#!/bin/sh

getTimeStamp() {
  (date -u +"%Y-%m-%dT%H:%M:%SZ")
}

uppercase() {
  echo "$1" | tr '[:lower:] [:upper:]'
}

# $1: message, $2: level, $3: status, $4: operation, $5: code
writeJsonLog() {
  PROGRAM_NAME="cfddns"
  DEFAULT_CODE=99
  DEFAULT_LEVEL="info"
  DEFAULT_MESSAGE="An unspecified error has occurred"
  DEFAULT_OPERATION="unspecified"
  DEFAULT_STATUS="ERR"

  if [ -z "$1" ]; then
    PROPS="$(
      jq --null-input \
        --arg level "err" \
        --arg pName "$PROGRAM_NAME" \
        --arg operation "$DEFAULT_OPERATION" \
        --arg status "$DEFAULT_STATUS" \
        --arg code "$DEFAULT_CODE" \
        --arg message "$DEFAULT_MESSAGE" \
        '{"level":$level, "programName":$pName, "status":$status, "operation":$operation, "code":$code, "message":$message}' \
    )"
  else
    PROPS="$(
      jq --null-input \
        --arg level "${2:-$DEFAULT_LEVEL}" \
        --arg pName "$PROGRAM_NAME" \
        --arg status "$(uppercase "${3:-$DEFAULT_STATUS}")" \
        --arg operation "${4:-$DEFAULT_OPERATION}" \
        --arg code "${5:-$DEFAULT_CODE}" \
        --arg message "$1" \
        '{"level":$level, "programName":$pName, "status":$status, "operation":$operation, "code":$code, "message":$message}' \
    )"
  fi

  echo "$PROPS" | jq "."
  return
}

# $1: message, $2: level, $3: status,  $4: operation, $5: code
writeJournalLog() {
  PROGRAM_NAME="cfddns"
  DEFAULT_CODE=99
  DEFAULT_LEVEL="info"
  DEFAULT_MESSAGE="An unspecified error has occurred"
  DEFAULT_OPERATION="unspecified"
  DEFAULT_STATUS="ERR"

  # translate error levels
  if [ -z "$2" ]; then
    LOG_LEVEL=1
  else
    case "$2" in
    "emergency" | "emerg")
      LOG_LEVEL=7
      ;;
    "alert")
      LOG_LEVEL=6
      ;;
    "critical" | "crit")
      LOG_LEVEL=5
      ;;
    "error" | "err")
      LOG_LEVEL=4
      ;;
    "warning" | "warn")
      LOG_LEVEL=3
      ;;
    "notice")
      LOG_LEVEL=2
      ;;
    "info")
      LOG_LEVEL=1
      ;;
    "debug")
      LOG_LEVEL=0
      ;;
    esac
  fi

  # log the message
  if [ -z "$1" ]; then
    logger --journald <<end
MESSAGE_ID="$(systemd-id128 new)"
SYSLOG_TIMESTAMP="$(getTimeStamp)"
SYSLOG_FACILITY=3
SYSLOG_IDENTIFIER="${PROGRAM_NAME}"
PRIORITY=4
ERRNO="${DEFAULT_CODE}"
OPERATION="${DEFAULT_OPERATION}"
MESSAGE="${DEFAULT_MESSAGE}"
STATUS="${DEFAULT_STATUS}"
end
  else
    logger --journald <<end
MESSAGE_ID="$(systemd-id128 new)"
SYSLOG_TIMESTAMP="$(getTimeStamp)"
SYSLOG_FACILITY=3
SYSLOG_IDENTIFIER="${PROGRAM_NAME}"
PRIORITY="${LOG_LEVEL}"
ERRNO="${5:-$DEFAULT_CODE}"
OPERATION="${4:-$DEFAULT_OPERATION}"
MESSAGE="$1"
STATUS="${3:-$DEFAULT_STATUS}"
end
  fi

  return
}

if [ "$1" = "json" ]; then
  writeJsonLog # this will generate a generic error message
  writeJsonLog "This is a test message" # generate this message at the default level with the default code
  writeJsonLog "This is a test message" "warning" # generate this message at the 'warning' level with the default code
  writeJsonLog "This is a test message" "error" "testing" # generate this message at the 'error' level, part of a 'test' operation, and with the default code
  writeJsonLog "This is a test message" "alert" "testing" 10 # generate this message at the 'alert' level with all parameters set
elif [ "$1" = "journal" ]; then
  writeJournalLog # this will generate a generic error message
  writeJournalLog "This is a test message" # generate this message at the default level with the default code
  writeJournalLog "This is a test message" "warning" # generate this message at the 'warning' level with the default code
  writeJournalLog "This is a test message" "error" "testing" # generate this message at the 'error' level as part of a 'test' operation, and with the default code
  writeJournalLog "This is a test message" "alert" "testing" 10 # generate this message at the 'alert' level with all parameters set
else
  printf "\nPlease specify either 'json' or 'journal' after the script name. Exiting.\n\n"
  exit 1
fi

exit 0