#!/bin/bash
set -e

# ============================================
# 串口关机控制器 - 更换串口脚本
# ============================================

INSTALL_DIR="/opt/ttyshutdown"
CONFIG_FILE="${INSTALL_DIR}/config.json"
SIGNAL_SCRIPT="/usr/lib/systemd/system-shutdown/send_signal.sh"
SERVICE_NAME="ttyshutdown"

# 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 change_port.sh"
        exit 1
    fi
}

# 检查是否已安装
check_installed() {
    if [ ! -f "$CONFIG_FILE" ]; then
        error "未找到配置文件 $CONFIG_FILE，请先运行 install.sh 安装"
        exit 1
    fi
}

# 读取当前配置
read_current_config() {
    CURRENT_PORT=$(grep -oP '"port"\s*:\s*"\K[^"]+' "$CONFIG_FILE")
    CURRENT_BAUD=$(grep -oP '"baudRate"\s*:\s*\K[0-9]+' "$CONFIG_FILE")
    CURRENT_WORD=$(grep -oP '"shutdownWord"\s*:\s*"\K[^"]+' "$CONFIG_FILE")

    echo -e "${CYAN}=== 当前配置 ===${NC}"
    echo "  串口设备: $CURRENT_PORT"
    echo "  波特率:   $CURRENT_BAUD"
    echo "  关机指令: $CURRENT_WORD"
    echo ""
}

# 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() {
    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

    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
        local marker=""
        if [ "$p" = "$CURRENT_PORT" ]; then
            marker=" ${YELLOW}<-- 当前${NC}"
        fi
        echo "  [$i] $p  ($desc)${marker}"
        ((i++))
    done
    echo -e "${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
}

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

    cat > "$CONFIG_FILE" <<EOF
{
  "port": "${port}",
  "baudRate": ${baud_rate},
  "shutdownWord": "${shutdown_word}"
}
EOF
    info "已更新配置文件: $CONFIG_FILE"
}

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

    cat > "$SIGNAL_SCRIPT" <<EOF
#!/bin/bash

TTY_DEVICE="${port}"

ACTION=\$1

if [ "\$ACTION" = "poweroff" ] ; then
    if [ -w "\$TTY_DEVICE" ]; then
        stty -F "\$TTY_DEVICE" ${baud_rate} cs8 -cstopb -parenb
        printf "ok\r\n" > "\$TTY_DEVICE"
    fi
fi
exit 0
EOF
    chmod +x "$SIGNAL_SCRIPT"
    info "已更新关机钩子: $SIGNAL_SCRIPT"
}

# 重启服务
restart_service() {
    systemctl restart "$SERVICE_NAME"
    info "已重启服务: $SERVICE_NAME"
}

# 主流程
main() {
    check_root
    check_installed

    echo -e "${CYAN}========================================${NC}"
    echo -e "${CYAN}   串口关机控制器 - 更换串口${NC}"
    echo -e "${CYAN}========================================${NC}"
    echo ""

    # 1. 显示当前配置
    read_current_config

    # 2. 选择新串口
    select_serial_port

    if [ "$SELECTED_PORT" = "$CURRENT_PORT" ]; then
        warn "选择的新串口与当前串口相同，无需更改"
        exit 0
    fi

    info "新串口: $SELECTED_PORT"

    # 3. 可选修改波特率和关机指令
    local new_baud="$CURRENT_BAUD"
    local new_word="$CURRENT_WORD"

    echo ""
    read -rp "波特率 [当前 $CURRENT_BAUD，回车保持]: " input_baud
    if [ -n "$input_baud" ]; then
        new_baud="$input_baud"
    fi

    read -rp "关机指令 [当前 $CURRENT_WORD，回车保持]: " input_word
    if [ -n "$input_word" ]; then
        new_word="$input_word"
    fi

    # 4. 确认
    echo ""
    echo -e "${CYAN}=== 确认更改 ===${NC}"
    echo "  串口设备: $CURRENT_PORT -> $SELECTED_PORT"
    [ "$new_baud" != "$CURRENT_BAUD" ] && echo "  波特率:   $CURRENT_BAUD -> $new_baud"
    [ "$new_word" != "$CURRENT_WORD" ] && echo "  关机指令: $CURRENT_WORD -> $new_word"
    echo ""
    read -rp "确认更改? [Y/n]: " confirm
    if [[ "$confirm" =~ ^[Nn] ]]; then
        warn "已取消"
        exit 0
    fi

    # 5. 执行更改
    update_config "$SELECTED_PORT" "$new_baud" "$new_word"
    update_send_signal "$SELECTED_PORT" "$new_baud" "$new_word"
    restart_service

    echo ""
    echo -e "${GREEN}========================================${NC}"
    echo -e "${GREEN}串口更换完成!${NC}，重启或重启ttyshutdown服务后生效"
    echo -e "${GREEN}========================================${NC}"
    echo -e "  新串口:   ${CYAN}$SELECTED_PORT${NC}"
    echo -e "  波特率:   ${CYAN}$new_baud${NC}"
    echo -e "  服务状态: ${CYAN}systemctl status ttyshutdown${NC}"
    echo -e "  查看日志: ${CYAN}journalctl -u ttyshutdown -f${NC}"
}

main