name: '📚 Book · 👁️ Preview (Dev)'

env:
  # ==========================================================================
  # PATH CONFIGURATION - Uses GitHub Repository Variables (Settings > Variables)
  # ==========================================================================
  # MLSysBook content lives under book/ to accommodate TinyTorch at root
  # Use ${{ vars.BOOK_ROOT }}, ${{ vars.BOOK_TOOLS }}, etc. in workflow steps

on:
  workflow_dispatch:
    inputs:
      commit_sha:
        description: 'Optional: Specific commit SHA to deploy. Deploys the latest successful `dev` build if empty.'
        required: false
        type: string
  workflow_run:
    workflows: ["📚 Book · ✅ Validate (Dev)"]
    types:
      - completed

concurrency:
  group: deploy-preview-${{ github.ref }}
  cancel-in-progress: true

jobs:
  deploy:
    name: '📺 Deploy to GitHub Pages (Dev Preview)'
    if: (github.event.workflow_run.conclusion == 'success' && github.event.workflow_run.head_branch == 'dev') || github.event_name == 'workflow_dispatch'
    runs-on: ubuntu-latest
    # Deploys dev branch to: https://harvard-edge.github.io/cs249r_book_dev/
    permissions:
      contents: write # Allow write access to repository
      pages: write
      actions: read # Allow reading of workflow runs

    steps:
      - name: ⬇️ Get workflow run ID
        id: run_info
        run: |
          if [[ "${{ github.event_name }}" == "workflow_run" ]]; then
            echo "run_id=${{ github.event.workflow_run.id }}" >> $GITHUB_OUTPUT
            echo "head_sha=${{ github.event.workflow_run.head_sha }}" >> $GITHUB_OUTPUT
            exit 0
          fi

          COMMIT_SHA=$(echo "${{ github.event.inputs.commit_sha }}" | xargs)
          API_URL="repos/${{ github.repository }}/actions/workflows/book-validate-dev.yml/runs"

          if [[ -n "$COMMIT_SHA" ]]; then
            echo "🔎 Searching for successful 'Validate Dev' run for commit starting with: $COMMIT_SHA"
            JQ_QUERY=".workflow_runs[] | select((.head_sha | startswith(\"$COMMIT_SHA\")) and .status == \"completed\" and .conclusion == \"success\") | .id"
          else
            echo "🔎 No commit SHA provided. Searching for the latest successful 'Validate Dev' run on 'dev' branch."
            JQ_QUERY=".workflow_runs[] | select(.head_branch == \"dev\" and .status == \"completed\" and .conclusion == \"success\") | .id"
          fi

          latest_run_id=$(gh api "$API_URL" --jq "$JQ_QUERY" | head -n 1)

          if [ -z "$latest_run_id" ]; then
              if [[ -n "$COMMIT_SHA" ]]; then
                echo "::error::Could not find a successful 'Validate Dev' run for commit ${COMMIT_SHA}."
              else
                echo "::error::Could not find any successful 'Validate Dev' run on the 'dev' branch."
              fi
              exit 1
          fi

          echo "Found run ID: ${latest_run_id}"
          echo "run_id=${latest_run_id}" >> $GITHUB_OUTPUT

          latest_run_sha=$(gh api repos/${{ github.repository }}/actions/runs/${latest_run_id} --jq '.head_sha')
          echo "head_sha=${latest_run_sha}" >> $GITHUB_OUTPUT
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}

      - name: 📥 Download Vol1 HTML Artifact
        uses: actions/download-artifact@v7
        with:
          name: dev-html-vol1-linux
          run-id: ${{ steps.run_info.outputs.run_id }}
          path: ./html-vol1-artifact
          github-token: ${{ secrets.GITHUB_TOKEN }}

      - name: 📥 Download Vol2 HTML Artifact
        uses: actions/download-artifact@v7
        with:
          name: dev-html-vol2-linux
          run-id: ${{ steps.run_info.outputs.run_id }}
          path: ./html-vol2-artifact
          github-token: ${{ secrets.GITHUB_TOKEN }}

      - name: 📥 Download Vol1 PDF Artifact
        uses: actions/download-artifact@v7
        continue-on-error: true
        with:
          name: dev-pdf-vol1-linux
          run-id: ${{ steps.run_info.outputs.run_id }}
          path: ./pdf-vol1-artifact
          github-token: ${{ secrets.GITHUB_TOKEN }}

      - name: 📥 Download Vol2 PDF Artifact
        uses: actions/download-artifact@v7
        continue-on-error: true
        with:
          name: dev-pdf-vol2-linux
          run-id: ${{ steps.run_info.outputs.run_id }}
          path: ./pdf-vol2-artifact
          github-token: ${{ secrets.GITHUB_TOKEN }}

      - name: 📥 Download Vol1 EPUB Artifact
        uses: actions/download-artifact@v7
        continue-on-error: true
        with:
          name: dev-epub-vol1-linux
          run-id: ${{ steps.run_info.outputs.run_id }}
          path: ./epub-vol1-artifact
          github-token: ${{ secrets.GITHUB_TOKEN }}

      - name: 📥 Download Vol2 EPUB Artifact
        uses: actions/download-artifact@v7
        continue-on-error: true
        with:
          name: dev-epub-vol2-linux
          run-id: ${{ steps.run_info.outputs.run_id }}
          path: ./epub-vol2-artifact
          github-token: ${{ secrets.GITHUB_TOKEN }}

      - name: 📦 Build volume preview site
        run: |
          echo "📦 Preparing volume preview site..."
          mkdir -p ./preview-site/vol1 ./preview-site/vol2

          cp -r ./html-vol1-artifact/* ./preview-site/vol1/
          cp -r ./html-vol2-artifact/* ./preview-site/vol2/

          mkdir -p ./preview-site/vol1/assets/downloads ./preview-site/vol2/assets/downloads

          if [ -f "./pdf-vol1-artifact/Machine-Learning-Systems.pdf" ]; then
            cp "./pdf-vol1-artifact/Machine-Learning-Systems.pdf" "./preview-site/vol1/assets/downloads/Machine-Learning-Systems-Vol1.pdf"
          fi
          if [ -f "./epub-vol1-artifact/Machine-Learning-Systems.epub" ]; then
            cp "./epub-vol1-artifact/Machine-Learning-Systems.epub" "./preview-site/vol1/assets/downloads/Machine-Learning-Systems-Vol1.epub"
          fi
          if [ -f "./pdf-vol2-artifact/Machine-Learning-Systems.pdf" ]; then
            cp "./pdf-vol2-artifact/Machine-Learning-Systems.pdf" "./preview-site/vol2/assets/downloads/Machine-Learning-Systems-Vol2.pdf"
          fi
          if [ -f "./epub-vol2-artifact/Machine-Learning-Systems.epub" ]; then
            cp "./epub-vol2-artifact/Machine-Learning-Systems.epub" "./preview-site/vol2/assets/downloads/Machine-Learning-Systems-Vol2.epub"
          fi

      - name: 📝 Create .nojekyll file
        run: touch ./preview-site/.nojekyll

      - name: 📦 Inspect final site contents
        run: |
          echo "::group::Site Contents"
          ls -la ./preview-site
          echo "::endgroup::"

          echo "::group::Assets/Downloads Contents"
          if [ -d "./preview-site/assets/downloads" ]; then
            ls -la ./preview-site/assets/downloads
          else
            echo "No assets/downloads directory"
          fi
          echo "::endgroup::"

      - name: ⬇️ Checkout repository (for scripts)
        uses: actions/checkout@v6
        with:
          path: ./repo-scripts
          sparse-checkout: |
            ${{ vars.BOOK_TOOLS }}/scripts/publish/modify_dev_announcement.py
            .github/dev-landing/index.html
          sparse-checkout-cone-mode: false

      - name: 🔧 Modify announcement for dev preview
        run: |
          echo "🔧 Modifying announcement banner for development preview..."

          # Get commit info for display
          COMMIT_HASH="${{ steps.run_info.outputs.head_sha }}"
          COMMIT_SHORT="${COMMIT_HASH:0:8}"

          echo "📝 Adding dev preview banner with commit info: $COMMIT_SHORT"

          python3 ./repo-scripts/${{ vars.BOOK_TOOLS }}/scripts/publish/modify_dev_announcement.py \
            ./preview-site \
            --verbose \
            --commit-hash "$COMMIT_HASH" \
            --commit-short "$COMMIT_SHORT"

      - name: 🚀 Deploy to Dev Site via SSH
        env:
          SSH_DEPLOY_KEY: ${{ secrets.SSH_DEPLOY_KEY }}
        run: |
          echo "🔐 Starting ssh-agent..."
          eval "$(ssh-agent -s)"
          echo "$SSH_DEPLOY_KEY" | tr -d '\r' | ssh-add - > /dev/null
          # Add github.com to known hosts to avoid prompt
          mkdir -p ~/.ssh
          ssh-keyscan github.com >> ~/.ssh/known_hosts

          echo "🔧 Configuring git..."
          git config --global user.email "actions@github.com"
          git config --global user.name "GitHub Actions"

          echo "🔄 Cloning target repository (${{ vars.DEV_REPO }})..."
          git clone --depth=1 ${{ vars.DEV_REPO_URL }} target-repo

          echo "🔄 Entering target repository..."
          cd target-repo

          echo "🧹 Cleaning /${{ vars.DEV_BOOK_PATH }}/ subdirectory only (preserving /${{ vars.DEV_TINYTORCH_PATH }}/ and landing page)..."
          # Only remove book subdirectory, preserve other content
          rm -rf ${{ vars.DEV_BOOK_PATH }}
          mkdir -p ${{ vars.DEV_BOOK_PATH }}

          echo "🚚 Copying book content to /${{ vars.DEV_BOOK_PATH }}/ subdirectory..."
          cp -r "${{ github.workspace }}/preview-site/." ${{ vars.DEV_BOOK_PATH }}/

          echo "📄 Deploying landing page to root..."
          # Copy landing page (preserves tinytorch/ if it exists)
          cp "${{ github.workspace }}/repo-scripts/.github/dev-landing/index.html" index.html
          touch .nojekyll

          echo "🔍 Validating deployment content..."
          if [ ! -f "${{ vars.DEV_BOOK_PATH }}/vol1/index.html" ]; then
            echo "❌ CRITICAL: ${{ vars.DEV_BOOK_PATH }}/vol1/index.html is missing after copy. Aborting deployment."
            exit 1
          fi

          if [ ! -f "${{ vars.DEV_BOOK_PATH }}/vol2/index.html" ]; then
            echo "❌ CRITICAL: ${{ vars.DEV_BOOK_PATH }}/vol2/index.html is missing after copy. Aborting deployment."
            exit 1
          fi

          if [ ! -f "index.html" ]; then
            echo "❌ CRITICAL: Landing page index.html is missing. Aborting deployment."
            exit 1
          fi

          echo "📦 Repository structure:"
          ls -la
          echo ""
          echo "📦 /${{ vars.DEV_BOOK_PATH }}/ contents:"
          ls -la ${{ vars.DEV_BOOK_PATH }}/ | head -10

          echo "📦 Committing and pushing changes..."
          git add .
          git commit -m "🚀 Deploy book dev preview to /${{ vars.DEV_BOOK_PATH }}/ from ${{ steps.run_info.outputs.head_sha }}" --allow-empty || echo "🟡 Nothing to commit"
          git push origin main

          # DEV_REPO contains org/repo format, extract just repo name for GitHub Pages URL
          REPO_NAME="${{ vars.DEV_REPO }}"
          REPO_NAME="${REPO_NAME##*/}"
          echo "✅ Book deployed to: https://harvard-edge.github.io/${REPO_NAME}/${{ vars.DEV_BOOK_PATH }}/"