lj

#!/usr/bin/env zsh

# Create a mapping of log levels to their names
typeset -A _log_levels
_log_levels=(
  'emergency' 0
  'alert'     1
  'critical'  2
  'error'     3
  'warning'   4
  'notice'    5
  'info'      6
  'debug'     7
)

###
# Output usage information and exit
###
function _lumberjack_usage() {
  echo "\033[0;33mUsage:\033[0;m"
  echo "  lj [options] [<level>] <message>"
  echo
  echo "\033[0;33mOptions:\033[0;m"
  echo "  -h, --help      Output help text and exit"
  echo "  -v, --version   Output version information and exit"
  echo "  -f, --file      Set the logfile and exit"
  echo "  -l, --level     Set the log level and exit"
  echo
  echo "\033[0;33mLevels:\033[0;m"
  echo "  emergency"
  echo "  alert"
  echo "  critical"
  echo "  error"
  echo "  warning"
  echo "  notice"
  echo "  info"
  echo "  debug"
}

###
# Output the message to the logfile
###
function _lumberjack_message() {
  local level="$1" file="$2" logtype="$3" msg="${(@)@:4}"

  # If the file string is empty, output an error message
  if [[ -z $file ]]; then
    echo "\033[0;31mNo logfile has been set for this process. Use \`lumberjack --file /path/to/file\` to set it\033[0;m"
    exit 1
  fi

  # If the level is not set, assume 5 (notice)
  if [[ -z $level ]]; then
    level=5
  fi

  case $logtype in
    # If a valid logtype is passed
    emergency|alert|critical|error|warning|notice|info|debug )
      # We do nothing here
      ;;
    # In all other cases
    * )
      # Second argument was not a log level, so manually set it to notice
      # and include the first parameter in the message
      logtype='notice'
      msg="${(@)@:3}"
      ;;
  esac

  if [[ $_log_levels[$logtype] > $level ]]; then
    # The message being recorded is for a higher log level than the one
    # currently being recorded, so gracefully exit
    exit 0
  fi

  # Output the message to the logfile
  echo "[$(echo $logtype | tr '[a-z]' '[A-Z]')] [$(date '+%Y-%m-%d %H:%M:%S')] $msg" >> $file
}

###
# The main lumberjack process
###
function _lumberjack() {
  local help version logfile loglevel dir statefile state

  # Create the state directory if it doesn't exist
  dir="${ZDOTDIR:-$HOME}/.lumberjack"
  if [[ ! -d $dir ]]; then
    mkdir -p $dir
  fi

  # If a statefile already exists, load the level and file
  statefile="$dir/$PPID"
  if [[ -f $statefile ]]; then
    state=$(cat $statefile)
    level="$state[1]"
    file="${(@)state:2}"
  fi

  # Parse CLI options
  zparseopts -D h=help -help=help \
                v=version -version=version \
                f:=logfile -file:=logfile \
                l:=loglevel -level:=loglevel

  # If the help option is passed, output usage information and exit
  if [[ -n $help ]]; then
    _lumberjack_usage
    exit 0
  fi

  # If the version option is passed, output the version and exit
  if [[ -n $version ]]; then
    echo "0.1.1"
    exit 0
  fi

  # If the logfile option is passed, set the current logfile
  # for the parent process ID
  if [[ -n $logfile ]]; then
    shift logfile
    file=$logfile

    # Create the log file if it doesn't exist
    if [[ ! -f $file ]]; then
      touch $file
    fi
  fi

  # If the loglevel option is passed, set the current loglevel
  # for the parent process ID
  if [[ -n $loglevel ]]; then
    shift loglevel
    level=$_log_levels[$loglevel]
  fi

  if [[ -z $level ]]; then
    level=5
  fi

  # Check if we're setting options rather than logging
  if [[ -n $logfile || -n $loglevel ]]; then
    # Store the state
    echo "$level $file" >! $statefile

    # Exit gracefully
    exit 0
  fi

  # Log the message
  _lumberjack_message "$level" "$file" "$@"
}

_lumberjack "$@"