#!/usr/bin/env bash
# Install Server Monitor as a systemd service.
set -euo pipefail

if [[ "${EUID}" -ne 0 ]]; then
  echo "请使用 root 运行：sudo ./install.sh" >&2
  exit 1
fi

if ! command -v systemctl >/dev/null 2>&1; then
  echo "未找到 systemctl，此脚本需要 systemd。" >&2
  exit 1
fi

if ! command -v python3 >/dev/null 2>&1; then
  echo "未找到 python3，请先安装 Python 3.8+。" >&2
  exit 1
fi

if ! python3 -c 'import sys; raise SystemExit(0 if sys.version_info >= (3, 8) else 1)'; then
  echo "Python 版本过低，需要 3.8 或更新版本。" >&2
  exit 1
fi

SOURCE_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd -P)"
TARGET_DIR="/opt/server-monitor"
UNIT_PATH="/etc/systemd/system/server-monitor.service"
ENV_PATH="/etc/server-monitor.env"

for required in monitor.py servermon web deploy/server-monitor.service; do
  if [[ ! -e "${SOURCE_DIR}/${required}" ]]; then
    echo "安装文件不完整，缺少: ${SOURCE_DIR}/${required}" >&2
    echo "请在完整仓库目录中运行安装脚本。" >&2
    exit 1
  fi
done

install -d -m 0755 "${TARGET_DIR}"
TARGET_DIR="$(cd "${TARGET_DIR}" && pwd -P)"

if [[ "${SOURCE_DIR}" == "${TARGET_DIR}" ]]; then
  # The repository is already installed at /opt/server-monitor (a common
  # deployment). Copying a file onto itself would make install(1) fail and
  # deleting the target directories would delete the source we are running
  # from, so only install the systemd unit in this case.
  echo "当前目录就是安装目录 ${TARGET_DIR}，跳过文件复制。"
else
  install -m 0755 "${SOURCE_DIR}/monitor.py" "${TARGET_DIR}/monitor.py"
  rm -rf "${TARGET_DIR}/servermon" "${TARGET_DIR}/web"
  cp -a "${SOURCE_DIR}/servermon" "${TARGET_DIR}/servermon"
  cp -a "${SOURCE_DIR}/web" "${TARGET_DIR}/web"
  install -m 0644 "${SOURCE_DIR}/README.md" "${TARGET_DIR}/README.md"
fi

if [[ ! -f "${ENV_PATH}" ]]; then
  cat >"${ENV_PATH}" <<'EOF'
# Server Monitor 环境变量（可选）
# 取消下一行注释并改成自己的凭据即可启用 HTTP Basic 认证：
# SERVER_MONITOR_AUTH=admin:change-me
EOF
  chmod 0600 "${ENV_PATH}"
fi

install -m 0644 "${SOURCE_DIR}/deploy/server-monitor.service" "${UNIT_PATH}"
systemctl daemon-reload
systemctl enable --now server-monitor.service
systemctl restart server-monitor.service

echo
echo "Server Monitor 已安装并启动。"
echo "  访问:   http://<服务器IP>:8787/"
echo "  状态:   systemctl status server-monitor --no-pager"
echo "  日志:   journalctl -u server-monitor -f"
echo "  认证:   编辑 ${ENV_PATH} 后 systemctl restart server-monitor"
echo
systemctl --no-pager --lines=0 status server-monitor.service || true