#!/usr/bin/env bash
set -Eeuo pipefail

APP_DIR="${APP_DIR:-/opt/cmpp-platform}"
if [[ "$(id -u)" -ne 0 ]]; then echo "Run as root." >&2; exit 1; fi
for command_name in fail2ban-client nft nginx systemctl; do command -v "$command_name" >/dev/null || { echo "Missing command: $command_name" >&2; exit 1; }; done
agent_binary="$APP_DIR/dist/cmpp-security-agent"
[[ -x "$agent_binary" ]] || { echo "Missing built security agent: $agent_binary" >&2; exit 1; }

getent group cmpp-security >/dev/null || groupadd --system cmpp-security
id cmpp-api >/dev/null 2>&1 || useradd --system --home-dir /nonexistent --shell /usr/sbin/nologin cmpp-api
usermod -a -G cmpp-security cmpp-api
install -d -o root -g cmpp-security -m 0770 /run/cmpp-security-agent
install -d -o root -g cmpp-security -m 0750 /var/lib/cmpp-security-agent
install -d -o cmpp-api -g cmpp-security -m 0750 "$APP_DIR/logs/api"
[[ -d /var/lib/cmpp-platform/object-storage ]] && chown -R cmpp-api:cmpp-security /var/lib/cmpp-platform/object-storage

sed "s#@CMPP_SECURITY_AGENT_BIN@#$agent_binary#g" "$APP_DIR/deploy/security/cmpp-report-only.conf" >/etc/fail2ban/action.d/cmpp-report-only.conf
chmod 0640 /etc/fail2ban/action.d/cmpp-report-only.conf
install -m 0640 "$APP_DIR/deploy/security/cmpp-http-scan.conf" /etc/fail2ban/filter.d/cmpp-http-scan.conf
install -d -m 0750 /etc/nginx/snippets /etc/nftables.d
touch /etc/nginx/snippets/cmpp-security-deny.conf
chmod 0640 /etc/nginx/snippets/cmpp-security-deny.conf

cat >/etc/nftables.d/cmpp-security.nft <<'EOF'
table inet cmpp_security {
  set blocked_ipv4 { type ipv4_addr; flags timeout; }
  set blocked_ipv6 { type ipv6_addr; flags timeout; }
  chain input { type filter hook input priority -10; policy accept; ip saddr @blocked_ipv4 drop; ip6 saddr @blocked_ipv6 drop; }
}
EOF
grep -q 'cmpp-security.nft' /etc/nftables.conf || printf '\ninclude "/etc/nftables.d/cmpp-security.nft"\n' >>/etc/nftables.conf
nft -c -f /etc/nftables.conf
nft list table inet cmpp_security >/dev/null 2>&1 || nft -f /etc/nftables.d/cmpp-security.nft

sed "s#@CMPP_SECURITY_AGENT_BIN@#$agent_binary#g" "$APP_DIR/deploy/security/cmpp-security-agent.service" >/etc/systemd/system/cmpp-security-agent.service
if grep -Rqs '@CMPP_SECURITY_AGENT_BIN@' /etc/systemd/system/cmpp-security-agent.service /etc/fail2ban/action.d/cmpp-report-only.conf; then
  echo "Security agent executable placeholder was not rendered." >&2
  exit 1
fi
install -d -m 0755 /etc/systemd/system/cmpp-api.service.d
cat >/etc/systemd/system/cmpp-api.service.d/security-boundary.conf <<EOF
[Service]
User=cmpp-api
Group=cmpp-security
NoNewPrivileges=true
PrivateTmp=true
ProtectHome=true
ProtectSystem=true
ReadWritePaths=$APP_DIR/logs/api /var/lib/cmpp-platform/object-storage
EOF

fail2ban-client -t
nginx -t
systemctl daemon-reload
systemctl enable cmpp-security-agent
echo "Security boundary installed. Restart cmpp-security-agent and cmpp-api only in the approved release window."