#!/bin/sh
set -eu

label="app.pocketty.daemon"
bundle_id="app.pocketty.daemon"
releases="${POCKETTY_RELEASES:-https://dl.pocketty.app}"
bin_dir="$HOME/.local/bin"
bin="$bin_dir/pocketty"
app="${XDG_DATA_HOME:-$HOME/.local/share}/pocketty/pocketty.app"
exe="$app/Contents/MacOS/pocketty"
state="${XDG_STATE_HOME:-$HOME/.local/state}/pocketty"
plist="$HOME/Library/LaunchAgents/$label.plist"
log="$HOME/Library/Logs/pocketty.log"
unit="${XDG_CONFIG_HOME:-$HOME/.config}/systemd/user/pocketty.service"

say() {
  printf '%s\n' "$*"
}

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

usage() {
  say "Usage: install.sh [--uninstall]"
  say "Installs the pocketty daemon to $bin and starts it as a service."
}

target() {
  arch=$(uname -m)
  case "$(uname -s)" in
    Darwin)
      if [ "$arch" = x86_64 ] && [ "$(sysctl -n sysctl.proc_translated 2>/dev/null || true)" = 1 ]; then
        arch=arm64
      fi
      case "$arch" in
        arm64) say aarch64-apple-darwin ;;
        x86_64) say x86_64-apple-darwin ;;
        *) fail "this Mac has a $arch CPU, which pocketty does not support" ;;
      esac
      ;;
    Linux)
      case "$arch" in
        aarch64 | arm64) say aarch64-unknown-linux-musl ;;
        x86_64 | amd64) say x86_64-unknown-linux-musl ;;
        *) fail "this computer has a $arch CPU, which pocketty does not support" ;;
      esac
      ;;
    *) fail "pocketty runs on macOS and Linux, not $(uname -s)" ;;
  esac
}

fetch() {
  curl -fsSL --proto-redir =https "$1" -o "$2" || fail "could not download $1"
}

digest() {
  if command -v sha256sum >/dev/null 2>&1; then
    sha256sum "$1" | cut -d' ' -f1
  elif command -v shasum >/dev/null 2>&1; then
    shasum -a 256 "$1" | cut -d' ' -f1
  else
    fail "this computer needs sha256sum or shasum to check the download"
  fi
}

service_path() {
  extra=""
  if [ "$(uname -s)" = Darwin ]; then
    extra=":/opt/homebrew/bin:/usr/local/bin"
  fi
  printf '%s' "$bin_dir:$PATH$extra:/usr/bin:/bin:/usr/sbin:/sbin" |
    awk -v RS=: '/^\// && !seen[$0]++ { printf "%s%s", sep, $0; sep = ":" }'
}

xml() {
  printf '%s' "$1" | sed -e 's/&/\&amp;/g' -e 's/</\&lt;/g' -e 's/>/\&gt;/g'
}

has_agent_host() {
  if command -v herdr >/dev/null 2>&1 || command -v tailscale >/dev/null 2>&1; then
    return 0
  fi
  for path in "$bin_dir/herdr" /opt/homebrew/bin/herdr /usr/local/bin/herdr; do
    if [ -x "$path" ]; then
      return 0
    fi
  done
  [ "$(uname -s)" = Darwin ] && [ -x /Applications/Tailscale.app/Contents/MacOS/Tailscale ]
}

linked() {
  case "$(uname -s)" in
    Darwin) [ "$(readlink "$bin" 2>/dev/null)" = "$exe" ] ;;
    *) [ ! -L "$bin" ] ;;
  esac
}

place_app() {
  [ -d "$tmp/pocketty.app" ] || fail "the download has no pocketty.app"
  dir=$(dirname "$app")
  mkdir -p "$dir"
  rm -rf "$dir/.pocketty.app.new" "$dir/.pocketty.app.old"
  mv "$tmp/pocketty.app" "$dir/.pocketty.app.new"
  if [ -e "$app" ]; then
    mv "$app" "$dir/.pocketty.app.old"
  fi
  mv "$dir/.pocketty.app.new" "$app"
  rm -rf "$dir/.pocketty.app.old"
  ln -sfn "$exe" "$bin_dir/.pocketty.new"
  mv -f "$bin_dir/.pocketty.new" "$bin"
  say "Installed pocketty $version to $app"
}

place_binary() {
  cp "$tmp/pocketty" "$bin_dir/.pocketty.new"
  mv -f "$bin_dir/.pocketty.new" "$bin"
  say "Installed pocketty $version to $bin"
}

download() {
  latest="$tmp/latest"
  fetch "$releases/latest" "$latest"
  version=$(tr -d ' \r\n' <"$latest")
  case "$version" in
    "" | *[!0-9A-Za-z.+-]*) fail "the release server sent a bad version: $version" ;;
  esac

  current=$("$bin" --version 2>/dev/null | cut -d' ' -f2 || true)
  if [ "$current" = "$version" ] && linked; then
    say "pocketty $version is already installed."
    return
  fi

  file="pocketty-$platform.tar.gz"
  say "Downloading pocketty $version for $platform..."
  fetch "$releases/$version/$file" "$tmp/$file"
  fetch "$releases/$version/SHA256SUMS" "$tmp/SHA256SUMS"
  want=$(awk -v file="$file" '$2 == file || $2 == "*" file { print $1 }' "$tmp/SHA256SUMS")
  if [ -z "$want" ] || [ "$want" != "$(digest "$tmp/$file")" ]; then
    fail "the download does not match its checksum. Run the install command again."
  fi

  tar -xzf "$tmp/$file" -C "$tmp"
  [ -f "$tmp/pocketty" ] || fail "the download has no pocketty binary"
  chmod 755 "$tmp/pocketty"
  "$tmp/pocketty" --version >/dev/null 2>&1 || fail "the downloaded binary does not run on this computer"

  mkdir -p "$bin_dir"
  case "$(uname -s)" in
    Darwin) place_app ;;
    *) place_binary ;;
  esac
}

start_launchd() {
  domain="gui/$(id -u)"
  program=$(xml "$exe")
  path=$(xml "$(service_path)")
  output=$(xml "$log")
  kept=""
  if [ -f "$plist" ]; then
    kept=$(plutil -extract EnvironmentVariables xml1 -o - "$plist" 2>/dev/null | sed -e '1,/<plist/d' -e '/<\/plist>/,$d' || true)
  fi
  mkdir -p "$(dirname "$plist")" "$(dirname "$log")"
  launchctl bootout "$domain/$label" >/dev/null 2>&1 || true
  cat >"$plist" <<PLIST
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
  <key>Label</key>
  <string>$label</string>
  <key>AssociatedBundleIdentifiers</key>
  <string>$bundle_id</string>
  <key>ProgramArguments</key>
  <array>
    <string>$program</string>
    <string>daemon</string>
  </array>
  <key>EnvironmentVariables</key>
  <dict>
    <key>PATH</key>
    <string>$path</string>
  </dict>
  <key>RunAtLoad</key>
  <true/>
  <key>KeepAlive</key>
  <true/>
  <key>StandardOutPath</key>
  <string>$output</string>
  <key>StandardErrorPath</key>
  <string>$output</string>
</dict>
</plist>
PLIST
  if [ -n "$kept" ]; then
    plutil -replace EnvironmentVariables -xml "$kept" "$plist"
    plutil -replace EnvironmentVariables.PATH -string "$(service_path)" "$plist"
  fi

  if ! launchctl print "$domain" >/dev/null 2>&1; then
    say "pocketty starts the next time you log in to this Mac."
    say "Log: $log"
    return
  fi
  launchctl enable "$domain/$label"
  tries=0
  until error=$(launchctl bootstrap "$domain" "$plist" 2>&1); do
    tries=$((tries + 1))
    [ "$tries" -lt 5 ] || fail "launchd did not start pocketty: $error"
    sleep 1
  done
  say "Started pocketty as the launchd agent $label."
  say "Log: $log"
}

user_systemd() {
  [ -d /run/systemd/system ] && command -v systemctl >/dev/null 2>&1 || return 1
  if [ -z "${XDG_RUNTIME_DIR:-}" ] && [ -d "/run/user/$(id -u)" ]; then
    XDG_RUNTIME_DIR="/run/user/$(id -u)"
    export XDG_RUNTIME_DIR
  fi
  systemctl --user show-environment >/dev/null 2>&1
}

start_systemd() {
  if ! user_systemd; then
    say "pocketty is not running, because you have no systemd user session here."
    if command -v loginctl >/dev/null 2>&1; then
      say "To start one that stays up, run once, then run the install command again:"
      say "  loginctl enable-linger \"\$USER\""
    fi
    say "Or start pocketty in a terminal: pocketty daemon"
    return
  fi
  path=$(service_path | sed -e 's/%/%%/g' -e 's/["\\]/\\&/g')
  mkdir -p "$(dirname "$unit")"
  cat >"$unit" <<UNIT
[Unit]
Description=pocketty host daemon

[Service]
ExecStart=%h/.local/bin/pocketty daemon
Environment="PATH=$path"
Restart=always
RestartSec=2

[Install]
WantedBy=default.target
UNIT
  systemctl --user daemon-reload
  systemctl --user enable -q pocketty
  systemctl --user restart pocketty
  say "Started pocketty as the systemd user service pocketty."
  say "Log: journalctl --user -u pocketty -f"
  if [ "$(loginctl show-user "$(id -un)" -p Linger --value 2>/dev/null || true)" = no ]; then
    say ""
    say "pocketty stops when you log out. To keep it running, run once:"
    say "  loginctl enable-linger \"\$USER\""
  fi
}

check_path() {
  found=$(command -v pocketty 2>/dev/null || true)
  [ "$found" = "$bin" ] && return
  rc=.profile
  case "${SHELL##*/}" in
    zsh) rc=.zshrc ;;
    bash) if [ "$(uname -s)" = Darwin ]; then rc=.bash_profile; else rc=.bashrc; fi ;;
  esac
  fix="echo 'export PATH=\"\$HOME/.local/bin:\$PATH\"' >> \"\$HOME/$rc\""
  if [ "${SHELL##*/}" = fish ]; then
    fix="fish_add_path ~/.local/bin"
  fi
  say ""
  if [ -n "$found" ]; then
    say "Your shell runs $found when you type pocketty."
  else
    say "Your shell does not find pocketty yet."
  fi
  say "To run commands like pocketty approve, put $bin_dir first on your PATH:"
  say "  $fix"
}

install() {
  platform=$(target)
  for prefix in /opt/homebrew /usr/local /home/linuxbrew/.linuxbrew "$HOME/.linuxbrew"; do
    if [ -e "$prefix/opt/pocketty" ]; then
      fail "pocketty is installed with Homebrew. Update it with: brew upgrade pocketty"
    fi
  done
  tmp=$(mktemp -d)
  trap 'rm -rf "$tmp"' EXIT
  trap 'exit 130' INT TERM
  download

  say ""
  if ! has_agent_host; then
    say "pocketty needs herdr or Tailscale on this computer, and it found neither."
    say "Install one of them, then run the install command again to start pocketty."
  else
    case "$(uname -s)" in
      Darwin) start_launchd ;;
      Linux) start_systemd ;;
    esac
  fi
  check_path
  say ""
  say "Next: open pocketty on your phone and connect to this computer."
}

uninstall() {
  case "$(uname -s)" in
    Darwin)
      launchctl bootout "gui/$(id -u)/$label" >/dev/null 2>&1 || true
      rm -f "$plist"
      rm -rf "$app"
      rmdir "$(dirname "$app")" 2>/dev/null || true
      ;;
    Linux)
      user_systemd || true
      systemctl --user disable --now pocketty >/dev/null 2>&1 || true
      rm -f "$unit"
      systemctl --user daemon-reload >/dev/null 2>&1 || true
      ;;
  esac
  rm -f "$bin"
  say "Removed pocketty and its service."
  say "Your paired phones stay in $state. Delete that folder to forget them too."
}

main() {
  if [ "$(id -u)" = 0 ] && [ -n "${SUDO_USER:-}" ]; then
    fail "run this as your own user, without sudo"
  fi
  case "${1:-}" in
    "") install ;;
    --uninstall) uninstall ;;
    -h | --help) usage ;;
    *) usage >&2; exit 2 ;;
  esac
}

main "$@"