#!/bin/bash

die() {
    ERROR_MESSAGE="Sometning went wrong..."
    if [[ -n "$1" ]]; then
        ERROR_MESSAGE="Error on: $1"
    fi
    logger -t mysqlbackup -s "$ERROR_MESSAGE"
    exit 1
}

########################################

if [[ ${UID} != 0 ]]; then
    die "Not root!"
fi

if [[ -n "$1" ]]; then
    FILE_DIR="$1"
else
    die "Unknown dir!"
fi

FILE_COUNTS=0
if [[ -n "$2" ]]; then
    FILE_COUNTS=$(expr 1 + $2)
fi

########################################

HOST_NAME="$(hostname)"
if [[ -z "${HOST_NAME}" ]]; then
    HOST_NAME="unknown"
fi

########################################

CONFIG="$(mktemp)"
echo "[mysqldump]" > "${CONFIG}"

cat /etc/mysql/debian.cnf | grep "host" | head -n1 >> "${CONFIG}" || die "host"
cat /etc/mysql/debian.cnf | grep "user" | head -n1 >> "${CONFIG}" || die "user"
cat /etc/mysql/debian.cnf | grep "password" | head -n1 >> "${CONFIG}" || die "password"
cat /etc/mysql/debian.cnf | grep "socket" | head -n1 >> "${CONFIG}" || die "socket"

mkdir -p "${FILE_DIR}"
CURDATE=$(date '+%Y%m%d_%H%M%S')

mysqldump --defaults-file="${CONFIG}" --all-databases | gzip -7 --rsyncable > "${FILE_DIR}/${HOST_NAME}-mysql-${CURDATE}.sql.gz"
rm "${CONFIG}"

########################################

if [[ ${FILE_COUNTS} > 0 ]]; then
    OLD_PWD=${PWD}
    cd ${FILE_DIR}
    ls -1 ${HOST_NAME}-mysql-* | tail -n +${FILE_COUNTS} | xargs rm -f 2>&1
    cd ${OLD_PWD}
fi