#!/bin/bash

set -euo pipefail

TARGET_USER=${TARGET_USER:-leador}
TARGET_IP=${TARGET_IP:-192.168.191.37}
SSH_PORT=${SSH_PORT:-22}
PASSWORD_AUTH=${PASSWORD_AUTH:-yes}
PUBKEY_AUTH=${PUBKEY_AUTH:-yes}
PERMIT_ROOT_LOGIN=${PERMIT_ROOT_LOGIN:-no}
CONNECTIVITY_HOSTS=${CONNECTIVITY_HOSTS:-"223.5.5.5 1.1.1.1 8.8.8.8"}
ROOT_PASSWORD=${ROOT_PASSWORD:-}

log_info() {
    echo "[INFO] $*"
}

log_warn() {
    echo "[WARN] $*" >&2
}

log_error() {
    echo "[ERROR] $*" >&2
}

need_cmd() {
    local name="$1"
    if ! command -v "$name" >/dev/null 2>&1; then
        log_error "缺少命令: $name"
        exit 1
    fi
}

validate_port() {
    if ! [[ "$SSH_PORT" =~ ^[0-9]+$ ]] || ((SSH_PORT < 1 || SSH_PORT > 65535)); then
        log_error "SSH_PORT 必须是 1-65535 之间的数字，当前值: $SSH_PORT"
        exit 1
    fi
}

validate_yes_no() {
    local name="$1"
    local value="$2"
    if [[ "$value" != "yes" && "$value" != "no" ]]; then
        log_error "$name 只能是 yes 或 no，当前值: $value"
        exit 1
    fi
}

run_root() {
    if [[ "$(id -u)" -eq 0 ]]; then
        "$@"
    else
        sudo "$@"
    fi
}

write_sudo_bootstrap_script() {
    local script_path="$1"
    cat > "$script_path" <<'BOOTSTRAP_SUDO'
#!/bin/bash
set -euo pipefail

target_user="$1"

if ! id "$target_user" >/dev/null 2>&1; then
    echo "[ERROR] 用户不存在: $target_user" >&2
    exit 1
fi

if ! command -v sudo >/dev/null 2>&1; then
    if command -v apt-get >/dev/null 2>&1; then
        apt-get update
        apt-get install -y sudo
    else
        echo "[ERROR] 系统未安装 sudo，且找不到 apt-get 自动安装" >&2
        exit 1
    fi
fi

if command -v groupadd >/dev/null 2>&1 && ! getent group sudo >/dev/null 2>&1; then
    groupadd sudo
fi

if command -v usermod >/dev/null 2>&1 && getent group sudo >/dev/null 2>&1; then
    usermod -aG sudo "$target_user"
fi

mkdir -p /etc/sudoers.d
tmp_file=$(mktemp /tmp/start-bootstrap-sudoers.XXXXXX)
trap 'rm -f "$tmp_file"' EXIT

cat > "$tmp_file" <<EOF
# Generated by start.sh to let the target user prepare SSH and deployment sudo.
${target_user} ALL=(ALL:ALL) ALL
EOF

if command -v visudo >/dev/null 2>&1; then
    visudo -cf "$tmp_file" >/dev/null
fi

install -o root -g root -m 0440 "$tmp_file" "/etc/sudoers.d/90-${target_user}-sudo"
BOOTSTRAP_SUDO
    chmod 700 "$script_path"
}

bootstrap_sudo_with_root() {
    local target_user="$1"
    log_info "当前 shell 是 root，正在给用户 ${target_user} 添加 sudo 权限"

    local bootstrap_script=""
    bootstrap_script=$(mktemp /tmp/start-bootstrap-sudo.XXXXXX)
    write_sudo_bootstrap_script "$bootstrap_script"

    local status=0
    set +e
    "$bootstrap_script" "$target_user"
    status=$?
    set -e
    rm -f "$bootstrap_script"
    return "$status"
}

bootstrap_sudo_with_su() {
    local target_user="$1"
    need_cmd su

    log_warn "当前用户没有可用 sudo 权限，尝试通过 root 用户为 ${target_user} 添加 sudo 权限"

    local bootstrap_script=""
    bootstrap_script=$(mktemp /tmp/start-bootstrap-sudo.XXXXXX)
    write_sudo_bootstrap_script "$bootstrap_script"

    local status=0
    set +e
    if [[ -n "$ROOT_PASSWORD" ]]; then
        printf '%s\n' "$ROOT_PASSWORD" | su root -c "bash '$bootstrap_script' '$target_user'"
        status=$?
    else
        su root -c "bash '$bootstrap_script' '$target_user'"
        status=$?
    fi
    set -e

    rm -f "$bootstrap_script"
    return "$status"
}

ensure_sudo_access() {
    log_info "检查 ${TARGET_USER} 的 sudo 权限"

    if [[ "$(id -u)" -eq 0 ]]; then
        bootstrap_sudo_with_root "$TARGET_USER"
        return
    fi

    if [[ "$(id -un)" == "$TARGET_USER" ]] && command -v sudo >/dev/null 2>&1 && sudo -n true 2>/dev/null; then
        log_info "当前用户已有免密 sudo 权限"
        return
    fi

    if [[ "$(id -un)" == "$TARGET_USER" ]] && [[ -t 0 ]] && command -v sudo >/dev/null 2>&1 && sudo -v; then
        log_info "当前用户已有 sudo 权限"
        return
    fi

    bootstrap_sudo_with_su "$TARGET_USER"

    if [[ "$(id -un)" == "$TARGET_USER" ]] && command -v sudo >/dev/null 2>&1 && sudo -n true 2>/dev/null; then
        log_info "sudo 权限已补齐"
        return
    fi

    if [[ "$(id -un)" == "$TARGET_USER" ]] && [[ -t 0 ]] && command -v sudo >/dev/null 2>&1 && sudo -v; then
        log_info "sudo 权限已补齐"
        return
    fi

    if [[ "$(id -un)" != "$TARGET_USER" ]]; then
        log_info "已为 ${TARGET_USER} 写入 sudo 授权，后续 root 操作继续由当前用户执行"
        return
    fi

    log_error "已尝试添加 sudo 权限，但 ${TARGET_USER} 仍无法执行 sudo"
    log_error "如果刚加入 sudo 组仍不生效，请重新登录；如果 root 被禁用，请先用具备管理员权限的账号处理"
    exit 1
}

detect_target_ip() {
    if [[ -n "$TARGET_IP" ]]; then
        return
    fi

    local detected=""
    detected=$(ip -o -4 addr show scope global 2>/dev/null | awk '{print $4}' | cut -d/ -f1 | head -n 1 || true)
    if [[ -n "$detected" ]]; then
        TARGET_IP="$detected"
    else
        TARGET_IP="<target-ip>"
    fi
}

check_connectivity() {
    log_info "检查目标设备联网状态"

    local ok=0
    local host=""
    for host in $CONNECTIVITY_HOSTS; do
        if ping -c 1 -W 2 "$host" >/dev/null 2>&1; then
            log_info "网络连通: ping $host 成功"
            ok=1
            break
        fi
    done

    if [[ "$ok" -ne 1 ]]; then
        log_error "目标设备无法 ping 通联网检测地址: $CONNECTIVITY_HOSTS"
        log_error "请先修复网络、DNS、网关、代理或 ZeroTier/LAN 路由，再重新执行本脚本"
        exit 1
    fi

    if ! getent hosts archive.ubuntu.com >/dev/null 2>&1 && ! getent hosts mirrors.aliyun.com >/dev/null 2>&1; then
        log_warn "DNS 解析 apt 源域名失败。ping IP 虽然成功，但 apt update 可能失败"
    fi
}

install_ssh_server() {
    if command -v sshd >/dev/null 2>&1; then
        log_info "openssh-server 已存在，跳过安装"
        return
    fi

    if command -v dpkg >/dev/null 2>&1 && dpkg -s openssh-server >/dev/null 2>&1; then
        log_info "openssh-server 已安装，跳过安装"
        return
    fi

    log_info "安装 openssh-server"
    need_cmd apt-get
    run_root apt-get update
    run_root apt-get install -y openssh-server
}

configure_sshd() {
    log_info "写入 SSH 配置: port=${SSH_PORT}, password=${PASSWORD_AUTH}, pubkey=${PUBKEY_AUTH}, root=${PERMIT_ROOT_LOGIN}"

    run_root mkdir -p /etc/ssh/sshd_config.d
    run_root tee /etc/ssh/sshd_config.d/10-remote-login.conf >/dev/null <<EOF
Port ${SSH_PORT}
PasswordAuthentication ${PASSWORD_AUTH}
PubkeyAuthentication ${PUBKEY_AUTH}
KbdInteractiveAuthentication no
PermitRootLogin ${PERMIT_ROOT_LOGIN}
UsePAM yes
EOF

    run_root sshd -t
}

configure_firewall() {
    log_info "配置防火墙放行 ${SSH_PORT}/tcp"

    if command -v ufw >/dev/null 2>&1; then
        local ufw_status=""
        ufw_status=$(run_root ufw status | head -n 1 || true)
        if [[ "$ufw_status" == *active* || "$ufw_status" == *活动* ]]; then
            run_root ufw allow "${SSH_PORT}/tcp"
            run_root ufw reload
            log_info "UFW 已放行 ${SSH_PORT}/tcp"
        else
            log_info "UFW 未启用，跳过 UFW 放行"
        fi
    fi

    if command -v firewall-cmd >/dev/null 2>&1; then
        if run_root firewall-cmd --state >/dev/null 2>&1; then
            run_root firewall-cmd --add-port="${SSH_PORT}/tcp" --permanent
            run_root firewall-cmd --reload
            log_info "firewalld 已放行 ${SSH_PORT}/tcp"
        else
            log_info "firewalld 未运行，跳过 firewalld 放行"
        fi
    fi
}

restart_ssh() {
    log_info "启动并重启 SSH 服务"
    run_root systemctl enable --now ssh
    run_root systemctl restart ssh
}

verify_ssh() {
    log_info "验证 SSH 服务状态"

    run_root sshd -t
    systemctl is-active --quiet ssh

    if ss -lntp 2>/dev/null | grep -qE ":${SSH_PORT}[[:space:]]"; then
        log_info "SSH 端口已监听: ${SSH_PORT}"
    else
        log_error "未发现 SSH 端口监听: ${SSH_PORT}"
        log_error "最近 SSH 日志如下:"
        run_root journalctl -u ssh -n 80 --no-pager || true
        exit 1
    fi

    log_info "当前 sshd 关键配置:"
    run_root sshd -T | grep -E '^(port|passwordauthentication|pubkeyauthentication|permitrootlogin|usepam) '
}

resolve_cmd_path() {
    local name="$1"
    local path=""
    path=$(type -P "$name" 2>/dev/null || true)
    if [[ -z "$path" ]]; then
        log_error "目标设备缺少必要命令: $name"
        exit 1
    fi
    printf '%s' "$path"
}

write_deploy_sudoers() {
    local deploy_user="$1"
    local sudoers_tmp=""

    log_info "写入完整免密 sudo 规则: user=${deploy_user}"

    resolve_cmd_path install >/dev/null
    resolve_cmd_path mkdir >/dev/null
    resolve_cmd_path visudo >/dev/null

    sudoers_tmp=$(mktemp /tmp/ecu-debug-client-deploy-sudoers.XXXXXX)

    cat > "$sudoers_tmp" <<EOF
# Generated by start.sh for ecu-debug-client deployment.
${deploy_user} ALL=(root) NOPASSWD: ALL
EOF

    run_root visudo -cf "$sudoers_tmp" >/dev/null
    run_root mkdir -p /etc/sudoers.d
    run_root install -o root -g root -m 0440 "$sudoers_tmp" /etc/sudoers.d/ecu-debug-client-deploy
    run_root visudo -cf /etc/sudoers.d/ecu-debug-client-deploy >/dev/null
    rm -f "$sudoers_tmp"
}

verify_deploy_sudoers() {
    local deploy_user="$1"
    local systemctl_path=""

    systemctl_path=$(resolve_cmd_path systemctl)

    log_info "验证 ${deploy_user} 可以无密码执行部署 sudo 命令"

    if [[ "$(id -u)" -ne 0 && "$(id -un)" == "$deploy_user" ]]; then
        sudo -k
        sudo -n "$systemctl_path" daemon-reload
        return
    fi

    need_cmd su
    run_root su -s /bin/bash -c "sudo -k; sudo -n '$systemctl_path' daemon-reload" "$deploy_user"
}

print_next_steps() {
    cat <<EOF

[SUCCESS] SSH 和部署 sudo 权限已准备完成

目标信息：
  用户: ${TARGET_USER}
  IP: ${TARGET_IP}
  端口: ${SSH_PORT}
  sudoers: /etc/sudoers.d/ecu-debug-client-deploy
  sudoers 权限: 完整免密 sudo

请在部署机执行连通性验证：
  nc -vz -w 3 ${TARGET_IP} ${SSH_PORT}
  ssh -p ${SSH_PORT} ${TARGET_USER}@${TARGET_IP} "hostname && whoami && sudo -n id"

验证通过后，在部署机执行：
  cd /media/mxhou/fast2t/ws/nav2/chassis/param_set/client
  ./client-deploy.sh --deploy-only
EOF

    if [[ "$SSH_PORT" != "22" ]]; then
        cat <<EOF

[WARN] 当前 SSH_PORT=${SSH_PORT}，如果 client-deploy.sh 仍按默认 22 端口连接，
       需要同步给部署脚本增加端口支持，或在部署机 ~/.ssh/config 中配置目标 Host/Port。
EOF
    fi
}

main() {
    validate_port
    validate_yes_no PASSWORD_AUTH "$PASSWORD_AUTH"
    validate_yes_no PUBKEY_AUTH "$PUBKEY_AUTH"
    validate_yes_no PERMIT_ROOT_LOGIN "$PERMIT_ROOT_LOGIN"

    need_cmd ping
    need_cmd getent
    need_cmd ip
    need_cmd systemctl
    need_cmd ss
    need_cmd awk
    need_cmd cut
    need_cmd head
    need_cmd grep
    need_cmd mktemp
    need_cmd install

    ensure_sudo_access
    detect_target_ip
    check_connectivity
    install_ssh_server
    configure_sshd
    configure_firewall
    restart_ssh
    verify_ssh
    write_deploy_sudoers "$TARGET_USER"
    verify_deploy_sudoers "$TARGET_USER"
    print_next_steps
}

main "$@"