#!/usr/bin/env bash
set -euo pipefail

RSI_TERMINAL_LAUNCHER=1
RSI_TERMINAL_VERSION="0.5.2"
RSI_GAME_URL="${RSI_GAME_URL:-https://www.paradigm.xyz/research/rsi/game}"
RSI_TERMINAL_SOURCE_URL="${RSI_TERMINAL_SOURCE_URL:-https://rsi.justinwang.xyz}"
TERMINAL_BROWSER_INSTALL_URL="${RSI_TERMINAL_BROWSER_INSTALL_URL:-https://terminal-browser.sh/install}"

BIN_HOME="${XDG_BIN_HOME:-$HOME/.local/bin}"
DATA_HOME="${XDG_DATA_HOME:-$HOME/.local/share}"
RSI_BIN="$BIN_HOME/rsi"
TTY_PATH="${RSI_TERMINAL_TTY:-}"
BROWSER=""
BROWSER_INSTALLED_NOW=false

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

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

usage() {
  cat <<'EOF'
Usage: rsi [--version | --help]

Launch the Paradigm RSI game in terminal-browser.
EOF
}

unsupported_terminal() {
  local name="$1"
  printf '\n  %s cannot display terminal-browser.\n\n' "$name" >&2
  printf '  Use a terminal with Kitty graphics support, such as:\n' >&2
  printf '  Ghostty, Kitty, WezTerm, or VS Code\047s integrated terminal.\n' >&2
  printf '  https://github.com/zenbu-labs/terminal-browser\n' >&2
  printf '\n  Or play in a normal browser:\n' >&2
  printf '  %s\n\n' "$RSI_GAME_URL" >&2
  exit 1
}

require_supported_terminal() {
  case "${TERM_PROGRAM:-}" in
    Apple_Terminal) unsupported_terminal "Apple Terminal" ;;
    iTerm.app) unsupported_terminal "iTerm2" ;;
  esac
}

running_from_pipe() {
  local source_file="${BASH_SOURCE[0]:-}"
  [[ -z "$source_file" || ! -f "$source_file" ]]
}

resolve_tty_path() {
  [[ -n "$TTY_PATH" ]] && return

  local candidate=""
  if [[ -t 0 ]]; then
    candidate="$(tty 2>/dev/null || true)"
  else
    # `curl | bash` occupies stdin. Ask stdout for the concrete terminal path;
    # terminal-browser's detached daemon cannot reopen the /dev/tty alias.
    exec 9>&1
    candidate="$(tty <&9 2>/dev/null || true)"
    exec 9>&-
  fi

  [[ "$candidate" == /dev/* ]] || fail "could not determine the current terminal device"
  TTY_PATH="$candidate"
}

prepare_terminal_input() {
  if [[ ! -t 0 ]]; then
    resolve_tty_path
    [[ -r "$TTY_PATH" && -w "$TTY_PATH" ]] || fail "cannot use terminal device $TTY_PATH"
  fi
}

run_in_terminal() {
  if [[ -t 0 ]]; then
    "$@"
  else
    "$@" <"$TTY_PATH"
  fi
}

launcher_version_at() {
  local launcher="$1"
  [[ -x "$launcher" ]] || return 1
  "$launcher" --launcher-version 2>/dev/null
}

install_launcher() {
  local installed_version=""
  installed_version="$(launcher_version_at "$RSI_BIN" || true)"
  [[ "$installed_version" == "$RSI_TERMINAL_VERSION" ]] && return

  command -v curl >/dev/null 2>&1 || fail "curl is required to install rsi"
  mkdir -p "$BIN_HOME"

  local staged source_file
  staged="$(mktemp "$BIN_HOME/.rsi.XXXXXX")"
  source_file="${BASH_SOURCE[0]:-}"
  if [[ -n "$source_file" && -f "$source_file" ]]; then
    if ! cp "$source_file" "$staged"; then
      rm -f "$staged"
      fail "could not stage the rsi launcher"
    fi
  elif ! curl -fsSL --retry 3 --retry-delay 2 "$RSI_TERMINAL_SOURCE_URL" -o "$staged"; then
    rm -f "$staged"
    fail "could not download the rsi launcher"
  fi

  if ! grep -q '^RSI_TERMINAL_LAUNCHER=1$' "$staged" || ! bash -n "$staged"; then
    rm -f "$staged"
    fail "the downloaded rsi launcher is invalid"
  fi

  chmod 755 "$staged"
  mv "$staged" "$RSI_BIN"
  say "installed rsi $RSI_TERMINAL_VERSION to $RSI_BIN"

  case ":$PATH:" in
    *":$BIN_HOME:"*) ;;
    *) say "add $BIN_HOME to PATH to run rsi later" ;;
  esac
}

find_terminal_browser() {
  local found="${RSI_TERMINAL_BROWSER_BIN:-}"
  if [[ -n "$found" && -x "$found" ]]; then
    BROWSER="$found"
    return
  fi

  found="$(command -v terminal-browser 2>/dev/null || true)"
  if [[ -n "$found" && -x "$found" ]]; then
    BROWSER="$found"
    return
  fi

  for found in \
    "$BIN_HOME/terminal-browser" \
    "$DATA_HOME/terminal-browser/app/bin/terminal-browser"; do
    if [[ -x "$found" ]]; then
      BROWSER="$found"
      return
    fi
  done
  return 1
}

install_terminal_browser() {
  command -v curl >/dev/null 2>&1 || fail "curl is required to install terminal-browser"

  local installer
  installer="$(mktemp "${TMPDIR:-/tmp}/rsi-terminal-browser.XXXXXX")"
  if [[ -n "${RSI_TERMINAL_BROWSER_INSTALLER_FILE:-}" ]]; then
    cp "$RSI_TERMINAL_BROWSER_INSTALLER_FILE" "$installer" || {
      rm -f "$installer"
      fail "could not stage the terminal-browser installer"
    }
  elif ! curl -fsSL --retry 3 --retry-delay 2 "$TERMINAL_BROWSER_INSTALL_URL" -o "$installer"; then
    rm -f "$installer"
    fail "could not download the terminal-browser installer"
  fi

  if ! bash -n "$installer"; then
    rm -f "$installer"
    fail "the terminal-browser installer is invalid"
  fi
  if ! run_in_terminal env TERMINAL_BROWSER_SKIP_EDITOR_SETUP=1 bash "$installer"; then
    rm -f "$installer"
    fail "terminal-browser installation failed"
  fi
  rm -f "$installer"
  BROWSER_INSTALLED_NOW=true
}

ensure_terminal_browser() {
  find_terminal_browser && return
  install_terminal_browser
  find_terminal_browser || fail "terminal-browser was installed but could not be found"
}

setup_terminal_browser() {
  "$BROWSER" setup || say "rsi: terminal-browser setup did not complete" >&2
}

launch() {
  say "Starting RSI — press Ctrl+Q to quit."
  if [[ -t 0 ]]; then
    exec "$BROWSER" open "$RSI_GAME_URL" --no-toolbar --no-frame
  else
    exec "$BROWSER" open "$RSI_GAME_URL" --no-toolbar --no-frame <"$TTY_PATH"
  fi
}

main() {
  case "${1:-}" in
    --launcher-version)
      printf '%s\n' "$RSI_TERMINAL_VERSION"
      return
      ;;
    --version|-v)
      printf 'rsi %s\n' "$RSI_TERMINAL_VERSION"
      return
      ;;
    --help|-h)
      usage
      return
      ;;
    "") ;;
    *) fail "unknown argument $1" ;;
  esac

  require_supported_terminal
  prepare_terminal_input
  install_launcher
  ensure_terminal_browser

  if running_from_pipe || [[ "$BROWSER_INSTALLED_NOW" == true ]]; then
    setup_terminal_browser
  fi
  if running_from_pipe; then
    printf '\nRSI is installed. Launching now.\n\n'
    printf 'Next time, run:\n\n  rsi\n\n'
  fi
  launch
}

main "$@"