#!/bin/sh
set -e

BEFORE_RULES=/etc/ufw/before.rules

# Remove the rule blocks this package inserted, together with the single blank
# line that precedes each one, so before.rules returns to its original content.
strip_ufw_blocks() {
    [ -f "$BEFORE_RULES" ] || return 0
    grep -q '^# ROUTER MSS RULES START$\|^# IPSEC RULES START$' "$BEFORE_RULES" || return 0

    tmp="$(mktemp)"
    awk '
        /^# (IPSEC|WIREGUARD|P2S DNS|ROUTER FORWARD|ROUTER NAT|ROUTER MSS) RULES START$/ {
            skip = 1; pending = 0; next
        }
        /^# (IPSEC|WIREGUARD|P2S DNS|ROUTER FORWARD|ROUTER NAT|ROUTER MSS) RULES END$/ {
            skip = 0; next
        }
        skip { next }
        /^$/ { pending++; next }
        {
            while (pending > 0) { print ""; pending-- }
            print
        }
        END { while (pending > 0) { print ""; pending-- } }
    ' "$BEFORE_RULES" > "$tmp"

    cat "$tmp" > "$BEFORE_RULES"
    rm -f "$tmp"
}

case "$1" in
    purge)
        strip_ufw_blocks

        # Let ucf forget the file before it is removed, or a reinstall finds a
        # stale hash and declines to lay the file down again.
        if command -v ucf >/dev/null 2>&1; then
            ucf --purge /etc/vpn-router/vpn-router.conf
        fi
        if command -v ucfr >/dev/null 2>&1; then
            ucfr --purge vpn-router /etc/vpn-router/vpn-router.conf
        fi

        rm -f /etc/swanctl/conf.d/remote-site.conf \
              /etc/swanctl/conf.d/road-warrior.conf \
              /etc/systemd/resolved.conf.d/p2s-forwarder.conf \
              /etc/wireguard/wg0.conf \
              /etc/vpn-router/vpn-router.conf

        # Key material is not package state: /etc/vpn-router/pki, the WireGuard
        # key pair and everything under /etc/swanctl are left in place.
        rmdir --ignore-fail-on-non-empty /etc/vpn-router 2>/dev/null || true
        ;;
esac

#DEBHELPER#