feat: add replyIssueComment

app/github/route.ts

@@ -1,4 +1,5 @@
 import { handleGithubAuth } from "@lib/handleGithubAuth"
+import { replyIssueComment } from "@lib/replyIssueComment"
 import { summarizePullRequest } from "@lib/summarizePullRequest"
 import { NextRequest, NextResponse } from "next/server"
 
@@ -9,9 +10,17 @@ export async function POST(req: NextRequest) {
 
   try {
     if (payload.action == "opened" || payload.action == "synchronize") {
+      // If a PR is opened or updated, summarize it
       const octokit = await handleGithubAuth(payload)
 
       await summarizePullRequest(payload, octokit)
+    } else if (payload.action == "created") {
+      if (payload.comment.body.includes("/codex-ask")) {
+        // If a comment is created, reply to it
+        const octokit = await handleGithubAuth(payload)
+
+        await replyIssueComment(payload, octokit)
+      }
     }
 
     return NextResponse.json("ok")

lib/replyIssueComment.ts

@@ -0,0 +1,55 @@
+import { Octokit } from "@octokit/rest"
+import { ChatCompletionRequestMessage } from "openai-streams"
+import { generateChatGpt } from "../utils/generateChatGpt"
+import { getCodeDiff } from "../utils/getCodeDiff"
+
+export const startDescription = "\n\n<!-- start pr-codex -->"
+export const endDescription = "<!-- end pr-codex -->"
+const systemPrompt =
+  "You are a Git diff assistant. Given a code diff, you answer any question related to it. Be concise. Always wrap file names, functions, objects and similar in backticks (`)."
+
+export async function replyIssueComment(payload: any, octokit: Octokit) {
+  // Get relevant PR information
+  const { repository, issue, sender, comment } = payload
+
+  const question = comment.body.split("/codex-ask")[1].trim()
+
+  if (question) {
+    const { owner, repo, issue_number } = {
+      owner: repository.owner.login,
+      repo: repository.name,
+      issue_number: issue.number
+    }
+
+    // Get the diff content using Octokit and GitHub API
+    const { codeDiff } = await getCodeDiff(owner, repo, issue_number, octokit)
+
+    // If there are changes, trigger workflow
+    if (codeDiff?.length != 0) {
+      const messages: ChatCompletionRequestMessage[] = [
+        {
+          role: "system",
+          content: systemPrompt
+        },
+        {
+          role: "user",
+          content: `${question}\n\nHere is the code diff:\n\n${codeDiff}`
+        }
+      ]
+
+      const codexResponse = await generateChatGpt(messages)
+
+      const description = `> ${question}\n\n@${sender.login} ${codexResponse}`
+
+      await octokit.issues.createComment({
+        owner,
+        repo,
+        issue_number,
+        body: description
+      })
+
+      return codexResponse
+    }
+    throw new Error("No changes in PR")
+  }
+}