#!/bin/bash

# DcRouter Installer Script
# Installs the self-extracting Linux binary by default, or builds the NodeNext
# source package when --source is specified.
#
# Usage:
#   Binary install:
#     curl -sSL https://code.foss.global/serve.zone/dcrouter/raw/branch/main/install.sh | sudo bash
#
#   Source install:
#     curl -sSL https://code.foss.global/serve.zone/dcrouter/raw/branch/main/install.sh | sudo bash -s -- --source
#
# Options:
#   -h, --help             Show this help message
#   --version VERSION      Install a specific tag/version (e.g. vX.Y.Z)
#   --install-dir DIR      Installation directory (default: /opt/dcrouter)
#   --binary               Install release binary (default)
#   --source               Clone the tag and build the NodeNext package locally

set -euo pipefail

SHOW_HELP=0
SPECIFIED_VERSION=""
INSTALL_DIR="/opt/dcrouter"
INSTALL_MODE="binary"
GITEA_BASE_URL="https://code.foss.global"
GITEA_REPO="serve.zone/dcrouter"
SERVICE_NAME="dcrouter"
BIN_DIR="/usr/local/bin"

while [[ $# -gt 0 ]]; do
  case "$1" in
    -h|--help)
      SHOW_HELP=1
      shift
      ;;
    --version)
      if [[ $# -lt 2 ]]; then
        echo "Error: --version requires a value"
        exit 1
      fi
      SPECIFIED_VERSION="$2"
      shift 2
      ;;
    --install-dir)
      if [[ $# -lt 2 ]]; then
        echo "Error: --install-dir requires a value"
        exit 1
      fi
      INSTALL_DIR="$2"
      shift 2
      ;;
    --binary)
      INSTALL_MODE="binary"
      shift
      ;;
    --source)
      INSTALL_MODE="source"
      shift
      ;;
    *)
      echo "Unknown option: $1"
      echo "Use -h or --help for usage information"
      exit 1
      ;;
  esac
done

if [[ $SHOW_HELP -eq 1 ]]; then
  echo "DcRouter Installer Script"
  echo "Installs DcRouter as a self-extracting binary or NodeNext source build."
  echo ""
  echo "Usage: $0 [options]"
  echo ""
  echo "Options:"
  echo "  -h, --help             Show this help message"
  echo "  --version VERSION      Install a specific tag/version (e.g. vX.Y.Z)"
  echo "  --install-dir DIR      Installation directory (default: /opt/dcrouter)"
  echo "  --binary               Install release binary (default)"
  echo "  --source               Clone the tag and build the NodeNext package locally"
  echo ""
  echo "Examples:"
  echo "  curl -sSL https://code.foss.global/serve.zone/dcrouter/raw/branch/main/install.sh | sudo bash"
  echo "  curl -sSL https://code.foss.global/serve.zone/dcrouter/raw/branch/main/install.sh | sudo bash -s -- --source"
  echo "  curl -sSL https://code.foss.global/serve.zone/dcrouter/raw/branch/main/install.sh | sudo bash -s -- --version vX.Y.Z"
  exit 0
fi

if [[ "$EUID" -ne 0 ]]; then
  echo "Please run as root (sudo bash install.sh or pipe to sudo bash)"
  exit 1
fi

case "$INSTALL_DIR" in
  ""|"/")
    echo "Error: unsafe install directory: $INSTALL_DIR"
    exit 1
    ;;
esac

require_command() {
  if ! command -v "$1" >/dev/null 2>&1; then
    echo "Error: required command not found: $1"
    exit 1
  fi
}

ensure_pnpm() {
  if command -v pnpm >/dev/null 2>&1; then
    return
  fi
  if command -v corepack >/dev/null 2>&1; then
    corepack enable
  fi
  if ! command -v pnpm >/dev/null 2>&1; then
    echo "Error: pnpm is required for --source installs. Install Node.js with corepack/pnpm first."
    exit 1
  fi
}

make_executable_if_present() {
  if [[ -f "$1" ]]; then
    chmod 0755 "$1"
  fi
}

get_latest_version() {
  echo "Fetching latest release version from Gitea..." >&2

  local api_url="${GITEA_BASE_URL}/api/v1/repos/${GITEA_REPO}/releases/latest"
  local response
  if ! response=$(curl -fsSL "$api_url" 2>/dev/null); then
    echo "Error: Failed to fetch latest release information from Gitea API" >&2
    echo "URL: $api_url" >&2
    exit 1
  fi

  local version
  version=$(printf '%s' "$response" | sed -n 's/.*"tag_name"[[:space:]]*:[[:space:]]*"\([^"]*\)".*/\1/p')
  if [[ -z "$version" ]]; then
    echo "Error: Could not determine latest version from API response" >&2
    exit 1
  fi

  echo "$version"
}

detect_binary_name() {
  local os
  local arch
  os=$(uname -s)
  arch=$(uname -m)

  if [[ "$os" != "Linux" ]]; then
    echo "Error: binary installer currently supports Linux only. Use --source for this platform." >&2
    exit 1
  fi

  case "$arch" in
    x86_64|amd64)
      echo "dcrouter-linux-x64"
      ;;
    aarch64|arm64)
      echo "dcrouter-linux-arm64"
      ;;
    *)
      echo "Error: unsupported architecture for binary install: $arch. Use --source." >&2
      exit 1
      ;;
  esac
}

echo "================================================"
echo "  DcRouter Installation Script"
echo "================================================"
echo ""

require_command curl
require_command sed

if [[ -n "$SPECIFIED_VERSION" ]]; then
  VERSION="$SPECIFIED_VERSION"
  echo "Installing specified version: $VERSION"
else
  VERSION=$(get_latest_version)
  echo "Installing latest version: $VERSION"
fi
echo "Install mode: $INSTALL_MODE"
echo ""

SOURCE_REF="$VERSION"
REPO_URL="${GITEA_BASE_URL}/${GITEA_REPO}.git"
TEMP_DIR=$(mktemp -d)
SOURCE_DIR="$TEMP_DIR/source"
BACKUP_DIR=""
SERVICE_WAS_RUNNING=0
SERVICE_STOPPED=0
SYSTEMD_AVAILABLE=0

cleanup_temp() {
  rm -rf "$TEMP_DIR"
}
trap cleanup_temp EXIT

if command -v systemctl >/dev/null 2>&1; then
  SYSTEMD_AVAILABLE=1
  if systemctl is-active --quiet "$SERVICE_NAME" 2>/dev/null; then
    SERVICE_WAS_RUNNING=1
  fi
fi

restore_previous_installation() {
  if [[ -n "$BACKUP_DIR" && -d "$BACKUP_DIR" ]]; then
    echo "Restoring previous installation from $BACKUP_DIR..."
    rm -rf "$INSTALL_DIR" || true
    mv "$BACKUP_DIR" "$INSTALL_DIR" || true
    if [[ -f "$INSTALL_DIR/dcrouter" ]]; then
      mkdir -p "$BIN_DIR" || true
      ln -sf "$INSTALL_DIR/dcrouter" "$BIN_DIR/dcrouter" || true
    elif [[ -f "$INSTALL_DIR/cli.js" ]]; then
      mkdir -p "$BIN_DIR" || true
      ln -sf "$INSTALL_DIR/cli.js" "$BIN_DIR/dcrouter" || true
    fi
  fi
}

restart_previous_service_on_error() {
  if [[ $SERVICE_STOPPED -eq 1 && $SYSTEMD_AVAILABLE -eq 1 ]]; then
    echo "Installation failed after stopping DcRouter; restarting previous service..."
    systemctl start "$SERVICE_NAME" || true
  fi
}

handle_install_error() {
  trap - ERR
  restore_previous_installation
  restart_previous_service_on_error
}
trap handle_install_error ERR

stop_service_if_running() {
  if [[ $SERVICE_WAS_RUNNING -eq 1 && $SYSTEMD_AVAILABLE -eq 1 ]] && systemctl is-active --quiet "$SERVICE_NAME" 2>/dev/null; then
    echo "Stopping DcRouter service..."
    systemctl stop "$SERVICE_NAME"
    SERVICE_STOPPED=1
  fi
}

move_previous_installation() {
  mkdir -p "$(dirname "$INSTALL_DIR")"
  if [[ -d "$INSTALL_DIR" ]]; then
    BACKUP_DIR="${INSTALL_DIR}.previous.$$"
    echo "Moving previous installation to $BACKUP_DIR"
    mv "$INSTALL_DIR" "$BACKUP_DIR"
  fi
}

install_source_build() {
  require_command git
  require_command node
  ensure_pnpm

  echo "Cloning DcRouter source from $REPO_URL ($SOURCE_REF)..."
  git clone --depth 1 --branch "$SOURCE_REF" "$REPO_URL" "$SOURCE_DIR"

  echo "Installing dependencies..."
  pnpm --dir "$SOURCE_DIR" install --frozen-lockfile

  echo "Building DcRouter..."
  pnpm --dir "$SOURCE_DIR" run build

  echo "Validating built CLI..."
  node "$SOURCE_DIR/cli.js" --version >/dev/null

  stop_service_if_running
  move_previous_installation

  echo "Installing source build to $INSTALL_DIR"
  mv "$SOURCE_DIR" "$INSTALL_DIR"
  make_executable_if_present "$INSTALL_DIR/cli.js"
  make_executable_if_present "$INSTALL_DIR/cli.ts.js"
  make_executable_if_present "$INSTALL_DIR/cli.child.js"

  mkdir -p "$BIN_DIR"
  ln -sf "$INSTALL_DIR/cli.js" "$BIN_DIR/dcrouter"
}

install_release_binary() {
  local binary_name
  local download_url
  local temp_file

  binary_name=$(detect_binary_name)
  download_url="${GITEA_BASE_URL}/${GITEA_REPO}/releases/download/${VERSION}/${binary_name}"
  temp_file="$TEMP_DIR/$binary_name"

  echo "Downloading DcRouter binary: $download_url"
  curl -fSL "$download_url" -o "$temp_file"
  chmod 0755 "$temp_file"

  echo "Validating downloaded binary..."
  "$temp_file" --version >/dev/null

  stop_service_if_running
  move_previous_installation

  echo "Installing binary to $INSTALL_DIR"
  mkdir -p "$INSTALL_DIR"
  install -m 0755 "$temp_file" "$INSTALL_DIR/dcrouter"

  mkdir -p "$BIN_DIR"
  ln -sf "$INSTALL_DIR/dcrouter" "$BIN_DIR/dcrouter"
}

if [[ "$INSTALL_MODE" == "source" ]]; then
  install_source_build
else
  install_release_binary
fi

echo "Symlink created: $BIN_DIR/dcrouter"

if ! "$BIN_DIR/dcrouter" --version >/dev/null; then
  echo "Error: Installed DcRouter CLI failed validation"
  restore_previous_installation
  restart_previous_service_on_error
  exit 1
fi

if [[ -n "$BACKUP_DIR" && -d "$BACKUP_DIR" ]]; then
  rm -rf "$BACKUP_DIR"
fi

if [[ $SERVICE_WAS_RUNNING -eq 1 && $SYSTEMD_AVAILABLE -eq 1 ]]; then
  echo "Restarting DcRouter service..."
  systemctl restart "$SERVICE_NAME"
  SERVICE_STOPPED=0
  echo "Service restarted successfully."
  echo ""
fi

trap - ERR

echo "================================================"
echo "  DcRouter Installation Complete!"
echo "================================================"
echo ""
echo "Installation details:"
echo "  Install directory: $INSTALL_DIR"
echo "  Symlink location: $BIN_DIR/dcrouter"
echo "  Version: $VERSION"
echo "  Mode: $INSTALL_MODE"
echo ""
echo "Get started:"
echo ""
echo "  dcrouter --version"
echo "  dcrouter --help"
echo ""