#! /usr/bin/env bash

d2_args=( )
d2_input_file=

function print_help() {
  cat <<EOF
Usage:
  wd2 [FLAGS...] file.d2 [file.svg | file.png]

A wrapper over d2 which allows to use \`layout\`, \`theme\`, \`pad\`
attributes from d2 file. All arguments will be passed to the d2 cli,
but these additional configs overwrite cli arguments with the
same name.

See \`d2 --help\` or \`man d2\` for detailed docs.

See more docs and the source code at https://oss.terrastruct.com/d2
EOF
}


function parse_args() {
  if [ "$#" == "0" ]; then
    print_help
    exit 1
  fi

  while (( "$#" )); do
    case "$1" in
      --help)
        print_help
        exit 0
        ;;
      # extract input file arg
      *.d2)
        d2_input_file="$1"
        d2_args+=( "$1" )
        ;;
      # other args
      *)
        d2_args+=( "$1" )
        ;;
    esac

    shift
  done
}

function get_attr_value() {
  head -n3 "$d2_input_file" | grep "$1" | awk '{ print $3 }'
}

parse_args "$@"

if [ -z "$d2_input_file" ]; then
  print_help
  exit 1
fi

d2_layout=$(get_attr_value "layout")
d2_theme=$(get_attr_value "theme")
d2_pad=$(get_attr_value "pad")

d2 "${d2_args[@]}" \
  ${d2_layout:+--layout ${d2_layout}} \
  ${d2_theme:+--theme ${d2_theme}} \
  ${d2_pad:+--pad ${d2_pad}}