#!/usr/bin/env bash

#TODO Probably awk or perl can be used in a lot of places
set -euo pipefail
IFS=$'\n\t'


jdeps="jdeps"

if ! hash ${jdeps} 2>/dev/null; then
  echo "No jdeps found - is it installed and on your PATH?"; exit 1
fi

fastutil_regex='it\.unimi\.dsi\.fastutil\..*'

function check_exec()  {
  for exec in $@; do
    if ! hash "$exec"; then
      echo "$exec not found"; exit 1
    fi
  done
}

function print_synopsis() {
  >&2
  #    |                                                                               |
  echo "Synopsis: \"$(basename $0) <command> <args>\", where command is"
  echo "  - \"find\" (searches for usages of fastutil in your project) or"
  echo "  - \"minimize\" (creates a jar containing transitive dependencies of fastutil)"
  echo ""
  echo "Arguments:"
  echo " find:"
  echo "   <paths to analyse> - Analyses the given path (jar or directory) for usages"
  echo "       of fastutil classes"
  echo "   --cp <path> - Adds the given path (jar or directory) to the searched class-"
  echo "       path. This is useful if you have a big library making use of a lot of"
  echo "       fastutil, but you only use a small subset of that library. Make sure"
  echo "       not to include fastutil itself here!"
  echo "   --src - Output paths to the .java files"
  echo "   --cls - Output paths to the .class files"
  echo " minimize: <path to complete fastutil.jar> <path to class list>"
}

function print_usage() {
  >&2
  #    |                                                                               |
  echo "Usage: Typically, you want to first create the list of fastutil dependencies by"
  echo "running this script with \"find\" on your project classes and write this"
  echo "dependency list into a file:"
  echo ""
  echo "  $(basename $0) find path-to-project > dependencies.txt"
  echo ""
  echo "Then call \"minimize\" onto the matching fastutil jar to create a compact"
  echo "version, containing only the necessary classes:"
  echo ""
  echo "  $(basename $0) minimize fastutil.jar dependencies.txt"
  echo ""
  echo "Note that the fastutil.jar used here is the global jar containing all"
  echo "classes generated by \"ant jar\"."
  echo ""
  echo "A more advanced usage would be to build a minimized jar based on manually"
  echo "written \"dependencies.txt\" which can be directly passed to \"minimize\"."
}

function invalid_argument() {
  print_synopsis
  exit 1
}

[ ${#} -ge 1 ] || invalid_argument
command="$1"

case "$command" in
  "find")
  shift

  output_mode="class"
  declare -a class_paths=()
  declare -a analyse_paths=()

  while [ ${#} -gt 0 ]; do
    case "$1" in
      "--classpath"|"--cp")
        [ ${#} -ge 1 ] || invalid_argument
        class_paths+=("$2")
        shift
      ;;
      "--source"|"--src")
         output_mode="source"
      ;;
      "--class"|"--cls")
         output_mode="class"
      ;;
      *)
        analyse_paths+=("$1")
    esac
    shift
  done

  [ ${#analyse_paths[@]} -ge 1 ] || invalid_argument

  for path in "${class_paths[@]+"${class_paths[@]}"}" "${analyse_paths[@]}"; do
    if [ ! -e "$path" ]; then
      >&2 echo "Path \"$path\" does not exist"; exit 1
    fi
    case "$path" in
      *"fastutil"*)
        >&2 echo "Path $path looks like a fastutil jar - you probably don't want to include this" ;;
    esac
  done

  if [ $(find "${analyse_paths[@]}" -name "*.class" | wc -l) -eq 0 ]; then
    echo "No *.class files found in any of the specified paths"; exit 1
  fi

  if [ ${#class_paths[@]} -gt 0 ]; then
    function join_by { local IFS="$1"; shift; echo "$*"; }
    declare -a classpath_argument=("-cp" $(join_by ':' "${class_paths[@]}"))
  fi

  if ! dependencies=$(jdeps -recursive -verbose:class \
    "${classpath_argument[@]+"${classpath_argument[@]}"}" "${analyse_paths[@]}" |\
    awk '/it\.unimi\.dsi\.fastutil\..*not found$/ { print $2 }' | sort | uniq) \
    || [ -z "$dependencies" ]
  then
    >&2 echo "No unresolved references found - is fastutil on the classpath?"
    exit 1
  fi

  if [ "$output_mode" == "class" ]; then
    echo "$dependencies" | sed 's!\.!/!g' | sed 's!^\(.*\)$!\1.class!'
  else
    echo "$dependencies" | grep -v '\$' | sed 's!\.!/!g' | sed 's!^\(.*\)$!\1.java!'
  fi
  exit 0
  ;;

  "minimize")
  shift
  check_exec "zip" "unzip"

  [ ${#} -ge 2 ] || invalid_argument

  jar_path="$(realpath $1)"
  if [ ! -f "$jar_path" ]; then
    >&2 echo "No file at \"$jar_path\""
    exit 1
  fi

  class_list_path="$(realpath $2)"
  if [ ! -f "$class_list_path" ]; then
    >&2 echo "No file at \"$class_list_path\""
    exit 1
  fi

  dest_path="${jar_path%\.jar}-min.jar"
  if [ -e "$dest_path" ]; then
    >&2 echo "Destination path $dest_path exists"
    exit 1
  fi

  jar_name="$(basename ${dest_path})"

  tmp_dir=$(mktemp -d -t "fastutil-min.XXXX")
  trap "{ rm -rf \"${tmp_dir}\"; exit 255; }" EXIT

  ( >&2 echo "Resolving transitive dependencies" )

  class_paths=$(cat "$class_list_path" | grep '.class$')
  if [ -z "$class_paths" ]; then
    >&2 echo "No classes found in $class_list_path - make sure they are proper paths to .class files"
    exit 1
  fi

  class_list=${class_paths//.class/}
  class_list=${class_list//\//.}

  if ! transitive_dependencies=$(cd ${tmp_dir} && jdeps -recursive -regex "$fastutil_regex" \
    -verbose:class -cp "$jar_path" ${class_list} | awk '/      -> / { gsub(/\./, "/", $2) ".class"; print $2 ".class" }')\
    || [ -z "$transitive_dependencies" ]
  then
    >&2 echo "Could not resolve dependencies with $jar_path - probably not a complete fastutil jar."
    exit 1
  fi

  dependencies=( ${class_paths[@]} ${transitive_dependencies[@]} )
  ( >&2 echo "Unpacking jar from $jar_path" )
  if ! output=$(unzip -q "$jar_path" "META-INF/*" $(printf '%s\n' "${dependencies[@]}" | sort | uniq) -d "$tmp_dir" 2>&1); then
    >&2 echo "Error: $output"; exit 1
  fi

  ( >&2 echo "Creating minimized jar at $dest_path" )
  if ! output=$(cd "$tmp_dir" && zip -9 -q -r "$dest_path" "it" "META-INF" 2>&1); then
    >&2 echo "Error: $output"; exit 1
  fi
  ;;
  "-h"|"--help")
  print_synopsis
  >&2 echo ""
  print_usage
  ;;
  *)
  invalid_argument
  ;;
esac