#!/bin/sh
# Installs rack for the current user: curl -fsSL https://rack.monothread.dev/install | sh
# Running it again updates to the latest release. RACK_RELEASES points it at another release host.
set -eu

releases=${RACK_RELEASES:-https://rack.monothread.dev}
share=${XDG_DATA_HOME:-$HOME/.local/share}
apps=$share/rack/app
bin=$HOME/.local/bin

say() { printf 'rack: %s\n' "$*"; }
fail() { printf 'rack: %s\n' "$*" >&2; exit 1; }

platform() {
  [ "$(uname -s)" = Linux ] || fail "rack runs on Linux only for now"
  case "$(uname -m)" in
    x86_64 | amd64) echo linux-x86_64 ;;
    *) fail "rack is built for x86_64 only for now, this machine is $(uname -m)" ;;
  esac
}

require() {
  for tool in "$@"; do
    command -v "$tool" >/dev/null 2>&1 || fail "$tool is required"
  done
}

has_library() {
  ldconfig -p 2>/dev/null | grep -qF "$1" && return 0
  for dir in /usr/lib /usr/lib64 /usr/lib/x86_64-linux-gnu /usr/local/lib; do
    [ -e "$dir/$1" ] && return 0
  done
  return 1
}

has_webkit() { has_library libwebkit2gtk-4.1.so.0; }

# Canonical's libappindicator shows no icon; rack runs without it, only the tray icon needs it.
has_appindicator() { has_library libayatana-appindicator3.so.1; }

package_manager() {
  for manager in pacman apt-get dnf zypper; do
    command -v "$manager" >/dev/null 2>&1 && echo "$manager" && return 0
  done
  return 0
}

webkit_package() {
  case "$1" in
    pacman) echo webkit2gtk-4.1 ;;
    apt-get) echo libwebkit2gtk-4.1-0 ;;
    dnf) echo webkit2gtk4.1 ;;
    zypper) echo libwebkit2gtk-4_1-0 ;;
  esac
}

appindicator_package() {
  case "$1" in
    pacman) echo libayatana-appindicator ;;
    apt-get) echo libayatana-appindicator3-1 ;;
    dnf) echo libayatana-appindicator-gtk3 ;;
    zypper) echo libayatana-appindicator3-1 ;;
  esac
}

install_command() {
  case "$1" in
    pacman) echo "sudo pacman -S --needed --noconfirm $2" ;;
    apt-get) echo "sudo apt-get install -y $2" ;;
    dnf) echo "sudo dnf install -y $2" ;;
    zypper) echo "sudo zypper install -y $2" ;;
  esac
}

install_packages() {
  command=$(install_command "$1" "$2")
  say "installing $2 with $1, sudo may ask for your password"
  if (: </dev/tty) 2>/dev/null; then
    sh -c "$command" </dev/tty
  else
    sh -c "$command"
  fi
}

ensure_libraries() {
  manager=$(package_manager)
  webkit=$(webkit_package "$manager")
  tray=$(appindicator_package "$manager")
  has_webkit && webkit=""
  has_appindicator && tray=""
  if [ -n "$webkit" ] && [ -n "$tray" ]; then
    install_packages "$manager" "$webkit $tray" || install_packages "$manager" "$webkit" || true
  elif [ -n "$webkit$tray" ]; then
    install_packages "$manager" "$webkit$tray" || true
  fi
  if ! has_webkit; then
    [ -n "$webkit" ] || fail "the rack window needs WebKitGTK 4.1: install it with your package manager, then run this again"
    fail "WebKitGTK 4.1 did not install: run \"$(install_command "$manager" "$webkit")\" yourself, then run this again"
  fi
  has_appindicator || say "no tray icon: it needs libayatana-appindicator, rack runs fine without it"
}

field() {
  sed -n "s/.*\"$1\" *: *\"\([^\"]*\)\".*/\1/p" "$2" | head -n 1
}

write_launcher() {
  mkdir -p "$share/applications"
  cat >"$share/applications/rack.desktop" <<DESKTOP
[Desktop Entry]
Type=Application
Name=rack
Comment=Workspace manager for terminal coding agents
Exec=$apps/current/rack-shell
Icon=$apps/current/rack.png
Terminal=false
Categories=Development;
DESKTOP
}

health() {
  curl -fsS -m 1 "http://127.0.0.1:${RACK_PORT:-4780}/health" 2>/dev/null
}

running_version() {
  health | sed -n 's/.*"version" *: *"\([^"]*\)".*/\1/p'
}

# Keeps the new version, the one before it, and whatever version a running daemon still uses.
prune() {
  previous=$(ls -1 "$apps" | grep -vx -e current -e "$1" | sort -V | tail -n 1)
  ls -1 "$apps" | grep -vx -e current -e "$1" -e "${previous:-current}" -e "${2:-current}" | while read -r old; do
    rm -rf "${apps:?}/$old"
  done
}

report_running() {
  health=$(health) || return 0
  running=$(printf '%s' "$health" | sed -n 's/.*"version" *: *"\([^"]*\)".*/\1/p')
  pid=$(printf '%s' "$health" | sed -n 's/.*"pid" *: *\([0-9]*\).*/\1/p')
  [ "$running" = "$1" ] && return 0
  say "a rack ${running:-older} daemon is still running; stop it with \"kill $pid\" to use $1 (its terminals end)"
}

main() {
  target=$(platform)
  require curl tar sha256sum sed
  ensure_libraries

  work=$(mktemp -d)
  trap 'rm -rf "$work"' EXIT
  curl -fsSL "$releases/latest-$target.json" -o "$work/latest.json" || fail "could not reach $releases"
  version=$(field version "$work/latest.json")
  url=$(field url "$work/latest.json")
  sha256=$(field sha256 "$work/latest.json")
  [ -n "$version" ] && [ -n "$url" ] && [ -n "$sha256" ] || fail "$releases/latest-$target.json is not a rack release"

  if [ "$(readlink "$apps/current" 2>/dev/null)" = "$version" ] && [ -x "$apps/$version/rack" ]; then
    say "rack $version is already installed"
    report_running "$version"
    exit 0
  fi

  say "downloading rack $version"
  curl -fsSL "$url" -o "$work/rack.tar.gz" || fail "could not download $url"
  [ "$(sha256sum "$work/rack.tar.gz" | cut -d ' ' -f 1)" = "$sha256" ] || fail "the download does not match its checksum, nothing was changed"
  tar -xzf "$work/rack.tar.gz" -C "$work"
  [ -x "$work/rack-$version/rack" ] && [ -x "$work/rack-$version/rack-shell" ] || fail "the release archive is incomplete, nothing was changed"

  mkdir -p "$apps" "$bin"
  rm -rf "${apps:?}/$version"
  mv "$work/rack-$version" "$apps/$version"
  ln -sfn "$version" "$apps/current.next"
  mv -Tf "$apps/current.next" "$apps/current"
  ln -sfn "$apps/current/rack" "$bin/rack"
  write_launcher
  prune "$version" "$(running_version)"

  say "rack $version installed: open it from your app launcher, or run $apps/current/rack-shell"
  say "to remove it later: curl -fsSL ${releases}/uninstall | sh"
  case ":$PATH:" in
    *":$bin:"*) ;;
    *) say "add $bin to your PATH to use the rack command" ;;
  esac
  report_running "$version"
}

main