#!/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

#
# Get php-fpm version
#
phpfpm=$(systemctl list-unit-files --type=service | awk '/php[0-9]+\.[0-9]+-fpm\.service/ {sub(".service","",$1); print $1; exit}')
if [[ -z "$phpfpm" ]]; then printf "\nUnable to detect php-fpm version. Is PHP-FPM installed?\n\n" ; exit 1 ; fi

#
# Check if required services are running or not
#
for svc in nginx mariadb "$phpfpm"; do systemctl is-active --quiet "$svc" || { printf "\n%s is not running, cannot continue...\n\n" "${svc^}" ; exit 1 ; }; done

#
# 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

#
# Define variables and functions
#
ubuntuversion="24.04"
fallbackversion="7.0"

#
# Function usage
#
usage() {
    printf -- "\nzabbixinstall (Ubuntu 24.04 + Zabbix 7.0 LTS)\n\n"

    if [[ "$socketauth" == "yes" ]]; then
        printf -- "SOCKET DETECTED — no need for -a or -m\n\n"
        printf -- "Installs Zabbix Server using MariaDB socket authentication.\n\n"
        printf -- "Usage:\n"
        printf -- "  sudo ./zabbixinstall -n <domain> -p <zabbix db password>\n\n"
        printf -- "Example:\n"
        printf -- "  sudo ./zabbixinstall -n zabbix.something.xyz -p zabbixdbpwd\n\n"
    else
        printf -- "NO SOCKET DETECTED — you must use -a and -m\n\n"
        printf -- "Installs Zabbix Server using MariaDB admin credentials.\n\n"
        printf -- "Usage:\n"
        printf -- "  sudo ./zabbixinstall -n <domain> -p <zabbix db password> -m <adminpwd> [-a <adminuser>]\n\n"
        printf -- "Examples:\n"
        printf -- "  sudo ./zabbixinstall -n zabbix.something.xyz -p zabbixdbpwd -m rootpwd\n"
        printf -- "  sudo ./zabbixinstall -n zabbix.something.xyz -p zabbixdbpwd -a admin -m adminpwd\n\n"
    fi

    printf -- "Options:\n"
    printf -- "  -h | -help | --help   Show this help screen\n\n"
}

#
# Let's go
#
clear

#
# 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

#
# Parse and validate input
#
if [[ -z "$hostname" || -z "$dbpass" ]]; then
    usage
    printf "\nERROR: Both -n (domain) and -p (database password) are required.\n\n"
    exit 1
fi

# Convert to lowercase (domains are case-insensitive)
hostname=$(echo "$hostname" | tr '[:upper:]' '[:lower:]')

# Disallow leading hyphen
if [[ "$hostname" =~ ^- ]]; then
    printf "\nERROR: Domain cannot start with a hyphen.\n"
    printf "Example of valid input: zabbix.example.com\n\n"
    exit 1
fi

# Disallow spaces, slashes, underscores
if [[ "$hostname" =~ [[:space:]/_] ]]; then
    printf "\nERROR: Domain cannot contain spaces, slashes, or underscores.\n\n"
    exit 1
fi

# Validate domain format (RFC 1123)
if [[ ! "$hostname" =~ ^([a-z0-9]+(-[a-z0-9]+)*\.)+[a-z]{2,}$ ]]; then
    printf "\nERROR: Invalid domain format.\n"
    printf "Example of valid input: zabbix.example.com\n\n"
    exit 1
fi

# Check for spaces in DB credentials
if [[ "$dbpass" =~ [[:space:]] ]]; then
    printf "\nERROR: Database password cannot contain spaces.\n\n"
    exit 1
fi

#
# 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"

#
# Ensure curl and wget are installed
#
for tool in curl wget; do dpkg -s "$tool" &>/dev/null || apt install -y -qq "$tool" ; done

#
# 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/g" /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
#