#!/bin/bash
# ================================================================
# Nexus Agent Install Script
# Usage: curl -fsSL https://YOUR_NEXUS_DOMAIN/agent/install.sh | bash -s -- --url https://YOUR_NEXUS_DOMAIN --key API_KEY --id SERVER_ID
# ================================================================

set -e

CENTRAL_URL=""
WEB_URL=""
API_KEY=""
SERVER_ID=""
AGENT_PORT="8601"
INSTALL_DIR="/opt/nexus-agent"

while [[ $# -gt 0 ]]; do
    case $1 in
        --url)      CENTRAL_URL="$2"; shift 2 ;;
        --web-url)  WEB_URL="$2"; shift 2 ;;
        --key)      API_KEY="$2"; shift 2 ;;
        --id)       SERVER_ID="$2"; shift 2 ;;
        --port)     AGENT_PORT="$2"; shift 2 ;;
        *)          shift ;;
    esac
done

[ -z "$CENTRAL_URL" ] && echo "ERROR: --url is required" && exit 1
[ -z "$SERVER_ID" ] && echo "ERROR: --id is required (server ID from Nexus dashboard)" && exit 1
[ -z "$API_KEY" ] && echo "ERROR: --key is required (API key from Nexus settings)" && exit 1

echo ""
echo "=========================================="
echo "  Nexus Agent Install"
echo "=========================================="
echo "  Server:  $CENTRAL_URL"
echo "  ID:      $SERVER_ID"
echo "  Port:    $AGENT_PORT"
echo "=========================================="
echo ""

# 1. Install Python
echo "[1/5] Install Python..."
if command -v apt-get >/dev/null 2>&1; then
    apt-get update -qq 2>/dev/null || true
    apt-get install -y -qq python3 python3-pip curl 2>/dev/null || true
elif command -v yum >/dev/null 2>&1; then
    yum install -y -q python3 python3-pip curl 2>/dev/null || true
elif command -v dnf >/dev/null 2>&1; then
    dnf install -y -q python3 python3-pip curl 2>/dev/null || true
fi
pip3 install fastapi uvicorn httpx psutil python-multipart 2>/dev/null \
    || pip3 install fastapi uvicorn httpx psutil python-multipart --break-system-packages 2>/dev/null \
    || true

# 2. Create dir
echo "[2/5] Create directory..."
mkdir -p "$INSTALL_DIR"

# 3. Download agent.py
echo "[3/5] Download agent.py..."
[ -z "$WEB_URL" ] && WEB_URL="${CENTRAL_URL}"
curl -fsSL "${WEB_URL}/agent/agent.py" -o "$INSTALL_DIR/agent.py" || {
    echo "ERROR: Cannot download from $WEB_URL/agent/agent.py"
    exit 1
}

# 4. Config
echo "[4/5] Write config..."
# Extract central IP from URL for IP allowlist
CENTRAL_HOST=$(echo "${CENTRAL_URL}" | sed 's~https\?://~~' | cut -d'/' -f1 | cut -d':' -f1)

cat > "$INSTALL_DIR/config.json" << EOF
{
  "server_id": ${SERVER_ID},
  "central": { "url": "${CENTRAL_URL}", "api_key": "${API_KEY}" },
  "api_key": "${API_KEY}",
  "heartbeat_interval": 60,
  "allowed_ips": ["${CENTRAL_HOST}"],
  "log_file": "/var/log/nexus-agent.log",
  "log_level": "INFO",
  "server": { "host": "127.0.0.1", "port": ${AGENT_PORT} }
}
EOF
echo "  IP allowlist: ${CENTRAL_HOST}"

# 5. systemd + firewall + start
echo "[5/5] Setup service + firewall + start..."

cat > /etc/systemd/system/nexus-agent.service << EOF
[Unit]
Description=Nexus Agent
After=network.target

[Service]
Type=simple
User=root
WorkingDirectory=${INSTALL_DIR}
ExecStart=python3 -m uvicorn agent:app --host 0.0.0.0 --port ${AGENT_PORT} --log-level info
Restart=always
RestartSec=5

[Install]
WantedBy=multi-user.target
EOF

# Firewall
if command -v ufw &>/dev/null && ufw status 2>/dev/null | grep -q 'Status: active'; then
    ufw allow ${AGENT_PORT}/tcp 2>/dev/null && echo "  ufw: opened ${AGENT_PORT}/tcp"
elif command -v firewall-cmd &>/dev/null && firewall-cmd --state 2>/dev/null | grep -q 'running'; then
    firewall-cmd --add-port=${AGENT_PORT}/tcp --permanent 2>/dev/null
    firewall-cmd --reload 2>/dev/null && echo "  firewalld: opened ${AGENT_PORT}/tcp"
else
    iptables -C INPUT -p tcp --dport ${AGENT_PORT} -j ACCEPT 2>/dev/null \
        || iptables -I INPUT -p tcp --dport ${AGENT_PORT} -j ACCEPT
    echo "  iptables: opened ${AGENT_PORT}/tcp"
fi

systemctl daemon-reload
systemctl enable nexus-agent
systemctl start nexus-agent
sleep 2

STATUS="running"
systemctl is-active --quiet nexus-agent || STATUS="FAILED"

HOSTNAME=$(hostname 2>/dev/null || echo "unknown")
IP=$(hostname -I 2>/dev/null | awk '{print $1}' || echo "unknown")

echo ""
echo "=========================================="
echo "  Done! Status: ${STATUS}"
echo "=========================================="
echo ""
echo "  Agent:     http://${IP}:${AGENT_PORT}"
echo "  Server ID: ${SERVER_ID}"
echo ""
echo "  Commands:"
echo "    systemctl status nexus-agent"
echo "    journalctl -u nexus-agent -f"
echo "    systemctl restart nexus-agent"
echo ""