latex.yml

name: LaTeX to PDF

on: [push, pull_request]

env:
  OUTPUT_DIR: "output"
  MAIN_TEX_FOLDER: "src"
  IMPRINT_URL: "https://cdn.helpwave.de/imprint.json"
  DEPENDENCIES: |
    head.tex
    version.tex
    imprint.tex
    logo.svg
    header.tex
    title.tex

jobs:
  get_tex_commit_history:
    runs-on: ubuntu-latest
    steps:
      - name: Checkout repository
        uses: actions/checkout@v3
        with:
          ref: ${{ github.event.pull_request.head.sha }}
          fetch-depth: 0

      - name: Check if any dependencies changed
        id: check_dependencies
        run: |
          changed_files=$(git diff --name-only HEAD^ HEAD)

          echo "Changed files: $changed_files"

          dependencies_pattern=$(echo "${{ env.DEPENDENCIES }}" | sed 's/ /\\|/g')

          if echo "$changed_files" | grep -E "$dependencies_pattern"; then
            echo "Dependencies changed, updating .tex files."
            echo "dependencies_changed=true" >> $GITHUB_ENV
          else
            echo "No dependencies changed."
            echo "dependencies_changed=false" >> $GITHUB_ENV
          fi

      - name: Touch all .tex files if dependencies changed
        if: env.dependencies_changed == 'true'
        run: |
          mkdir -p tex_commit_history

          commit_hash=$(git rev-parse HEAD)

          echo "Dependencies changed. Updating all .tex files..."

          for file in $(find ${{ env.MAIN_TEX_FOLDER }} -name "*.tex"); do
            echo "$file=$commit_hash" >> tex_commit_history/commit_hashes.txt
            echo "Update $file"
          done

          cat tex_commit_history/commit_hashes.txt

      - name: Find latest commits for .tex files
        if: env.dependencies_changed == 'false'
        run: |
          echo "Fetching latest commit hashes for .tex files..."

          mkdir -p tex_commit_history

          for file in $(find ${{ env.MAIN_TEX_FOLDER }} -name "*.tex"); do
            commit_hash=$(git log -n 1 --pretty=format:%H -- "$file")
            
            echo "$file=$commit_hash" >> tex_commit_history/commit_hashes.txt
          done

          cat tex_commit_history/commit_hashes.txt

      - name: Upload commit hash file
        uses: actions/upload-artifact@v3
        with:
          name: tex_commit_hashes
          path: tex_commit_history/commit_hashes.txt

  compile_latex:
    runs-on: ubuntu-latest
    needs: get_tex_commit_history
    outputs:
      commit_hash: ${{ steps.get_commit_hash.outputs.commit_hash }}
      changed_files: ${{ steps.determine_changed_files.outputs.changed_files }}
    steps:
      - name: Checkout repository
        uses: actions/checkout@v4
        with:
          ref: ${{ github.event.pull_request.head.sha }}

      - name: Download commit hash artifact
        uses: actions/download-artifact@v3
        with:
          name: tex_commit_hashes
          path: tex_commit_history

      - name: Get commit hash
        id: get_commit_hash
        run: |
          commit_hash=$(git rev-parse HEAD)
          echo $commit_hash
          echo "commit_hash=$commit_hash" >> $GITHUB_OUTPUT

      - name: Determine changed .tex files
        id: determine_changed_files
        run: |
          echo "Determining changed .tex files based on commit history..."
          changed_files=$(grep "${{ steps.get_commit_hash.outputs.commit_hash }}" tex_commit_history/commit_hashes.txt | cut -d'=' -f1 | tr ' ' '\n')
          echo "Changed files: $changed_files"
          echo "changed_files<<EOF" >> $GITHUB_ENV
          echo -e "$changed_files" >> $GITHUB_ENV
          echo "EOF" >> $GITHUB_ENV

          echo "changed_files<<EOF" >> $GITHUB_OUTPUT
          echo -e "$changed_files" >> $GITHUB_OUTPUT
          echo "EOF" >> $GITHUB_OUTPUT

      - name: Inject version
        run: |
          sed -i "s/ffffff/${{ steps.get_commit_hash.outputs.commit_hash }}/g" version.tex

      - name: Download JSON file
        run: |
          curl -o imprint.json ${{ env.IMPRINT_URL }}

      - name: Replace placeholders in LaTeX file
        run: |
          FILE_TO_UPDATE="imprint.tex"
          
          for key in $(jq -r 'keys[]' imprint.json); do
            value=$(jq -r --arg key "$key" '.[$key]' imprint.json)
            
            placeholder=$(echo $key | tr '.' '_')
            sed -i "s|{$placeholder}|{$value}|g" $FILE_TO_UPDATE
          done

      - name: Compile changed LaTeX documents
        if: env.changed_files != ''
        uses: xu-cheng/latex-action@v3
        with:
          root_file: ${{ env.changed_files }}
          extra_system_packages: "inkscape"
          latexmk_shell_escape: true

      - name: Create output directory and move PDFs
        if: env.changed_files != ''
        run: |
          mkdir -p ${{ env.OUTPUT_DIR }}
          mv *.pdf ${{ env.OUTPUT_DIR }}
          echo ${{ github.sha }} > ${{ env.OUTPUT_DIR }}/version.txt

      - name: Upload PDFs as artifacts
        if: env.changed_files != ''
        uses: actions/upload-artifact@v4
        with:
          name: pdfs
          path: ${{ env.OUTPUT_DIR }}

  upload_to_cdn:
    runs-on: ubuntu-latest
    needs: compile_latex
    if: needs.compile_latex.outputs.commit_hash != '' && needs.compile_latex.outputs.changed_files != ''
    steps:
      - name: Download PDFs
        uses: actions/download-artifact@v4
        with:
          name: pdfs
          path: ${{ env.OUTPUT_DIR }}

      - name: Upload to CDN build
        uses: ryand56/r2-upload-action@latest
        with:
          r2-account-id: ${{ secrets.R2_ACCOUNT_ID }}
          r2-access-key-id: ${{ secrets.R2_ACCESS_KEY_ID }}
          r2-secret-access-key: ${{ secrets.R2_SECRET_ACCESS_KEY }}
          r2-bucket: ${{ secrets.R2_BUCKET }}
          source-dir: ${{ env.OUTPUT_DIR }}
          destination-dir: ${{ needs.compile_latex.outputs.commit_hash }}

  release_on_cdn:
    runs-on: ubuntu-latest
    needs: compile_latex
    if: github.ref == 'refs/heads/main' && needs.compile_latex.outputs.commit_hash != '' && needs.compile_latex.outputs.changed_files != ''
    steps:
      - name: Download PDFs
        uses: actions/download-artifact@v4
        with:
          name: pdfs
          path: ${{ env.OUTPUT_DIR }}

      - name: Release on CDN
        uses: ryand56/r2-upload-action@latest
        with:
          r2-account-id: ${{ secrets.R2_ACCOUNT_ID }}
          r2-access-key-id: ${{ secrets.R2_ACCESS_KEY_ID }}
          r2-secret-access-key: ${{ secrets.R2_SECRET_ACCESS_KEY }}
          r2-bucket: ${{ secrets.R2_BUCKET }}
          source-dir: ${{ env.OUTPUT_DIR }}
          destination-dir: main
          keep-file-fresh: true

  pr_comment:
    runs-on: ubuntu-latest
    if: github.event_name == 'pull_request'
    needs: [get_tex_commit_history, upload_to_cdn]
    steps:
      - name: Download commit hash file
        uses: actions/download-artifact@v3
        with:
          name: tex_commit_hashes
          path: tex_commit_history

      - name: Generate CDN links and comment on PR
        uses: actions/github-script@v6
        with:
          script: |
            const fs = require('fs');

            const commitHashes = {};
            const commitHashFile = fs.readFileSync('tex_commit_history/commit_hashes.txt', 'utf8');
            commitHashFile.split('\n').forEach(line => {
              if (line.trim()) {
                const [file, hash] = line.split('=');
                commitHashes[file] = hash;
              }
            });

            const prNumber = context.payload.pull_request.number;
            const cdnUrl = '${{ secrets.CDN_URL }}';

            let commentBody = `☁️ **Compiled LaTeX Versions** ☁️\n\n| File | Commit Hash | PDF Link |\n|------|-------------|----------|\n`;

            Object.keys(commitHashes).forEach(file => {
              const fileName = file.replace(/^.*\//, '').replace('.tex', '');
              const hash = commitHashes[file];
              const url = `${cdnUrl}/${hash}/${fileName}.pdf`;
              commentBody += `| \`${file}\` | \`${hash}\` | [📄 Download PDF](${url}) |\n`;
            });

            const { data: comments } = await github.rest.issues.listComments({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: prNumber,
            });

            const existingComment = comments.find(comment => 
              comment.user.login === 'github-actions[bot]' && 
              comment.body.includes('☁️ **Compiled LaTeX Versions** ☁️')
            );

            if (existingComment) {
              await github.rest.issues.updateComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                comment_id: existingComment.id,
                body: commentBody,
              });
            } else {
              await github.rest.issues.createComment({
                owner: context.repo.owner,
                repo: context.repo.repo,
                issue_number: prNumber,
                body: commentBody,
              });
            }