#!/bin/bash
#
# Purpose : coredesktop-dev try: run the working copy's code as if it were the
#           deployed CoreDesktop, in a throwaway home with its own session

try_usage() {
  cat << EOF
Usage: coredesktop-dev try [--keep] [command...]

Runs command (or a shell) with a throwaway HOME where
~/.local/share/coredesktop is the working copy, and update, configure, version
etc. in ~/.local/bin are the working copy's. It gets its own XDG_RUNTIME_DIR
and D-Bus session, and no display, so it can't touch your desktop session.

sudo, yay, pacman and systemctl still change this machine.

  --keep   Keep the throwaway folder afterwards, and print where it is

Example: coredesktop-dev try configure --list
EOF
}

TRY_COMMANDS=(update refresh sibling version configure audit)

cmd_try() {
  local keep=0
  while [ $# -gt 0 ]; do
    case "$1" in
      -h | --help) try_usage; return 0 ;;
      --keep) keep=1; shift ;;
      --) shift; break ;;
      *) break ;;
    esac
  done
  require_working_copy

  local tmp home runtime cmd status
  tmp="$(mktemp -d "${TMPDIR:-/tmp}/coredesktop-dev-try.XXXXXX")" || return 1
  home="$tmp/home"
  runtime="$tmp/runtime"
  mkdir -p "$home/.local/share" "$home/.local/bin" "$home/.local/state" \
    "$home/.config" "$home/.cache"
  mkdir -m 700 "$runtime"

  ln -s "$WORKING_COPY" "$home/.local/share/coredesktop"
  for cmd in "${TRY_COMMANDS[@]}"; do
    ln -s "$WORKING_COPY/$cmd" "$home/.local/bin/$cmd"
  done

  echo "coredesktop-dev try: HOME is $home, with the working copy as CoreDesktop." >&2
  echo "Careful: sudo, yay, pacman and systemctl still change this machine." >&2

  (( $# > 0 )) || set -- bash
  env -u DISPLAY -u WAYLAND_DISPLAY -u DBUS_SESSION_BUS_ADDRESS -u SSH_AUTH_SOCK \
    HOME="$home" \
    XDG_CONFIG_HOME="$home/.config" \
    XDG_DATA_HOME="$home/.local/share" \
    XDG_STATE_HOME="$home/.local/state" \
    XDG_CACHE_HOME="$home/.cache" \
    XDG_RUNTIME_DIR="$runtime" \
    PATH="$home/.local/bin:$PATH" \
    dbus-run-session -- "$@"
  status=$?

  if (( keep )); then
    echo "Kept $tmp" >&2
  else
    rm -rf "$tmp"
  fi
  return $status
}