core/course_bot.py

from __future__ import annotations

import base64
import json
import re
import time
from dataclasses import dataclass
from pathlib import Path
from typing import Callable

from selenium.common.exceptions import NoSuchElementException, TimeoutException, WebDriverException
from selenium.webdriver.common.by import By
from selenium.webdriver.remote.webdriver import WebDriver
from selenium.webdriver.remote.webelement import WebElement
from selenium.webdriver.support.wait import WebDriverWait

import onnx_inference
import webdriver_utils
from core.db import Database


URL_LOGIN = "http://id.scu.edu.cn/enduser/sp/sso/scdxplugin_jwt23?enterpriseId=scdx&target_url=index"
URL_SELECT_COURSE = "http://zhjw.scu.edu.cn/student/courseSelect/courseSelect/index"
LOGIN_SUCCESS_PREFIXES = (
    "http://zhjw.scu.edu.cn/index",
    "http://zhjw.scu.edu.cn/",
    "https://zhjw.scu.edu.cn/index",
    "https://zhjw.scu.edu.cn/",
)
CATEGORY_META = {
    "plan": {"label": "方案选课", "tab_id": "faxk"},
    "free": {"label": "自由选课", "tab_id": "zyxk"},
}

LOGIN_STUDENT_SELECTORS = [
    (By.XPATH, "//*[@id='app']//form//input[@type='text']"),
    (By.XPATH, "//*[@id='app']/div[1]/div/div[2]/div/div[1]/div[2]/div[2]/div/form/div[1]/div/div/div[2]/div/input"),
]
LOGIN_PASSWORD_SELECTORS = [
    (By.XPATH, "//*[@id='app']//form//input[@type='password']"),
    (By.XPATH, "//*[@id='app']/div[1]/div/div[2]/div/div[1]/div[2]/div[2]/div/form/div[2]/div/div/div[2]/div/input"),
]
LOGIN_CAPTCHA_INPUT_SELECTORS = [
    (By.XPATH, "//*[@id='app']/div[1]/div/div[2]/div/div[1]/div[2]/div[2]/div/form/div[3]//input"),
    (By.XPATH, "//*[@id='app']//form//input[contains(@placeholder, '验证码')]"),
]
LOGIN_CAPTCHA_IMAGE_SELECTORS = [
    (By.XPATH, "//*[@id='app']/div[1]/div/div[2]/div/div[1]/div[2]/div[2]/div/form/div[3]//img"),
    (By.XPATH, "//*[@id='app']//form//img"),
]
LOGIN_BUTTON_SELECTORS = [
    (By.XPATH, "//*[@id='app']//form//button"),
    (By.XPATH, "//*[@id='app']/div[1]/div/div[2]/div/div[1]/div[2]/div[2]/div/form/div[4]/div/button"),
]
SUBMIT_CAPTCHA_IMAGE_SELECTORS = [
    (By.XPATH, "//div[contains(@class,'dialog') or contains(@class,'modal') or contains(@class,'popup')]//img[contains(@src,'base64') or contains(translate(@src,'ABCDEFGHIJKLMNOPQRSTUVWXYZ','abcdefghijklmnopqrstuvwxyz'),'captcha')]"),
    (By.XPATH, "//img[contains(@src,'base64')]"),
    (By.XPATH, "//img[contains(translate(@alt,'ABCDEFGHIJKLMNOPQRSTUVWXYZ','abcdefghijklmnopqrstuvwxyz'),'captcha') or contains(translate(@class,'ABCDEFGHIJKLMNOPQRSTUVWXYZ','abcdefghijklmnopqrstuvwxyz'),'captcha')]"),
]
SUBMIT_CAPTCHA_INPUT_SELECTORS = [
    (By.XPATH, "//input[contains(@placeholder,'验证码')]"),
    (By.XPATH, "//input[contains(translate(@id,'ABCDEFGHIJKLMNOPQRSTUVWXYZ','abcdefghijklmnopqrstuvwxyz'),'captcha')]"),
    (By.XPATH, "//input[contains(translate(@name,'ABCDEFGHIJKLMNOPQRSTUVWXYZ','abcdefghijklmnopqrstuvwxyz'),'captcha')]"),
]
SUBMIT_CAPTCHA_BUTTON_SELECTORS = [
    (By.XPATH, "//button[contains(.,'确定') or contains(.,'提交') or contains(.,'确认') or contains(.,'验证')]"),
    (By.XPATH, "//input[(@type='button' or @type='submit') and (contains(@value,'确定') or contains(@value,'提交') or contains(@value,'确认') or contains(@value,'验证'))]"),
]


class FatalCredentialsError(Exception):
    pass


class RecoverableAutomationError(Exception):
    pass


@dataclass(slots=True)
class TaskResult:
    status: str
    error: str = ""


class CourseBot:
    def __init__(
        self,
        *,
        config,
        store: Database,
        task_id: int,
        user: dict,
        password: str,
        logger: Callable[[str, str], None],
    ) -> None:
        self.config = config
        self.store = store
        self.task_id = task_id
        self.user = user
        self.password = password
        self.logger = logger
        self.root_dir = Path(__file__).resolve().parent.parent
        self.select_course_js = (self.root_dir / "javascript" / "select_course.js").read_text(encoding="utf-8")
        self.check_result_js = (self.root_dir / "javascript" / "check_result.js").read_text(encoding="utf-8")
        self.captcha_solver = onnx_inference.CaptchaONNXInference(
            model_path=str(self.root_dir / "ocr_provider" / "captcha_model.onnx")
        )

    def run(self, stop_event) -> TaskResult:
        exhausted_sessions = 0
        while not stop_event.is_set():
            courses = self.store.list_courses_for_user(self.user["id"])
            if not courses:
                self.logger("INFO", "当前没有待抢课程，任务自动结束。")
                return TaskResult(status="completed")

            driver: WebDriver | None = None
            session_ready = False
            session_error_count = 0
            try:
                self.logger(
                    "INFO",
                    f"启动新的 Selenium 会话。累计已重建 {exhausted_sessions}/{self.config.selenium_restart_limit} 次。",
                )
                driver = webdriver_utils.configure_browser(
                    chrome_binary=self.config.chrome_binary,
                    chromedriver_path=self.config.chromedriver_path,
                    page_timeout=self.config.browser_page_timeout,
                )
                wait = WebDriverWait(driver, self.config.browser_page_timeout, 0.5)

                while not stop_event.is_set():
                    try:
                        if not session_ready:
                            self._login(driver, wait)
                            session_ready = True

                        current_courses = self.store.list_courses_for_user(self.user["id"])
                        if not current_courses:
                            self.logger("INFO", "所有目标课程都已经从队列中移除，任务完成。")
                            return TaskResult(status="completed")

                        if not self._goto_select_course(driver, wait):
                            session_error_count = 0
                            self._sleep_with_cancel(stop_event, self.config.poll_interval_seconds, "当前不是选课时段，等待下一轮检查。")
                            continue

                        attempts = 0
                        successes = 0
                        grouped_courses = {"plan": [], "free": []}
                        for course in current_courses:
                            grouped_courses[course["category"]].append(course)

                        for category, items in grouped_courses.items():
                            if not items:
                                continue
                            for course in items:
                                if stop_event.is_set():
                                    break
                                attempts += 1
                                if self._attempt_single_course(driver, wait, course):
                                    successes += 1

                        if attempts == 0:
                            self.logger("INFO", "没有可执行的课程项目，下一轮将自动重试。")
                        elif successes == 0:
                            self.logger("INFO", "本轮没有抢到目标课程，准备稍后重试。")
                        else:
                            self.logger("INFO", f"本轮处理 {attempts} 门课程，成功更新 {successes} 门。")

                        session_error_count = 0
                        if exhausted_sessions:
                            self.logger("INFO", "当前 Selenium 会话已恢复稳定，浏览器重建错误计数已清零。")
                            exhausted_sessions = 0

                        if not self.store.list_courses_for_user(self.user["id"]):
                            self.logger("INFO", "全部课程均已处理完成。")
                            return TaskResult(status="completed")

                        self._sleep_with_cancel(stop_event, self.config.poll_interval_seconds, "等待下一轮刷新。")
                    except FatalCredentialsError as exc:
                        self.logger("ERROR", str(exc))
                        return TaskResult(status="failed", error=str(exc))
                    except RecoverableAutomationError as exc:
                        session_ready = False
                        session_error_count += 1
                        self.logger(
                            "WARNING",
                            f"当前 Selenium 会话第 {session_error_count}/{self.config.selenium_error_limit} 次可恢复错误: {exc}",
                        )
                        if session_error_count < self.config.selenium_error_limit:
                            self._sleep_with_cancel(
                                stop_event,
                                self.config.task_backoff_seconds,
                                "将在当前 Selenium 会话内继续重试",
                            )
                            continue

                        exhausted_sessions += 1
                        if exhausted_sessions >= self.config.selenium_restart_limit:
                            message = (
                                f"Selenium 会话连续达到错误上限并已重建 {exhausted_sessions} 次，任务终止。"
                                f"最后错误: {exc}"
                            )
                            self.logger("ERROR", message)
                            return TaskResult(status="failed", error=message)

                        self.logger(
                            "WARNING",
                            f"当前 Selenium 会话连续错误达到 {self.config.selenium_error_limit} 次，准备重建浏览器。"
                            f"已耗尽 {exhausted_sessions}/{self.config.selenium_restart_limit} 个会话。",
                        )
                        break
                    except Exception as exc:  # pragma: no cover - defensive fallback
                        session_ready = False
                        session_error_count += 1
                        self.logger(
                            "WARNING",
                            f"当前 Selenium 会话第 {session_error_count}/{self.config.selenium_error_limit} 次未知错误: {exc}",
                        )
                        if session_error_count < self.config.selenium_error_limit:
                            self._sleep_with_cancel(
                                stop_event,
                                self.config.task_backoff_seconds,
                                "当前会话发生未知错误，稍后重试",
                            )
                            continue

                        exhausted_sessions += 1
                        if exhausted_sessions >= self.config.selenium_restart_limit:
                            message = (
                                f"Selenium 会话连续达到错误上限并已重建 {exhausted_sessions} 次，任务终止。"
                                f"最后错误: {exc}"
                            )
                            self.logger("ERROR", message)
                            return TaskResult(status="failed", error=message)

                        self.logger(
                            "WARNING",
                            f"未知错误累计达到上限，准备重建 Selenium 会话。"
                            f"已耗尽 {exhausted_sessions}/{self.config.selenium_restart_limit} 个会话。",
                        )
                        break
            finally:
                if driver is not None:
                    try:
                        driver.quit()
                    except Exception:
                        pass

        self.logger("INFO", "收到停止信号，任务已结束。")
        return TaskResult(status="stopped")

    def _login(self, driver: WebDriver, wait: WebDriverWait) -> None:
        for attempt in range(1, self.config.login_retry_limit + 1):
            self._open_page(driver, wait, URL_LOGIN, f"登录页（第 {attempt} 次）", log_on_success=True)

            std_id_box = self._find_first_visible(driver, LOGIN_STUDENT_SELECTORS, "登录学号输入框", timeout=6)
            password_box = self._find_first_visible(driver, LOGIN_PASSWORD_SELECTORS, "登录密码输入框", timeout=6)
            captcha_box = self._find_first_visible(driver, LOGIN_CAPTCHA_INPUT_SELECTORS, "登录验证码输入框", timeout=6)
            login_button = self._find_first_visible(driver, LOGIN_BUTTON_SELECTORS, "登录按钮", timeout=6)
            captcha_image = self._find_first_visible(driver, LOGIN_CAPTCHA_IMAGE_SELECTORS, "登录验证码图片", timeout=6)

            captcha_text = self._solve_captcha_text(captcha_image, scene="登录")
            self.logger("INFO", f"登录尝试 {attempt}/{self.config.login_retry_limit}，验证码 OCR 输出: {captcha_text}")

            std_id_box.clear()
            std_id_box.send_keys(self.user["student_id"])
            password_box.clear()
            password_box.send_keys(self.password)
            captcha_box.clear()
            captcha_box.send_keys(captcha_text)
            self.logger("INFO", f"登录尝试 {attempt}/{self.config.login_retry_limit}，准备提交登录表单。")
            submit_method = self._trigger_non_blocking_action(
                driver,
                login_button,
                label="登录表单",
                allow_form_submit=True,
            )
            self.logger("INFO", f"登录表单已触发提交，方式={submit_method}，开始等待登录结果。")

            state, error_message = self._wait_for_login_outcome(driver, timeout_seconds=10)
            if state == "success":
                self.logger("INFO", f"登录成功，耗费 {attempt} 次尝试。")
                return

            if any(token in error_message for token in ("用户名或密码错误", "密码错误", "账号或密码错误", "用户不存在")):
                raise FatalCredentialsError("学号或密码错误，任务已停止，请在面板中更新后重新启动。")

            if error_message:
                self.logger("WARNING", f"登录失败，第 {attempt} 次尝试: {error_message}")
            else:
                self.logger(
                    "WARNING",
                    f"登录失败，第 {attempt} 次尝试，未读取到明确错误提示。{self._page_snapshot(driver, include_body=True)}",
                )

            time.sleep(0.6)

        raise RecoverableAutomationError("连续多次登录失败，可能是验证码识别失败、页面异常或系统暂时不可用。")

    def _goto_select_course(self, driver: WebDriver, wait: WebDriverWait) -> bool:
        self._open_page(driver, wait, URL_SELECT_COURSE, "选课页")
        if self._is_session_expired(driver):
            raise RecoverableAutomationError("检测到登录会话已失效，准备重新登录。")

        body_text = self._safe_body_text(driver)
        if "非选课" in body_text or "未到选课时间" in body_text:
            self.logger("INFO", body_text.strip() or "当前不是选课时段。")
            return False
        return True

    def _attempt_single_course(self, driver: WebDriver, wait: WebDriverWait, course: dict) -> bool:
        category_name = CATEGORY_META[course["category"]]["label"]
        course_key = f'{course["course_id"]}_{course["course_index"]}'
        self.logger("INFO", f"开始尝试 {category_name} {course_key}。")

        if not self._goto_select_course(driver, wait):
            self.logger("INFO", f"跳过 {course_key}，当前系统暂时不在可选课页面。")
            return False
        self._open_category_tab(driver, wait, course["category"])

        try:
            wait.until(lambda current_driver: current_driver.find_element(By.ID, "ifra"))
            driver.switch_to.frame("ifra")
            course_id_box = self._find(driver, By.ID, "kch")
            search_button = self._find(driver, By.ID, "queryButton")
            course_id_box.clear()
            course_id_box.send_keys(course["course_id"])
            search_button.click()
            wait.until(
                lambda current_driver: current_driver.execute_script(
                    "return document.getElementById('queryButton').innerText.indexOf('正在') === -1"
                )
            )
        except TimeoutException as exc:
            raise RecoverableAutomationError(
                f"课程查询超时，页面可能暂时无响应。{self._page_snapshot(driver, include_body=True)}"
            ) from exc
        finally:
            driver.switch_to.default_content()

        time.sleep(0.2)
        try:
            found_target = driver.execute_script(self.select_course_js, course_key) == "yes"
        except WebDriverException as exc:
            raise RecoverableAutomationError(f"执行课程勾选脚本失败。{self._page_snapshot(driver, include_body=True)}") from exc
        if not found_target:
            self.logger("INFO", f"本轮未找到目标课程 {course_key}。")
            return False

        self.logger("INFO", f"已勾选目标课程 {course_key}，准备提交。")
        results = self._submit_with_optional_captcha(driver, wait, course_key)
        if not results:
            self.logger("WARNING", f"提交 {course_key} 后没有读取到结果列表。")
            return False

        satisfied = False
        for result in results:
            detail = (result.get("detail") or "").strip()
            subject = (result.get("subject") or course_key).strip()
            if result.get("result"):
                self.logger("SUCCESS", f"成功抢到课程: {subject}")
                satisfied = True
            elif any(token in detail for token in ("已选", "已选择", "已经选", "已在已选课程")):
                self.logger("INFO", f"课程已在系统中存在，自动从队列移除: {subject}")
                satisfied = True
            else:
                self.logger("WARNING", f"课程 {subject} 抢课失败: {detail or '未知原因'}")

        if satisfied:
            self.store.remove_course_by_identity(
                self.user["id"],
                course["category"],
                course["course_id"],
                course["course_index"],
            )
            return True
        return False

    def _submit_with_optional_captcha(self, driver: WebDriver, wait: WebDriverWait, course_key: str) -> list[dict]:
        submit_button = self._find(driver, By.ID, "submitButton")
        submit_method = self._trigger_non_blocking_action(
            driver,
            submit_button,
            label=f"课程提交按钮 {course_key}",
            allow_form_submit=True,
        )
        self.logger("INFO", f"课程 {course_key} 已触发提交，方式={submit_method}。")

        for attempt in range(1, self.config.submit_captcha_retry_limit + 1):
            state = self._wait_for_submit_state(driver, wait)
            if state == "result":
                return self._read_result_page(driver, wait)
            if state == "captcha":
                self.logger("INFO", f"提交 {course_key} 时检测到验证码，第 {attempt} 次自动识别。")
                if not self._solve_visible_submit_captcha(driver):
                    raise RecoverableAutomationError("提交选课时检测到验证码，但未能自动完成识别与提交。")
                continue
            self.logger("WARNING", f"提交 {course_key} 后页面未返回结果，也未检测到验证码。")

        raise RecoverableAutomationError("提交选课后连续多次遇到验证码或未返回结果。")

    def _wait_for_submit_state(self, driver: WebDriver, wait: WebDriverWait) -> str:
        script = """
            const visible = (el) => {
                if (!el) return false;
                const style = window.getComputedStyle(el);
                const rect = el.getBoundingClientRect();
                return style.display !== 'none' && style.visibility !== 'hidden' && rect.width > 0 && rect.height > 0;
            };
            if (document.querySelector('#xkresult tbody tr')) return 'result';
            const input = Array.from(document.querySelectorAll('input')).find((el) => {
                const text = `${el.placeholder || ''} ${el.id || ''} ${el.name || ''} ${el.className || ''}`;
                return visible(el) && /验证码|captcha/i.test(text);
            });
            const img = Array.from(document.querySelectorAll('img')).find((el) => {
                const text = `${el.src || ''} ${el.id || ''} ${el.alt || ''} ${el.className || ''}`;
                return visible(el) && (/captcha/i.test(text) || (el.src || '').includes('base64') || (el.naturalWidth >= 50 && el.naturalWidth <= 240 && el.naturalHeight >= 20 && el.naturalHeight <= 120));
            });
            const button = Array.from(document.querySelectorAll('button, input[type="button"], input[type="submit"]')).find((el) => {
                const text = `${el.innerText || ''} ${el.value || ''}`;
                return visible(el) && /确定|提交|确认|验证/.test(text);
            });
            if (input && img && button) return 'captcha';
            return 'pending';
        """
        try:
            wait.until(lambda current_driver: current_driver.execute_script(script) != "pending")
        except TimeoutException:
            return "pending"
        return str(driver.execute_script(script))

    def _solve_visible_submit_captcha(self, driver: WebDriver) -> bool:
        image = self._find_first_visible_optional(driver, SUBMIT_CAPTCHA_IMAGE_SELECTORS, timeout=3)
        input_box = self._find_first_visible_optional(driver, SUBMIT_CAPTCHA_INPUT_SELECTORS, timeout=3)
        button = self._find_first_visible_optional(driver, SUBMIT_CAPTCHA_BUTTON_SELECTORS, timeout=3)
        if not image or not input_box or not button:
            return False

        captcha_text = self._solve_captcha_text(image, scene="提交")
        self.logger("INFO", f"提交验证码 OCR 输出: {captcha_text}")
        input_box.clear()
        input_box.send_keys(captcha_text)
        submit_method = self._trigger_non_blocking_action(
            driver,
            button,
            label="提交验证码确认按钮",
            allow_form_submit=True,
        )
        self.logger("INFO", f"提交验证码确认已触发，方式={submit_method}。")
        time.sleep(1.0)
        return True

    def _open_category_tab(self, driver: WebDriver, wait: WebDriverWait, category: str) -> None:
        tab_id = CATEGORY_META[category]["tab_id"]
        tab = self._find(driver, By.ID, tab_id)
        tab.click()
        webdriver_utils.wait_for_ready(wait, allow_interactive=True)
        time.sleep(0.2)

    def _read_result_page(self, driver: WebDriver, wait: WebDriverWait) -> list[dict]:
        try:
            webdriver_utils.wait_for_ready(wait, allow_interactive=True)
            wait.until(
                lambda current_driver: current_driver.execute_script(
                    """
                    const node = document.querySelector('#xkresult tbody tr');
                    return Boolean(node);
                    """
                )
            )
            return json.loads(driver.execute_script(self.check_result_js))
        except Exception as exc:
            raise RecoverableAutomationError(
                f"读取选课结果失败，页面结构可能发生变化。{self._page_snapshot(driver, include_body=True)}"
            ) from exc

    def _open_page(
        self,
        driver: WebDriver,
        wait: WebDriverWait,
        url: str,
        label: str,
        *,
        allow_interactive: bool = True,
        log_on_success: bool = False,
    ) -> None:
        timed_out = webdriver_utils.open_with_recovery(driver, url)
        if timed_out:
            self.logger("WARNING", f"{label} 页面加载超时，尝试停止页面并继续执行。")
        try:
            ready_state = webdriver_utils.wait_for_ready(wait, allow_interactive=allow_interactive)
        except TimeoutException as exc:
            raise RecoverableAutomationError(f"{label} 页面加载失败。{self._page_snapshot(driver, include_body=True)}") from exc
        if log_on_success or timed_out:
            self.logger("INFO", f"{label} 页面已打开，readyState={ready_state}。{self._page_snapshot(driver, include_body=timed_out)}")

    def _wait_for_login_outcome(self, driver: WebDriver, timeout_seconds: int = 10) -> tuple[str, str]:
        deadline = time.monotonic() + max(1, timeout_seconds)
        last_error = ""
        while time.monotonic() < deadline:
            try:
                current_url = driver.current_url or ""
            except WebDriverException:
                time.sleep(0.3)
                continue
            if self._is_login_success_url(current_url):
                return "success", ""
            last_error = self._read_login_error(driver)
            if last_error:
                return "error", last_error
            time.sleep(0.4)
        return "unknown", self._read_login_error(driver)

    def _read_login_error(self, driver: WebDriver) -> str:
        script = """
            const visible = (node) => {
                if (!node) return false;
                const style = window.getComputedStyle(node);
                const rect = node.getBoundingClientRect();
                return style.display !== 'none' && style.visibility !== 'hidden' && rect.width > 0 && rect.height > 0;
            };
            const selectors = [
                '.el-message',
                '[role="alert"]',
                '.message',
                '.toast',
                '.el-form-item__error',
                '.error'
            ];
            for (const selector of selectors) {
                for (const node of Array.from(document.querySelectorAll(selector))) {
                    const text = (node.innerText || '').trim();
                    if (visible(node) && text) {
                        return text;
                    }
                }
            }
            const nodes = Array.from(document.querySelectorAll('body span, body div'));
            for (const node of nodes) {
                const text = (node.innerText || '').trim();
                if (!text || !visible(node)) continue;
                if (/验证码|密码|用户|账号/.test(text)) return text;
            }
            return '';
        """
        try:
            raw_message = driver.execute_script(script) or ""
        except WebDriverException:
            return ""
        return re.sub(r"\s+", " ", str(raw_message)).strip()

    def _trigger_non_blocking_action(
        self,
        driver: WebDriver,
        element: WebElement,
        *,
        label: str,
        allow_form_submit: bool = False,
    ) -> str:
        script = """
            const target = arguments[0];
            const allowFormSubmit = Boolean(arguments[1]);
            const form = allowFormSubmit && target ? (target.form || target.closest('form')) : null;
            let method = 'unavailable';

            if (form && typeof form.requestSubmit === 'function') {
                method = 'scheduled-requestSubmit';
            } else if (target && typeof target.click === 'function') {
                method = 'scheduled-js-click';
            } else if (target) {
                method = 'scheduled-dispatch-click';
            } else if (form && typeof form.submit === 'function') {
                method = 'scheduled-form-submit';
            }

            if (!target && !form) {
                return 'unavailable';
            }

            window.setTimeout(() => {
                const dispatchFallback = (node) => {
                    if (!node) return false;
                    ['pointerdown', 'mousedown', 'mouseup', 'click'].forEach((type) => {
                        node.dispatchEvent(new MouseEvent(type, {
                            bubbles: true,
                            cancelable: true,
                            view: window,
                        }));
                    });
                    return true;
                };

                try {
                    if (target && typeof target.scrollIntoView === 'function') {
                        target.scrollIntoView({block: 'center', inline: 'center'});
                    }
                } catch (error) {}

                try {
                    if (form && typeof form.requestSubmit === 'function') {
                        form.requestSubmit(target || undefined);
                        return;
                    }
                } catch (error) {}

                try {
                    if (target && typeof target.click === 'function') {
                        target.click();
                        return;
                    }
                } catch (error) {}

                try {
                    if (dispatchFallback(target)) {
                        return;
                    }
                } catch (error) {}

                try {
                    if (form && typeof form.submit === 'function') {
                        form.submit();
                    }
                } catch (error) {}
            }, 0);

            return method;
        """
        try:
            method = str(driver.execute_script(script, element, allow_form_submit) or "").strip()
            if method and method != "unavailable":
                return method
            self.logger("WARNING", f"{label} 的 JS 非阻塞提交未找到可用方式，回退到原生点击。")
        except Exception as exc:
            self.logger("WARNING", f"{label} 的 JS 非阻塞提交失败，回退到原生点击。原因: {exc}")

        try:
            element.click()
            return "native-click"
        except TimeoutException:
            self.logger("WARNING", f"{label} 的原生点击触发后页面响应超时，已执行 window.stop() 并继续等待。")
            self._stop_loading(driver)
            return "native-click-timeout"
        except WebDriverException as exc:
            raise RecoverableAutomationError(f"{label} 触发失败: {exc}") from exc

    @staticmethod
    def _stop_loading(driver: WebDriver) -> None:
        try:
            driver.execute_script("window.stop();")
        except Exception:
            pass

    def _solve_captcha_text(self, image_element: WebElement, *, scene: str) -> str:
        last_candidate = ""
        for attempt in range(1, 3):
            raw_text = self.captcha_solver.classification(self._extract_image_bytes(image_element))
            normalized = re.sub(r"[^0-9A-Za-z]", "", str(raw_text or "")).strip()
            if len(normalized) >= 4:
                return normalized[:4]
            last_candidate = normalized
            self.logger("WARNING", f"{scene}验证码 OCR 输出异常，第 {attempt} 次结果: {raw_text!r}")
            try:
                image_element.click()
                time.sleep(0.4)
            except Exception:
                pass
        if len(last_candidate) >= 3:
            return last_candidate[:4]
        raise RecoverableAutomationError(f"{scene}验证码 OCR 未能识别出有效内容。")

    def _is_login_success_url(self, url: str) -> bool:
        if not url:
            return False
        if any(url.startswith(prefix) for prefix in LOGIN_SUCCESS_PREFIXES):
            return True
        return "zhjw.scu.edu.cn" in url and "id.scu.edu.cn" not in url

    def _is_session_expired(self, driver: WebDriver) -> bool:
        current_url = driver.current_url or ""
        if "id.scu.edu.cn" in current_url:
            return True
        password_box = self._find_first_visible_optional(driver, LOGIN_PASSWORD_SELECTORS, timeout=1)
        return password_box is not None

    def _safe_body_text(self, driver: WebDriver) -> str:
        try:
            body = self._find(driver, By.TAG_NAME, "body")
            return body.text or ""
        except RecoverableAutomationError:
            return ""

    def _page_snapshot(self, driver: WebDriver, *, include_body: bool = False) -> str:
        script = """
            const body = document.body ? (document.body.innerText || '') : '';
            return JSON.stringify({
                url: window.location.href || '',
                title: document.title || '',
                readyState: document.readyState || '',
                body: body.replace(/\\s+/g, ' ').trim().slice(0, 180)
            });
        """
        try:
            raw = driver.execute_script(script)
            data = json.loads(raw) if isinstance(raw, str) else raw
        except Exception:
            current_url = getattr(driver, "current_url", "") or ""
            return f" url={current_url or '-'}"

        parts = [
            f"url={data.get('url') or '-'}",
            f"title={data.get('title') or '-'}",
            f"readyState={data.get('readyState') or '-'}",
        ]
        body_excerpt = (data.get("body") or "").strip()
        if include_body and body_excerpt:
            parts.append(f"body={body_excerpt}")
        return " " + " | ".join(parts)

    def _extract_image_bytes(self, image_element: WebElement) -> bytes:
        source = image_element.get_attribute("src") or ""
        if "base64," in source:
            return base64.b64decode(source.split("base64,", 1)[1])
        return image_element.screenshot_as_png

    def _find_first_visible(self, driver: WebDriver, selectors: list[tuple[str, str]], label: str, timeout: int = 0):
        element = self._find_first_visible_optional(driver, selectors, timeout=timeout)
        if element is None:
            raise RecoverableAutomationError(f"页面元素未找到: {label}。{self._page_snapshot(driver, include_body=True)}")
        return element

    @staticmethod
    def _find_first_visible_optional(driver: WebDriver, selectors: list[tuple[str, str]], timeout: int = 0):
        deadline = time.monotonic() + max(0, timeout)
        while True:
            for by, value in selectors:
                try:
                    elements = driver.find_elements(by, value)
                except WebDriverException:
                    continue
                for element in elements:
                    try:
                        if element.is_displayed():
                            return element
                    except WebDriverException:
                        continue
            if timeout <= 0 or time.monotonic() >= deadline:
                return None
            time.sleep(0.2)

    @staticmethod
    def _find(driver: WebDriver, by: str, value: str):
        try:
            return driver.find_element(by, value)
        except NoSuchElementException as exc:
            raise RecoverableAutomationError(f"页面元素未找到: {value}") from exc
        except WebDriverException as exc:
            raise RecoverableAutomationError(f"浏览器操作失败: {value}") from exc

    def _sleep_with_cancel(self, stop_event, seconds: int, reason: str) -> None:
        if seconds <= 0:
            return
        self.logger("INFO", f"{reason} 大约 {seconds} 秒。")
        for _ in range(seconds):
            if stop_event.is_set():
                return
            time.sleep(1)