#!/usr/bin/env bash
# Builds Halkyon Learn's agent on this machine and copies it to its user on
# the host it runs on (Halkyon's ADR 0044, D52), which has no Dart SDK:
#
#   apps/learn/halkyon_learn_agent/tool/install.sh <ssh target>
#
# e.g. `claude@halkyon-li-host`. Each build goes into a folder of its own,
# ~/.local/lib/halkyon-agent/<commit>, `current` pointing to it and
# ~/.local/bin/halkyon-agent to its executable, so an agent still running
# keeps its files; the build before stays, the older ones go.
set -euo pipefail

target=${1:?"usage: $0 <ssh target>"}
package=$(cd "$(dirname "$0")/.." && pwd)

# `dart build cli` builds for this machine alone.
remote_arch=$(ssh "$target" uname -m)
if [[ $remote_arch != "$(uname -m)" ]]; then
  echo "The host is $remote_arch, this machine $(uname -m): build on one like it." >&2
  exit 1
fi

version=$(git -C "$package" rev-parse --short=12 HEAD)
if [[ -n $(git -C "$package" status --porcelain -- . ../halkyon_learn_core ../../../packages) ]]; then
  version="$version-dirty-$(date +%Y%m%d%H%M%S)"
fi

build=$(mktemp -d)
trap 'rm -rf "$build"' EXIT
(cd "$package" && dart build cli -o "$build")

# tar rather than rsync, which the host may lack; for its user alone.
tar -C "$build/bundle" -cz . | ssh "$target" "
  set -eu
  umask 077
  lib=\$HOME/.local/lib/halkyon-agent
  mkdir -p \"\$lib/$version\" \"\$HOME/.local/bin\"
  tar -C \"\$lib/$version\" -xz
  previous=\$(readlink \"\$lib/current\" || true)
  ln -sfn '$version' \"\$lib/current\"
  ln -sfn \"\$lib/current/bin/halkyon_agent\" \"\$HOME/.local/bin/halkyon-agent\"
  for old in \"\$lib\"/*/; do
    old=\$(basename \"\$old\")
    # current/ is a link to a build, never one itself.
    if [ ! -L \"\$lib/\$old\" ] && [ \"\$old\" != '$version' ] && [ \"\$old\" != \"\$previous\" ]; then
      rm -rf \"\$lib/\$old\"
    fi
  done
  \"\$HOME/.local/bin/halkyon-agent\" --help > /dev/null
"
echo "Installed $version on $target: ~/.local/bin/halkyon-agent." >&2