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

log() {
  printf "[lexis-install] %s\n" "$*"
}

fail() {
  printf "[lexis-install] error: %s\n" "$*" >&2
  exit 1
}

has_cmd() {
  command -v "$1" >/dev/null 2>&1
}

npm_global_prefix() {
  local prefix
  prefix="$(npm config get prefix 2>/dev/null || true)"
  prefix="${prefix//$'\r'/}"

  case "$prefix" in
    ""|null|undefined)
      return 1
      ;;
  esac

  printf "%s" "$prefix"
}

refresh_path_for_npm_global_bin() {
  local prefix
  prefix="$(npm_global_prefix || true)"
  if [ -n "$prefix" ] && [ -d "$prefix/bin" ]; then
    export PATH="$prefix/bin:$PATH"
  fi

  hash -r 2>/dev/null || true
}

resolve_lexis_command() {
  if has_cmd lexis; then
    printf "lexis"
    return 0
  fi

  local prefix
  prefix="$(npm_global_prefix || true)"
  if [ -n "$prefix" ] && [ -x "$prefix/bin/lexis" ]; then
    printf "%s" "$prefix/bin/lexis"
    return 0
  fi

  return 1
}

require_cmd() {
  if ! has_cmd "$1"; then
    fail "missing required command: $1"
  fi
}

run_with_optional_sudo() {
  if [ "$(id -u)" -eq 0 ]; then
    "$@"
    return $?
  fi

  if has_cmd sudo; then
    sudo "$@"
    return $?
  fi

  return 1
}

ensure_npm_installed() {
  if has_cmd npm; then
    return 0
  fi

  log "npm not found. Attempting to install Node.js + npm..."

  case "$(uname -s)" in
    Darwin)
      ensure_homebrew_available
      brew install node
      ;;
    Linux)
      if has_cmd apt-get; then
        run_with_optional_sudo apt-get update || fail "failed to run apt-get update"
        run_with_optional_sudo apt-get install -y nodejs npm || fail "failed to install nodejs/npm with apt-get"
      elif has_cmd dnf; then
        run_with_optional_sudo dnf install -y nodejs npm || fail "failed to install nodejs/npm with dnf"
      elif has_cmd yum; then
        run_with_optional_sudo yum install -y nodejs npm || fail "failed to install nodejs/npm with yum"
      elif has_cmd pacman; then
        run_with_optional_sudo pacman -Sy --noconfirm nodejs npm || fail "failed to install nodejs/npm with pacman"
      elif has_cmd zypper; then
        run_with_optional_sudo zypper --non-interactive install nodejs npm || fail "failed to install nodejs/npm with zypper"
      elif has_cmd apk; then
        run_with_optional_sudo apk add --no-cache nodejs npm || fail "failed to install nodejs/npm with apk"
      else
        install_node_with_nvm_fallback
      fi
      ;;
    *)
      fail "unsupported platform for auto-installing npm"
      ;;
  esac

  if ! has_cmd npm; then
    fail "npm is still unavailable after auto-install attempt"
  fi
}

install_node_with_nvm_fallback() {
  if ! has_cmd curl; then
    fail "npm is missing, no supported package manager found, and curl is unavailable for nvm fallback"
  fi

  log "No supported package manager found. Installing Node.js via nvm fallback..."

  export NVM_DIR="$HOME/.nvm"
  if [ ! -s "$NVM_DIR/nvm.sh" ]; then
    curl -fsSL https://raw.githubusercontent.com/nvm-sh/nvm/v0.40.3/install.sh | bash
  fi

  # shellcheck disable=SC1090
  . "$NVM_DIR/nvm.sh"
  nvm install --lts
  nvm use --lts
}

ensure_homebrew_available() {
  if has_cmd brew; then
    return 0
  fi

  if ! has_cmd curl; then
    fail "Homebrew is required on macOS but curl is not installed"
  fi

  log "Homebrew not found. Installing Homebrew..."
  NONINTERACTIVE=1 /bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

  if [ -x "/opt/homebrew/bin/brew" ]; then
    export PATH="/opt/homebrew/bin:$PATH"
  elif [ -x "/usr/local/bin/brew" ]; then
    export PATH="/usr/local/bin:$PATH"
  fi

  if ! has_cmd brew; then
    fail "Homebrew installation completed but brew is unavailable. Open a new shell and rerun installer."
  fi
}

append_user_path_exports() {
  local line='export PATH="$HOME/.local/bin:$PATH"'
  local rc

  for rc in "$HOME/.profile" "$HOME/.bashrc" "$HOME/.zshrc"; do
    if [ ! -f "$rc" ]; then
      touch "$rc"
    fi

    if ! grep -Fq "$line" "$rc"; then
      printf "\n%s\n" "$line" >> "$rc"
    fi
  done
}

install_global_with_fallbacks() {
  local source="$1"

  if npm install -g "$source"; then
    return 0
  fi

  if [ "$(id -u)" -ne 0 ] && has_cmd sudo; then
    log "Global install needs elevated permissions. Retrying with sudo..."
    if sudo npm install -g "$source"; then
      return 0
    fi
  fi

  local user_prefix="$HOME/.local"
  log "Falling back to user-level npm prefix: $user_prefix"
  npm install -g --prefix "$user_prefix" "$source"
  export PATH="$user_prefix/bin:$PATH"
  append_user_path_exports
  return 0
}

is_valid_hook_mode() {
  case "$1" in
    auto|lx)
      return 0
      ;;
  esac
  return 1
}

read_from_tty() {
  local prompt="$1"
  local value

  if [ -r /dev/tty ]; then
    printf "%s" "$prompt" > /dev/tty
    IFS= read -r value < /dev/tty || true
    printf "%s" "$value"
    return 0
  fi

  return 1
}

choose_hook_mode() {
  local current="${LEXIS_HOOK_MODE:-}"
  if is_valid_hook_mode "$current"; then
    printf "%s" "$current"
    return 0
  fi

  local answer
  answer="$(read_from_tty "Hook mode [auto/lx] (default: auto): " || true)"
  answer="${answer:-auto}"

  if ! is_valid_hook_mode "$answer"; then
    log "Invalid hook mode '$answer'. Using auto."
    answer="auto"
  fi

  printf "%s" "$answer"
}

resolve_install_source() {
  if [ -n "${LEXIS_INSTALL_SOURCE:-}" ]; then
    printf "%s" "$LEXIS_INSTALL_SOURCE"
    return 0
  fi

  local script_dir
  script_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
  local repo_root
  repo_root="$(cd "$script_dir/../.." && pwd)"
  local local_pkg="$repo_root/lexis"

  if [ -f "$local_pkg/package.json" ]; then
    printf "%s" "$local_pkg"
    return 0
  fi

  printf "%s" "@hridyacodes/lexis"
}

main() {
  ensure_npm_installed
  require_cmd node
  require_cmd npm

  local install_source
  install_source="$(resolve_install_source)"

  log "Installing Lexis from: $install_source"
  install_global_with_fallbacks "$install_source"

  refresh_path_for_npm_global_bin

  local lexis_cmd
  lexis_cmd="$(resolve_lexis_command || true)"

  if [ -z "$lexis_cmd" ]; then
    local prefix
    prefix="$(npm_global_prefix || true)"
    fail "'lexis' command not found after install (npm prefix: ${prefix:-unknown}). Add your npm global bin to PATH and retry."
  fi

  local hook_mode
  hook_mode="$(choose_hook_mode)"

  local -a setup_args=(setup --hook-mode "$hook_mode")
  if [ -n "${LEXIS_PROVIDER:-}" ]; then
    setup_args+=(--provider "$LEXIS_PROVIDER")
  fi
  if [ -n "${LEXIS_MODEL:-}" ]; then
    setup_args+=(--model "$LEXIS_MODEL")
  fi

  log "Running setup (hook-mode=$hook_mode)"
  "$lexis_cmd" "${setup_args[@]}"

  log "Done. Open a new terminal and run: lx doctor"
}

main "$@"