#!/usr/bin/env bash

# Author        : Allan Christensen
# First Created : 11012021 (DD-MM-YYYY)
# Description   : Installs Zabbix on Ubuntu 24.04
# License       : MIT License (see LICENSE file for details)

#
# Are we root
#
if [[ $(id -u) -ne 0 ]]; then echo "" && echo "Must be root or use sudo" && echo "" ; exit 1 ; fi

#
# Define variables and functions
#
phpver=$(php -r 'echo PHP_MAJOR_VERSION.".".PHP_MINOR_VERSION;' 2>/dev/null || echo "8.3") ; phpfpm="php$phpver-fpm"
ubuntuversion="24.04"
fallbackversion="7.0"

#
# Function usage
#
usage () {
    printf -- "\nzabbixinstall (Ubuntu 24.04 + Zabbix 7.0 LTS)\n\n"
    printf -- "%s\n\n" "$socket"
    printf -- "Usage:\n"
    printf -- "sudo ./zabbixinstall -n <domain> -p <zabbix db password> [options]\n\n"
    printf -- "Options:\n"
    printf -- "  -a <mariadb admin user>     Optional admin username $socketusage\n"
    printf -- "  -m <mariadb admin password> Optional admin password $socketusage\n"
    printf -- "  -h | -help | --help         Show this help screen\n\n"
    printf -- "Examples:\n"
    printf -- "  sudo ./zabbixinstall -n zabbix.something.xyz -p zabbixdbpwd\n"
    printf -- "  sudo ./zabbixinstall -n zabbix.something.xyz -p zabbixdbpwd -a admin -m adminpwd\n\n"
}

#
# Function to check if a service is already running or not
#
serviceno () { printf "\n%s" "$service" ; printf " is not running cannot continue...\n\n"; }
servicedead () { status=$(systemctl is-active "$service"); if [[ "$status" != "active" ]]; then serviceno ; exit 1 ; fi; }

#
# Function inputcheck
#
inputcheck () {
    [[ -z "$hostname" ]] && { usage; echo ""; echo "Error! Hostname empty."; echo ""; exit 1; }
    [[ -z "$dbpass"   ]] && { usage; echo ""; echo "Error! Database password empty."; echo ""; exit 1; }
}

#
# If Nginx and MariaDB is not running then die
#
service="mariadb" ; servicedead ; service="nginx" ; servicedead

#
# Check MariaDB authentication method (socket or not)
#
if mysql -u root -e ";" 2>/dev/null; then
    socket="SOCKET DETECTED — no need for -a or -m"
    socketusage="SOCKET DETECTED — this flag is not needed"
    socketauth="yes"
else
    socket="NO SOCKET DETECTED — you must use -a and -m"
    socketusage="NO SOCKET DETECTED — these flags are required"
    socketauth="no"
fi

#
# Let's go
#
clear

#
# Try to determine the latest Zabbix version
#
zabbix_version=$(curl -s https://repo.zabbix.com/zabbix/ | grep -oP '(?<=href=")[0-9]+\.[0]' | sort -V | tail -1)

# Use fallback version if fetch failed
if [[ -z "$zabbix_version" ]]; then printf "Could not determine latest Zabbix version. Falling back to version %s\n\n" "$fallbackversion" ; zabbix_version="$fallbackversion" ; fi

printf "Using Zabbix version: %s\n\n" "$zabbix_version"

#
# Configure command line options
#
if [[ "$1" == "-help" || "$1" == "--help" ]]; then usage ; exit 0 ; fi
if [[ $# -eq 0 || ! $1 =~ ^- ]]; then usage ; exit 1 ; fi

while getopts ":n:p:m:a:h" option; do
    case "$option" in
        n) hostname=$(echo "$OPTARG" | tr '[:upper:]' '[:lower:]');;
        p) dbpass="$OPTARG";;
        m) mariadbpwd="$OPTARG";;
        a) mariadbadmin="$OPTARG";;
        h) usage; exit 0;;
        :) usage; echo ""; echo "Error! Option -$OPTARG requires an argument."; echo ""; exit 1;;
        \?) usage; echo ""; echo "Error! Invalid option: -$OPTARG"; echo ""; exit 1;;
    esac
done
inputcheck "$hostname" "$dbpass"

#
# Download and install the Zabbix repository
#
tmpfile="/tmp/zabbix-release_latest_${zabbix_version}+ubuntu${ubuntuversion}_all.deb"
download="https://repo.zabbix.com/zabbix/${zabbix_version}/ubuntu/pool/main/z/zabbix-release/zabbix-release_latest_${zabbix_version}+ubuntu${ubuntuversion}_all.deb"

wget --no-verbose -O "$tmpfile" "$download"
dpkg -i "$tmpfile"
apt update

#
# Install Zabbix components
#
apt install -y zabbix-server-mysql zabbix-frontend-php zabbix-nginx-conf zabbix-sql-scripts zabbix-agent fping

#
# Clone nginx-snippets; if nginx-snippets exists then just pull latest changes
#
nginxsnippets="/etc/nginx/nginx-snippets"
repo="https://git.x-files.dk/webserver/nginx-snippets.git"
if [[ -d "$nginxsnippets/.git" ]]; then git -C "$nginxsnippets" pull --quiet; else git clone --quiet "$repo" "$nginxsnippets"; fi

#
# Determine MariaDB login method
#
mariadbadmin="${mariadbadmin:-root}"

printf "\nChecking MariaDB access method...\n"

if [[ "$socketauth" == "yes" ]]; then
    dbmethod="socket"
    printf "Socket authentication detected (root)\n"
elif [[ -n "$mariadbpwd" && -n "$mariadbadmin" ]]; then
    dbmethod="admin"
    printf "Using admin user authentication (%s)\n" "$mariadbadmin"
else
    printf "\nERROR: No valid MariaDB authentication method found.\n"
    printf "Tried socket, admin user, and root password.\n\n"
    exit 1
fi

#
# Create Zabbix database
#
case "$dbmethod" in
    socket)
        mysql -u root <<EOF
CREATE DATABASE IF NOT EXISTS zabbix CHARACTER SET utf8mb4 COLLATE utf8mb4_bin;
CREATE USER IF NOT EXISTS 'zabbix'@'localhost' IDENTIFIED BY '${dbpass//\'/\'\\\'\'}';
GRANT ALL PRIVILEGES ON zabbix.* TO 'zabbix'@'localhost';
SET GLOBAL log_bin_trust_function_creators = 1;
FLUSH PRIVILEGES;
EOF
        ;;
    admin)
        mysql -u "${mariadbadmin}" -p"${mariadbpwd}" <<EOF
CREATE DATABASE IF NOT EXISTS zabbix CHARACTER SET utf8mb4 COLLATE utf8mb4_bin;
CREATE USER IF NOT EXISTS 'zabbix'@'localhost' IDENTIFIED BY '${dbpass//\'/\'\\\'\'}';
GRANT ALL PRIVILEGES ON zabbix.* TO 'zabbix'@'localhost';
SET GLOBAL log_bin_trust_function_creators = 1;
FLUSH PRIVILEGES;
EOF
        ;;
esac

#
# Import Zabbix database schema
#
schema="/usr/share/zabbix-sql-scripts/mysql/server.sql.gz"
if [[ -f "$schema" ]]; then
    zcat "$schema" | mysql --default-character-set=utf8mb4 -uzabbix -p"$dbpass" zabbix
else
    echo "" ; echo "Error! Could not find Zabbix schema file at $schema" ; echo ""
    exit 1
fi

#
# Disable trust
#
case "$dbmethod" in
    socket)
        mysql -u root <<EOF
SET GLOBAL log_bin_trust_function_creators = 0;
FLUSH PRIVILEGES;
EOF
        ;;
    admin)
        mysql -u "${mariadbadmin}" -p"${mariadbpwd}" <<EOF
SET GLOBAL log_bin_trust_function_creators = 0;
FLUSH PRIVILEGES;
EOF
        ;;
esac

#
# Configure Nginx and Zabbix
#
cp "$nginxsnippets/hostfiles/zabbix.80.conf" /etc/nginx/conf.d/"$hostname".conf
sed -i "s/^# DBPassword=.*/DBPassword=$dbpass/" /etc/zabbix/zabbix_server.conf
sed -i "s/DOMAIN/$hostname/" /etc/nginx/conf.d/"$hostname".conf
rm -f /etc/nginx/conf.d/zabbix.conf

#
# Enable and start Zabbix
#
systemctl enable zabbix-server zabbix-agent
systemctl restart zabbix-server zabbix-agent
systemctl restart "$phpfpm" && systemctl restart nginx

#
# Zabbix postinstall notice
#
zabbixnotice=$(cat <<EOF
---------------------------------------------------------------------------------------------------
IMPORTANT: Go to http://$hostname and modify the following settings:

DATABASE SETTINGS ---------------------------------------------------------------------------------
DATABASE PASSWORD                          = $dbpass

SETTINGS ------------------------------------------------------------------------------------------
ZABBIX SERVER NAME                         = Your Sitename

LOGIN ---------------------------------------------------------------------------------------------
DEFAULT USER                               = Admin
DEFAULT PASSWORD                           = zabbix
---------------------------------------------------------------------------------------------------
EOF
)

#
# Display post install note
#
printf '%s\n' "$zabbixnotice"

#
# Cleaning up
#
rm -f "$tmpfile"

#
# All done
#
printf "\nAll Done...\n\n"

#
# End of script