gemini_review.yml

name: Gemini Automated Code Review

on:
  pull_request:
    types: [opened, synchronize, reopened]
    branches: [main]

  push:
    branches:
      - main

  workflow_dispatch:
    inputs:
      pr_number:
        description: "리뷰할 PR 번호 (수동 실행 시 필수)"
        required: true

jobs:
  code-review:
    runs-on: ubuntu-latest
    permissions:
      contents: read
      pull-requests: write

    env:
      GH_TOKEN: ${{ github.token }}
      GEMINI_API_KEY: ${{ secrets.GEMINI_API_KEY }}

    steps:
      - name: Checkout repository
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Install GitHub CLI
        run: sudo apt-get install -y gh jq

      - name: Set up Node.js
        uses: actions/setup-node@v4
        with:
          node-version: 20

      - name: Install GoogleGenerativeAI SDK
        run: npm install @google/generative-ai@latest

      - name: Get git diff for PR
        if: github.event_name == 'pull_request'
        run: |
          echo "EVENT_TYPE=pull_request" >> $GITHUB_ENV
          echo "PR_NUMBER=${{ github.event.pull_request.number }}" >> $GITHUB_ENV

          git fetch origin "${{ github.event.pull_request.base.ref }}"
          git fetch origin "${{ github.event.pull_request.head.ref }}"
          git diff --unified=0 "origin/${{ github.event.pull_request.base.ref }}" "origin/${{ github.event.pull_request.head.ref }}" > diff.txt

      - name: Get git diff for manual PR review
        if: github.event_name == 'workflow_dispatch'
        run: |
          PR_NUMBER="${{ github.event.inputs.pr_number }}"
          echo "EVENT_TYPE=pull_request" >> $GITHUB_ENV
          echo "PR_NUMBER=$PR_NUMBER" >> $GITHUB_ENV

          BASE=$(gh pr view $PR_NUMBER --json baseRefName -q .baseRefName)
          HEAD=$(gh pr view $PR_NUMBER --json headRefName -q .headRefName)

          git fetch origin $BASE
          git fetch origin $HEAD

          git diff --unified=0 origin/$BASE origin/$HEAD > diff.txt

      - name: Detect PR for push event
        if: github.event_name == 'push'
        run: |
          PR_NUMBER=$(gh pr list --state open --json number,headRefName \
            --jq ".[] | select(.headRefName==\"${GITHUB_REF_NAME}\") | .number")

          if [ -z "$PR_NUMBER" ]; then
            echo "Push된 커밋과 연결된 PR을 찾을 수 없습니다."
            exit 1
          fi

          echo "EVENT_TYPE=pull_request" >> $GITHUB_ENV
          echo "PR_NUMBER=$PR_NUMBER" >> $GITHUB_ENV

          BASE=$(gh pr view $PR_NUMBER --json baseRefName -q .baseRefName)
          HEAD=$(gh pr view $PR_NUMBER --json headRefName -q .headRefName)

          git fetch origin $BASE
          git fetch origin $HEAD

          git diff --unified=0 origin/$BASE origin/$HEAD > diff.txt

      - name: Run Gemini Review (File-based Chunking)
        id: gemini_review
        uses: actions/github-script@v7
        with:
          script: |
            const fs = require("fs");
            const { GoogleGenerativeAI } = require("@google/generative-ai");

            const rawDiff = fs.readFileSync("diff.txt", "utf8");

            const fileDiffs = rawDiff
              .split("diff --git")
              .slice(1)
              .map(block => "diff --git" + block);

            const tsDiffs = fileDiffs.filter(block =>
              /a\/src\/.*\.(ts|tsx)/.test(block)
            );

            console.log("Filtered ts/tsx files:", tsDiffs.length);

            const genAI = new GoogleGenerativeAI(process.env.GEMINI_API_KEY);
            const model = genAI.getGenerativeModel({ model: "gemini-2.5-flash" });

            let allComments = [];

            for (let i = 0; i < tsDiffs.length; i++) {
              const diffBlock = tsDiffs[i];

              const prompt = `
              당신은 시니어 프론트엔드 개발자입니다.

              아래는 특정 파일의 diff입니다.
              **src/ 내부의 .ts / .tsx 파일만 리뷰합니다.**

              JSON 배열 형식만 출력하세요:

            [
              {
                "path": "파일경로",
                "line": 라인번호,
                "text": "리뷰내용",
                "side": "RIGHT"
              }
            ]

            JSON 외 텍스트 금지.

              <file diff ${i + 1}/${tsDiffs.length}>
              ${diffBlock}
              </file diff>
                            `;

              console.log("Reviewing file " + (i + 1));

              try {
                const result = await model.generateContent(prompt);
                const text = result.response.text();
                const parsed = JSON.parse(text);
                allComments.push(...parsed);
              } catch (err) {
                console.log("⚠️ Gemini error for file", i + 1);
                console.log(err);
              }
            }

            fs.writeFileSync("review_result.txt", JSON.stringify(allComments, null, 2));
            console.log("Review saved!");

      - name: Add PR Review Comments
        uses: nbaztec/add-pr-review-comment@v1.0.7
        with:
          comments: ${{ steps.gemini_review.outputs.comment }}
          repo-token: ${{ secrets.GITHUB_TOKEN }}
          repo-token-user-login: "github-actions[bot]"
          allow-repeats: false