#!/bin/bash
set -e

INSTALL_DIR="/opt/server-monitor"
AGENT="$INSTALL_DIR/monitor-agent.sh"
CONFIG="$INSTALL_DIR/config.env"
CRON_CMD="$AGENT >/dev/null 2>&1"
API_URL="https://itschool.pbcv.dev/api/report.php"

# ============================
# CHECK ROOT
# ============================
if [[ $EUID -ne 0 ]]; then
  echo " Run as root (sudo)"
  exit 1
fi

echo " Installing Server Monitor Agent (IPv4 only)..."

# ============================
# CREATE DIR
# ============================
mkdir -p "$INSTALL_DIR"
chmod 755 "$INSTALL_DIR"

# ============================
# CONFIG FILE
# ============================
cat > "$CONFIG" <<EOF
API_URL="$API_URL"
EOF

chmod 600 "$CONFIG"

# ============================
# AGENT SCRIPT
# ============================
cat > "$AGENT" <<'EOF'
#!/bin/bash
set -e

source /opt/server-monitor/config.env

HOSTNAME=$(hostname)

# ============================
# CPU
# ============================
CPU_LOAD=$(uptime | awk -F'load average:' '{print $2}' | cut -d',' -f1 | xargs)
CPU_CORES=$(nproc)

# ============================
# RAM / SWAP
# ============================
RAM_TOTAL=$(free -m | awk '/Mem:/ {print $2}')
RAM_USED=$(free -m | awk '/Mem:/ {print $3}')

SWAP_TOTAL=$(free -m | awk '/Swap:/ {print $2}')
SWAP_USED=$(free -m | awk '/Swap:/ {print $3}')

# ============================
# DISK (KB)
# ============================
DISK_TOTAL=$(df -k / | awk 'NR==2 {print $2}')
DISK_USED=$(df -k / | awk 'NR==2 {print $3}')

# ============================
# NETWORK (IPv4 ONLY)
# ============================
IFACE=$(ip -4 route get 1.1.1.1 2>/dev/null | awk '{print $5; exit}')
RX_BYTES=$(cat /sys/class/net/$IFACE/statistics/rx_bytes)
TX_BYTES=$(cat /sys/class/net/$IFACE/statistics/tx_bytes)

# ============================
# PROCESSES
# ============================
PROC_TOTAL=$(ps ax --no-headers | wc -l)
PROC_ZOMBIE=$(ps axo stat | grep -c Z || true)

# ============================
# SYSTEMD
# ============================
FAILED_SERVICES=$(systemctl --failed --no-legend 2>/dev/null | wc -l)

# ============================
# NETWORK PORTS (IPv4 ONLY)
# ============================
OPEN_PORTS=$(ss -4 -lntu | tail -n +2 | wc -l)

# ============================
# OS / KERNEL
# ============================
OS_NAME=$(lsb_release -ds 2>/dev/null || grep PRETTY_NAME /etc/os-release | cut -d= -f2 | tr -d '"')
KERNEL=$(uname -r)
ARCH=$(uname -m)

# ============================
# UPTIME
# ============================
UPTIME=$(uptime -p)

# ============================
# SEND DATA (IPv4 FORCED)
# ============================
curl -4 -s -X POST "$API_URL" \
  -H "Content-Type: application/json" \
  -d "{
    \"hostname\": \"$HOSTNAME\",

    \"cpu\": \"$CPU_LOAD\",
    \"cpu_cores\": $CPU_CORES,

    \"ram_used\": $RAM_USED,
    \"ram_total\": $RAM_TOTAL,

    \"swap_used\": $SWAP_USED,
    \"swap_total\": $SWAP_TOTAL,

    \"disk_used\": $DISK_USED,
    \"disk_total\": $DISK_TOTAL,

    \"rx_bytes\": $RX_BYTES,
    \"tx_bytes\": $TX_BYTES,

    \"processes\": $PROC_TOTAL,
    \"zombies\": $PROC_ZOMBIE,

    \"failed_services\": $FAILED_SERVICES,
    \"open_ports\": $OPEN_PORTS,

    \"os\": \"$OS_NAME\",
    \"kernel\": \"$KERNEL\",
    \"arch\": \"$ARCH\",

    \"uptime\": \"$UPTIME\"
  }"
EOF

chmod +x "$AGENT"

# ============================
# CRON (no duplicates)
# ============================
(
  crontab -l 2>/dev/null | grep -v "$AGENT" || true
  echo "* * * * * $CRON_CMD"
) | crontab -

# ============================
# FINAL
# ============================
echo " Server Monitor installed successfully (IPv4 only)"
echo " Reporting to: $API_URL"
echo " Interval: every 1 minute"
echo " Test manual: $AGENT"