#!/bin/bash

start_usage() {
  if [ -n "$1" ]
  then
    echo "Error:" "$@" >&2
  fi

  echo "usage: $0 start -n name -i instance" >&2
  exit 1
}

stop_usage() {
  if [ -n "$1" ]
  then
    echo "Error:" "$@" >&2
  fi

  echo "usage: $0 stop -n name -i instance" >&2
  exit 1
}

# TODO: set ulimit
# TODO: set umask
# TODO: change group newgrp/sg
method_start() {
  run_control start_usage "start" "$@"
}

method_stop() {
  run_control stop_usage "stop" "$@"
}

run_control() {
  local usage=$0; shift
  local method=$1; shift
  local name
  local instance

  while getopts "n:i:" opt
  do
    case $opt in
      n)
        name=$OPTARG
        ;;
      i)
        instance=$OPTARG
        ;;
      \?)
        $usage "Invalid option: -$OPTARG" 
        ;;
    esac
  done

  assert_is_instance $usage "$name" "$instance"

  (
    cd $name/$instance/current

    bin=`get_conf $BASEDIR $name $instance app.method`

    if [ -z "$bin" ]
    then
      bin=$BASEDIR/.app/lib/pid-method
    fi

    if [ ! -x "$bin" ]
    then
      echo "Invalid executable: $bin" >&2
      exit 1
    fi

    e="`get_conf_in_group $BASEDIR $name $instance env`"

    # Set a default PATH which can be overridden by the application's settings
    set +e
    env -i \
      PATH=/bin:/usr/bin \
      $e \
      APPSH_METHOD=$method \
      APPSH_BASEDIR=$BASEDIR \
      APPSH_NAME=$name \
      APPSH_INSTANCE=$instance \
      $bin
    local ret=$?
    set +x
    set -e

    case $ret in
      0)
        echo "Application ${method}ed"
        ;;
      *)
        echo "Error starting $name/$instance"
        ;;
    esac
  )
}

method_operate_usage() {
  if [ -n "$1" ]
  then
    echo "Error:" $@ >&2
  fi

  echo "usage: $0 operate <method>" >&2
  echo "" >&2
  echo "Available methods:" >&2
  echo "  start" >&2
  echo "  stop" >&2
  echo "  restart" >&2
  echo "  status" >&2
}

method_operate() {
  if [ $# -gt 0 ]
  then
    method=$1
    shift
  fi

  case "$method" in
    start)   method_start $first "$@" ;;
    stop)    method_stop $first "$@" ;;
    status)  method_status $first "$@" ;;
    restart) method_restart $first "$@" ;;
    *)       method_operate_usage ;;
  esac
  exit $?
}