name: 'Enforce Flutter Version Constraint'
description: 'Scans all pubspec.yaml files to ensure they use the required Flutter SDK constraint.'
inputs:
  expected_version:
    description: 'The exact Flutter SDK constraint expected (e.g., ^3.19.0)'
    required: true
    default: '^3.19.0'

runs:
  using: 'composite'
  steps:
    - name: Scan pubspec files
      shell: bash
      run: |
        ERROR_COUNT=0
        EXPECTED="${{ inputs.expected_version }}"
        
        while IFS= read -r -d '' pubspec; do
          # Skip non-Flutter Dart packages
          if ! grep -q "sdk:[[:space:]]*flutter" "$pubspec" && ! grep -q "^flutter:" "$pubspec"; then
            echo "Skipping non-Flutter package: $pubspec"
            continue
          fi

          CONSTRAINT=$(awk '/^environment:/{flag=1; next} /^[^ ]/{flag=0} flag && /^  flutter:/ {print $2}' "$pubspec" | tr -d "'" | tr -d '"')
          
          if [ "$CONSTRAINT" != "$EXPECTED" ]; then
            echo "::error file=$pubspec::Invalid Flutter constraint in $pubspec. Expected '$EXPECTED', found '$CONSTRAINT'."
            ERROR_COUNT=$((ERROR_COUNT+1))
          fi
        done < <(find . -name "pubspec.yaml" -print0)

        if [ $ERROR_COUNT -gt 0 ]; then
          echo "Workflow failed: Found $ERROR_COUNT pubspec(s) with unauthorized Flutter SDK constraints."
          exit 1
        fi