#!/bin/bash
#===============================================================================
# 气象站接收服务 一体化脚本
#   - 内嵌 systemd service 定义，无需单独的 .service 文件
#   - 安装 / 卸载 / 状态 / 重启
# 用法:
#   sudo ./install-service.sh            # 安装 + 启用 + 启动（默认）
#   sudo ./install-service.sh install    # 同上
#   sudo ./install-service.sh uninstall  # 停止 + 禁用 + 删除 service
#   sudo ./install-service.sh status     # 查看运行状态
#   sudo ./install-service.sh restart    # 重启服务
#===============================================================================
set -uo pipefail

SERVICE_NAME="weather-station-receiver"
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
TARGET_SCRIPT="${SCRIPT_DIR}/receive.sh"
DST_SERVICE="/etc/systemd/system/${SERVICE_NAME}.service"

ACTION="${1:-install}"

#-------------------------------------------------------------------------------
# 必须以 root 运行
#-------------------------------------------------------------------------------
check_root() {
    if (( EUID != 0 )); then
        echo "[错误] 请使用 root 运行: sudo $0 $ACTION"
        exit 1
    fi
}

#-------------------------------------------------------------------------------
# 内嵌的 systemd service 单元文件
# WorkingDirectory / ExecStart 使用脚本所在目录，移动目录后重新安装即可
#-------------------------------------------------------------------------------
write_service_file() {
    cat > "$DST_SERVICE" <<EOF
[Unit]
Description=Weather Station Serial Receiver
After=network-online.target
Wants=network-online.target

[Service]
Type=simple
User=root
WorkingDirectory=${SCRIPT_DIR}
ExecStart=/bin/bash ${TARGET_SCRIPT}

# 自动重启
Restart=always
RestartSec=10

# 防止无限重启：60 秒内超过 3 次则停止
StartLimitInterval=60
StartLimitBurst=3

# 日志输出到 journald
StandardOutput=journal
StandardError=journal
SyslogIdentifier=weather-station

[Install]
WantedBy=multi-user.target
EOF
    chmod 0644 "$DST_SERVICE"
}

#-------------------------------------------------------------------------------
# 前置检查：receive.sh 是否存在、可执行
#-------------------------------------------------------------------------------
preflight() {
    if [[ ! -f "$TARGET_SCRIPT" ]]; then
        echo "[错误] 找不到接收脚本: $TARGET_SCRIPT"
        exit 1
    fi
    if [[ ! -x "$TARGET_SCRIPT" ]]; then
        echo "[信息] 为 receive.sh 添加可执行权限..."
        chmod +x "$TARGET_SCRIPT"
    fi
}

#-------------------------------------------------------------------------------
# 安装：写出 service -> daemon-reload -> enable -> start
#-------------------------------------------------------------------------------
do_install() {
    echo "========================================"
    echo "  安装气象站接收服务"
    echo "========================================"
    preflight

    echo "[1/5] 生成 service 文件 -> $DST_SERVICE"
    write_service_file

    echo "[2/5] 重新加载 systemd"
    systemctl daemon-reload

    echo "[3/5] 启用开机自启"
    systemctl enable "$SERVICE_NAME"

    echo "[4/5] 启动服务"
    systemctl restart "$SERVICE_NAME"

    echo "[5/5] 运行状态:"
    systemctl --no-pager --full status "$SERVICE_NAME" || true
    echo "========================================"
    echo "  安装完成"
    echo "  查看日志: journalctl -u $SERVICE_NAME -f"
    echo "========================================"
}

#-------------------------------------------------------------------------------
# 卸载：stop -> disable -> remove -> daemon-reload
#-------------------------------------------------------------------------------
do_uninstall() {
    echo "========================================"
    echo "  卸载气象站接收服务"
    echo "========================================"
    echo "[1/4] 停止服务"
    systemctl stop "$SERVICE_NAME" 2>/dev/null || true

    echo "[2/4] 禁用开机自启"
    systemctl disable "$SERVICE_NAME" 2>/dev/null || true

    echo "[3/4] 删除 service 文件"
    rm -f "$DST_SERVICE"

    echo "[4/4] 重新加载 systemd"
    systemctl daemon-reload
    systemctl reset-failed "$SERVICE_NAME" 2>/dev/null || true
    echo "========================================"
    echo "  卸载完成"
    echo "========================================"
}

#-------------------------------------------------------------------------------
# 状态
#-------------------------------------------------------------------------------
do_status() {
    systemctl --no-pager --full status "$SERVICE_NAME" || true
    echo
    echo "开机自启: $(systemctl is-enabled "$SERVICE_NAME" 2>/dev/null || echo '未知')"
    echo "当前状态: $(systemctl is-active  "$SERVICE_NAME" 2>/dev/null || echo '未知')"
}

#-------------------------------------------------------------------------------
# 重启
#-------------------------------------------------------------------------------
do_restart() {
    systemctl restart "$SERVICE_NAME"
    do_status
}

#-------------------------------------------------------------------------------
# 主入口
#-------------------------------------------------------------------------------
check_root
case "$ACTION" in
    install)   do_install ;;
    uninstall) do_uninstall ;;
    status)    do_status ;;
    restart)   do_restart ;;
    *)
        echo "用法: sudo $0 {install|uninstall|status|restart}"
        exit 1
        ;;
esac