#!/bin/sh -eu

fetch_latest () {
  if [ -z ${MAFIA_TEST_MODE+x} ]; then
    TZ=$(date +"%T")
    curl --silent "https://raw.githubusercontent.com/ambiata/mafia/master/script/mafia?$TZ"
  else
    cat ../script/mafia
  fi
}

latest_version () {
  git ls-remote https://github.com/ambiata/mafia | grep refs/heads/master | cut -f 1
}

local_version () {
  awk '/^# Version: / { print $3; exit 0; }' $0
}

run_upgrade () {
  MAFIA_TEMP=$(mktemp 2>/dev/null || mktemp -t 'upgrade_mafia')

  clean_up () {
    rm -f "$MAFIA_TEMP"
  }

  trap clean_up EXIT

  MAFIA_CUR="$0"

  if [ -L "$MAFIA_CUR" ]; then
    echo 'Refusing to overwrite a symlink; run `upgrade` from the canonical path.' >&2
    exit 1
  fi

  echo "Checking for a new version of mafia ..."
  fetch_latest > $MAFIA_TEMP

  LATEST_VERSION=$(latest_version)
  echo "# Version: $LATEST_VERSION" >> $MAFIA_TEMP

  if ! cmp $MAFIA_CUR $MAFIA_TEMP >/dev/null 2>&1; then
    mv $MAFIA_TEMP $MAFIA_CUR
    chmod +x $MAFIA_CUR
    echo "New version found and upgraded. You can now commit it to your git repo."
  else
    echo "You have latest mafia."
  fi
}

exec_mafia () {
  MAFIA_VERSION=$(local_version)

  if [ "x$MAFIA_VERSION" = "x" ]; then
    # If we can't find the mafia version, then we need to upgrade the script.
    run_upgrade
  else
    MAFIA_BIN=$HOME/.ambiata/mafia/bin
    MAFIA_FILE=mafia-$MAFIA_VERSION
    MAFIA_PATH=$MAFIA_BIN/$MAFIA_FILE

    [ -f "$MAFIA_PATH" ] || {
      # Create a temporary directory which will be deleted when the script
      # terminates. Unfortunately `mktemp` doesn't behave the same on
      # Linux and OS/X so we need to try two different approaches.
      MAFIA_TEMP=$(mktemp -d 2>/dev/null || mktemp -d -t 'exec_mafia')

      # Create a temporary file in MAFIA_BIN so we can do an atomic copy/move dance.
      mkdir -p $MAFIA_BIN

      clean_up () {
        rm -rf "$MAFIA_TEMP"
      }

      trap clean_up EXIT

      echo "Building $MAFIA_FILE in $MAFIA_TEMP"

      ( cd "$MAFIA_TEMP"

        git clone https://github.com/ambiata/mafia
        cd mafia

        git reset --hard $MAFIA_VERSION

        bin/bootstrap ) || exit $?

      MAFIA_PATH_TEMP=$(mktemp --tmpdir=$MAFIA_BIN $MAFIA_FILE-XXXXXX 2>/dev/null || TMPDIR=$MAFIA_BIN mktemp -t $MAFIA_FILE)

      clean_up_temp () {
        clean_up
        rm -f "$MAFIA_PATH_TEMP"
      }
      trap clean_up_temp EXIT

      cp "$MAFIA_TEMP/mafia/.cabal-sandbox/bin/mafia" "$MAFIA_PATH_TEMP"
      chmod 755 "$MAFIA_PATH_TEMP"
      mv "$MAFIA_PATH_TEMP" "$MAFIA_PATH"

      clean_up_temp
    }

    exec $MAFIA_PATH "$@"
  fi
}

#
# The actual start of the script.....
#

if [ $# -gt 0 ]; then
  MODE="$1"
else
  MODE=""
fi

case "$MODE" in
upgrade) shift; run_upgrade "$@" ;;
*) exec_mafia "$@"
esac
# Version: dbbe635d8f98be1815130f04465c155f414985bf