/**
 * 易班 videoajax.js 封装
 * 用于与易班平台交互：用户数据存取、课程进度上报等
 */

import { useUserStore } from "@/stores";
import type {
	BreakPointParams,
	StorageBackend,
	StorageOptions,
	UserDefineParam,
	UserStorageFetchResult,
	VideoAjax,
	VideoAjaxResponse,
	YibanRequestResult,
} from "@/types/yiban";

// 超时时间
const TIMEOUT_MS = 1000 * 6;

// 课时前缀
const LESSON_PREFIX = "hsgrl";

// 初始化 videoajax 实例
let videoajaxInstance: VideoAjax | null = null;

/**
 * 检测 videoajax.js 是否已加载
 */
export function isVideoAjaxAvailable() {
	return typeof globalThis.videoAjax === "function";
}

/**
 * 记录 videoajax 不可用的诊断信息
 */
function warnVideoAjaxUnavailable(description: string) {
	console.warn(`[yiban] videoajax unavailable: ${description}`, {
		hasVideoAjax: isVideoAjaxAvailable(),
	});
}

/**
 * 从 URL 参数初始化易班会话状态
 * 在 React 渲染前调用，确保页面首次读取进度时 courseId / userId 已写入 store
 */
export function initializeYibanSession() {
	const params = new URLSearchParams(window.location.search);
	const courseId = params.get("courseId") ?? params.get("courseid");
	const uid = params.get("uid");
	const forceYiban = params.get("yiban") === "1";
	const hasYibanParams = !!(courseId || uid);
	const hasVideoAjax = isVideoAjaxAvailable();
	const isYibanEnv = import.meta.env.DEV
		? hasYibanParams && forceYiban
		: hasYibanParams;
	const storageMode = isYibanEnv && hasVideoAjax ? "yiban" : "session";
	const userStore = useUserStore.getState();

	userStore.setYibanConnectionStatus(
		storageMode === "yiban" ? "connected" : "disconnected",
	);
	if (courseId) userStore.setCourseId(courseId);
	if (uid) userStore.setUserInfo({ userId: uid });

	console.info(
		storageMode === "yiban"
			? "[yiban] initialized"
			: "[yiban] use session storage fallback",
		{
			courseId,
			uid,
			isDev: import.meta.env.DEV,
			forceYiban,
			hasYibanParams,
			hasVideoAjax,
			storageMode,
		},
	);
}

/**
 * 获取 VideoAjax 实例
 */
function getVideoAjax(): VideoAjax {
	if (!videoajaxInstance) {
		const createVideoAjax = globalThis.videoAjax;
		if (typeof createVideoAjax !== "function") {
			throw new Error(
				"videoAjax is not available. Please ensure public/videoajax/videoajax.js is loaded.",
			);
		}
		videoajaxInstance = createVideoAjax();
		videoajaxInstance.setHost("/");
	}
	return videoajaxInstance;
}

/**
 * 生成存储键
 */
const getStorageKey = (lessonId: string | number, key: string | number) => {
	const { courseId, userId } = useUserStore.getState();
	const courseScope = courseId || "dev-course";
	const userScope = userId || "guest";

	return `${LESSON_PREFIX}_${courseScope}_${userScope}_${lessonId}_${key}`;
};

/**
 * 解析存储后端
 */
const resolveStorageBackend = (
	backend: StorageBackend = "auto",
): "yiban" | "session" => {
	if (backend === "session") return backend;

	if (backend === "yiban") {
		if (!isVideoAjaxAvailable()) {
			warnVideoAjaxUnavailable("force yiban storage fallback to session");
			return "session";
		}
		return backend;
	}

	const { yibanConnectionStatus } = useUserStore.getState();
	if (yibanConnectionStatus === "connected" && isVideoAjaxAvailable()) {
		return "yiban";
	}

	if (yibanConnectionStatus === "connected") {
		warnVideoAjaxUnavailable("auto storage fallback to session");
	}

	return "session";
};

/**
 * 统一的易班请求封装
 * 处理超时、错误、日志
 */
async function yibanRequest<T>(options: {
	method: (callback: (res: T) => void) => void;
	timeout?: number;
	description?: string;
}): Promise<YibanRequestResult<T>> {
	const { method, timeout = TIMEOUT_MS, description = "request" } = options;

	return new Promise((resolve) => {
		let settled = false;

		const timeoutId = setTimeout(() => {
			if (!settled) {
				settled = true;
				console.warn(`[yiban] ${description} timeout`);
				resolve({ success: false, error: "timeout" });
			}
		}, timeout);

		try {
			method((res) => {
				if (!settled) {
					settled = true;
					clearTimeout(timeoutId);
					resolve({ success: true, data: res });
				}
			});
		} catch (error) {
			if (!settled) {
				settled = true;
				clearTimeout(timeoutId);
				console.error(`[yiban] ${description} failed`, error);
				resolve({ success: false, error: String(error) });
			}
		}
	});
}

async function yibanStatusRequest<T>(options: {
	method: (callback: (status: boolean, data: T) => void) => void;
	timeout?: number;
	description?: string;
}): Promise<YibanRequestResult<T>> {
	const { method, timeout = TIMEOUT_MS, description = "request" } = options;

	return new Promise((resolve) => {
		let settled = false;

		const timeoutId = setTimeout(() => {
			if (!settled) {
				settled = true;
				console.warn(`[yiban] ${description} timeout`);
				resolve({ success: false, error: "timeout" });
			}
		}, timeout);

		try {
			method((status, data) => {
				if (!settled) {
					settled = true;
					clearTimeout(timeoutId);
					resolve(
						status
							? { success: true, data }
							: { success: false, error: `${description} returned false` },
					);
				}
			});
		} catch (error) {
			if (!settled) {
				settled = true;
				clearTimeout(timeoutId);
				console.error(`[yiban] ${description} failed`, error);
				resolve({ success: false, error: String(error) });
			}
		}
	});
}

/**
 * 设置用户存储数据
 * @param lessonId 课时唯一ID
 * @param key 数据键
 * @param value 数据值
 * @param options 存储选项
 */
export async function setUserStorage(
	lessonId: string | number,
	key: string | number,
	value: string,
	options: StorageOptions = {},
): Promise<YibanRequestResult> {
	const backend = resolveStorageBackend(options.backend);

	if (backend === "session") {
		sessionStorage.setItem(getStorageKey(lessonId, key), value);
		return { success: true };
	}

	const param: UserDefineParam = {
		lessonId: `${LESSON_PREFIX}_${lessonId}`,
		key,
		content: value,
	};

	const result = await yibanRequest({
		method: (callback) => getVideoAjax().addUserDefine(param, callback),
		description: `setUserStorage(${lessonId}, ${key})`,
	});

	return result;
}

/**
 * 获取用户存储数据
 * @param lessonId 课时唯一ID
 * @param key 数据键
 * @param options 存储选项
 * @returns Promise<UserStorageFetchResult>
 */
export async function getUserStorage(
	lessonId: string | number,
	key: string | number,
	options: StorageOptions = {},
): Promise<UserStorageFetchResult> {
	const backend = resolveStorageBackend(options.backend);

	if (backend === "session") {
		const itemValue = sessionStorage.getItem(getStorageKey(lessonId, key));
		return itemValue === null || itemValue === "null" || itemValue === ""
			? { status: "empty", content: "" }
			: { status: "success", content: itemValue };
	}

	const param: UserDefineParam = {
		lessonId: `${LESSON_PREFIX}_${lessonId}`,
		order: key,
	};

	const result = await yibanRequest<VideoAjaxResponse | undefined>({
		method: (callback) =>
			getVideoAjax().getUserDefineInfoByUser(param, callback),
		description: `getUserStorage(${lessonId}, ${key})`,
	});

	if (!result.success) {
		return {
			status: "error",
			content: "",
			message: result.error || "请求失败",
		};
	}

	const res = result.data;
	if (!res || res === null || res === ("null" as unknown)) {
		return { status: "empty", content: "" };
	}

	if (res.code === 202) {
		return {
			status: "unauthenticated",
			content: "",
			code: res.code,
			message: res.msg,
		};
	}

	if (res.code !== 200) {
		return {
			status: "error",
			content: "",
			code: res.code,
			message: res.msg || "学习进度获取失败",
		};
	}

	const value = res.data?.value;
	if (
		value === undefined ||
		value === null ||
		value === "null" ||
		value === ""
	) {
		return { status: "empty", content: "" };
	}

	const json = Array.isArray(value) ? value : [];
	const content = json[0]?.content || "";

	return content === "" || content === "null"
		? { status: "empty", content: "" }
		: { status: "success", content };
}

/**
 * 上报课程进度到易班平台
 * @param order 课时顺序号
 * @returns Promise<boolean> 是否成功上报
 */
export async function reportCourseProgress(order: number): Promise<boolean> {
	const { yibanConnectionStatus, courseId } = useUserStore.getState();

	if (yibanConnectionStatus !== "connected") {
		console.info(`[yiban] skip finishCourse: disconnected, order=${order}`);
		return false;
	}

	if (courseId === undefined || courseId === null || courseId === "") {
		console.info(`[yiban] skip finishCourse: missing courseId, order=${order}`);
		return false;
	}

	if (!isVideoAjaxAvailable()) {
		warnVideoAjaxUnavailable(`skip finishCourse, order=${order}`);
		return false;
	}

	if (order <= 0) {
		console.info(`[yiban] skip finishCourse: invalid order=${order}`);
		return false;
	}

	const result = await yibanStatusRequest<unknown>({
		method: (callback) =>
			getVideoAjax().finishCourse(
				{ order, co: courseId, process: 100 },
				callback,
			),
		description: `reportCourseProgress(${order})`,
	});

	if (result.success) {
		console.info(`[yiban] finishCourse success, order=${order}`);
	}

	return result.success;
}

/**
 * 获取课程进度
 * @param order 课时顺序号
 * @returns Promise<课程进度数据 | null>
 */
export async function getCourseProgress(
	order: number,
): Promise<unknown | null> {
	const { yibanConnectionStatus, courseId } = useUserStore.getState();

	if (yibanConnectionStatus !== "connected" || !courseId) {
		return null;
	}

	if (!isVideoAjaxAvailable()) {
		warnVideoAjaxUnavailable(`skip getfinishCourse, order=${order}`);
		return null;
	}

	const result = await yibanRequest<unknown>({
		method: (callback) =>
			getVideoAjax().getfinishCourse({ order, co: courseId }, callback),
		description: `getCourseProgress(${order})`,
	});

	return result.success && result.data ? result.data : null;
}

/**
 * 保存播放断点
 * @param params 断点参数
 * @returns Promise<boolean> 是否成功保存
 */
export async function saveBreakPoint(
	params: BreakPointParams & { breakPoint: number },
): Promise<boolean> {
	const { yibanConnectionStatus } = useUserStore.getState();

	if (yibanConnectionStatus !== "connected") {
		return false;
	}

	if (!isVideoAjaxAvailable()) {
		warnVideoAjaxUnavailable(
			`skip quitBreakPoint, lessonId=${params.lessonId}`,
		);
		return false;
	}

	const result = await yibanStatusRequest<unknown>({
		method: (callback) =>
			getVideoAjax().quitBreakPoint(
				{
					user_id: params.userId,
					course_id: params.courseId,
					lesson_id: params.lessonId,
					break_point: params.breakPoint,
				},
				callback,
			),
		description: `saveBreakPoint(${params.lessonId}, ${params.breakPoint})`,
	});

	return result.success;
}

/**
 * 获取播放断点
 * @param params 断点参数
 * @returns Promise<断点数据 | null>
 */
export async function getBreakPoint(
	params: BreakPointParams,
): Promise<unknown | null> {
	const { yibanConnectionStatus } = useUserStore.getState();

	if (yibanConnectionStatus !== "connected") {
		return null;
	}

	if (!isVideoAjaxAvailable()) {
		warnVideoAjaxUnavailable(`skip getBreakPoint, lessonId=${params.lessonId}`);
		return null;
	}

	const result = await yibanStatusRequest<unknown>({
		method: (callback) =>
			getVideoAjax().getBreakPoint(
				{
					user_id: params.userId,
					course_id: params.courseId,
					lesson_id: params.lessonId,
				},
				callback,
			),
		description: `getBreakPoint(${params.lessonId})`,
	});

	return result.success ? result.data : null;
}

/**
 * 保存用户答题记录
 * @param params 答题参数
 * @returns Promise<boolean> 是否成功保存
 */
export async function saveUserAnswer(params: {
	userId: string;
	lessonId: string;
	courseId: string;
	questionOrder: number;
	answer: string;
}): Promise<boolean> {
	const { yibanConnectionStatus } = useUserStore.getState();

	if (yibanConnectionStatus !== "connected") {
		return false;
	}

	if (!isVideoAjaxAvailable()) {
		warnVideoAjaxUnavailable(
			`skip saveUserAnswer, lessonId=${params.lessonId}`,
		);
		return false;
	}

	// 易班 API 以 getUserAnswer 写入答题记录，方法名与「保存」语义相反，属平台既有命名
	const result = await yibanStatusRequest<unknown>({
		method: (callback) =>
			getVideoAjax().getUserAnswer(
				{
					user_id: params.userId,
					lesson_id: params.lessonId,
					course_id: params.courseId,
					question_order: params.questionOrder,
					answer: params.answer,
				},
				callback,
			),
		description: `saveUserAnswer(${params.lessonId}, Q${params.questionOrder})`,
	});

	return result.success;
}