: buildWalkthroughMessage(summary),
+  });
+  info(`posted walkthrough`);
 }