#!/usr/bin/env bash
set -euo pipefail

#===============================================================================
# 登录信息展示脚本 (Login Info)
# 用途: 快速查看系统/资源/网络/Docker 等信息，适合作为 SSH 登录后提示。
#
# 手动运行:
#   bash login-info/login-info.sh
#
# 安装为登录自动展示:
#   sudo bash login-info/install_login-info.sh
#
# 环境变量:
#   LOGIN_INFO_MODE=summary|full      # 默认 summary
#   LOGIN_INFO_COLOR=auto|always|never # 默认 auto
#===============================================================================

usage() {
    local prog
    prog=${0##*/}

    cat <<EOF
用法:
  ${prog} [--summary|--full] [--no-docker] [--no-color] [--help]

说明:
  --summary     快速模式(默认)，适合登录时自动展示
  --full        详细模式(包含 GPU/磁盘明细/软件包统计等)
  --no-docker   不显示 Docker 信息
  --no-color    禁用颜色输出
EOF
}

has_cmd() { command -v "$1" >/dev/null 2>&1; }

init_colors() {
    local color_mode=${LOGIN_INFO_COLOR:-auto}

    case "$color_mode" in
        auto|always|never) ;;
        *) color_mode=auto ;;
    esac

    local enable_color=0
    if [ "$color_mode" = "always" ]; then
        enable_color=1
    elif [ "$color_mode" = "never" ] || [ -n "${NO_COLOR:-}" ]; then
        enable_color=0
    else
        if [ -t 1 ] && [ "${TERM:-}" != "dumb" ]; then
            enable_color=1
        fi
    fi

    if [ "$enable_color" -eq 1 ]; then
        C_RESET='\033[0m'
        C_BOLD='\033[1m'
        C_TITLE='\033[1;36m'
        C_INFO='\033[1;33m'
        C_VALUE='\033[0;37m'
        C_LABEL='\033[0;32m'
        C_SUBTLE='\033[1;30m'
        C_BLUE='\033[1;34m'
        C_RED='\033[0;31m'
    else
        C_RESET=''
        C_BOLD=''
        C_TITLE=''
        C_INFO=''
        C_VALUE=''
        C_LABEL=''
        C_SUBTLE=''
        C_BLUE=''
        C_RED=''
    fi

    HR='───────────────────────────────────────────────────────────────────────────────'
}

print_hr() { printf '%b%s%b\n' "${C_SUBTLE}" "${HR}" "${C_RESET}"; }
print_title() { printf '%b%s%b\n' "${C_TITLE}${C_BOLD}" "$1" "${C_RESET}"; }
print_kv() { printf '  %b%s:%b %b%s%b\n' "${C_LABEL}" "$1" "${C_RESET}" "${C_VALUE}" "$2" "${C_RESET}"; }
print_kv_info() { printf '  %b%s:%b %b%s%b\n' "${C_LABEL}" "$1" "${C_RESET}" "${C_INFO}" "$2" "${C_RESET}"; }

format_kb() {
    local kb=${1:-}
    case "$kb" in
        ''|*[!0-9]*) printf 'N/A'; return 0 ;;
    esac

    if [ "$kb" -ge 1048576 ]; then
        awk -v v="$kb" 'BEGIN{printf "%.1fGiB", v/1048576}'
    elif [ "$kb" -ge 1024 ]; then
        awk -v v="$kb" 'BEGIN{printf "%.1fMiB", v/1024}'
    else
        printf '%sKiB' "$kb"
    fi
}

get_os_pretty_name() {
    local os=''

    if has_cmd lsb_release; then
        os=$(lsb_release -ds 2>/dev/null || true)
        os=${os#\"}
        os=${os%\"}
    fi

    if [ -z "$os" ] && [ -r /etc/os-release ]; then
        os=$(
            awk -F= '
                $1=="PRETTY_NAME"{
                    gsub(/^"/,"",$2); gsub(/"$/,"",$2);
                    print $2; exit
                }' /etc/os-release 2>/dev/null || true
        )
    fi

    printf '%s' "${os:-N/A}"
}

get_boot_time() {
    local boot=''
    if has_cmd uptime; then
        boot=$(uptime -s 2>/dev/null || true)
    fi
    if [ -z "$boot" ] && has_cmd who; then
        boot=$(who -b 2>/dev/null | awk '{print $3" "$4}' || true)
    fi
    printf '%s' "${boot:-N/A}"
}

get_uptime_pretty() {
    local up=''
    if has_cmd uptime; then
        up=$(uptime -p 2>/dev/null | sed 's/^up //')
    fi

    if [ -z "$up" ] && [ -r /proc/uptime ]; then
        local seconds
        seconds=$(awk '{print int($1)}' /proc/uptime 2>/dev/null || echo 0)
        if [ "$seconds" -gt 0 ] 2>/dev/null; then
            local days hours minutes
            days=$((seconds / 86400))
            hours=$(((seconds % 86400) / 3600))
            minutes=$(((seconds % 3600) / 60))
            if [ "$days" -gt 0 ]; then
                up="${days}天 ${hours}小时 ${minutes}分钟"
            elif [ "$hours" -gt 0 ]; then
                up="${hours}小时 ${minutes}分钟"
            else
                up="${minutes}分钟"
            fi
        fi
    fi

    printf '%s' "${up:-N/A}"
}

get_load_avg() {
    local load=''
    if [ -r /proc/loadavg ]; then
        load=$(awk '{print $1" "$2" "$3}' /proc/loadavg 2>/dev/null || true)
    fi
    if [ -z "$load" ] && has_cmd uptime; then
        load=$(uptime 2>/dev/null | awk -F'load average: ' '{print $2}' || true)
    fi
    printf '%s' "${load:-N/A}"
}

get_cpu_model() {
    local model=''
    if [ -r /proc/cpuinfo ]; then
        model=$(awk -F': *' '/model name/{print $2; exit}' /proc/cpuinfo 2>/dev/null || true)
        [ -n "$model" ] || model=$(awk -F': *' '/Hardware/{print $2; exit}' /proc/cpuinfo 2>/dev/null || true)
        [ -n "$model" ] || model=$(awk -F': *' '/Processor/{print $2; exit}' /proc/cpuinfo 2>/dev/null || true)
    fi
    if [ -z "$model" ] && has_cmd lscpu; then
        model=$(lscpu 2>/dev/null | awk -F': *' '/Model name:/{print $2; exit}' || true)
    fi
    printf '%s' "${model:-N/A}"
}

get_cpu_cores() {
    local cores=''
    if has_cmd nproc; then
        cores=$(nproc 2>/dev/null || true)
    fi
    if [ -z "$cores" ] && [ -r /proc/cpuinfo ]; then
        cores=$(awk -F': *' '/^processor/{c++} END{print c+0}' /proc/cpuinfo 2>/dev/null || true)
    fi
    printf '%s' "${cores:-N/A}"
}

get_cpu_temp_c() {
    local temp=''

    if has_cmd sensors; then
        temp=$(
            sensors 2>/dev/null | awk '
                BEGIN{IGNORECASE=1}
                /(package id 0|tctl|tdie|cpu temperature|core 0|composite|temp1)/{
                    for(i=1;i<=NF;i++){
                        if($i ~ /^[+]?[0-9]+([.][0-9]+)?°C$/){
                            gsub(/[+°C]/,"",$i);
                            print $i; exit
                        }
                    }
                }' || true
        )
    fi

    if [ -z "$temp" ]; then
        local zone
        for zone in /sys/class/thermal/thermal_zone*; do
            [ -r "$zone/temp" ] || continue
            local temp_raw
            temp_raw=$(cat "$zone/temp" 2>/dev/null || true)
            case "$temp_raw" in
                ''|*[!0-9]*) continue ;;
            esac
            if [ "$temp_raw" -gt 0 ] 2>/dev/null; then
                if [ "$temp_raw" -ge 1000 ]; then
                    temp=$(awk -v t="$temp_raw" 'BEGIN{printf "%.1f", t/1000}')
                else
                    temp=$temp_raw
                fi
                break
            fi
        done
    fi

    printf '%s' "$temp"
}

section_system() {
    print_hr
    print_title "系统概览"
    print_kv "主机名" "$(hostname 2>/dev/null || echo N/A)"
    print_kv "操作系统" "$(get_os_pretty_name)"
    print_kv "内核版本" "$(uname -sr 2>/dev/null || echo N/A)"
    print_kv "系统架构" "$(uname -m 2>/dev/null || echo N/A)"
    print_kv "启动时间" "$(get_boot_time)"
    print_kv "运行时间" "$(get_uptime_pretty)"
    print_kv "平均负载" "$(get_load_avg)"
    print_kv "当前时间" "$(date '+%F %T %Z' 2>/dev/null || echo N/A)"
    print_hr
}

section_resources() {
    print_title "硬件与资源"

    local cpu_model cpu_cores cpu_temp
    cpu_model=$(get_cpu_model)
    cpu_cores=$(get_cpu_cores)
    cpu_temp=$(get_cpu_temp_c)

    if [ -n "$cpu_temp" ]; then
        print_kv_info "CPU" "${cpu_model} (${cpu_cores} 核, ${cpu_temp}°C)"
    else
        print_kv "CPU" "${cpu_model} (${cpu_cores} 核)"
    fi

    local mem_total_kb mem_avail_kb mem_used_percent
    mem_total_kb=$(awk '/MemTotal:/ {print $2; exit}' /proc/meminfo 2>/dev/null || true)
    mem_avail_kb=$(awk '/MemAvailable:/ {print $2; exit}' /proc/meminfo 2>/dev/null || true)

    mem_used_percent=$(
        awk -v t="${mem_total_kb:-0}" -v a="${mem_avail_kb:-0}" '
            BEGIN{
                if(t>0 && a>0){
                    printf "%.1f%%", (t-a)*100/t
                } else {
                    print "N/A"
                }
            }' 2>/dev/null || true
    )
    print_kv "内存" "总计: $(format_kb "$mem_total_kb") | 已用: ${mem_used_percent} | 可用: $(format_kb "$mem_avail_kb")"

    local disk_type disk_size disk_used disk_avail disk_percent
    disk_type=$(df -hPT / 2>/dev/null | awk 'NR==2 {print $2}' || true)
    disk_size=$(df -hPT / 2>/dev/null | awk 'NR==2 {print $3}' || true)
    disk_used=$(df -hPT / 2>/dev/null | awk 'NR==2 {print $4}' || true)
    disk_avail=$(df -hPT / 2>/dev/null | awk 'NR==2 {print $5}' || true)
    disk_percent=$(df -hPT / 2>/dev/null | awk 'NR==2 {print $6}' || true)
    if [ -n "$disk_size" ] && [ -n "$disk_percent" ]; then
        print_kv "磁盘(/)" "${disk_type:-N/A} 总:${disk_size} 已用:${disk_used} (${disk_percent}) 可用:${disk_avail}"
    else
        print_kv "磁盘(/)" "N/A"
    fi
}

section_storage_full() {
    print_title "存储明细"
    if ! has_cmd df; then
        print_kv "df" "未安装"
        return 0
    fi

    df -hPT \
        -x tmpfs -x devtmpfs -x devpts -x proc -x sysfs -x cgroup -x cgroup2 \
        -x securityfs -x pstore -x efivarfs -x autofs -x debugfs -x mqueue \
        -x hugetlbfs -x tracefs -x fusectl -x squashfs 2>/dev/null \
        | awk 'NR==1{next} {printf "%s|%s|%s|%s|%s|%s\n",$7,$2,$3,$4,$6,$1}' \
        | while IFS='|' read -r mount fs_type size used percent device; do
            case "$mount" in
                /var/lib/docker/*|/run/*|/snap/*) continue ;;
            esac
            printf '  %b%s%b (%b%s%b - %s)\n' "${C_INFO}" "$mount" "${C_RESET}" "${C_VALUE}" "$device" "${C_RESET}" "$fs_type"
            printf '    %b总:%b %b%s%b, %b已用:%b %b%s%b (%b%s%b)\n' \
                "${C_LABEL}" "${C_RESET}" "${C_BLUE}" "$size" "${C_RESET}" \
                "${C_LABEL}" "${C_RESET}" "${C_BLUE}" "$used" "${C_RESET}" \
                "${C_VALUE}" "$percent" "${C_RESET}"
        done
}

section_network() {
    print_title "网络连接"

    if has_cmd ip; then
        local default_route default_iface default_gw
        default_route=$(ip route show default 2>/dev/null | head -n 1 || true)
        if [ -n "$default_route" ]; then
            default_gw=$(printf '%s\n' "$default_route" | awk '{print $3}' || true)
            default_iface=$(printf '%s\n' "$default_route" | awk '{for(i=1;i<=NF;i++) if($i=="dev"){print $(i+1); exit}}' || true)
            [ -n "$default_iface" ] && print_kv "默认路由" "dev=${default_iface} gw=${default_gw:-N/A}"
        fi

        local has_ip=0
        local iface
        while IFS= read -r iface; do
            [ -n "$iface" ] || continue
            case "$iface" in
                lo|docker*|veth*|br-*|virbr* ) continue ;;
            esac

            local ipv4 ipv6 mac
            ipv4=$(ip -o -4 addr show dev "$iface" scope global 2>/dev/null | awk '{print $4}' | cut -d/ -f1 | paste -sd' ' - || true)
            ipv6=$(ip -o -6 addr show dev "$iface" scope global 2>/dev/null | awk '{print $4}' | cut -d/ -f1 | paste -sd' ' - || true)
            mac=$(ip link show dev "$iface" 2>/dev/null | awk '/link\/ether/ {print $2; exit}' || true)

            if [ -n "$ipv4" ] || [ -n "$ipv6" ]; then
                has_ip=1
                printf '  %b%s%b\n' "${C_INFO}${C_BOLD}" "$iface" "${C_RESET}"
                [ -n "$ipv4" ] && printf '    %bIPv4:%b %b%s%b\n' "${C_LABEL}" "${C_RESET}" "${C_VALUE}" "$ipv4" "${C_RESET}"
                [ -n "$ipv6" ] && printf '    %bIPv6:%b %b%s%b\n' "${C_LABEL}" "${C_RESET}" "${C_VALUE}" "$ipv6" "${C_RESET}"
                [ -n "$mac" ] && printf '    %bMAC:%b  %b%s%b\n' "${C_LABEL}" "${C_RESET}" "${C_VALUE}" "$mac" "${C_RESET}"
            fi
        done < <(ip -o link show up 2>/dev/null | awk -F': ' '{print $2}' | cut -d'@' -f1)

        if [ "$has_ip" -eq 0 ]; then
            print_kv "状态" "未检测到活动的网络连接或 IP 地址"
        fi
    else
        local ips
        ips=$(hostname -I 2>/dev/null | tr -s ' ' ' ' | sed 's/ $//' || true)
        if [ -n "$ips" ]; then
            print_kv "IP" "$ips"
        else
            print_kv "状态" "未检测到 IP（ip 命令不可用）"
        fi
    fi
}

section_docker() {
    local mode=$1

    if ! has_cmd docker; then
        return 0
    fi

    if ! docker ps >/dev/null 2>&1; then
        return 0
    fi

    local running total
    running=$(docker ps -q 2>/dev/null | wc -l | awk '{print $1}' || true)
    total=$(docker ps -aq 2>/dev/null | wc -l | awk '{print $1}' || true)

    print_title "Docker 容器"
    print_kv "容器数量" "运行中: ${running:-0} / 总计: ${total:-0}"

    if [ "$mode" = "full" ] && [ "${running:-0}" -gt 0 ] 2>/dev/null; then
        local names
        names=$(docker ps --format '{{.Names}}' 2>/dev/null | paste -sd', ' - || true)
        [ -n "$names" ] && print_kv "运行列表" "$names"
    fi
}

section_activity() {
    local mode=$1
    local user from_ip tty last_login

    user=${USER:-}
    [ -n "$user" ] || user=$(id -un 2>/dev/null || echo N/A)

    from_ip=''
    if [ -n "${SSH_CONNECTION:-}" ]; then
        from_ip=$(printf '%s\n' "$SSH_CONNECTION" | awk '{print $1}' || true)
    fi
    if [ -z "$from_ip" ] && has_cmd who; then
        from_ip=$(who -m 2>/dev/null | awk -F'[()]' '{print $2}' | awk '{print $1}' || true)
    fi

    tty=$(tty 2>/dev/null || true)

    print_title "登录与统计"
    print_kv "当前用户" "$user"
    [ -n "$from_ip" ] && print_kv "来源地址" "$from_ip"
    [ -n "$tty" ] && print_kv "终端" "$tty"

    last_login=$(
        last -n 5 -w "$user" 2>/dev/null \
            | awk -v u="$user" '$1==u && $0 !~ /wtmp begins/ && $0 !~ /still logged in/ {print; exit}' \
            || true
    )
    [ -n "$last_login" ] && print_kv "上次登录" "$last_login"

    if [ "$mode" = "full" ]; then
        local package_count='N/A'
        if has_cmd dpkg-query; then
            package_count=$(dpkg-query -f '${Package}\n' -W 2>/dev/null | wc -l | awk '{print $1}' || true)
            print_kv "软件包数" "${package_count:-N/A} (Debian/APT)"
        elif has_cmd rpm; then
            package_count=$(rpm -qa 2>/dev/null | wc -l | awk '{print $1}' || true)
            print_kv "软件包数" "${package_count:-N/A} (RPM/Yum/Dnf)"
        elif has_cmd pacman; then
            package_count=$(pacman -Qq 2>/dev/null | wc -l | awk '{print $1}' || true)
            print_kv "软件包数" "${package_count:-N/A} (Pacman)"
        fi
    fi
}

section_gpu() {
    if ! has_cmd lspci; then
        return 0
    fi

    local gpus
    gpus=$(lspci 2>/dev/null | awk -F': ' '/VGA compatible controller|3D controller|Display controller/{print $2}' || true)
    [ -n "$gpus" ] || return 0

    print_title "图形处理器 (GPU)"
    while IFS= read -r line; do
        [ -n "$line" ] || continue
        printf '  %b%s%b\n' "${C_VALUE}" "$line" "${C_RESET}"
    done <<<"$gpus"
}

main() {
    local mode=${LOGIN_INFO_MODE:-summary}
    local show_docker=1

    while [ $# -gt 0 ]; do
        case "$1" in
            --summary|--fast) mode=summary ;;
            --full) mode=full ;;
            --no-docker) show_docker=0 ;;
            --no-color) LOGIN_INFO_COLOR=never ;;
            -h|--help) usage; return 0 ;;
            *) printf '错误: 未知参数: %s\n' "$1" >&2; usage; return 2 ;;
        esac
        shift
    done

    init_colors

    section_system
    section_resources

    if [ "$mode" = "full" ]; then
        section_gpu
        section_storage_full
    fi

    section_network

    if [ "$show_docker" -eq 1 ]; then
        section_docker "$mode"
    fi

    section_activity "$mode"
    print_hr

    if [ "$mode" = "summary" ]; then
        printf '%b提示:%b 运行 %blogin-info --full%b 查看更完整信息\n' \
            "${C_SUBTLE}" "${C_RESET}" "${C_INFO}" "${C_RESET}"
    fi
}

main "$@"