#!/bin/bash
set -e
# Detect Operation System
if command -v apt >/dev/null 2>&1; then
    echo "Detected apt-based system"
    sudo apt update
    sudo apt install -y wget curl tar 
elif command -v dnf >/dev/null 2>&1; then
    echo "Detected dnf-based system"
    sudo dnf install -y wget curl tar 
else
    echo "Unsupported package manager"
    exit 1
fi

# Download Blackbox Exporter
VERSION="0.28.0"
ARCH="amd64"
CN_URL="https://s3.cloudyun.top/downloads/blackbox_exporter-${VERSION}.linux-${ARCH}.tar.gz"
GLOBAL_URL="https://github.com/prometheus/blackbox_exporter/releases/download/v${VERSION}/blackbox_exporter-${VERSION}.linux-${ARCH}.tar.gz"
TARGET="/tmp/blackbox_exporter.tar.gz"
is_cn=false

echo "Detecting geographic location..."
COUNTRY=$(curl -s --max-time 3 https://ipinfo.littlediary.cn/country || true)
if [ "$COUNTRY" = "CN" ]; then
    is_cn=true
fi

if [ "$is_cn" = true ]; then
    echo "Geolocation: China mainland detected"
    DOWNLOAD_URL="$CN_URL"
else
    echo "Geolocation: non-China region detected"
    DOWNLOAD_URL="$GLOBAL_URL"
fi

echo "Downloading from: $DOWNLOAD_URL"
curl -fL -o "$TARGET" "$DOWNLOAD_URL"

# Extract
echo "Extracting Blackbox Exporter..."
tar -zxvf "$TARGET" -C /tmp
sudo mkdir -p /blackbox_exporter
sudo cp "/tmp/blackbox_exporter-${VERSION}.linux-${ARCH}/blackbox_exporter" /blackbox_exporter/
sudo cp "/tmp/blackbox_exporter-${VERSION}.linux-${ARCH}/blackbox.yml" /blackbox_exporter/

# choosing port
DEFAULT_PORT=9115
if [ -t 0 ]; then
    while true; do
        read -rp "Please enter blackbox_exporter listen port [default: ${DEFAULT_PORT}]: " PORT
        PORT=${PORT:-$DEFAULT_PORT}
        if [[ "$PORT" =~ ^[0-9]+$ ]] && [ "$PORT" -ge 1 ] && [ "$PORT" -le 65535 ]; then
            break
        else
            echo "Invalid port. Please enter a number between 1 and 65535."
        fi
    done
else
    PORT=$DEFAULT_PORT
    echo "No TTY detected, using default port: $PORT"
fi

# Create system user if not exists
if ! id -u blackbox_exporter >/dev/null 2>&1; then
    echo "Creating blackbox_exporter system user..."
    sudo useradd --no-create-home --shell /bin/false blackbox_exporter
fi

# Set permissions and capabilities
echo "Setting permissions and capabilities..."
sudo chown -R blackbox_exporter:blackbox_exporter /blackbox_exporter
# Grant raw socket capability for ICMP probing
if command -v setcap >/dev/null 2>&1; then
    sudo setcap 'cap_net_raw+ep' /blackbox_exporter/blackbox_exporter
else
    echo "Warning: setcap not found. ICMP probing might require root."
fi



# Create systemd service file
SERVICE_FILE="/etc/systemd/system/blackbox_exporter.service"
echo "Creating systemd service file..."
sudo tee "$SERVICE_FILE" > /dev/null <<EOF
[Unit]
Description=Blackbox Exporter
Wants=network-online.target
After=network-online.target

[Service]
User=blackbox_exporter
Group=blackbox_exporter
WorkingDirectory=/blackbox_exporter
ExecStart=/blackbox_exporter/blackbox_exporter --config.file=/blackbox_exporter/blackbox.yml --web.listen-address=":${PORT}"
Restart=always
NoNewPrivileges=true
PrivateTmp=true
ProtectSystem=full
ProtectHome=true

[Install]
WantedBy=multi-user.target
EOF

# Reload systemd, enable and start service
echo "Enabling and starting blackbox_exporter service..."
sudo systemctl daemon-reload
sudo systemctl enable --now blackbox_exporter.service

echo "========================================================="
echo "Blackbox Exporter installation completed!"
echo "Listening on port: ${PORT}"
echo "Config file: /blackbox_exporter/blackbox.yml"
echo "========================================================="