#!/bin/sh

NPMRC_STORE="${HOME}/.npmrcs";
NPMRC="${HOME}/.npmrc";

printUsage() {
  echo ""
  echo "Usage: npmrc [-c] [name]"
}

activate() {
  if [ ! -e "${NPMRC_STORE}/${1}" ]; then
    echo "Couldn't find npmrc file '${1}', looked in ${NPMRC_STORE}/${1}";
    exit 1;
  fi;

  echo "Removing old .npmrc ($(readlink ${NPMRC}))";
  rm -f "${NPMRC}" || exit 1;

  echo "Activating .npmrc '${1}'";
  ln -s "${NPMRC_STORE}/${1}" "${NPMRC}" || exit 1;
}

if [ "${1}" = "--help" -o "${1}" = "-h" ]; then
  echo "npmrc"
  echo ""
  echo "  Switch between different .npmrc files with ease and grace."
  printUsage;
  echo ""
  echo "Example:"
  echo "  Creating and activating a new .npmrc called 'work':"
  echo "  > touch ~/.npmrcs/work"
  echo "  > npmrc work"
  exit 1
fi

# init ~/.npmrc & ~/npmrc/default
if [ ! -d "$NPMRC_STORE" ]; then
  echo "Initialising npmrc..."
  echo "Creating ${NPMRC_STORE}"
  mkdir ${NPMRC_STORE}

  # create default npmrc if it doesn't exist
  if [ ! -e "${NPMRC}" ]; then
    touch ${NPMRC_STORE}/default
  else
    # make existing config 'default'
    echo "Making ${NPMRC} the default npmrc file"
    mv ${NPMRC} ${NPMRC_STORE}/default
  fi;

  # use the config we just created
  $0 default
  exit $?
fi

if [ "x${1}" = "x" ]; then
  echo "Available npmrcs:";
  echo;
  find "${NPMRC_STORE}" -type f | while read FILE; do
    if [ "$(readlink ${NPMRC})" = "${FILE}" ]; then
      echo "* $(basename ${FILE})";
    else
      echo "  $(basename ${FILE})";
    fi;
  done;

  exit 0;
fi;

if [ "${1}" = "--create" -o "${1}" = "-c" ]; then
  if [ "x${2}" = "x" ]; then
    echo "What do you want to call your new npm configuration?"
    printUsage;
    exit 1;
  fi

  if [ -e "${NPMRC_STORE}/${2}" ]; then
    echo "npmrc file '${2}', already exists: ${NPMRC_STORE}/${2}";
    exit 1;
  fi;

  touch ${NPMRC_STORE}/${2}

  activate $2
  exit 0;
fi

if [ ! -e "${NPMRC_STORE}/${1}" ]; then
  FILES=$(find "${NPMRC_STORE}" -name "${1}*")

  # As $(echo "" | wc -l) will also return 1 we explicitly check if $FILES is empty
  if [ "x${FILES}" = "x" ]; then
    RESULTS=0
  else
    RESULTS=$(echo "$FILES" | wc -l)
  fi;

  if [ $RESULTS = 1 ]; then
    $0 $(basename $FILES)
    exit $?
  elif [ $RESULTS -gt 1 ]; then
    echo "'${1}' is ambiguous. Found multiple matching npmrcs:"
    echo;

    echo "$FILES" | while read FILE; do
      if [ "$(readlink ${NPMRC})" = "${FILE}" ]; then
        echo "* $(basename ${FILE})";
      else
        echo "  $(basename ${FILE})";
      fi;
    done;

    exit 1;
  fi

  echo "Couldn't find npmrc file '${1}', looked in ${NPMRC_STORE}/${1}";
  exit 1;
fi;

if [ -e "${NPMRC}" ]; then
  if [ ! -h "${NPMRC}" ]; then
    echo "Current .npmrc (${NPMRC}) is not a symlink. You may want to copy it into ${NPMRC_STORE}";
    exit 1;
  fi;

  if [ "$(readlink ${NPMRC})" = "${NPMRC_STORE}/${1}" ]; then
    echo "Current .npmrc (${NPMRC}) is already '${1}' (${NPMRC_STORE}/${1})";
    exit 1;
  fi;
fi;

activate $1