#!/bin/bash
set -e

# ============================================
# 串口关机控制器 - 安装脚本
# ============================================

INSTALL_DIR="/opt/ttyshutdown"
SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"

# 颜色定义
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
CYAN='\033[0;36m'
NC='\033[0m'

info()  { echo -e "${GREEN}[INFO]${NC} $1"; }
warn()  { echo -e "${YELLOW}[WARN]${NC} $1"; }
error() { echo -e "${RED}[ERROR]${NC} $1"; }

# 检查 root 权限
check_root() {
    if [ "$(id -u)" -ne 0 ]; then
        error "请使用 root 权限运行此脚本: sudo bash install.sh"
        exit 1
    fi
}

# 扫描可用串口
scan_serial_ports() {
    local ports=()
    for pattern in "ttyUSB*" "ttyACM*" "ttyS*"; do
        for dev in /dev/$pattern; do
            if [ -e "$dev" ]; then
                ports+=("$dev")
            fi
        done
    done
    echo "${ports[@]}"
}

# 交互选择串口
select_serial_port() {
    echo -e "${CYAN}========================================${NC}"
    echo -e "${CYAN}   串口关机控制器 - 安装向导${NC}"
    echo -e "${CYAN}========================================${NC}"
    echo ""

    local ports
    ports=$(scan_serial_ports)

    if [ -z "$ports" ]; then
        warn "未检测到串口设备"
        echo -e "请手动输入串口设备路径 (如 ${YELLOW}/dev/ttyUSB0${NC}): "
        read -r SELECTED_PORT
        if [ ! -e "$SELECTED_PORT" ]; then
            warn "设备 $SELECTED_PORT 当前不存在，仍将配置（设备可能稍后接入）"
        fi
        return
    fi

    # 转为数组
    local port_array=($ports)
    echo -e "检测到以下串口设备:${GREEN}"
    local i=1
    for p in "${port_array[@]}"; do
        local desc=""
        case "$p" in
            /dev/ttyUSB*) desc="USB转串口" ;;
            /dev/ttyACM*)  desc="USB CDC虚拟串口" ;;
            /dev/ttyS*)    desc="原生串口(COM口)" ;;
        esac
        echo "  [$i] $p  ($desc)"
        ((i++))
    done
    echo -e "${NC}"

    local last_index=${#port_array[@]}
    echo "  [$((last_index + 1))] 手动输入其他路径"
    echo ""

    local choice
    while true; do
        read -rp "请选择串口 [1-$((last_index + 1))]: " choice
        if [[ "$choice" =~ ^[0-9]+$ ]] && [ "$choice" -ge 1 ] && [ "$choice" -le "$((last_index + 1))" ]; then
            break
        fi
        error "无效选择，请重新输入"
    done

    if [ "$choice" -le "$last_index" ]; then
        SELECTED_PORT="${port_array[$((choice - 1))]}"
    else
        read -rp "请输入串口设备路径: " SELECTED_PORT
        if [ -z "$SELECTED_PORT" ]; then
            error "路径不能为空"
            exit 1
        fi
    fi
}

# 生成 config.json
generate_config() {
    local port="$1"
    local baud_rate="$2"
    local shutdown_word="$3"

    cat > "${INSTALL_DIR}/config.json" <<EOF
{
  "port": "${port}",
  "baudRate": ${baud_rate},
  "shutdownWord": "${shutdown_word}"
}
EOF
    info "已生成配置文件: ${INSTALL_DIR}/config.json"
}

# 生成 send_signal.sh
generate_send_signal() {
    local port="$1"
    local baud_rate="$2"
    local shutdown_word="$3"

    cat > "/usr/lib/systemd/system-shutdown/send_signal.sh" <<EOF
#!/bin/bash

TTY_DEVICE="${port}"

ACTION=\$1

if [ "\$ACTION" = "poweroff" ] ; then
    if [ -w "\$TTY_DEVICE" ]; then
        stty -F "\$TTY_DEVICE" ${baud_rate} cs8 -cstopb -parenb
        printf "ok\r\n" > "\$TTY_DEVICE"
    fi
fi
exit 0
EOF
    chmod +x "/usr/lib/systemd/system-shutdown/send_signal.sh"
    info "已安装关机钩子: /usr/lib/systemd/system-shutdown/send_signal.sh"
}

# 生成 systemd service
generate_service() {
    cat > /etc/systemd/system/ttyshutdown.service <<EOF
[Unit]
Description=ttyshutdown

[Service]
Type=simple
User=root
WorkingDirectory=${INSTALL_DIR}
ExecStart=${INSTALL_DIR}/shutdown
Restart=always
RestartSec=3

[Install]
WantedBy=multi-user.target
EOF
    info "已生成 systemd 服务: /etc/systemd/system/ttyshutdown.service"
}

# 主安装流程
main() {
    check_root

    # 1. 选择串口
    select_serial_port
    info "已选择串口: $SELECTED_PORT"

    # 2. 可选参数
    local baud_rate=115200
    local shutdown_word="SHUTDOWN"
    echo ""
    read -rp "波特率 [默认 115200]: " input_baud
    if [ -n "$input_baud" ]; then
        baud_rate="$input_baud"
    fi

    read -rp "关机指令 [默认 SHUTDOWN]: " input_word
    if [ -n "$input_word" ]; then
        shutdown_word="$input_word"
    fi

    echo ""
    echo -e "${CYAN}=== 确认配置 ===${NC}"
    echo "  串口设备: $SELECTED_PORT"
    echo "  波特率:   $baud_rate"
    echo "  关机指令: $shutdown_word"
    echo "  安装目录: $INSTALL_DIR"
    echo ""
    read -rp "确认安装? [Y/n]: " confirm
    if [[ "$confirm" =~ ^[Nn] ]]; then
        warn "已取消安装"
        exit 0
    fi

    # 3. 检查二进制文件
    if [ ! -f "${SCRIPT_DIR}/shutdown" ]; then
        error "未找到预编译的 shutdown 二进制文件"
        echo "请将 shutdown 二进制文件复制到 ${SCRIPT_DIR} 目录下"
        exit 1
    fi

    # 4. 安装文件
    mkdir -p "$INSTALL_DIR"
    cp "${SCRIPT_DIR}/shutdown" "${INSTALL_DIR}/shutdown"
    chmod +x "${INSTALL_DIR}/shutdown"

    # 5. 生成配置
    generate_config "$SELECTED_PORT" "$baud_rate" "$shutdown_word"

    # 6. 安装关机钩子
    mkdir -p /usr/lib/systemd/system-shutdown
    generate_send_signal "$SELECTED_PORT" "$baud_rate" "$shutdown_word"

    # 7. 生成并启用 systemd 服务
    generate_service
    systemctl daemon-reload
    systemctl enable ttyshutdown.service
    systemctl start ttyshutdown.service

    echo ""
    echo -e "${GREEN}========================================${NC}"
    echo -e "${GREEN}   安装完成!${NC}"
    echo -e "${GREEN}========================================${NC}"
    echo -e "  服务状态: ${CYAN}systemctl status ttyshutdown${NC}"
    echo -e "  查看日志: ${CYAN}journalctl -u ttyshutdown -f${NC}"
    echo -e "  停止服务: ${CYAN}systemctl stop ttyshutdown${NC}"
    echo -e "  卸载:     ${CYAN}sudo bash ${SCRIPT_DIR}/uninstall.sh${NC}"
}

main