#!/bin/bash
#
# Written by an LLM (Claude Code) — review before trusting on a machine
# other than the one this was diagnosed on. See README.md.
#
# Installs the docker-tailscale-route fix: a systemd timer that keeps an
# ip rule in place routing Docker's bridge traffic around Tailscale's
# exit-node catch-all route. See docker-tailscale-route.sh for the full
# explanation of the underlying problem.
#
# Usage:
#   sudo ./install.sh [--subnet CIDR] [--priority N] [--table NAME]
#
# The optional flags only need to be passed if Docker's default address
# pool doesn't apply on this machine (see the comment in
# docker-tailscale-route.sh); they're written to
# /etc/default/docker-tailscale-route and sourced by the script at
# runtime.

set -euo pipefail

if [ "$(id -u)" -ne 0 ]; then
    echo "Must be run as root (sudo ./install.sh)" >&2
    exit 1
fi

SCRIPT_DIR="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd)"

SUBNET=""
PRIORITY=""
TABLE=""

while [ $# -gt 0 ]; do
    case "$1" in
        --subnet) SUBNET="$2"; shift 2 ;;
        --priority) PRIORITY="$2"; shift 2 ;;
        --table) TABLE="$2"; shift 2 ;;
        *) echo "Unknown argument: $1" >&2; exit 1 ;;
    esac
done

install -o root -g root -m 0755 "$SCRIPT_DIR/docker-tailscale-route.sh" /usr/local/sbin/docker-tailscale-route.sh
install -o root -g root -m 0644 "$SCRIPT_DIR/docker-tailscale-route.service" /etc/systemd/system/docker-tailscale-route.service
install -o root -g root -m 0644 "$SCRIPT_DIR/docker-tailscale-route.timer" /etc/systemd/system/docker-tailscale-route.timer

if [ -n "$SUBNET" ] || [ -n "$PRIORITY" ] || [ -n "$TABLE" ]; then
    {
        [ -n "$SUBNET" ] && echo "DOCKER_SUBNET=\"$SUBNET\""
        [ -n "$PRIORITY" ] && echo "RULE_PRIORITY=\"$PRIORITY\""
        [ -n "$TABLE" ] && echo "TARGET_TABLE=\"$TABLE\""
    } > /etc/default/docker-tailscale-route
    chown root:root /etc/default/docker-tailscale-route
    chmod 0644 /etc/default/docker-tailscale-route
fi

systemctl daemon-reload
systemctl enable --now docker-tailscale-route.timer

echo "Installed. Current status:"
systemctl status docker-tailscale-route.timer --no-pager
echo
echo "ip rule list:"
ip rule list