name: Roll Dart Dependencies

on:
  workflow_dispatch:
    inputs:
      dart_hash:
        description: 'The Dart SDK commit hash to update to'
        required: true
        type: string

jobs:
  update-deps:
    runs-on: ubuntu-latest
    permissions:
      contents: write
      pull-requests: write

    steps:
      - name: Checkout Repository
        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
        with:
          repository: flutteractionsbot/flutter
          token: ${{ secrets.FLUTTERACTIONSBOT_CP_TOKEN }}
          ref: master
          persist-credentials: false

      - name: Configure git
        run: |
          gh auth setup-git
          git config --global user.name "flutteractionsbot"
          git config --global user.email "<flutter-actions-bot@google.com>"
        env:
          GH_TOKEN: ${{ secrets.FLUTTERACTIONSBOT_CP_TOKEN }}

      - name: Fetch upstream
        run: |
          git remote add upstream https://github.com/flutter/flutter.git
          git fetch upstream "$REF_NAME"

          BRANCH_NAME="sync-dart-$DART_HASH"
          echo "BRANCH_NAME=$BRANCH_NAME" >> "$GITHUB_ENV"

          git checkout -b "$BRANCH_NAME" "upstream/$REF_NAME"
        env:
          GH_TOKEN: ${{ secrets.FLUTTERACTIONSBOT_CP_TOKEN }}
          REF_NAME: ${{ github.ref_name }}
          DART_HASH: ${{ inputs.dart_hash }}

      - name: Download and Decode Dart DEPS
        id: download-deps
        run: |
          URL="https://dart.googlesource.com/sdk/+/$DART_HASH/DEPS?format=TEXT"

          echo "Fetching DEPS from $URL"

          # Googlesource returns base64 encoded text when format=TEXT is used
          if ! RESPONSE=$(curl -s -f "$URL"); then
            echo "::error::Failed to download DEPS file. Please verify the Dart hash: $DART_HASH"
            exit 1
          fi

          echo "$RESPONSE" | base64 --decode > dart_deps_file

          if [ ! -s dart_deps_file ]; then
            echo "::error::Downloaded DEPS file is empty or decoding failed."
            exit 1
          fi
        env:
          DART_HASH: ${{ inputs.dart_hash }}

      - name: Run Update Script
        id: run-script
        run: |
          DART_DEPS="dart_deps_file"
          FLUTTER_DEPS="DEPS" # Root of the repository
          SCRIPT="engine/src/tools/dart/create_updated_flutter_deps.py"

          if [ ! -f "$SCRIPT" ]; then
            echo "::error::Update script not found at $SCRIPT"
            exit 1
          fi

          echo "Running $SCRIPT..."

          # Execute the python script
          if ! python3 "$SCRIPT" -d "$DART_DEPS" -f "$FLUTTER_DEPS" -r "$DART_HASH"; then
            echo "::error::The python update script failed during execution."
            exit 1
          fi
        env:
          DART_HASH: ${{ inputs.dart_hash }}

      - name: Check for Changes
        id: git-check
        env:
          DART_HASH: ${{ inputs.dart_hash }}
        run: |
          # Check if the root DEPS file has changed
          if git diff --exit-code DEPS; then
            echo "changed=false" >> "$GITHUB_OUTPUT"
            echo "## ✅ Dart version already up to date" >> "$GITHUB_STEP_SUMMARY"
            echo "The DEPS file is already up to date with Dart hash \`$DART_HASH\`." >> "$GITHUB_STEP_SUMMARY"
          else
            echo "changed=true" >> "$GITHUB_OUTPUT"
          fi

      - name: Create PR if Changed
        if: steps.git-check.outputs.changed == 'true'
        run: |
          gh auth setup-git
          git add DEPS
          git commit -m "Update flutter DEPS to dart $DART_HASH"
          git push origin "$BRANCH_NAME" --force

          PR_URL=$(gh pr create \
            --title "[$REF_NAME] Update Flutter DEPS to Dart $DART_HASH" \
            --body "This PR updates the transitive dependencies in the engine \`DEPS\` file based on Dart SDK hash \`$DART_HASH\`." \
            --repo flutter/flutter \
            --base "$REF_NAME" \
            --head "flutteractionsbot:$BRANCH_NAME")

          # Nice big PR Success Summary
          {
            echo "## 🚀 PR Created Successfully"
            echo "Updated dart dependencies to \`$DART_HASH\`."
            echo ""
            echo "🔗 **View Pull Request:** $PR_URL"
          } >> "$GITHUB_STEP_SUMMARY"
        env:
          GH_TOKEN: ${{ secrets.FLUTTERACTIONSBOT_CP_TOKEN }}
          DART_HASH: ${{ inputs.dart_hash }}
          REF_NAME: ${{ github.ref_name }}