name: Calculate data hash
inputs:
- {name: Data}
- {name: Hash algorithm, type: String, default: SHA256, description: "Hash algorithm to use. Supported values are MD5, SHA1, SHA256, SHA512, SHA3"}
outputs:
- {name: Hash}
metadata:
  annotations:
    author: Alexey Volkov <alexey.volkov@ark-kun.com>
implementation:
  container:
    image: alpine
    command:
    - sh
    - -exc
    - |
      data_path="$0"
      hash_algorithm="$1"
      hash_path="$2"
      mkdir -p "$(dirname "$hash_path")"
      
      hash_algorithm=$(echo "$hash_algorithm" | tr '[:upper:]' '[:lower:]')
      case "$hash_algorithm" in
          md5|sha1|sha256|sha512|sha3)  hash_program="${hash_algorithm}sum";;
          *)  echo "Unsupported hash algorithm $hash_algorithm"; exit 1;;
      esac
      
      if [ -d "$data_path" ]; then
          # Calculating hash for directory
          cd "$data_path"
          find . -type f -print0 |
              sort -z |
              xargs -0 "$hash_program" |
              "$hash_program" |
              cut -d ' ' -f 1 > "$hash_path"         
      else
          # Calculating hash for file
          "$hash_program" "$data_path" |
              cut -d ' ' -f 1 > "$hash_path"
      fi
    - {inputPath: Data}
    - {inputValue: Hash algorithm}
    - {outputPath: Hash}