// ==UserScript==
// @name         WHUT选课跳过弹窗
// @namespace    http://tampermonkey.net/
// @version      1.1
// @description  安全状态机版：仅在选课入口页跳过确认弹窗，先校验/同步 Authorization Cookie，再清洗入口接口并点击入口按钮，进入后立即停止，避免重复 POST 卡死。
// @author       毫厘
// @match        https://jwxk.whut.edu.cn/*
// @run-at       document-start
// @grant        unsafeWindow
// @license MIT
// ==/UserScript==

(function() {
    'use strict';

    const pageWindow = typeof unsafeWindow !== 'undefined' ? unsafeWindow : window;
    const PROFILE_PATH = '/xsxk/profile/index';
    const ENTRY_SCAN_INTERVAL = 100;
    const ENTRY_SCAN_DURATION = 30000;
    const PROFILE_STUCK_KEY = 'WHUT_SKIP_ENTRY_PROFILE_VISITS_V110';
    const COOKIE_PROMPT_KEY = 'WHUT_SKIP_ENTRY_COOKIE_PROMPT_AT_V110';

    let entryTimer = null;
    let stopTimer = null;
    let state = 'idle';
    let lastHref = '';
    let patchedAt = 0;
    let confirmClickedAt = 0;
    let enterClickedAt = 0;
    let conflictPromptedAt = 0;
    const clickedElements = new WeakSet();

    console.log('%c WHUT跳过弹窗: v1.1 状态机版已启动', 'background:#2655c8;color:#fff;font-weight:bold;');

    function isProfilePage() {
        const href = pageWindow.location?.href || location.href;
        return href.includes(PROFILE_PATH);
    }

    function isWhutSameOrigin(url) {
        try {
            return new URL(String(url || ''), location.href).origin === 'https://jwxk.whut.edu.cn';
        } catch (error) {
            return false;
        }
    }

    function isEntryGateApiUrl(url) {
        try {
            const parsed = new URL(String(url || ''), location.href);
            return parsed.origin === 'https://jwxk.whut.edu.cn' && (
                parsed.pathname.includes('/xsxk/elective/user') ||
                parsed.pathname.includes('/web/now')
            );
        } catch (error) {
            return false;
        }
    }

    function getCookieValues(name) {
        const prefix = `${name}=`;
        return document.cookie
            .split(';')
            .map(item => item.trim())
            .filter(item => item.startsWith(prefix))
            .map(item => item.slice(prefix.length))
            .map(value => {
                try {
                    return decodeURIComponent(value);
                } catch (error) {
                    return value;
                }
            })
            .filter(Boolean);
    }

    function decodeJwtPayload(token) {
        try {
            const payload = String(token || '').split('.')[1];
            if (!payload) return null;
            const normalized = payload.replace(/-/g, '+').replace(/_/g, '/');
            const padded = normalized + '='.repeat((4 - normalized.length % 4) % 4);
            return JSON.parse(atob(padded));
        } catch (error) {
            return null;
        }
    }

    function getTokenTimestamp(token) {
        const payload = decodeJwtPayload(token);
        return Number(payload?.time || payload?.iat || 0) || 0;
    }

    function pickLatestAuthorizationToken(values = getCookieValues('Authorization')) {
        const uniqueValues = [...new Set(values.filter(Boolean))];
        if (uniqueValues.length <= 1) return uniqueValues[0] || '';
        return uniqueValues.sort((left, right) =>
            getTokenTimestamp(right) - getTokenTimestamp(left)
        )[0] || uniqueValues.at(-1) || '';
    }

    function getAuthorizationCookieConflict() {
        const values = getCookieValues('Authorization');
        const uniqueValues = [...new Set(values)];
        return {
            values,
            uniqueValues,
            conflict: uniqueValues.length > 1
        };
    }

    function expireAuthorizationCookieAtPath(path) {
        const host = location.hostname;
        const domains = ['', host, `.${host}`];
        domains.forEach(domain => {
            const domainPart = domain ? `; domain=${domain}` : '';
            document.cookie =
                `Authorization=; path=${path}${domainPart}; expires=Thu, 01 Jan 1970 00:00:00 GMT; max-age=0; secure; SameSite=Lax`;
            document.cookie =
                `Authorization=; path=${path}${domainPart}; expires=Thu, 01 Jan 1970 00:00:00 GMT; max-age=0; SameSite=Lax`;
        });
    }

    function syncAuthorizationCookiesToLatest(token = '') {
        const latestToken = token || pickLatestAuthorizationToken();
        if (!latestToken || !/^[A-Za-z0-9_.-]+$/.test(latestToken)) return false;

        const encodedToken = encodeURIComponent(latestToken);
        const host = location.hostname;
        const domains = ['', host, `.${host}`];
        const paths = ['/', '/xsxk'];

        paths.forEach(path => {
            domains.forEach(domain => {
                const domainPart = domain ? `; domain=${domain}` : '';
                document.cookie =
                    `Authorization=${encodedToken}; path=${path}${domainPart}; secure; SameSite=Lax`;
            });
        });
        return true;
    }

    function repairAuthorizationCookies() {
        const values = getCookieValues('Authorization');
        const uniqueValues = [...new Set(values)];
        const latestToken = pickLatestAuthorizationToken(uniqueValues);
        if (!latestToken) return false;

        ['/', '/xsxk', '/xsxk/', '/xsxk/profile', '/xsxk/elective'].forEach(expireAuthorizationCookieAtPath);
        syncAuthorizationCookiesToLatest(latestToken);
        console.log('%c WHUT跳过弹窗: 已清理重复 Authorization Cookie', 'color:#10b981;font-weight:bold;');
        return true;
    }

    function promptCookieConflict() {
        const now = Date.now();
        const lastPromptAt = Math.max(
            conflictPromptedAt,
            Number(localStorage.getItem(COOKIE_PROMPT_KEY) || 0)
        );
        if (now - lastPromptAt < 60000) return;
        conflictPromptedAt = now;
        localStorage.setItem(COOKIE_PROMPT_KEY, String(now));

        setTimeout(() => {
            if (!isProfilePage()) return;
            const confirmed = window.confirm(
                '检测到多个不同的 Authorization Cookie。\n\n继续自动点击“选课”可能导致服务端 302 跳回首页，形成卡死循环。\n\n是否现在清理重复 Cookie，并只保留时间最新的 token？'
            );
            if (confirmed) {
                repairAuthorizationCookies();
                window.alert('登录 Cookie 已同步。请刷新页面后再进入选课。');
            }
        }, 300);
    }

    function ensureCookieReady() {
        const values = getCookieValues('Authorization');
        if (values.length === 0) return false;

        const latest = pickLatestAuthorizationToken(values);
        if (!latest) return false;
        syncAuthorizationCookiesToLatest(latest);

        const afterSync = getAuthorizationCookieConflict();
        if (afterSync.conflict) {
            state = 'cookie_conflict';
            stopAutoEntry();
            promptCookieConflict();
            return false;
        }

        if (state === 'idle' || state === 'stopped') state = 'cookie_ready';
        return true;
    }

    function cleanEntryGateData(json) {
        let modified = false;

        const fixItem = (item) => {
            if (!item || typeof item !== 'object') return;

            if ('needConfirm' in item && item.needConfirm != 0 && item.needConfirm !== '0') {
                item.needConfirm = '0';
                modified = true;
            }
            if ('isConfirmed' in item && item.isConfirmed != 1 && item.isConfirmed !== '1') {
                item.isConfirmed = '1';
                modified = true;
            }
            if ('canSelect' in item && item.canSelect != 1 && item.canSelect !== '1') {
                item.canSelect = '1';
                modified = true;
            }
            ['countDown', 'countdown', 'confirmSeconds', 'remainSeconds', 'remainingSeconds', 'waitSeconds'].forEach(key => {
                if (key in item && Number(item[key]) > 0) {
                    item[key] = 0;
                    modified = true;
                }
            });
        };

        const visit = (value) => {
            if (Array.isArray(value)) {
                value.forEach(visit);
                return;
            }
            if (!value || typeof value !== 'object') return;
            fixItem(value);
            Object.values(value).forEach(visit);
        };

        visit(json);
        return modified;
    }

    function markEntryGatePatched() {
        patchedAt = Date.now();
        if (!['confirmed', 'entering', 'done'].includes(state)) state = 'patched';
    }

    function createPatchedJsonResponse(response, json) {
        const HeadersCtor = pageWindow.Headers || Headers;
        const headers = new HeadersCtor(response.headers || {});
        headers.set('content-type', 'application/json;charset=UTF-8');
        const ResponseCtor = pageWindow.Response || Response;
        return new ResponseCtor(JSON.stringify(json), {
            status: response.status,
            statusText: response.statusText,
            headers
        });
    }

    function patchEntryGateXhrResponse(xhr) {
        try {
            const responseType = xhr.responseType || '';
            let json = null;
            let patchedText = '';
            let modified = false;

            if (responseType === '' || responseType === 'text') {
                const text = xhr.responseText;
                if (!text) return false;
                json = JSON.parse(text);
                modified = cleanEntryGateData(json);
                if (modified) {
                    patchedText = JSON.stringify(json);
                    try {
                        Object.defineProperty(xhr, 'responseText', {
                            configurable: true,
                            get: () => patchedText
                        });
                    } catch (error) {}
                    try {
                        Object.defineProperty(xhr, 'response', {
                            configurable: true,
                            get: () => patchedText
                        });
                    } catch (error) {}
                }
            } else if (responseType === 'json' && xhr.response && typeof xhr.response === 'object') {
                json = xhr.response;
                modified = cleanEntryGateData(json);
                if (modified) {
                    try {
                        Object.defineProperty(xhr, 'response', {
                            configurable: true,
                            get: () => json
                        });
                    } catch (error) {}
                }
            } else {
                return false;
            }

            syncAuthorizationCookiesToLatest();
            markEntryGatePatched();
            if (modified) {
                console.log('%c WHUT跳过弹窗: XHR入口数据已清洗', 'color:#17a2b8;font-weight:bold;');
            }
            return modified;
        } catch (error) {
            return false;
        }
    }

    function installFetchInterceptor() {
        try {
            if (typeof pageWindow.fetch !== 'function' || pageWindow.fetch.__whutSkipPatched) return;
            const originalFetch = pageWindow.fetch.bind(pageWindow);

            const wrappedFetch = async function(input, init = {}) {
                const url = typeof input === 'string'
                    ? input
                    : (input?.url || String(input || ''));
                const response = await originalFetch(input, init);

                if (isProfilePage() && isEntryGateApiUrl(response.url || url)) {
                    try {
                        const json = await response.clone().json();
                        const modified = cleanEntryGateData(json);
                        syncAuthorizationCookiesToLatest();
                        markEntryGatePatched();
                        if (modified) {
                            console.log('%c WHUT跳过弹窗: Fetch入口数据已清洗', 'color:#17a2b8;font-weight:bold;');
                            return createPatchedJsonResponse(response, json);
                        }
                    } catch (error) {}
                }
                return response;
            };
            Object.defineProperty(wrappedFetch, '__whutSkipPatched', { value: true });
            pageWindow.fetch = wrappedFetch;
        } catch (error) {
            console.warn('WHUT跳过弹窗: Fetch拦截安装失败', error);
        }
    }

    function installXhrInterceptor() {
        try {
            const XHR = pageWindow.XMLHttpRequest;
            const prototype = XHR?.prototype;
            if (!prototype || prototype.__whutSkipPatched) return;

            const originalOpen = prototype.open;
            const originalSend = prototype.send;

            prototype.open = function(method, url) {
                this.__whutSkipUrl = String(url || '');
                return originalOpen.apply(this, arguments);
            };

            prototype.send = function(body) {
                const isEntryGateRequest =
                    isProfilePage() &&
                    isWhutSameOrigin(this.__whutSkipUrl) &&
                    isEntryGateApiUrl(this.__whutSkipUrl);

                if (isEntryGateRequest) {
                    const originalReadyStateHandler = this.onreadystatechange;
                    if (typeof originalReadyStateHandler === 'function') {
                        this.onreadystatechange = function(...args) {
                            if (this.readyState === 4) patchEntryGateXhrResponse(this);
                            return originalReadyStateHandler.apply(this, args);
                        };
                    }
                    this.addEventListener('readystatechange', function() {
                        if (this.readyState === 4) patchEntryGateXhrResponse(this);
                    }, { once: true });
                }

                return originalSend.apply(this, arguments);
            };

            Object.defineProperty(prototype, '__whutSkipPatched', {
                value: true,
                configurable: true
            });
        } catch (error) {
            console.warn('WHUT跳过弹窗: XHR拦截安装失败', error);
        }
    }

    function stopAutoEntry() {
        if (entryTimer) clearInterval(entryTimer);
        if (stopTimer) clearTimeout(stopTimer);
        entryTimer = null;
        stopTimer = null;
        if (!['done', 'cookie_conflict', 'entry_timeout'].includes(state)) state = 'stopped';
    }

    function markDone() {
        state = 'done';
        stopAutoEntry();
    }

    function isButtonClickable(button) {
        return Boolean(
            button &&
            button.isConnected &&
            button.getClientRects().length > 0 &&
            !button.disabled &&
            !button.classList.contains('is-disabled') &&
            button.getAttribute('aria-disabled') !== 'true'
        );
    }

    function safeClick(button, nextState) {
        if (!isButtonClickable(button) || clickedElements.has(button)) return false;
        clickedElements.add(button);
        syncAuthorizationCookiesToLatest();
        button.click();
        state = nextState || state;
        console.log(`%c WHUT跳过弹窗: 自动点击 ${button.innerText.trim()}`, 'color:#17a2b8;');

        if (nextState === 'entering') {
            setTimeout(() => {
                if (!isProfilePage()) markDone();
            }, 1200);
        }
        return true;
    }

    function getPrimaryButtons() {
        return [...document.querySelectorAll('button.el-button--primary')]
            .filter(isButtonClickable)
            .map(button => ({
                button,
                text: button.innerText.replace(/\s+/g, '')
            }));
    }

    function scanAutoEntryTargets() {
        if (!isProfilePage()) {
            markDone();
            return;
        }

        const currentHref = pageWindow.location?.href || location.href;
        if (lastHref && currentHref !== lastHref && !currentHref.includes(PROFILE_PATH)) {
            markDone();
            return;
        }
        lastHref = currentHref;

        if (!ensureCookieReady()) return;

        if (state === 'entering') {
            if (enterClickedAt && Date.now() - enterClickedAt > 6000) {
                state = 'entry_timeout';
                stopAutoEntry();
                console.warn('WHUT跳过弹窗: 点击进入后仍停留在首页，已暂停自动入口。可尝试修复 Cookie 后刷新。');
            }
            return;
        }

        const buttons = getPrimaryButtons();
        const confirmButton = buttons.find(({ text }) =>
            ['确定', '确认', '我知道了', '同意'].some(keyword => text.includes(keyword))
        )?.button;
        if (
            confirmButton &&
            ['cookie_ready', 'patched'].includes(state) &&
            (!confirmClickedAt || Date.now() - confirmClickedAt > 2500)
        ) {
            confirmClickedAt = Date.now();
            safeClick(confirmButton, 'confirmed');
            return;
        }

        const enterButton = buttons.find(({ text }) =>
            text === '选课' || text === '进入选课' || text === '进入'
        )?.button;
        if (
            enterButton &&
            ['cookie_ready', 'patched', 'confirmed'].includes(state) &&
            !enterClickedAt
        ) {
            enterClickedAt = Date.now();
            safeClick(enterButton, 'entering');
        }
    }

    function recordProfileVisitAndWarn() {
        if (!isProfilePage()) return;
        const now = Date.now();
        const visits = (() => {
            try {
                return JSON.parse(localStorage.getItem(PROFILE_STUCK_KEY) || '[]');
            } catch (error) {
                return [];
            }
        })()
            .map(Number)
            .filter(time => Number.isFinite(time) && now - time < 60000);
        visits.push(now);
        localStorage.setItem(PROFILE_STUCK_KEY, JSON.stringify(visits));
        if (visits.length < 3) return;

        const lastPromptAt = Number(localStorage.getItem(COOKIE_PROMPT_KEY) || 0);
        if (now - lastPromptAt < 60000) return;
        localStorage.setItem(COOKIE_PROMPT_KEY, String(now));

        setTimeout(() => {
            if (!isProfilePage()) return;
            const confirmed = window.confirm(
                '检测到你短时间内多次回到选课首页。\n\n常见原因是 Authorization Cookie 冲突，导致进入选课页时 302 回跳。\n\n是否清理重复 Cookie，并只保留时间最新的 token？'
            );
            if (confirmed) {
                repairAuthorizationCookies();
                window.alert('登录 Cookie 已同步。请刷新页面后再进入选课。');
            }
        }, 800);
    }

    function startAutoEntry() {
        if (entryTimer || !isProfilePage()) return;
        state = 'idle';
        confirmClickedAt = 0;
        enterClickedAt = 0;
        patchedAt = 0;
        lastHref = pageWindow.location?.href || location.href;

        scanAutoEntryTargets();
        entryTimer = setInterval(scanAutoEntryTargets, ENTRY_SCAN_INTERVAL);
        stopTimer = setTimeout(stopAutoEntry, ENTRY_SCAN_DURATION);
    }

    installFetchInterceptor();
    installXhrInterceptor();

    if (document.readyState === 'loading') {
        document.addEventListener('DOMContentLoaded', () => {
            recordProfileVisitAndWarn();
            startAutoEntry();
        });
    } else {
        recordProfileVisitAndWarn();
        startAutoEntry();
    }

})();