#! /usr/bin/env bash

generate_from_stdin() {
  outfile=$1
  language=$2

  echo "Generating '$language' ..."

  pandoc --metadata-file=epub-metadata.yaml --metadata=lang:$2 --from=markdown -o $1 <&0

  echo "Done! You can find the '$language' book at ./$outfile"
}

generate_with_solutions () {
  tmpfile=$(mktemp /tmp/sytem-design-primer-epub-generator.XXX)

  cat ./README.md >> $tmpfile

  for dir in ./solutions/system_design/*; do 
    case $dir in *template*) continue;; esac
    case $dir in *__init__.py*) continue;; esac
    : [[ -d "$dir" ]] && ( cd "$dir" && cat ./README.md >> $tmpfile && echo "" >> $tmpfile )
  done

  cat $tmpfile | generate_from_stdin 'README.epub' 'en'

  rm "$tmpfile"
}

generate () {
  name=$1
  language=$2

  cat $name.md | generate_from_stdin $name.epub $language
}


# Check if depencies exist
check_dependencies () {
  ITER=-1
  for dependency in "${dependencies[@]}"
  do
    ITER=$(expr $ITER + 1)
    if ! [ -x "$(command -v $dependency)" ]; then
      echo "Error: $dependency is not installed." >&2
      exit 1
    else
      requiredver="${dependencies_minimun_version[ITER]}"
      currentver=$($dependency --version | head -1 | cut -d " " -f 2)
      if [ "$(printf '%s\n' "$requiredver" "$currentver" | sort -V | head -n1)" != "$requiredver" ]; then
      echo "$dependency verion must be >= ${requiredver}"
      exit 1
      fi
    fi
  done
}

dependencies=("pandoc")
dependencies_minimun_version=("2.3")

check_dependencies
generate_with_solutions
generate README-ja ja
generate README-zh-Hans zh-Hans
generate README-zh-TW zh-TW