ci.yml

name: Build Typst Projects

on:
  push:
    branches: [ main ]
  pull_request:
    branches: [ main ]
  workflow_dispatch:

jobs:
  check_changes:
    runs-on: ubuntu-22.04
    outputs:
      should_build: ${{ steps.check_changes.outputs.should_build }}
    
    steps:
      - name: Checkout repository
        uses: actions/checkout@v4
        with:
          fetch-depth: 0  # Fetch all history for git log commands
      
      - name: Check for changes in Typst projects or README
        id: check_changes
        run: |
          # Get the hash of the previous commit
          if [ "${{ github.event_name }}" == "pull_request" ]; then
            # For pull requests, compare against the base commit
            PREVIOUS_COMMIT=${{ github.event.pull_request.base.sha }}
          else
            # For pushes, compare against the previous commit
            PREVIOUS_COMMIT=$(git rev-parse HEAD^1 || echo "")
          fi
          
          if [ -z "$PREVIOUS_COMMIT" ]; then
            # If this is the first commit, we should build
            echo "should_build=true" >> $GITHUB_OUTPUT
            echo "First commit, building all projects"
            exit 0
          fi
          
          # Check if any .typ or .typst files or README.md has changed
          CHANGED_FILES=$(git diff --name-only $PREVIOUS_COMMIT HEAD)
          TYPST_CHANGES=$(echo "$CHANGED_FILES" | grep -E '\.typ(st)?$' || true)
          README_CHANGES=$(echo "$CHANGED_FILES" | grep -E 'README\.md$' || true)
          ASSETS_CHANGES=$(echo "$CHANGED_FILES" | grep -E 'assets/' || true)
    
          if [ -n "$TYPST_CHANGES" ] || [ -n "$README_CHANGES" ] || [ -n "$ASSETS_CHANGES" ] || [ "${{ github.event_name }}" == "workflow_dispatch" ]; then
            echo "should_build=true" >> $GITHUB_OUTPUT
            echo "Changes detected in Typst files or README.md, proceeding with build"
          else
            echo "should_build=false" >> $GITHUB_OUTPUT
            echo "No changes detected in Typst files or README.md, skipping build"
          fi

  build:
    needs: check_changes
    if: needs.check_changes.outputs.should_build == 'true'
    runs-on: ubuntu-latest
    
    steps:
      - name: Checkout repository
        uses: actions/checkout@v4
        with:
          fetch-depth: 0  # Fetch all history for git log commands

      - name: Install packages
        run: |
          sudo apt-get update
          sudo apt-get install -y poppler-utils

      - name: Setup Typst
        uses: typst-community/setup-typst@v3
        with:
          typst-version: latest
          
      - name: Find Typst projects with main.typst
        id: find_projects
        run: |
          echo "TYPST_DIRS=$(find . -name "main.typst" -o -name "main.typ" | xargs dirname | tr '\n' ' ')" >> $GITHUB_ENV
          mkdir -p build

      - name: Copy assets
        id: copy_assets
        run: |
          cp -r ./assets ./build
          
      - name: Build PDFs from Typst projects
        run: |
          # Create a file to store modification dates
          touch modification_dates.txt
          
          for dir in $TYPST_DIRS; do
            if [ -f "$dir/main.typst" ]; then
              main_file="$dir/main.typst"
            else
              main_file="$dir/main.typ"
            fi
            
            # Get relative path from repository root
            rel_dir="${dir#./}"
            
            echo "Building $main_file to build/$rel_dir/main.pdf"
            mkdir -p "build/$rel_dir"
            
            # Try to compile, continue if there's an error
            typst compile "$main_file" "build/$rel_dir/main.pdf" || echo "Failed to build $main_file, continuing..."
            
            # If build was successful, get the last modified date based on content changes
            if [ -f "build/$rel_dir/main.pdf" ]; then
              # Get the last commit date that modified ANY file in this directory or subdirectories
              # This captures changes to includes, images, data files, etc.
              last_modified=$(git log -1 --format="%ad" --date=format:"%Y-%m-%d" -- "$dir")
              
              # If git log fails (e.g., directory not yet committed), use file system date
              if [ -z "$last_modified" ]; then
                last_modified=$(find "$dir" -type f -printf "%TY-%Tm-%Td\n" | sort -r | head -n1)
              fi
              
              # Store the file path and its last modified date
              echo "$rel_dir/main.pdf|$last_modified" >> modification_dates.txt
            fi
          done
      
      - name: Generate Enhanced README
        run: |
          # Create header with site info
          if [ -f "README.md" ]; then
            echo "$(head -n 1 README.md)" >> build/README.md
          fi
          cat > build/README.md << 'EOF'

          <div align="center">
            <h3>Automatically Generated PDF Documents</h3>
            <p>
              <em>This site hosts the compiled PDF files from the Typst project source files of <a href="https://github.com/Huy-DNA/MPiSC/tree/main">MPiSC</a>.</em>
            </p>
          </div>

          ---

          ## 📄 Available Documents
          
          <table>
            <thead>
              <tr>
                <th align="left">Document</th>
                <th align="left">Last Content Update</th>
                <th align="center">View</th>
                <th align="center">Download</th>
              </tr>
            </thead>
            <tbody>
          EOF
          
          # Add table rows for each PDF
          while IFS="|" read -r file_path last_mod_date; do
            pdf_name=$(pdfinfo "build/$file_path" | grep "Title")
            pdf_name=${pdf_name:6}
            echo "      <tr>" >> build/README.md
            echo "        <td><strong>$pdf_name</strong></td>" >> build/README.md
            echo "        <td>$last_mod_date</td>" >> build/README.md
            echo "        <td align=\"center\"><a href=\"$file_path\">📕 View</a></td>" >> build/README.md
            echo "        <td align=\"center\"><a href=\"$file_path\" download>⬇️ PDF</a></td>" >> build/README.md
            echo "      </tr>" >> build/README.md
          done < modification_dates.txt
          
          # Close the table
          echo "    </tbody>" >> build/README.md
          echo "  </table>" >> build/README.md
          echo "" >> build/README.md
          
          # Add original README content if it exists
          echo "## 📝 Project Information" >> build/README.md
          echo "" >> build/README.md
          
          if [ -f "README.md" ]; then
            echo "" >> build/README.md
            cat README.md | tail -n +2 | sed -E 's/^(#+)/\1#/' >> build/README.md
            echo "" >> build/README.md
          fi

          # Add footer with build info
          cat >> build/README.md << EOF
          
          ---
          
          <div align="center">
            <p>
              <small>Last build: $(date)</small><br>
              <small>Generated by GitHub Actions • <a href="https://github.com/${GITHUB_REPOSITORY}/tree/main">View Source</a></small>
            </p>
          </div>
          EOF
      
      - name: Deploy to GitHub Pages
        uses: JamesIves/github-pages-deploy-action@v4
        with:
          folder: build
          branch: gh-pages
          clean: true
          commit-message: "Deploy Typst PDFs to GitHub Pages [skip ci]"